A system method for safely supplying an efficient amount of oxygen to the organs needed during cardiopulmonary resuscitation.

Abstract

Systems for safely and efficiently supplying essential organs with oxygen during cardiopulmonary resuscitation (CPR), as well as methods and endotracheal devices for performing semi-spontaneous positive pressure ventilation, are further described. [Solution] The system consists of at least one limb compression device, a positive pressure ventilation system, an endotracheal tube, a cardiac stimulator, an endotracheal pressure sensor, and a synchronizer, and the method consists of the following: compressing at least one limb device to occlude blood flow to the limb, supplying a mixed gas, providing an endotracheal tube, providing an deployment configuration, providing a retention configuration, running the cardiac stimulator, determining the pressure, and synchronizing the timing. The endotracheal device consists of an elongated tube, a sealing cuff that assumes a deployment configuration and a retention configuration.

Description

Detailed Description of the Invention

[0001] (Technical Field) The present invention generally relates to the fields of emergency medicine and cardiology, and more specifically, to means for improving the meaningful outcome of cardiac arrest.

[0002] (Introduction) Cardiac arrest is the cause of death for more than 500,000 people annually in the United States and millions of people worldwide. The cause of cardiac arrest in the majority of patients is severe stenosis or occlusion of the coronary artery, leading to the cessation of the heart's pumping function. As a result, blood flow suddenly stops, and oxygen supply to tissues ceases. The consequences are devastating. Some tissues (such as skin, fat, muscle) have oxygen storage and high-energy compound storage and can survive for several hours without irreversible damage, while other tissues (such as myocardium and brain) do not have such storage and require continuous high oxygen supply, so they cannot withstand short-term ischemia without irreversible damage and injury to cells.

[0003] The current American Heart Association (AHA) protocol for saving the lives of cardiac arrest patients is cardiopulmonary resuscitation, that is, performing chest compressions and electrical defibrillation to restore mechanical and electrical cardiac function, also known as the return of spontaneous circulation (ROSC).

[0004] The key to jumpstarting a stopped heart is to rapidly restore blood flow to the myocardium through the coronary arteries. However, today it is clearly understood that ROSC alone is not sufficient, and that avoiding neurological injury during cardiopulmonary resuscitation (CPR) is crucial for meaningful survival after cardiac arrest. In other words, blood flow and oxygen supply to the brain must be maintained during CPR. Unfortunately, the overall clinical experience of CPR, more than 60 years after the initial introduction of chest compressions, is quite disappointing. A recent study performed CPR on 8,000 patients who witnessed cardiac arrest outside of hospitals. Half of them received intravenous administration of epinephrine (Epi), while the other half followed the same CPR protocol but without epinephrine. In the Epi-administered group, the ROSC at hospital arrival was significantly higher than in patients who did not receive Epi. However, when comparing neurological injury-free survival rates 30 days after cardiac arrest, no statistically significant difference was found between the two groups.

[0005] Therefore, while the use of Epi is beneficial in that it revives the heartbeat, it is clear that its use does not help, and may even harm, the brain's ability to survive. Similar results have been shown in multiple clinical and experimental studies. The flowchart in Figure 1 shows the sequence of physiological events that occur between cardiac arrest and CPR. It is clear that better methods are needed to improve the meaningful outcomes of CPR.

[0006] (Analysis of current practices and mechanisms during CPR that worsen neurological outcomes) The administration of epinephrine and other vascular compressive agents constricts arteries, including cerebral arteries, resulting in increased resistance to blood flow. While this may raise blood pressure, it clearly impedes blood flow and inhibits oxygen delivery to brain tissue.

[0007] (a) Due to the physiological mechanism of "reactive hyperemia," also known as hypoxic vasodilation, arterioles throughout the body dilate to their maximum extent. Therefore, when epinephrine or other vasodilators are injected intravenously, they move slowly through the widened arteries. Consequently, the timing of when intravenously injected epinephrine or other vasodilators reach body tissues is highly uneven during CPR. Tissues closer to the heart, such as the brain, receive the drug first, while distant tissues, such as the legs, receive it considerably later. As a result, cerebral circulation constricts faster than peripheral circulation. Due to the simple properties of fluid dynamics, the blood flow generated by chest compressions CPR preferentially flows to the widened periphery, while its flow into the constricted cerebral arteries is hindered. Epinephrine reaches the periphery later. However, due to its short half-life of 4 minutes and the slow blood flow from CPR, it is already partially inactivated by the time it reaches the periphery. This paradoxical "stealing effect" deprives cells of essential oxygen transport from brain tissue.

[0008] If the patient is not breathing, positive pressure ventilation is of course necessary. (a) If the ventilation volume is too high compared to the significantly reduced metabolic production of CO2 during CPR, arterial PCO2 (PaCO2) decreases. Low PaCO2 is a strong cause of cerebral vasoconstriction, again obstructing cerebral blood flow. (b) Low PaCO2 causes a leftward shift in the oxygen-hemoglobin dissociation curve (Bohr effect). This shift strengthens the binding of oxygen to hemoglobin and reduces the offloading of oxygen molecules in tissues. As a result, the amount of oxygen supplied per ml of blood flowing through the capillaries is considerably less (e.g., 20-35% less), regardless of the level of PO2 in the capillaries. Even if tissues try to extract more oxygen from the blood, it is ineffective because it would require lowering the PO2 at the capillary terminals, thereby reducing the diffusion driving force that carries oxygen molecules from the capillaries to the mitochondria. The obstructed flow, reduced oxygen supply, and smaller partial pressure gradient critically limit oxygen transport to the brain. Multiple animal studies and clinical research have confirmed that hyperventilation during CPR must be absolutely avoided. (c) Positive pressure ventilation with a relatively large tidal volume increases intrathoracic pressure, expands the alveoli, thereby hindering the return of venous blood to the right side of the heart, compresses the pulmonary capillaries and increases resistance to their flow, and also stretches the pulmonary capillaries and increases resistance to their flow. These phenomena fill the chambers of the heart, and even when compressed, only a small amount of blood is expelled with each compression. Attempts to counteract these effects of positive pressure ventilation by maintaining the reduction of chest volume due to chest compression by preventing airflow into the airways (e.g., by an "impedance threshold device") and by applying negative pressure to the airways by using chest wall compression-decompression (suction) forces during CPR should be noted as having limited effectiveness due to the dynamic collapse nature of the central veins and pulmonary vessels, and the non-cartilaginous airways distal to the lungs. Under certain circumstances, negative intrathoracic pressure on thoracic blood vessels and small airways can cause duct collapse, restricted airflow, and flutter.

[0009] The decrease in PaCO2 associated with relatively excessive ventilation, followed by an increase in pH ("respiratory alkalosis"), is an independent cause of a leftward shift in the O2-hemoglobin dissociation curve. This is further exacerbated by the intravenous administration of sodium bicarbonate to counteract metabolic acidosis, which has been practiced for many years but is no longer recommended, likely due to lactate production by anaerobic metabolism in the tissues. Bicarbonate administration further shifts the O2 dissociation curve to the left, resulting in restricted transport of O2 molecules from the blood to the tissues.

[0010] The diagrams shown in the drawings illustrate the outline of these mechanisms.

[0011] (background art) The use of vasodilators during CPR has previously been shown to be beneficial in multiple animal studies by significantly increasing cerebral blood flow. The previously used compound was intravenous administration of sodium nitroprusside (Na-Nitroprusside (SNP)), known as a potent vasodilator. These animal studies also revealed that SNP administration lowered systemic blood pressure, which is expected when vasodilation is induced. A decrease in blood pressure is also known to occur when PaCO2 increases.

[0012] Attempts to counteract the extreme vasodilation described in point 2 above using mechanical means have so far been largely unsuccessful, as outlined below.

[0013] Studies using military (medical) anti-shock pants (MAST), which are garments equipped with an inflatable bladder that covers the entire lower body, including the abdomen and legs, have not shown any beneficial effects. There are three main reasons why this method failed.

[0014] MAST does not inflate sequentially from distal to proximal. Therefore, it does not compress blood from periphery to periphery. In fact, if the proximal bladder inflates before the distal bladder, the MAST may function as a venous tourniquet, potentially trapping blood in the periphery without automatic transfusion.

[0015] MAST cannot be removed gradually. Removing it by contracting the bladder or opening the Velcro fasteners often leads to a sudden opening of the peripheral vascular bed, causing a rapid decrease in peripheral resistance and blood pressure, and a re-disruption of the patient's homeostasis.

[0016] Compression of the abdomen by the abdominal bladder shifts the internal organs caudally and restricts the expansion of the lower ribs, causing significant difficulty in breathing.

[0017] The application of MAST takes too long (more than 5 minutes). Researchers have tried to increase peripheral resistance by tightly binding the abdomen during CPR. This method also did not improve outcomes in CPR experiments with experimental animals (pigs).

[0018] Raising the legs during CPR has been attempted before. However, only 45% of the blood is drained from the legs by raising them (Blond et Al, Acta Ortho Scand. 2001). Furthermore, with each chest compression, blood flows into the dilated arteries of the lower limbs, minimizing the benefits of leg elevation, which requires extra personnel during transport.

[0019] In 1951, Dr. Woolworth of Tasmania reported that tying the legs with Esmarch bandages had a beneficial effect in re-expanding the heart during open-chest cardiac massage in a child who had experienced cardiac arrest after receiving ether anesthesia for orthopedic surgery. The child did not survive.

[0020] The application of tourniquets, such as those used for hemostasis in trauma or air hemostasis, is a well-known technique that, in theory, can improve the effectiveness of cardiac massage by increasing vascular resistance and directing stroke volume to the necessary organs. However, as is well known in orthopedics, stopping blood flow to the limbs without first completely emptying the blood vessels often leads to intravascular coagulation. These thrombi rapidly travel to the lungs and brain when hemostasis is released (Sulek 1999), resulting in pulmonary embolism or stroke.

[0021] Blocking the aorta with an inflated balloon inserted through the femoral artery is a heroic method that yields significant beneficial effects in experimental animals (Sesma et Al, Am.J. Emerg.Med. Effect of Intra-aortic occlusion balloon in external thoracic compressions during CPR in pigs - ScienceDirect), https: / / www.sciencedirect.com / science / article / abs / pii / S0735675702000402.

[0022] A significant prior art is the use of extracorporeal membrane oxygenation (ECMO) during CPR to deliver oxygenated blood to essential organs (Speidl 2015 Extracorporeal membrane oxygenation in cardiac arrest). While ECMO is often successful when used (meaning a 4-54% survival rate), it is rarely used due to logistical difficulties, team and equipment availability, and cost. In large European cities, it is used for only 1-2% of cardiac arrest patients. https: / / www.escardio.org / static-file / Escardio / Congresses / Congress management / Acute Cardiovascular Care / Documents / Slides_FP344.pdf (Summary of the invention) The following summary of the present invention is provided to illustrate a basic understanding of several principles that form the basis of various aspects and features of the invention. This summary is not a comprehensive overview of the invention and is therefore not intended to specifically identify all key or important elements of the invention, nor to define its scope. Its sole purpose is to present some of the concepts of the invention in a simplified form as a preliminary step to the more detailed description below.

