Devices and methods for non-invasive ventilation therapy

Abstract

Non-invasive ventilation therapy systems and methods are disclosed. The system comprises a ventilation device, a computing device coupled to the ventilation device, and a plurality of sensors for acquiring a physiological bioelectrical impedance signal from a patient, wherein the sensors are functionally connected to the computing device. The computing device receives the physiological bioelectrical impedance signal from the sensors, analyzes the physiological bioelectrical impedance signal, and, based on the analyzed physiological bioelectrical impedance signal, transmits a signal to the ventilation device to adjust therapy levels.

Description

REFERENCE TO RELATED APPLICATIONS[0001]The present application is a continuation in part of U.S. application Ser. No. 14 / 246,862, filed Apr. 7, 2014, and entitled “Devices and Methods for Respiratory Variation Monitoring by Measurement of Respiratory Volumes, Motion and Variability,” which is a continuation in part of U.S. application Ser. No. 13 / 210,360, filed Aug. 15, 2011, and entitled “Devices And Methods For Respiratory Variation Monitoring by Measurement of Respiratory Volumes, Motion and Variability,” which claims priority to Provisional U.S. Application No. 61 / 373,548, filed Aug. 13, 2010 and entitled “Devices and Methods for Respiratory Variation Monitoring by Measurement of Respiratory Volumes, Motion and Variability,” 61 / 449811, filed Mar. 7, 2011 and entitled “Respiratory Variation Monitoring Instrument,” 61 / 480105 filed Apr. 28, 2011 and entitled “Systems and Methods of Respiratory Monitoring,” and 61 / 509952, filed Jul. 20, 2011 and entitled “Use of Impedance Measuremen...

AI Technical Summary

Problems solved by technology

However, it would still take time before scientists recognized the advantages of monitoring a physiological signal in a clinical environment.

However, current scoring methods do not accurately predict patient outcomes in approximately 15% of ICU patients, and it may be worse for patients in a respiratory intensive care unit, which provide care in hospitals with large number of patients with acute respiratory failure.

Furthermore, differences in currently monitored vital signs such as blood oxygenation occur late in the progression of respiratory or circulatory compromise.

However, respiratory rate alone fails to indicate important physiological changes, such as changes in respiratory volumes.

However, there are currently no adequate systems that can accurately and conveniently determine respiratory volumes, which motivates the need for a non-invasive respiratory monitor that can trace changes in breath volume.

These methods are often inconvenient to use and inaccurate.

While end tidal CO2 monitoring is useful during anesthesia and in the evaluation of intubated patients in a variety of environments, it is inaccurate for non-ventilated patients.

The spirometer and pneumotachometer are limited in their measurements are highly dependent on patient effort and proper coaching by the clinician.

However, these two prerequisites are not necessarily enforced in clinical practice like they are in research studies and pulmonary function labs.

The major drawback of mainstream spirometers is that they require the patient to breathe through a tube so that the volume and / or flow rate of his breath can be measured.

Thus it is impossible to use these devices to accurately measure a patient's normal breathing.

Also, many physicians do not have the skills needed to accurately interpret the data gained from pulmonary function tests.

According to the American Thoracic Society, the largest source of intrasubject variability is improper performance of test.

Therefore much of the intrapatient and interpatient variability in pulmonary function testing is produced by human error.

Impedance-based respiratory monitoring fills an important void because current spirometry measurements are unable to provide continuous measurements because of the requirement for patient cooperation and breathing through a tube.

Even with acceptable spirometry measurements, the interpretations of the data by primary physicians were deemed as incorrect 50% of the time by pulmonologists.

However, resources to train a large number of people and enforce satisfactory quality assurance are unreasonable and inefficient.

Even in a dedicated research setting, technician performance falls over time.

In addition to human error due to the patient and healthcare provider, spirometry contains systematic errors that ruin breathing variability measurements.

Also, the discomfort and inconvenience involved during measurement with these devices prevents them from being used for routine measurements or as long-term monitors.

Other less intrusive techniques such as thermistors or strain gauges have been used to predict changes in volume, but these methods provide poor information on respiratory volume.

Respiratory belts have also shown promise in measuring respiration volume, but groups have shown that they are less accurate and have a greater variability than measurements from impedance pneumography.

Specifically, elderly patients and patients with pulmonary diseases may be at risk for respiratory complications when placed under a ventilator for surgery.

However, these tests cannot be replicated mid-surgery, or in narcotized patients or those who cannot or will not cooperate.

Testing may be uncomfortable in a postoperative setting and disruptive to patient recovery.

Unfortunately, it is generally inaccurate and difficult to implement in the non-ventilated patient, and other complementary respiratory monitoring methods would have great utility.

Fenichel et al. determined that respiratory motion can cause interference with echocardiograms if it is not controlled for.

These effects on the echocardiography signal can decrease the accuracy of measurements recorded or inferred from echocardiograms.

They reported difficulty in separating the cardiac signal artifacts and also noted artifacts during body movements.

They have a low resistivity in the longitudinal direction but a high resistivity in all other directions, which leads to a tendency to conduct current in a direction that is parallel to the skin.

Another potential signal artifact comes from subject movements, which may move electrodes and disturb calibrations.

Furthermore, electrode movements may be more prevalent in obese and elderly patients, which may require repetitive lead recalibration during periods of long-term monitoring.

The inability for a patient to separate from a mechanical ventilator occurs in approximately 20% of patientsand current methods to predict successful separation are poor and add little to a physician's decision.

While certain contact probes record respiratory rate, to date, no device or method has been specifically devised to record or to analyze respiratory patterns or variability, to correlate respiratory patterns or variability with physiologic condition or viability, or to use respiratory patterns or variability to predict impending collapse.

Respiratory rate and respiratory effort rise with stiff lungs and poor air exchange due to pulmonary edema or other reasons for loss of pulmonary compliance.

However, the implications of the rate, which is the only parameter objectively monitored is frequently not identified soon enough to best treat the patient.

However, patients are discouraged from pressing the button if they are getting too drowsy as this may prevent therapy for quicker recovery.

Pulse oximeters, respiratory rate and capnograph monitors may be used to warn of respiratory depression caused by pain medication and cut off the PCA dose, but each has serious limitations regarding at least accuracy, validity, and implementation.

COPD is a lung disease that makes it hard to breathe.

It is caused by damage to the lungs over many years, usually from smoking.

This can narrow or block the airways, making it hard for you to breathe.

However, with emphysema, these air sacs are damaged and lose their stretch.

Less air gets in and out of the lungs, which causes shortness of breath.

COPD patients often have difficulty getting enough oxygenation and / or CO2 removal and their breathing can be difficult and labored.

Long-term issues include difficulty breathing and coughing up sputum as a result of frequent lung infections.

Each of these therapeutic methods has a common drawback, there is no way of knowing how much air is actually getting into the lungs.

This can be inaccurate and is not a direct measurement of oxygen ventilation.

Furthermore, therapies using masks can be inaccurate due to leakage and problems associated with mask placement.

Additionally, kinking and malfunctions in the pneumatic airway circuits can provide and inaccurate measure of the amount of air which is getting into the lungs

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