[0023] The present invention has been made in view of the shortcomings of the prior art and provides systems, methods and processes for overcoming these shortcomings. Means for solving the problems, according to some embodiments and aspects of the present invention, a system is provided for safely delivering an efficient amount of oxygen to essential organs during cardiopulmonary resuscitation (CPR). The system comprises at least one limb compression device configured to apply sequential compressive force to the limbs from distal to proximal, thereby occluding blood flow to the limbs, and a positive pressure ventilation system configured to deliver a mixed gas by positive pressure. According to some embodiments and aspects of the present invention, the positive pressure ventilation system comprises a carbon dioxide reservoir containing a concentrated carbon dioxide gas, a molecular oxygen reservoir containing a concentrated molecular oxygen gas, a controllable mixing module operably connected to the carbon dioxide reservoir and the molecular oxygen reservoir and configured to controllably mix the concentrated molecular oxygen gas with the concentrated carbon dioxide gas, and at least one carbon dioxide partial pressure sensor selected from the group consisting of:

[0024] An arterial blood carbon dioxide partial pressure sensor and an end-tidal carbon dioxide partial pressure sensor configured to detect the partial pressure of carbon dioxide in arterial blood; a controllable mixing module and a controller operably connected to at least one carbon dioxide partial pressure sensor, the controller being configured to control at least one ratio selected from the group consisting of: at least one ratio selected from the group consisting of the ratio of molecular oxygen enriched gas and the ratio of carbon dioxide enriched gas in a mixture of molecular oxygen enriched gas and carbon dioxide enriched gas; a controller operably connected to a controllable mixing module and at least one carbon dioxide partial pressure sensor configured to control at least one ratio selected from the group consisting of: an endotracheal tube including a sealing cuff disposed at a distal portion of the endotracheal tube, the endotracheal tube being configured to repeatedly assume the following configuration: an endotracheal tube including a sealing cuff disposed at a distal portion of the endotracheal tube: a deployed configuration in which the sealing cuff engages the inner surface of the trachea while maintaining the inflow of gas from the endotracheal tube into the trachea, and a non-deployed configuration in which the sealing cuff disengages from the inner surface of the trachea while maintaining the natural outflow of gas from the trachea.

[0025] According to some embodiments and aspects of the present invention, the system includes a cardiac stimulation device configured to restore spontaneous circulation of arterial blood by applying at least one stimulus selected from the group consisting of mechanical and electrical stimuli to the myocardium at predetermined time intervals, an endotracheal pressure sensor configured to continuously determine the pressure within the trachea, and a synchronizer configured to synchronize the injection phase of a positive pressure ventilation system with the start of the decompression phase of the cardiac stimulation.

[0026] In some embodiments, the sequential compressive force from distal to proximal on the extremities is achieved by an ascending constricting elastic ring.

[0027] In some embodiments, the sequential compressive force from distal to proximal on the extremities is achieved by applying at least one element selected from the group consisting of an elastic bandage, an elastic extremity wrap having an adjustable closure, and an inflatable extremity wrap having an adjustable closure.

[0028] In some embodiments, at least one limb compression device is configured to occlude arterial inflow of blood to the limbs by applying a surface skin pressure range selected from the group consisting of 100 mmHg and 200 mmHg, 200 mmHg and 300 mmHg.

[0029] In some embodiments, the mixed gas is selected from the group consisting of 95% molecular oxygen and 5% carbon dioxide, 0.1 - 2.0% carbon dioxide (the remainder being molecular oxygen), 2.1 - 4.0% carbon dioxide (the remainder being molecular oxygen), 4.1 - 5.6% carbon dioxide (the remainder being molecular oxygen), 0.1 - 5.0% carbon dioxide (the remainder being molecular oxygen), 30 - 50% molecular oxygen and the chemical element xenon, 0.1 - 5.0% carbon dioxide (the remainder being molecular oxygen) and the chemical element argon.

[0030] In some embodiments, the controllable mixing module controllably mixes a mixed gas of 5% carbon dioxide and 95% molecular oxygen with pure 100% molecular oxygen according to feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of an arterial blood carbon dioxide partial pressure sensor and an end - tidal carbon dioxide partial pressure sensor, and maintains the arterial blood carbon dioxide partial pressure level at 41 - 45 mmHg.

[0031] In some embodiments, the controllable mixing module controllably mixes a hydrocarbon gas of 5% carbon dioxide and 95% molecular oxygen with pure 100% molecular oxygen according to feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of an arterial blood carbon dioxide partial pressure sensor and an end - tidal carbon dioxide partial pressure sensor, and maintains the arterial blood carbon dioxide partial pressure level at at least one pressure range selected from the group consisting of 41 - 45 mmHg, 46 - 50 mmHg, 51 - 55 mmHg, 56 - 65 mmHg according to feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of an arterial blood carbon dioxide partial pressure sensor and an end - tidal carbon dioxide partial pressure sensor.

[0032] In some embodiments, a controllable mixing module controlsly mixes a gas mixture of 5% carbon dioxide, 30% molecular oxygen, and 65% elemental xenon with a gas mixture of 30% molecular oxygen and 70% elemental xenon, according to feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of arterial carbon dioxide partial pressure sensors and end-tidal carbon dioxide partial pressure sensors, thereby maintaining the arterial carbon dioxide partial pressure level at 41-65 mmHg.

[0033] In some embodiments, a controllable mixing module controlsly mixes a gas mixture of 5% carbon dioxide, 50% molecular oxygen, and 45% elemental xenon with another gas mixture of 5% carbon dioxide, 50% molecular oxygen, and 50% elemental xenon, according to feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of arterial carbon dioxide partial pressure sensors and end-tidal carbon dioxide partial pressure sensors, thereby maintaining the arterial carbon dioxide partial pressure level at 41-65 mmHg.

[0034] In some embodiments, a controllable mixing module controlsly mixes a gas mixture of 5% carbon dioxide, 30% molecular oxygen, and 65% elemental argon with a gas mixture of 30% molecular oxygen and 70% elemental argon, according to feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of arterial carbon dioxide partial pressure sensors and end-tidal carbon dioxide partial pressure sensors, thereby maintaining the arterial carbon dioxide partial pressure level at 41-65 mmHg.

[0035] In some embodiments, a controllable mixing module controlsly mixes a gas mixture of 5% carbon dioxide, 50% molecular oxygen, and 45% elemental argon with another gas mixture of 5% carbon dioxide, 50% molecular oxygen, and 45% elemental argon, according to feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of arterial carbon dioxide partial pressure sensors and end-tidal carbon dioxide partial pressure sensors, thereby maintaining the arterial carbon dioxide partial pressure level at 41-65 mmHg.

[0036] According to some embodiments and aspects of the present invention, a method is provided for safely delivering an efficient amount of oxygen to essential organs during cardiopulmonary resuscitation (CPR), comprising: compressing at least one limb device by applying sequential compressive force to the limbs from distal to proximal, thereby occluding blood flow to the limbs; and delivering a mixed gas by positive pressure ventilation. This delivery includes the steps of supplying concentrated carbon dioxide gas; supplying concentrated oxygen gas; controllably mixing the concentrated oxygen gas and the concentrated carbon dioxide gas; detecting the partial pressure of carbon dioxide in arterial blood; and controlling at least one ratio in the mixture of concentrated oxygen gas and concentrated carbon dioxide gas selected from the group consisting of the ratio of concentrated oxygen gas and the ratio of concentrated carbon dioxide gas.

[0037] According to some embodiments and aspects of the present invention, the method includes the steps of: providing an endotracheal tube including a sealing cuff positioned on the distal portion of the endotracheal tube; providing the sealing cuff with a deployment configuration that engages with the inner surface of the trachea while maintaining the inflow of gas from the endotracheal tube into the trachea; providing the sealing cuff with a retention configuration that detaches the sealing cuff from the inner surface of the trachea while maintaining the natural outflow of gas from the trachea; operating a myocardial stimulator by applying at least one stimulus selected from the group consisting of mechanical and electrical stimuli to the myocardium at predetermined time intervals in order to restore the natural circulation of arterial blood; and continuously measuring the pressure inside the trachea and synchronizing the start timing of the infusion phase of a positive pressure ventilation system with the start of the decompression phase of cardiac stimulation.

[0038] According to some embodiments and aspects of the present invention, an endotracheal device for performing semi-spontaneous positive pressure ventilation is provided. The endotracheal device includes an elongated tube configured for endotracheal deployment and a sealing cuff positioned at the distal portion of the elongated tube, the sealing cuff configured to iteratively assume a deployment configuration and a stationary configuration. In the deployment configuration, the sealing cuff is expanded to engage with the inner surface of the trachea while maintaining the inflow of gas from the endotracheal tube into the trachea, and in the stationary configuration, the sealing cuff is folded away from the inner surface of the trachea while maintaining the natural outflow of gas from the trachea.

[0039] In some embodiments, the sealing cuff consists of an inflatable toroidal structure containing an inflatable lumen.

[0040] In some embodiments, an endotracheal device for performing semi-spontaneous positive pressure ventilation further comprises at least one conduit connecting the inflatable lumen of a sealing cuff to the lumen of an elongated tube.

[0041] In some embodiments, the endotracheal device for performing semi-spontaneous positive pressure ventilation further comprises at least one outlet located in the anterior distal portion of the toroidal structure of the sealing cuff, configured to maintain the flow of gas from the inflatable lumen of the sealing cuff into the trachea.

[0042] In some embodiments, the elongated tube includes a one-way flow check valve configured to maintain the flow of gas from the endotracheal tube into the trachea.

[0043] The present invention discloses the prescription of a target hyperventilation (i.e., above-normal) level of PaCO2, the direct measurement of PCO2 (PaCO2) in arterial blood, or the monitoring of the CO2 fraction at the end of exhalation (also known as end-expiratory PCO2 (PETCO2)), and the use of PaCO2 as feedback information to change the mixing ratio of two gases: one containing 5% or 5.6% CO2 and oxygen, and optionally a neuroprotective inert gas such as xenon or argon, and the other containing the same composition but without CO2. The mixing device can increase or decrease the proportion of CO2 in the mixture, depending on the instantaneous level of PaCO2 (or PETCO2). A given hyperventilation level of PaCO2 is typically between 41 mmHg and 60 mmHg, and more commonly between 46 mmHg and 55 mmHg. These PaCO2 levels are known to cause (a) vasodilation, (b) a rightward shift in the O2-hemoglobin dissociation curve, and (c) stimulation of respiratory activity if the patient is able to return to spontaneous breathing.

[0044] Thus, in order to counteract the systemic vasodilation caused by administering CO2-concentrated gas to increase PaCO2, the present invention indicates the simultaneous use of means to constrict peripheral blood vessels, particularly those in the limbs. Accordingly, the present invention discloses the application of a distal-to-proximal sequential limb compression device that squeezes blood from the limbs back into the central circulation and prevents blood from re-entering the limbs. Such a device comprises, but is not limited to, elastic shrink rings, elastic shrink rings with shrink elastic sleeves (stockinettes), manual elastic wraps, manual elastic bandages, and sequentially inflatable pneumatic shrink wraps, as shown in the drawings and the detailed description of the invention.

[0045] Increasing PaCO2 leads to overall vasodilation, and increasing peripheral vascular resistance is key to directing much of the cardiac output generated by CPR to vital organs, particularly the cerebral circulation. A second advantage of increasing PaCO2 is that the O2 dissociation curve shifts to the right, which is not present with SNPs.

[0046] Another aspect of the present invention is a means for controlling PaCO2 to a desired level by servo-controlling a mixer that mixes two gases (one containing 5 or 5.6% CO2 and the other not). For example, if PaCO2 or PETCO2 is below a specified value, the mixer adjusts to supply a higher CO2 fraction (FCO2). The mixer-monitor feedback mechanism includes means for slowing down the change in FCO2 to avoid under-dampped feedback loops that could cause undesirable oscillations in PaCO2. Since FCO2 is not the only parameter that determines PaCO2, all parameters and their interactions are shown using (Equation 1).

[0047] (Formula 1)

[0048]

number

[0049] Here, FCO2 is the percentage of CO2 supplied that is necessary to maintain the CO2 concentration in the blood at a desired level.

[0050] PaCO2 (or PETCO2) is the desired partial pressure of CO2 in arterial blood, and f is the respiratory rate.

[0051] VT is the tidal volume.

[0052] VD stands for lung dead space. It is typically 2.2 times body weight (kg) (or body weight in lbs).

[0053]

number

[0054] This represents the rate of CO2 metabolism and production in tissues.

[0055] Figure 1a shows FCO2 and several ventilation levels (i.e., f and VT),

[0056]

number

[0057] This diagram illustrates the relationship between the two.

[0058] To further evaluate the sensitivity and safety of the novel administration of the hyperventilation mixed gas, it is necessary to confirm that sufficient oxygen is being supplied. Equation 2 calculates the effect of using this mixed gas on arterial oxygen partial pressure (PaO2).

[0059] (Formula 2)

[0060]

number

[0061] Here,

[0062]

number

[0063] This represents the amount of metabolic oxygen consumed by the tissue.

[0064] RQ stands for respiratory quotient, which is the ratio of CO2 production to O2 consumption. Its value is approximately 0.8 for individuals with a balanced diet. FIO2 is the percentage of O2 in the inhaled gas.

[0065]

number

[0066] This is the alveolar oxygen fraction.

[0067] Even when the O2-hemoglobin dissociation curve is shifted significantly to the right, i.e., P50 = 40 mmHg (P50 is the oxygen partial pressure at which hemoglobin is 50% saturated), in order to maintain the hemoglobin saturation in arterial blood at nearly 100% (e.g., 98%), it is necessary to concentrate the gas mixture with oxygen to keep PaO2 and PAlvO2 at levels higher than atmospheric pressure. Equation 3 shows the PaO2 required for 98% saturation calculated using Hill's equation.

[0068] (Formula 3)

[0069]

number

[0070] Then, by moving the elements of (Equation 3), we obtain (Equation 4).

[0071]

number

[0072] With O2Sat = 0.98 and P50 = 40, a PO2 of 160.6 mmHg is obtained.

[0073] Returning to (Equation 2), we can evaluate the minimum values ​​of FIO2, f, and VT for given Vdot CO2 and VD values. Thus, a key aspect of the present invention is a gas exchange calculator that helps determine the FICO2 required to maintain PaCO2 for various values ​​of tissue CO2 production. Intuitively, the lower the tissue production of CO2 metabolism, the higher the FICO2 must be to maintain PaCO2 at a desired level. Theoretically, this can be done by reducing alveolar ventilation (e.g., reducing respiratory rate or tidal volume). However, this leads to limiting oxygen supply, and PaO2 and O2Sat may become too low, as shown in (Equations 3) and (Equations 4). Thus, the gas exchange calculator sets a limit for minimum alveolar ventilation that is safe for patient tissue oxygenation, regardless of the level of metabolic rate.

[0074] An additional aspect of the present invention is that the servo-controlled mixed gas disclosed above is supplied not only for respiration but also to artificial lungs and cardiopulmonary bypass machines such as ECMO devices and bubble oxygen inhalers.

[0075] A further aspect of the present invention is maintaining mechanical ventilation of a patient's lungs at a very low or negative pressure. This means keeping the mean airway pressure low and minimizing the pressure increase during inspiration. Doing so reduces impairment of lung and chest expansion to venous return of blood from the periphery to the heart, and resistance to blood flow through the pulmonary capillaries. The present invention discloses means of doing so by using an endotracheal catheter ventilation method to synchronize the inspiratory (lung expansion) phase of the respiratory cycle with the decompression or reaction phase of CPR chest compressions and assisting exhalation by applying graded negative pressure.

[0076] This novel CPR-specific method of optimized mechanical ventilation is an integral part of the present invention by focusing on preventing ventilatory interference with pulmonary blood flow. A preferred embodiment of the mechanical ventilation component comprises the following steps, which, when applied together, promote venous return to the right heart and filling to the left heart during the "diastolic" or decompressive phase of chest compression CPR.

[0077] The inspiratory phase of artificial respiration and the decompression phase of cardiac massage are synchronized. This facilitates air introduction at low driving pressure. A preferred embodiment of this synchronization is the use of a high-frequency response intratracheal pressure sensor that supplies a processor to determine the correct timing of inspiratory air infusion into the lungs at the start of the decompression phase of CPR.

[0078] This method significantly reduces anatomical dead space, allowing alveolar ventilation to be maintained with a smaller tidal volume. This is achieved by using a thin endotracheal catheter inhaled through the main carina. While air is being injected, a balloon near the tip of the catheter briefly inflates to occlude the trachea, preventing leakage of the injected air. Once the desired volume has been injected, the balloon deflates, allowing gas to be expelled from the lung around the catheter (between the catheter and the tracheal wall). This reduces anatomical dead space by the volume of the upper airway and trachea (approximately 100 ml in adults), and the aerodynamic mixing of the jet further dynamically reduces dead space. As a result, the amount of tidal volume can be reduced by the amount of dead space, thereby suppressing lung pressure and chest expansion.

[0079] This invention discloses a method of actively expelling air from the lungs by applying controlled, graded, and synchronized negative pressure to the air outlet (glottis, mouth, or nose) using a laryngeal mask or an oro-nasal mask.

[0080] (definition) As used herein, the term "easily connectable" should be interpreted to include any structure and / or component configured to be conveniently connectable to other structures and / or components and / or parts of a larger system or assembly. However, the term "easily connectable" does not necessarily mean easily disconnectable or detachable. The term "easily connectable" is optionally satisfied by providing ease of one-time connection or joining.

[0081] As used herein, the terms operably connected, operably coupled, or similar means that the disclosed system and its various components are connected in a particular way that enables them to operate effectively in the manner described herein (for example, in a way that enables fluid to move and / or power or signals to be transmitted).

[0082] In this specification, the terms elastic or resilient are interpreted to refer to materials that are inherently ductile, having a tensile strength lower than the aforementioned tensile strength of flexible or resilient materials, and that can be optionally stretched or expanded efficiently, particularly having a UTS value of less than about 600 MPa.

[0083] As used herein, the terms "method" and "process" are construed to include any sequence of steps or constructive actions, regardless of the specific time order for their execution. Any particular step or constructive action in any given method or process is not necessarily presented in the order shown in the claims, description, or flowchart of the drawings, unless the context explicitly indicates otherwise. Any particular step or constructive action included in a given method or process may precede or follow any other particular step or constructive action in that method or process, unless the context explicitly indicates otherwise. Any particular step or constructive action and / or combination thereof included in any method or process may be performed repeatedly before or after any other particular step or action in that method or process, unless the context explicitly indicates otherwise. Furthermore, some steps or constructive actions and / or combination thereof may be combined, performed together, performed concurrently, and / or performed in parallel, unless the context explicitly indicates otherwise. Furthermore, some steps or constructive actions and / or combination thereof in any method or process may be skipped, omitted, exempted, and / or opted out of, unless the context explicitly indicates otherwise.

[0084] In this specification or in the claims, any term meaning an action or operation, such as a verb, whether in its base form, tense, genitive, or present / past participle, is not necessarily interpreted as something actually performed, but rather as something performed in a constitutive manner, that is, merely voluntarily or potentially.

[0085] As used herein, the term "substantially" is a broad term and should be given its usual, conventional meaning to those skilled in the art (not limited to any special or customized meaning), meaning, without limitation, the majority of, but not necessarily all, of the specified quantity or quality.

[0086] This term essentially means that a composition, method, or structure may include additional components, steps, and / or parts, provided that the additional components, steps, and / or parts do not substantially alter the basic and novel properties of the claimed composition, method, or structure.

[0087] As used herein, this term has a specific meaning, signifying an interval of plus or minus 10% (±10%). For any embodiment disclosed herein, disclosure of a specific value in some alternative embodiment is understood to disclose an interval that is approximately or nearly equal to that specific value (i.e., ±10%).

[0088] As used herein, the terms about or approximately modify a particular value by referring to a range equal to plus or minus 20% (+ / -20%) of that particular value. For any of the embodiments disclosed herein, the disclosure of a particular value may also be understood in various alternative embodiments as the disclosure of a range equal to that particular value (i.e., ±20%).

[0089] On the other hand, the terms and operators used herein are also terms and / or equivalent alternative operators unless it is clearly not the case in the context.

[0090] However, it should be understood that neither the summary nor the specific definitions provided herein are intended to limit the interpretation of the present invention to any particular form or example, but rather to cover all modifications, equivalents, and substitutes that fall within the scope of the invention.

[0091] (Drawing description) The present invention will be more comprehensively understood and appreciated from the following detailed description, which is accompanied by the attached drawings.

[0092] Figure 1 is a flowchart of the main physiological events at cardiac arrest and the start of CPR.

[0093] Figure 2 is a block diagram of the unified invention.

[0094] Figure 3 is a schematic diagram of an embodiment of the unified invention.

[0095] Figure 4 is a schematic diagram of an ETCO2-based servo-controlled carbon dioxide concentrate supply system for ventilators and cardiopulmonary bypass machines.

[0096] Figure 5 is a schematic diagram of CPR-synchronous ventilation and active exhalation.

[0097] Figure 6A is a flow chart of the airway pressure servo-controlled ventilation trigger device.

[0098] Figure 6B is a schematic diagram of the airway pressure servo-controlled ventilation trigger process.

[0099] Figure 7 shows prior art for endotracheal ventilation according to US7513256.

[0100] Figure 8A shows an example of a blood loss wrap for CPR that expands sequentially from distal to proximal.

[0101] Figure 8B shows an example of a spring-loaded one-way valve for a distal-to-proximal sequential tourniquet wrap for CPR.

[0102] Figure 8C shows an example of using a blood loss wrap for CPR, which is inflated sequentially from distal to proximal.

[0103] Figure 9A shows an example of a rotating device for blood loss in which the patient rolls sequentially from distal to proximal for CPR.

[0104] Figure 9B shows an example of the assembly of a distal-to-proximal split sleeve tourniquet for CPR.

[0105] Figure 9C shows an example of a tourniquet for CPR that is nearing completion, and a completed tourniquet with sequentially wrapped distal-to-proximal split sleeves.

[0106] Figure 10A shows the percentage of carbon dioxide in the delivery gas—FCO2—required to achieve four exemplary levels of arterial PCO2-PaCO2, as a function of the tissue carbon dioxide production rate—VdotCO2.

[0107] Figure 10B shows the carbon dioxide fraction in the supplied gas (FCO2) required to achieve an arterial PCO2-PaCO2 of 55 mmHg for four exemplary tidal volumes (VT), as a function of the tissue carbon dioxide production rate (VdotCO2).

[0108] Figure 10C shows the percentage of carbon dioxide in the supplied gas (FCO2) required to achieve an arterial PCO2-PaCO2 of 55 mmHg at four exemplary respiratory rates f, expressed as a function of the tissue carbon dioxide production rate (VdotCO2).

[0109] Figure 10B shows the percentage of carbon dioxide (FCO2) required in the delivery gas to achieve an arterial blood PCO2 (PaCO2) of 55 mmHg with an exemplary four-stage dead space (VD), as a function of the tissue carbon dioxide production rate (VdotCO2).

[0110] Figure 11A shows the oxygen fraction FO2 in the supplied gas, as a function of the tissue molecular oxygen consumption rate VdotO2, required to achieve four exemplary levels of arterial blood oxygen partial pressure PaO2.

[0111] Figure 11B shows the oxygen molecule fraction FO2 in the supplied gas required to achieve an arterial blood oxygen partial pressure PaO2 of 161 mmHg, as a function of the tissue molecular oxygen consumption rate VdotO2, for four exemplary tidal volumes VT.

[0112] Figure 11C shows the molecular oxygen fraction FO2 in the delivered gas required to achieve an arterial oxygen partial pressure PaO2 of 161 mmHg, using four exemplary levels of respiratory rate f as a function of the tissue molecular oxygen consumption rate VdotO2.

[0113] Figure 11D shows the molecular oxygen fraction FO2 in the supply gas required to achieve an arterial oxygen partial pressure PaO2 of 161 mmHg, using four exemplary levels of dead space VD as a function of the tissue molecular oxygen consumption rate VdotO2.

[0114] Figure 12A shows an example of the operation procedure for the gas exchange calculator.

[0115] Figure 12B illustrates the relationships between the parameters.

[0116] While the present invention may be subject to various modifications and alternative forms, specific embodiments are shown in the drawings merely as examples. The drawings are not necessarily complete, and the components are not necessarily to scale; instead, the focus is on clearly illustrating the underlying principles of the invention.

[0117] (Detailed disclosure of embodiments) According to the present invention, three means are used to optimally treat a cardiac arrest patient receiving cardiopulmonary resuscitation (CPR) so that the maximum amount of oxygen reaches the brain. Figure 2 is a schematic block diagram of the present invention, which is composed of three integral and inseparable elements. As described herein, these elements interact clinically and physiologically, not only enhancing the overall effect on oxygen delivery to the brain, but also potentially causing harm rather than benefit if one element is absent, as the effects of the other elements may become detrimental. This is best understood by examining the shortcomings of current techniques for performing CPR outlined in the block diagram of Figure 1, in accordance with the teachings of the American Heart Association.

[0118] The left side of Figure 1 outlines the physiological events immediately following cardiac arrest. The right side shows the outcomes of current treatments, collectively known as cardiopulmonary resuscitation (CPR). As mentioned earlier, in many cardiac arrest patients treated with current treatments, the heart resumes beating (also known as recovery of spontaneous circulation (ROSC)), but the brain suffers catastrophic and irreversible damage. The overall outcome is that only a small number of patients who receive CPR experience meaningful survival with tolerable mental function. The sequence of events begins with the acute event of cardiac arrest11 and the resulting cessation of cardiac output12. This results in two major events: oxygen is no longer supplied to all tissues14 and the function of the sympathetic nervous system, which controls the tone of smooth muscle in arterioles and other blood vessels, ceases13. The lack of blood flow to all tissues15 causes compensatory vasodilation18, also known as reactive hyperemia17, which is added to the effects of sympathetic cessation13 and the resulting loss of vasomotor tone16. Extreme vasodilation18 reduces total peripheral resistance19, causing a decrease in blood pressure and flow when cardiac massage is initiated as part of CPR. Peripheral vasodilation causes pooling of blood in the periphery, with most of the blood not returning to the heart and filling the ventricles37. To summarize the left side of the diagram, it can be simply said that cardiac arrest causes extreme vasodilation.

[0119] When CPR22 is performed, the patient receives chest compressions23 at a rate of 100 times per minute, positive pressure ventilation24 is performed, and epinephrine36 is injected according to the current AHA protocol. Once effective chest compressions are initiated, some cardiac output27 and oxygen supply28 are generated. This reverses, to some extent, the mechanism that causes reactive hyperemia29 and subsequent vasoconstriction34. Intravenous injection of epinephrine36 also causes vasoconstriction34, but this is primarily constriction of cerebral blood vessels31. Initiation of positive pressure ventilation (IPPV24), even with just 1-2 breaths for every 15 compressions, i.e., 6-12 breaths per minute, removes more CO2 from the lungs than is produced in the tissues25, rapidly lowering the arterial partial pressure of CO2 known as hypocapnia30. Hypocapnia30 directly affects cerebral circulation by causing vasoconstriction31, significantly reducing cerebral blood flow32 and oxygen transport35. Hypocapnia also causes a leftward shift in the oxygen-hemoglobin dissociation curve, meaning that for every milliliter of blood flowing through the tissue, less oxygen is released from hemoglobin and delivered to the tissue. This contributes to a reduction in oxygen transport to the brain, among other tissues.

[0120] Another adverse effect of positive pressure ventilation (IPPV) is lung and chest dilation and increased intrathoracic pressure. The increased intrathoracic pressure during IPPV further reduces venous blood return to the right side of the heart by decreasing the pressure gradient from extrathoracic veins to intrathoracic vena cava segments. Simultaneously, lung dilation due to IPPV leads to increased pulmonary vascular resistance, hindering blood flow from the right to the left side of the heart, thereby reducing venous return to the left ventricle. It is well known that IPPV reduces biventricular filling, and coupled with reduced venous return due to peripheral blood pooling, the cardiac output obtained from chest compressions during CPR is 1 / 300th of normal. rd The result is as follows: The final outcome is a further decrease in blood flow and oxygen transport to the brain.

[0121] Based on the information above, it is clear that combining positive pressure ventilation and epinephrine in a state of very low cardiac output drastically reduces oxygen delivery to brain tissue. Thus, this invention teaches that CPR must employ opposite approaches to protect the brain from injury: namely, it must induce and maintain vasodilation focused on cerebral circulation, compress and constrict peripheral blood vessels, absolutely avoid impaired cardiac blood flow caused by IPPV, and shift the O2-hemoglobin dissociation curve to the right rather than the left. This patent teaches how to do this by combining the following processes:

[0122] A schematic block diagram of the unified invention is shown in Figure 2. The most powerful and natural means of dilating arterioles and other blood vessels is to induce hyperventilation, which is an increase in the partial pressure of carbon dioxide (CO2). This can be easily done by supplying concentrated carbon dioxide gas 101 to the ventilator circuit and, if used, to the gas exchanger of an artificial cardiopulmonary bypass machine such as an ECMO or bubble oxygen inhaler. As briefly mentioned in 101, concentrated CO2 induces vasodilation, shifting the O2-hemoglobin dissociation curve to the right and promoting O2 transfer to cells and their mitochondria, stimulating the patient's respiratory drive. However, vasodilation by CO2 is global and leads to blood pooling in the periphery, and is therefore not entirely useful on its own. Means 107 to counteract peripheral vasodilation are needed. The invention teaches the use of means to squeeze blood from the periphery to the core by applying sequential distal-proximal automated transfusion and means to prevent blood from returning to the periphery by acting as a tourniquet 103. The combined effect of tourniquet 103 is to increase the preload on the heart by moving blood from the periphery to the core, while restricting peripheral flow to direct the flow generated by CPR to essential organs and minimizing blood shunts, which result in greater resistance to flow, also known as cardiac afterload.

[0123] Even by increasing venous return to the right heart by sequentially constricting the limbs as taught in 103, it is not possible to completely overcome the blood flow impairment caused by IPPV111. This means that the ventilation 105 must be modified to minimize the increase in pressure and expansion during mechanical ventilation. To this end, the invention teaches minimizing tidal volume by reducing the anatomical dead space by injecting inspiratory fresh gas into the distal trachea and doing so in sync with the decompression (passive or active) of CPR. The components of the invention in 105 also disclose applying negative pressure (suction) during the expiratory phase of the ventilation cycle. It also teaches reducing the tidal volume-VT to a level sufficient to achieve an arterial oxygen saturation of 98% or higher. This is done according to the mathematical algorithm described in Figures 11a, 11b, 11c, and 11d, which takes into account all factors affecting O2 transport, including tidal volume, dead space, respiratory rate, arterial PCO2, P50 (location of the O2 dissociation curve), tissue-mediated O2 consumption rate, and the use (if any) and effectiveness of cardiopulmonary bypass.

[0124] The ventilation scheme described in 105 interacts closely with the CO2 supply described in 101 through servo control of the CO2 fraction FCO2 supplied in the inhaled gas or in the cardiopulmonary bypass machine.109 Regardless of the CO2 partial pressure in 101, FCO2 is affected by the ventilation parameters in 105, and vice versa.

[0125] The combined effect of all three poles of this invention effectively influences the cerebral blood flow range of O2 transport to brain tissue 120, as schematically shown by the processes indicated by the interlocking arrows 113, 115, and 117.

[0126] To better understand the interrelated poles of the present invention, we now refer to Figure 3, which shows CPR chest compressions 130 for a cardiac arrest victim. First, we point out the sequentially applied distal-to-proximal limb compression and hemostatic device 132. This is a means to counteract the vasodilatory effect of the CO2 concentrated gas, preventing blood from moving from the limbs to the trunk and back. It is understandable, without showing in the drawings, that such a limb compression device can also be applied to the victim's arms. Next, we show a gas mixer 142 which is servo-controlled by receiving continuous information regarding the end-tidal CO2 level during exhalation via wired or wireless communication 160. This end-tidal CO2 is tracked by a CO2 analyzer 152 that communicates directly 150 with a facial or laryngeal mask 164 through which the exhaled gas passes. The CO2 partial pressure level at the end of exhalation corresponds to the arterial partial pressure of CO2 and can therefore be used to servo-control the mixed gas supplied by the mixer 142 to the ventilator 144 via a conduit 146. Another embodiment of this part of the present invention is the use of a transcutaneous CO2 monitor or an indwelling arterial CO2 electrode, which is not shown in these drawings. Yet another embodiment of the present invention is the division of the gas mixture passing through conduit 146 and supplying a portion thereof to a gas exchanger of cardiopulmonary bypass machine 163, which is also not shown in Figure 3. The servo-controlled gas mixer 142 mixes gases from several compressed gas cylinders 134 and 136 connected to the mixer 142 via corresponding conduits 138 and 140. In a preferred embodiment, one cylinder contains compressed pure (100%) oxygen and the other cylinder contains a gas mixture of 5% CO2, also known as carbogen. By mixing the two gases in any proportion, FCO2 levels between 0.0 (when all gas is supplied from 100% oxygen) and 0.05 (when all gas is supplied from the mixing cylinder) can be produced. Other embodiments consist of higher CO2 concentrations in the mixing cylinder, including levels of 5-6% or 6-8%. Furthermore, there are embodiments in which inert gases such as xenon or argon are added to the O2 mixture at an O2 ratio of 35% to 45%, thereby reducing the level of the inert gas to 65% to 55%.To ensure that the patient always receives sufficient oxygen, the inert gas-carbogen mixture must contain an equal proportion of oxygen.

[0127] Next, elements used to ventilate the patient in a manner that does not obstruct blood flow to the chest and blood flow through the lungs are disclosed in Figure 3. These are regulated and servo-controlled by a high-fidelity pressure sensor 148 communicating with the patient's airway 166. This signal is analyzed by a computer-based algorithm shown in Figure 6a, which determines when to initiate breathing by the synchronous positive pressure ventilator 144 or when to initiate vacuum evacuation of gas by the pump 162. In a preferred embodiment, the positive pressure ventilator 144 injects gas into the distal trachea through a thin catheter 150 with an inner diameter of 4 ± 1 mm. As soon as the gas begins to flow into the catheter 150, an elastic balloon 151 inflates to occlude the trachea and prevent air leakage. This intratracheal ventilation is described in detail in Figure 7 and U.S. Patent No. 7513256. By injecting gas in the distal part of the trachea and expelling the gas from around the catheter 150, it is confirmed that the interface of fresh gas moves to a deeper position from the airway opening (mouth / nose), thereby cutting dead space by approximately 100 cc in adults. In this way, the tidal volume can be reduced by the same amount, which helps to suppress lung and chest expansion. Another element of this preferred embodiment is the active expulsion of gas through the mask 164 and conduit 150, assisted by a regulated and synchronized vacuum pump 162, which is servo-controlled 156 by a signal from an airway pressure sensor 148.

[0128] As shown in Figure 4, it is possible to further describe the end-expiratory CO2-based servo control of the gas composition supplied to the ventilator and cardiopulmonary bypass machine. In this figure, clutter is reduced by focusing on the gas supply. The ventilator 158 and cardiopulmonary bypass machine 163 receive gas from a servo-controlled gas mixer 142 that mixes several gases 134 and 136 supplied from compressed gas cylinders via conduits 138 and 140. The mixed gas receives a signal from the end-expiratory CO2 monitor 152 and adjusts the level of CO2 in the mixed gas to ensure that the partial pressure ETCO2 is at the desired level. It is obvious to experts in this field that if the CO2 level in the expiratory gas is higher than the desired level, the FCO2 in the gas must be decreased, and if it is lower than the desired level, the FCO2 in the mixed gas must be increased. The feedback control is performed quickly enough, but not too quickly, to make changes effective in order to avoid undesirable fluctuations in CO2 (under-damping feedback loops).

[0129] Figure 5 illustrates another part of the present invention, in which the delivery of air to and delivery of air from the lungs is synchronized with the airway fluctuations caused by CPR chest compressions. A preferred embodiment is based on the use of compression signals obtained from an airway pressure sensor 148, which is inserted into the airway or connected to the airway lumen via a conduit 166. The pressure sensor needs to be highly sensitive to changes in airway pressure induced by CPR chest compressions with a sufficient frequency response of 0 Hz to 100 Hz or 0 Hz to 1000 Hz. The pressure sensor may be standalone or integrated into the air delivery catheter 150. Another preferred embodiment uses signals from a chest motion accelerometer that tracks the vertical movement of the chest wall. Yet another embodiment uses the lower one-third of the esophagus. rdA pressure signal is obtained from an esophageal pressure sensor located at [location]. In another preferred embodiment, central venous pressure (CVP) is used to monitor and track changes in intrathoracic pressure due to CPR chest compressions. It is also evident that such sensors can be used in any combination to obtain more accurate and reliable data for triggering the initiation of inspiration delivered by the positive pressure ventilator 144 and the active expiratory vacuum pump 162. In a preferred embodiment, the trigger signal is used to initiate gas delivery according to the flow diagram algorithm schematically shown in Figures 6a and 6b. The pressure signal is also used to initiate and control the expulsion of air from the lungs by ensuring that the airway pressure is kept at a moderate subatmospheric pressure but not too low, in the range of -2 to -7 cmH2O. Vacuum control is performed by opening and closing solenoid valves or MEMS components, or by controlling the speed of electric or electromagnetic vacuum pumps. Control and operation of the exhaust pump are not shown in the drawings. A preferred embodiment of the gas delivery positive pressure ventilator 144 is shown in Figure 7 as an endotracheal ventilator previously patented in U.S. Patent No. 7513256. Other types of externally triggerable volumetric or pressure ventilators can also be used.

[0130] A preferred embodiment of the algorithm used to convert a pressure signal into an air supply initiation trigger is shown in Figure 6a. A signal corresponding to instantaneous chest compression is obtained at 170 as an airway pressure signal. Other signals may also be used, as previously disclosed, such as chest wall acceleration, proximity signals, light reflection signals, auxiliary signals from mechanical compression devices, tracheal tube signals, or intravascular pressure signals. The time-series average of chest pressure or position is calculated at 172 to determine a reference point. This is done using a digital or analog integrator. The algorithm's path loops through 184 and continues acquiring signals at 170 as long as the chest diameter or pressure signal indicates that it exceeds the mean value Pmaw determined using the "if" box 174. This loop is repeated until the chest diameter or pressure value indicates that the chest diameter is less than Pmaw. Once this is detected, a secondary test is applied by 176 to confirm that the chest diameter or pressure is sloping in the direction of further decrease by calculating the first derivative of the chest diameter or pressure signal. If the gradient does not lead to a continuous decrease in diameter or pressure, the loop to 170 via path 184 continues. When both the actual size and the size derivative indicate the start of the chest decompression phase, the algorithm then checks whether it is the appropriate time to start breathing 178. If not, the loop from path 184 through 170 continues at a sufficient rate, e.g., every 5 msec. Once the examination of 178 detects that it is time to start breathing, the algorithm starts inspiration 182 by determining the elapsed time since the previous breath (e.g., 5 seconds, 10 seconds, 12 seconds) or the number of chest compressions since the previous breath (e.g., 15, 7, 8). This is done by inducing a positive airflow into the patient's trachea via an inserted catheter or tube, an example of which is shown in Figure 7. Subsequently, a timer, volume counter, or pressure signal from the airway is activated, and when a threshold is set indicating that sufficient gas has been injected into the lungs, the respiratory termination determination 180 is activated, air injection stops, and the control path 186 returns the algorithm to repeat the process in 170.

[0131] A schematic example of the breathing initiation process is shown in Figure 6B, which, for clarity, consists of three panels. Panel A 202 shows the anterior-posterior (AP) diameter of the chest 196 as a continuous trace 198. When the trace is upward ("OUT") 192, it means that the chest diameter is increasing. In this panel A, decompression is due to the passive elastic recoil of the chest wall. The time axis 194 shows the elapsed time from any time zero in seconds. The second trace in panel A (labeled 200) shows the airway pressure (Paw) 190 in cmH2O, with zero being relative to atmospheric pressure. It can be seen that when the chest is compressed (in), the pressure increases, and when decompressed (out), the Paw decreases, and can even become negative relative to atmospheric pressure.

[0132] Panel B similarly shows chest movement in the upper trace, as in Panel A, as passive recoil 210 and as when an active suction or decompression mechanism pulling the chest outward is activated 208. Both traces 208 and 210 refer to the chest diameter axis on the left side of the panel. Active decompression can actually expand the chest to have a higher AP diameter and volume than in the case of passive recoil. Furthermore, as shown in pressure trace 211, this can bring the airway pressure below atmospheric level, as referencing the second Y-axis on the right side. Timing gas delivery to the lungs to coincide with this negative decompression phase clearly demonstrates the advantages of the present invention over the prior art, which does not synchronize chest compression and gas delivery, resulting in higher intrathoracic and airway pressures. As previously described, this has the advantage of minimizing impairment to blood flow from the main vein to the right side of the heart. This is schematically shown in panel C, where the algorithm detects that (a) the pressure is negative and (b) the pressure is monotonically decreasing (dp / dt is positive), thus triggering the start of breathing 212. The balance between the negative pressure in the decompressed chest 216 and the positive pressure of the delivered gas gives a smaller pressure trace 214 than would have been achieved if synchronization had not been achieved.

[0133] Figure 7 incorporates the teachings of U.S. Patent No. 7,513,256 as an optimal and preferred embodiment for combination with two other forms of this patent. Other positive pressure ventilation modes can also be used, and triggered breathing initiation is possible, but there may not be enough response time to precisely synchronize with 100 CPRs per minute. The endotracheal ventilator operates with a narrow catheter that is half the size of a normal endotracheal tube. Halving the diameter requires a 16-fold increase in driving pressure, and the volume of air in the ventilator is also reduced to 1 / 16th (according to Boyle's Law). This means that the size of the ventilator can be reduced by the same proportion, resulting in a very fast frequency response and making it very suitable for ventilation synchronized with cardiopulmonary resuscitation. Furthermore, because the air outflow is around the narrow tube, the cross-sectional area available for lung expulsion is much larger, dramatically reducing lung expulsion resistance during the expiratory phase of the ventilation cycle. This further reduces the average volume of the lungs and chest, mitigating impairment of blood return to the right heart. Adding synchronized active gas suction by incorporating a vacuum pump further reduces the volume of the lungs and chest. It should be noted that any method of suctioning veins by creating negative intrathoracic pressure, whether through active chest decompression, the use of an inspiratory threshold device, or vacuum application during exhalation, is substantially limited by the collapsible nature of large veins. Therefore, it is necessary to apply a third component of this invention, namely, continuous distal-to-proximal limb compression as shown in Figures 8 and 9.

[0134] The practice of moving blood from the extremities to the trunk in emergencies has been around for a long time. Lifting the legs is documented in older literature and is actually used in orthopedic surgery as a means of blood loss before applying an air tourniquet to create a bloodless surgical field. A study by Blond et al., published in Acta Orthopedica Scandinavia in 2001-2002, showed that approximately 45% of blood moves from the extremities when they are raised, meaning 55% of the blood remains in the extremities. Attempts to use medical anti-shock pants for this purpose were unsuccessful (Bickel et al. 1987 Jun;16(6):653-8). (Hemaclear (RTM) www.hemaclear.com) A device called a carbogen is widely used in orthopedic surgery to move blood from the limbs to the trunk and prevent its re-entry, and a similar device called Hemashock (RTM) www.hemashock.com is available for emergency use. The present invention discloses two additional devices uniquely suited to rapidly and effectively squeeze blood distal to proximal as part of this CPR mode during cardiac arrest to prime the heart while increasing afterload, diastolic blood pressure, coronary perfusion pressure, and most importantly, cerebral blood flow, in order to counteract the vasodilatory effects of carbogen use.

[0135] Figure 8A discloses a pneumatic distal-proximal sequential inflatable blood loss wrap 250 for CPR applied to a single limb. The device consists of multiple inflatable bladders 264 embedded in a cloth bandage 262. The bladders are rectangular or parallelogram-shaped 266 to facilitate optimal coverage and compression of the limb when inflated. The wrap is quickly fitted to the limb and closed with a hook-and-loop fastener 256 or similar secure, adjustable closure. Inflation begins in the most distal compartment and is preferably performed by connecting a compressed gas cylinder controlled by a flow regulator 258 and a pressure regulator 260. When the pressure in the most distal bladder reaches a preset level controlled by a spring-loaded one-way valve 274 shown in Figure 8b, the second bladder begins to fill until all compartments are inflated to the desired pressure. In this way, the wrap sequentially compresses the limb from distal to proximal. In another embodiment, inflation may also be performed using a manual or electric pump (not shown). The bladder contraction process must be performed stepwise from proximal to distal. The bladder should be contracted one at a time, and the patient's vital signs should be assessed after each bladder has contracted. The bladder is contracted by applying vacuum through a thick-walled tube 270 connected from a vacuum pump 254 to a regulator 272 and valve 268. Note that after the most proximal bladder is empty, the spring-loaded one-way valve between the bladder should only open when the vacuum level exceeds the threshold for opening the spring-loaded valve. Therefore, the bladder should be contracted one at a time as needed.

[0136] A preferred embodiment of a pressure-regulating one-way valve between bladders is shown in schematic diagram 280 of Figure 8b. The valve plate 290 is pulled by a spring 286 that is firmly attached on its underside to a railing-like rigid support 282. When closed, the plate 286 rests tightly on a circular shelf 288, and an elastic cushion O-ring 284 acts as a seal between the spring-driven plate 290 and the closing shelf 288. As shown in Figure 8a, there is a spring-loaded one-way valve between each bladder. To open, the pressure difference between the lower and upper ends (distal and proximal ends) of the valve must be sufficient to overcome the tensile force of the spring, and in a preferred embodiment, it must be greater than 200 mmHg. In other embodiments, the spring force is set to require pressure differences of 100-150 mmHg, 150-200 mmHg, or 200-300 mmHg. A pressure difference can be created by inflating the distal bladder beyond the valve opening threshold or by applying a vacuum higher than the valve opening threshold. Further disclosing is the ability to apply wraps 292 to each leg, as shown in Figure 8c. This is done by connecting inflation tubes, as shown in 294 and 296, to each wrap or wrap, which are connected to a compressed gas cylinder 298 via a pressure regulator 300. It is obvious that smaller-sized wraps can be applied to the arms with a similar design if necessary. The blood volume in both arms of a healthy person is 150 ml, and that of both legs is over 500 ml, but this volume can be much greater when blood accumulates in the peripheral blood vessels during cardiac arrest.

[0137] Next, a new configuration of an elastic hemostatic tourniquet, as shown in Figure 9, will be described. This device is similar to the previously patented Hemashock in a common configuration consisting of an elastic ring around which an elastic sleeve is wound, where the ring wraps around the limb when a strap also wound around the ring is pulled. The unique configuration of the new device is that it does not include a strap. The device 302 is wound from distal to proximal by pulling the strap 310 or split sleeve 308 shown in Figure 9b. A preferred embodiment of this hemostatic device for CPR consists of an initially complete sleeve 306 wound around an elastic ring made of elastic stretchable silicone or a metal (steel) spring 304. The steel spring ring and wound sleeve 316 are wound around the limb by pulling the strap 310. When the patient is ready to remove the tourniquet, it is wound manually from proximal to distal in stages, while monitoring the patient's vital signs to avoid cardiovascular collapse.

[0138] Here, we turn our attention to an important safety feature of the gas exchange calculator, which is governed by (Equations 5) and (6) and uses the parameter input calculator in Figure 12a, as shown in the output of Figure 12b. Continuous adjustment of the servo-controlled gas mixer 142 is based on feedback from the end-expiratory CO2 monitor 152, but it is safer and more practical to adjust its initial settings and boundaries based on physiological parameters. The gas exchange calculator shown in Figure 12a determines these initial settings by inputting the patient's own parameters. Starting at 350 in Figure 12a, the user first inputs the patient's weight 352, followed by the ventilation rate 354 and the amount of each breath known as tidal volume 356. Next, the user inputs information about the ventilation method, from which the calculator determines the size of the dead space VD 358. For example, the dead space VD for a healthy person breathing spontaneously is approximately 2.2 ml / kg. However, when ventilating with a mask, the air in the mask is rebreathed and added to the normal anatomical VD, resulting in approximately 3.2 ml / kg. When the patient is intubated with an endotracheal tube, the upper airway is bypassed and the VD is reduced to 1.5 ml / kg. Finally, if endotracheal ventilation is used, the VD is reduced to 0.7 ml / kg. Next, the user inputs the target PaCO2 360. The effects of ambient pressure and water vapor partial pressure are input in 362 and 364, and the actual water vapor partial pressure is determined according to the patient's body temperature. Next, the inhaled oxygen fraction FiO2 is set by the user 366. The unknown parameter during CPR is the amount of CO2 the patient is actually producing due to metabolic 368. In a healthy, resting state, this is 2.8 ml / kg / min. The estimated actual value during CPR is determined based on the cardiac output generated by CPR chest compressions. If the cardiac output is 0.3 of the normal cardiac output, the estimated metabolic level should be approximately 0.3.

[0139] Using these parameters, the gas exchange calculator determines the required level of FICO2 by (Equation 5) and the expected PaO2 by (Equation 6). Equation 5 calculates the required FICO2 needed to maintain PaCO2 at the desired level, as shown in row 386 of Figure 12b. From the graph, it can be seen that the lower the metabolic production of CO2, as shown on the horizontal axis 388, the higher the FICO2, as shown on the left vertical axis 382. If metabolism has completely stopped and CO2 production is zero, the FICO2 must be higher than 0.05. As an example, if the metabolic rate is about 1 / 3 of normal, as shown by the vertical dashed line 374, the FICO2 needed to maintain the PaCO2 level used as the target in this example at 55 mmHg must be about 0.04 (4%), as shown by the horizontal dashed line 378.

[0140] Next, we focus on the required oxygen concentration in the inhaled gas. Equation 6 calculates the predicted PaO2 from the parameters entered into the gas exchange calculator. Equation 3 shows the minimum PaO2 required to achieve an oxygen saturation of at least 98%. This value is higher than usual because the Bohr effect, caused by a high concentration of PaCO2 (P50 40 mmHg instead of the usual 26.6 mmHg), shifts O2-hemoglobin dissociation to the right. Using Equation 3, we can see that a lower limit of 161 mmHg is required for PaO2. Next, looking at Equation 6 and the graph in Figure 12b, we can see that line 380 predicts PaO2. Also, at the working point indicated by the vertical dashed line 374, the value of line 380, where it intersects with the horizontal dashed line 376, is approximately 240 mmHg. This value is higher than the aforementioned safety lower limit of 161 mmHg. These parameters can be used in the gas exchange calculator. However, if a combination of parameters is selected that results in a PaO2 value lower than 161 at the work point, the calculator will generate an alarm signal. Thus, the gas exchange calculator is an essential safety feature when using mixed gases with high FICO2 values.

[0141] (Formula 5)

[0142]

number

[0143] (Formula 6)

[0144]

number

[0145] [Table 1] (Different aspects of the present invention) [Item 1] A system for safely and efficiently supplying necessary amounts of oxygen to essential organs during cardiopulmonary resuscitation (CPR), (a) At least one limb compression device configured to apply compressive force to the limbs sequentially from distal to proximal, thereby obstructing blood flow to the limbs, (b) comprising a positive pressure ventilation subsystem configured to supply a mixed gas under positive pressure, The positive pressure ventilation subsystem, (I) A carbon dioxide reservoir containing concentrated carbon dioxide gas, (II) A molecular oxygen reservoir containing molecular oxygen concentrated gas, (III) A controllable mixing module operably connected to the carbon dioxide reservoir and the molecular oxygen reservoir, and configured to controllably mix the molecular oxygen concentrate with the carbon dioxide concentrate; (IV) At least one carbon dioxide partial pressure sensor selected from the group consisting of arterial blood carbon dioxide partial pressure sensors and end-tidal carbon dioxide partial pressure sensors, wherein the carbon dioxide partial pressure sensor is configured to detect the partial pressure of carbon dioxide in arterial blood, (V) A controller operably connected to the controllable mixing module and the at least one carbon dioxide partial pressure sensor, the controller configured to control at least one ratio selected from the group consisting of the ratio of molecular oxygen concentrate and the ratio of carbon dioxide concentrate in the mixture of molecular oxygen concentrate and carbon dioxide concentrate, (VI) an endotracheal tube including a sealing cuff positioned at its distal portion, which is configured to be repeatedly assumed, The aforementioned endotracheal tube is (i) A deployable configuration in which the sealing cuff engages with the inner surface of the trachea, thereby effectively sealing the gas passage between the sealing cuff and the inner surface of the trachea while maintaining the flow of gas from the endotracheal tube into the trachea, (ii) A retaining configuration which allows the sealing cuff to detach from the inner surface of the trachea while maintaining the natural outflow of the gas from the trachea, The aforementioned system (c) A myocardial stimulator configured to restore the spontaneous circulation of arterial blood by applying at least one type of stimulus selected from the group consisting of mechanical and electrical stimuli to the myocardium at predetermined time intervals, (d) An intratracheal pressure sensor configured to continuously measure the pressure inside the trachea, (e) A system further comprising a synchronizer configured to synchronize the injection phase of the positive pressure ventilation system with the start of the decompression phase of the cardiac stimulation. [Item 2] The system according to item 1, wherein the sequential compressive force applied to the limbs from distal to proximal is achieved by an uprolling, retractable elastic ring. [Item 3] The system according to item 1, wherein the sequential compressive force applied to the limbs from distal to proximal is achieved by applying at least one element selected from the group consisting of elastic bandages, elastic limb wraps with adjustable closures, and inflatable limb wraps with adjustable closures. [Item 4] The system according to item 1, wherein at least one limb compression device is configured to occlude arterial blood flow to the limb by applying a surface skin pressure range selected from the group consisting of 100-200 mmHg and 200-300 mmHg. [Item 5] The aforementioned mixed gas, 95% molecular oxygen and 5% carbon dioxide, 0.1-2.0% carbon dioxide, the rest is molecular oxygen. 2.1-4.0% carbon dioxide, the remainder being molecular oxygen. 4.1-5.6% carbon dioxide, the remainder being molecular oxygen. It consists of 0.1-5.0% carbon dioxide, 30-50% molecular oxygen, and the remainder is the chemical element xenon. A system as described in item 1, selected from the group consisting of 0.1-5.0% carbon dioxide, 30-50% molecular oxygen, and the remainder being the chemical element argon. [Item 6] The system according to item 1, wherein the controllable mixing module controlsly mixes a mixed gas of 5% carbon dioxide and 95% molecular oxygen with pure 100% molecular oxygen in accordance with feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor, thereby maintaining the arterial carbon dioxide partial pressure level at 41-45 mmHg. [Item 7] The controllable mixing module controlsly mixes a mixture of 5% carbon dioxide and 95% molecular oxygen with pure 100% molecular oxygen according to feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial blood carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor. The system according to item 1, wherein the arterial carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor maintain the arterial carbon dioxide partial pressure level within at least one pressure range selected from the group consisting of 41-45 mmHg, 46-50 mmHg, 51-55 mmHg, and 56-65 mmHg. [Item 8] The system according to item 1, wherein the controllable mixing module controllably mixes a mixed gas of 5% carbon dioxide, 30% oxygen molecules, and 65% xenon with a mixed gas of 30% oxygen molecules and 70% xenon, according to feedback from the at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial blood carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor, thereby maintaining the arterial blood carbon dioxide partial pressure level at 41-65 mmHg. [Item 9] The system according to item 1, wherein the controllable mixing module controllably mixes a mixed gas of 5% carbon dioxide, 50% molecular oxygen, and 45% elemental xenon with a mixed gas of 50% molecular oxygen and 50% elemental xenon, according to feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor, thereby maintaining the arterial carbon dioxide partial pressure level at 41-65 mmHg. [Item 10] The system according to item 1, wherein the controllable mixing module controllably mixes a mixed gas of 5% carbon dioxide, 30% oxygen molecules, and 65% argon with a mixed gas of 30% oxygen molecules and 70% argon, according to feedback from the at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial blood carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor, thereby maintaining the arterial blood carbon dioxide partial pressure level at 41-65 mmHg. [Item 11] The system according to item 1, wherein the controllable mixing module controllably mixes a mixed gas of 5% carbon dioxide, 50% oxygen molecules, and 45% argon with a mixed gas of 50% carbon dioxide molecules and 50% argon, according to feedback from the at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial blood carbon dioxide partial pressure sensor and the end-expiratory carbon dioxide partial pressure sensor, thereby maintaining the arterial blood carbon dioxide partial pressure level at 41-65 mmHg. [Item 12] A method for safely supplying an efficient amount of oxygen to necessary organs during cardiopulmonary resuscitation (CPR), (a) A step of applying a sequential compressive force to the limb from distal to proximal by compressing at least one limb device and occluding blood flow to the limb, (b) The process of supplying the mixed gas by positive pressure ventilation is included, The process of supplying the mixed gas is (I) A process of supplying concentrated carbon dioxide gas, (II) A step of supplying molecular oxygen concentrated gas, (III) A step of controllingly mixing the molecular oxygen concentrated gas with the carbon dioxide concentrated gas, (IV) A step to detect the partial pressure of carbon dioxide in arterial blood, (V) A step of controlling at least one ratio selected from the group consisting of the ratio of molecular oxygen concentrated gas and the ratio of carbon dioxide concentrated gas in a mixed gas of molecular oxygen concentrated gas and carbon dioxide concentrated gas, The method described above is (c) A step of providing an endotracheal tube including a sealing cuff positioned at the distal portion of the endotracheal tube, (d) A step of providing the sealing cuff with an expandable structure, engaging the sealing cuff with the inner surface of the trachea, thereby effectively sealing the gas passage between the sealing cuff and the inner surface of the trachea while maintaining the flow of gas from the tracheal tube into the trachea, (e) A step of detaching the sealing cuff from the inner surface of the trachea while maintaining the natural outflow of the gas from the trachea, and providing a retaining structure to the sealing cuff, (f) A step of stimulating the myocardium in order to restore the spontaneous circulation of arterial blood by applying at least one type of stimulus selected from the group consisting of mechanical and electrical stimuli at predetermined time intervals, (g) A step of continuously measuring the pressure inside the trachea, (h) A method further comprising the step of synchronizing the timing of the injection phase of the positive pressure ventilation system with the start of the decompression phase of the cardiac stimulation. [Item 13] The system according to item 1, wherein the compression of at least one limb device and the occlusion of the blood flow to the limb are performed by an uprolling, retractable elastic ring. [Item 14] The system according to item 1, wherein the compression of the at least one limb device and the occlusion of the blood flow to the limb are performed by applying at least one element selected from the group consisting of an elastic bandage, an elastic limb wrap with an adjustable closure, and an inflatable limb wrap with an adjustable closure. [Item 15] The system according to item 1, wherein at least one limb device is configured to occlude arterial blood flow to the limb by applying a surface skin pressure range selected from the group consisting of 100–200 mmHg and 200–300 mmHg. [Item 16] The aforementioned mixed gas, 95% molecular oxygen and 5% carbon dioxide, 0.1-2.0% carbon dioxide, with the remainder being molecular oxygen. 2.1-4.0% carbon dioxide, with the remainder being molecular oxygen. 4.1-5.6% carbon dioxide, the rest is molecular oxygen, It consists of 0.1-5.0% carbon dioxide, 30-50% molecular oxygen, and the remainder being the chemical element xenon. The system described in item 1, selected from the group consisting of 0.1-5.0% carbon dioxide, 30-50% molecular oxygen, and the remainder being the chemical element argon. [Item 17] The system according to item 1, further comprising controllingly mixing a mixed gas of 5% carbon dioxide and 95% molecular oxygen with pure 100% molecular oxygen in accordance with feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of an arterial blood carbon dioxide partial pressure sensor and an end-tidal carbon dioxide partial pressure sensor, thereby maintaining the arterial blood carbon dioxide partial pressure level at 41-45 mmHg. [Item 18] The system according to item 1, further comprising controllingly mixing a hydrocarbon gas of 5% carbon dioxide and 95% molecular oxygen with pure 100% molecular oxygen in accordance with feedback from the group consisting of the arterial carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor, and maintaining the arterial carbon dioxide partial pressure level within at least one pressure range selected from the group consisting of 41–45 mmHg, 46–50 mmHg, 51–55 mmHg, and 56–65 mmHg. [Item 19] The system according to item 1, further comprising maintaining the arterial blood carbon dioxide partial pressure level at 41-65 mmHg by controllingly mixing a mixed gas of 5% carbon dioxide, 30% molecular oxygen, and 65% chemical element xenon with a mixed gas of 30% molecular oxygen and 70% chemical element xenon, in accordance with feedback from the group consisting of the arterial blood carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor. [Item 20] The system according to item 1, further comprising maintaining the arterial blood carbon dioxide partial pressure level at 41-65 mmHg by controllingly mixing a mixed gas of 5% carbon dioxide, 50% molecular oxygen, and 45% chemical element xenon with a mixed gas of 50% molecular oxygen and 50% chemical element xenon, in accordance with feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of an arterial blood carbon dioxide partial pressure sensor and an end-expiratory carbon dioxide partial pressure sensor. [Item 21] The system according to item 1, further comprising controllingly mixing a mixed gas of 5% carbon dioxide, 30% molecular oxygen, and 65% elemental argon with a mixed gas of 30% molecular oxygen and 70% elemental argon, according to feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of an arterial blood carbon dioxide partial pressure sensor and an end-tidal carbon dioxide partial pressure sensor, and maintaining the arterial blood carbon dioxide partial pressure level at 41-65 mmHg. [Item 22] The system according to item 1, further comprising maintaining the arterial blood carbon dioxide partial pressure level at 41-65 mmHg by controllingly mixing a mixed gas of 5% carbon dioxide, 50% molecular oxygen, and 45% elemental argon with a mixed gas of 50% molecular oxygen and 50% elemental argon, in accordance with feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial blood carbon dioxide partial pressure sensor and the end-expiratory carbon dioxide partial pressure sensor. [Item 23] An endotracheal device for performing semi-voluntary positive pressure ventilation, (a) A long, slender tube containing a lumen and configured for tracheal deployment, (b) A sealing cuff positioned at the distal portion of the elongated tube, configured to repeatedly assume an unfolded configuration and a retaining configuration, comprising: (c) In the deployed configuration, the sealing cuff is expanded to engage with the inner surface of the trachea, thereby effectively sealing the gas passage between the sealing cuff and the inner surface of the trachea while maintaining the flow of gas from the endotracheal tube into the trachea. (d) In the retaining configuration, the sealing cuff is folded away from the inner surface of the trachea while maintaining the natural outflow of the gas from the trachea. [Item 24] The intratracheal device according to item 23, wherein the sealing cuff comprises an inflatable toroidal structure including an inflatable lumen. [Item 25] The endotracheal device according to item 24, further comprising at least one conduit connecting the inflatable lumen of the sealing cuff to the lumen of the elongated tube. [Item 26] The intratracheal device according to item 24, further comprising at least one outlet in the anterior distal portion of the toroidal structure of the sealing cuff, configured to maintain the flow of gas from the inflatable lumen of the sealing cuff into the trachea. [Item 27] The endotracheal device according to item 23, wherein the elongated tube comprises a one-way flow check valve configured to maintain the flow of gas from the endotracheal tube into the trachea. [Brief explanation of the drawing]

[0146] [Figure 1] This is a flowchart of the main physiological events at cardiac arrest and the start of CPR. [Figure 2] This is a block diagram of the unified invention. [Figure 3] This is a schematic diagram of an embodiment of the unified invention. [Figure 4] This is a schematic diagram of an ETCO2-based servo-controlled carbon dioxide concentrate supply system for ventilators and cardiopulmonary bypass machines. [Figure 5] This is a schematic diagram of CPR-synchronous ventilation and active exhalation. [Figure 6A] This is a flowchart of an airway pressure servo-controlled ventilation trigger device. [Figure 6B] This is a schematic diagram of the airway pressure servo-controlled ventilation trigger process. [Figure 7] This is a prior art technique for endotracheal ventilation as described in US7513256. [Figure 8A] This is an example of a blood loss wrap for CPR that expands sequentially from distal to proximal. [Figure 8B] This is an example of a spring-loaded one-way valve for a sequential tourniquet wrap that applies blood flow from distal to proximal for CPR. [Figure 8C] This is an example of using a blood loss wrap that is inflated sequentially from distal to proximal for CPR. [Figure 9A] This is an example of a rotating device for blood loss in CPR, which rolls sequentially from distal to proximal. [Figure 9B] This is an example of assembling a distal-to-proximal split sleeve tourniquet for CPR. [Figure 9C] This shows an example of a tourniquet for CPR, including an assembly nearing completion and a completed tourniquet with sequential wrapping of divided sleeves from distal to proximal. [Figure 10A]This shows the percentage of carbon dioxide in the delivery gas (FCO2) required to achieve four exemplary levels of arterial PCO2-PaCO2, expressed as a function of the tissue carbon dioxide production rate (VdotCO2). [Figure 10B] This shows the carbon dioxide fraction in the supplied gas (FCO2) required to achieve an arterial PCO2 (PaCO2) of 55 mmHg for four exemplary tidal volumes (VT), expressed as a function of the tissue carbon dioxide production rate (VdotCO2). [Figure 10C] This example shows the percentage of carbon dioxide (FCO2) in the supplied gas required to achieve an arterial PCO2-PaCO2 of 55 mmHg at four different respiratory rates (f), expressed as a function of the tissue carbon dioxide production rate (VdotCO2). [Figure 10D] This shows the percentage of carbon dioxide (FCO2) required in the delivery gas to achieve an arterial blood PCO2 (PaCO2) of 55 mmHg with an exemplary four-stage dead space (VD), expressed as a function of the tissue carbon dioxide production rate (VdotCO2). [Figure 11A] This shows the oxygen fraction FO2 in the supplied gas, as a function of the tissue molecular oxygen consumption rate VdotO2, required to achieve four exemplary levels of arterial blood oxygen partial pressure (PaO2). [Figure 11B] This shows the oxygen molecule fraction FO2 in the supplied gas, required to achieve an arterial blood oxygen partial pressure (PaO2) of 161 mmHg, as a function of the tissue molecular oxygen consumption rate (VdotO2), using four exemplary tidal volumes (VT). [Figure 11C] The molecular oxygen fraction FO2 in the delivered gas is the amount of oxygen required to achieve an arterial oxygen partial pressure (PaO2) of 161 mmHg, using four exemplary levels of respiratory rate f, as a function of the tissue molecular oxygen consumption rate (VdotO2). [Figure 11D] As a function of the tissue molecular oxygen consumption rate VdotO2, the molecular oxygen fraction FO2 in the supply gas is required to achieve an arterial oxygen partial pressure PaO2 of 161 mmHg, using four exemplary levels of dead space VD. [Figure 12A] This is an example of the operating procedure for a gas exchange calculator. [Figure 12B] This diagram illustrates the relationships between parameters.

Claims

1. A system for delivering oxygen to necessary organs during cardiopulmonary resuscitation (CPR), (a) A limb compression device comprising at least one limb compression device configured to apply compressive force sequentially to the limbs from distal to proximal, thereby obstructing blood flow to the limbs, wherein the compressive force is applied constantly and not intermittently; (b) comprising a positive pressure ventilation subsystem configured to supply a mixed gas under positive pressure, The positive pressure ventilation subsystem, (I) A carbon dioxide reservoir containing concentrated carbon dioxide gas, (II) An oxygen reservoir containing pure oxygen or oxygen concentrate gas, (III) A controllable mixing module operably connected to the carbon dioxide reservoir and the oxygen reservoir, and configured to controllably mix the oxygen concentrate with the carbon dioxide concentrate; (IV) At least one carbon dioxide partial pressure sensor configured to detect the partial pressure of carbon dioxide in exhaled gas, (V) A controller operably connected to the controllable mixing module and the at least one carbon dioxide partial pressure sensor, configured to control at least one ratio selected from the group consisting of the ratio of oxygen gas in the gas mixture and the ratio of carbon dioxide gas in the gas mixture, wherein the controller is configured to contain a sufficient amount of oxygen in the gas, (VI) An endotracheal tube including a sealing cuff positioned at its distal portion, The aforementioned endotracheal tube is (i) A deployable configuration in which the sealing cuff engages with the inner surface of the trachea, thereby sealing the gas passage between the sealing cuff and the inner surface of the trachea while maintaining the flow of gas from the endotracheal tube into the trachea, wherein the deployable configuration is formed by the sealing cuff during the inspiratory phase, (ii) A retaining configuration in which the sealing cuff detaches from the inner surface of the trachea while maintaining the natural outflow of the gas from the trachea, and which is configured between the retaining configuration and the sealing cuff during the exhalation phase, The aforementioned system (c) A myocardial stimulator configured to restore the spontaneous circulation of arterial blood by applying at least one type of stimulus selected from the group consisting of mechanical and electrical stimuli to the myocardium at predetermined time intervals, (d) An intratracheal pressure sensor configured to continuously measure the pressure inside the trachea, (e) A system further comprising a synchronizer configured for synchronization between the positive pressure ventilation subsystem and the cardiac stimulation.

2. The system according to claim 1, wherein the sequential compressive force applied to the limbs from distal to proximal is achieved by a retractable elastic ring.

3. The system according to claim 1, wherein the sequential compressive force applied to the limbs from distal to proximal is achieved by applying at least one element selected from the group consisting of elastic bandages, elastic limb wraps with adjustable closures, and inflatable limb wraps with adjustable closures.

4. The system according to claim 1, wherein the at least one limb compression device is configured to occlude arterial blood flow to the limb by applying a surface skin pressure range selected from the group consisting of 100 to 200 mmHg and 200 to 300 mmHg.

5. The aforementioned mixed gas, 95% oxygen and 5% carbon dioxide, 0.1-2.0% carbon dioxide, the rest is oxygen. 2.1-4.0% carbon dioxide, the rest is oxygen. 4.1-5.6% carbon dioxide, the rest is oxygen. It consists of 0.1-5.0% carbon dioxide, 30-50% oxygen, and the remainder is the chemical element xenon. The system according to claim 1, selected from the group consisting of 0.1 to 5.0% carbon dioxide, 30 to 50% oxygen, and the remainder being the chemical element argon.

6. The system according to claim 1, wherein the controllable mixing module controlsly mixes a mixture of 5% carbon dioxide and 95% oxygen with pure 100% oxygen in accordance with feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor, thereby maintaining the arterial carbon dioxide partial pressure level at 41-45 mmHg.

7. The controllable mixing module controlsly mixes a mixture of 5% carbon dioxide and 95% oxygen with pure 100% oxygen according to feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial blood carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor. The system according to claim 1, wherein the arterial carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor maintain the arterial carbon dioxide partial pressure level within at least one pressure range selected from the group consisting of 41-45 mmHg, 46-50 mmHg, 51-55 mmHg, and 56-65 mmHg.

8. The system according to claim 1, wherein the controllable mixing module controllably mixes a mixed gas of 5% carbon dioxide, 30% oxygen, and 65% xenon with a mixed gas of 30% oxygen and 70% xenon, according to feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial blood carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor, and maintains the arterial blood carbon dioxide partial pressure level at 41 to 65 mmHg.

9. The system according to claim 1, wherein the controllable mixing module controllably mixes a mixed gas of 5% carbon dioxide, 50% oxygen, and 45% elemental xenon with a mixed gas of 50% oxygen and 50% elemental xenon, in accordance with feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor, and maintains the arterial carbon dioxide partial pressure level at 41 to 65 mmHg.

10. The system according to claim 1, wherein the controllable mixing module controllably mixes a mixed gas of 5% carbon dioxide, 30% oxygen, and 65% elemental argon with a mixed gas of 30% oxygen and 70% elemental argon, according to feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial blood carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor, and maintains the arterial blood carbon dioxide partial pressure level at 41 to 65 mmHg.

11. The system according to claim 1, wherein the controllable mixing module controllably mixes a mixed gas of 5% carbon dioxide, 50% oxygen, and 45% elemental argon with a mixed gas of 50% oxygen and 50% elemental argon, in accordance with feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial blood carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor, thereby maintaining the arterial blood carbon dioxide partial pressure level at 41 to 65 mmHg.

12. The system according to claim 1, wherein the carbon dioxide partial pressure sensor is selected from the group consisting of an arterial blood carbon dioxide partial pressure sensor and an end-tidal carbon dioxide partial pressure sensor.

13. The system according to claim 1, wherein the compression of the at least one limb device and the occlusion of the blood flow to the limb are performed by a retractable elastic ring.

14. The system according to claim 1, wherein the compression of the at least one limb device and the occlusion of the blood flow to the limb are performed by applying at least one element selected from the group consisting of an elastic bandage, an elastic limb wrap having an adjustable closure, and an inflatable limb wrap having an adjustable closure.

15. The system according to claim 1, wherein at least one limb device is configured to occlude arterial blood inflow into the limb by applying a surface skin pressure range selected from the group consisting of 100 to 200 mmHg and 200 to 300 mmHg.

16. The aforementioned mixed gas, 95% oxygen and 5% carbon dioxide, 0.1-2.0% carbon dioxide, with the remainder being oxygen. 2.1-4.0% carbon dioxide, with the remainder being oxygen. 4.1-5.6% carbon dioxide, with the remainder being oxygen. It consists of 0.1-5.0% carbon dioxide, 30-50% oxygen, and the remainder being the chemical element xenon. The system according to claim 1, comprising 0.1 to 5.0% carbon dioxide, 30 to 50% oxygen, and the remainder being the chemical element argon, selected from the group:

17. The system according to claim 1, further comprising controllingly mixing a mixed gas of 5% carbon dioxide and 95% oxygen with pure 100% oxygen in accordance with feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of an arterial blood carbon dioxide partial pressure sensor and an end-tidal carbon dioxide partial pressure sensor, thereby maintaining the arterial blood carbon dioxide partial pressure level at 41-45 mmHg.

18. The system according to claim 1, further comprising controllingly mixing a hydrocarbon gas of 5% carbon dioxide and 95% oxygen with pure 100% oxygen in accordance with feedback from the at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial blood carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor, and maintaining the arterial blood carbon dioxide partial pressure level within at least one pressure range selected from the group consisting of 41–45 mmHg, 46–50 mmHg, 51–55 mmHg, and 56–65 mmHg.

19. The system according to claim 1, further comprising maintaining the arterial blood carbon dioxide partial pressure level at 41 to 65 mmHg by controllingly mixing a mixed gas of 5% carbon dioxide, 30% oxygen, and 65% xenon with a mixed gas of 30% oxygen and 70% xenon, in accordance with feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of an arterial blood carbon dioxide partial pressure sensor and an end-tidal carbon dioxide partial pressure sensor.

20. The system according to claim 1, further comprising maintaining the arterial blood carbon dioxide partial pressure level at 41 to 65 mmHg by controllingly mixing a mixed gas of 5% carbon dioxide, 50% oxygen, and 45% xenon with a mixed gas of 50% oxygen and 50% xenon, in accordance with feedback from at least one carbon dioxide partial pressure sensor selected from the group consisting of an arterial blood carbon dioxide partial pressure sensor and an end-tidal carbon dioxide partial pressure sensor.

21. The system according to claim 1, further comprising controllingly mixing a mixed gas of 5% carbon dioxide, 30% oxygen, and 65% elemental argon with a mixed gas of 30% oxygen and 70% elemental argon, in accordance with feedback from the group consisting of the arterial blood carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor, and maintaining the arterial blood carbon dioxide partial pressure level at 41 to 65 mmHg.

22. The system according to claim 1, further comprising maintaining the arterial blood carbon dioxide partial pressure level at 41 to 65 mmHg by controllingly mixing a mixed gas of 5% carbon dioxide, 50% oxygen, and 45% elemental argon with a mixed gas of 50% oxygen and 50% elemental argon, in accordance with feedback from the at least one carbon dioxide partial pressure sensor selected from the group consisting of the arterial blood carbon dioxide partial pressure sensor and the end-tidal carbon dioxide partial pressure sensor.

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