Accessory detection in the capnography module

Abstract

A breathing gas flow coupler includes a device connector (30, 30M) having a female socket (40) or a male connector (40M), the female socket or the male connector having a lateral leakage path (60, 60M). A patient accessory connector (32) has a male connector (44) or a female socket adapted to be connected to the female socket or the male connector of the device connector. When the patient accessory connector is connected to the device connector, the patient accessory connector seals the lateral leakage path of the female socket or the male connector of the device connector. The lateral leakage path is arranged at a position so that a shorter male connector (44s) or a female socket of an incompatible patient accessory connector (32s) that is shorter than the male connector of the patient accessory connector does not seal the lateral leakage path when the incompatible patient accessory connector having the shorter male connector is connected to the device connector.

Description

Technical Field

[0001] The following generally relates to capnography or other respiratory gas monitoring devices, patient respiratory monitoring, nasal cannulas or other patient accessories for patient respiratory monitoring, and similar applications. Background Art

[0002] In capnography, carbon dioxide (CO 2 ) content, for example, using a sidestream flow path drawn from the expiratory flow of a mechanical ventilator. A common approach is to formulate the capnographic data as end-tidal CO 2 (etCO 2 ) Vital signs or their equivalent partial pressure (PETCO 2 Capnography data may be processed and / or utilized in other ways—for example, plotting CO against time (or alternatively against exhaled volume). 2 The graphed capnography waveform can be interpreted by a skilled medical professional to provide information such as breathing rate or cycle, information about gas exchange in the lungs, information about the efficacy of mechanical ventilation, etc. Although a common diagnosis in the context of mechanically ventilated patients, capnography is also applicable to respiratory monitoring of non-ventilated patients. In addition, although capnography is a common respiratory gas analyzer in clinical settings, other respiratory gas analyzers are sometimes used, for example, to track the oxygen content in the respiratory gases.

[0003] The reliability of a capnography or other respiratory gas analyzer depends on the connection to the patient. In a sidestream configuration, respiratory gas is drawn from exhaled gas exiting through the patient's nose or mouth or endotracheal tube. The capnography includes an air pump to pass CO 2 The sampling unit extracts the breathing gas. (In the alternative mainstream configuration, CO 2 The sampling unit is consistent with the breathing circuit). The sidestream configuration has certain advantages, but relies on a patient accessory to provide a flow path for the respiratory gas to enter the capnograph. The patient accessory can be, for example, a nasal cannula, a T-connection for the expiratory tube entering the ventilator flow circuit, etc. The patient accessory should have appropriate flow resistance, tubing length, or other features to ensure that CO 2 However, in practice, it is sometimes the case that non-standard patient accessories are able to be connected to the capnography machine, leading to unreliable capnography measurements and potential clinical misinterpretation. Naturally, if the patient accessory is not connected at all, the CO 2 The measurement results are completely invalid.

[0004] Certain improvements are disclosed below. Summary of the invention

[0005] In some embodiments disclosed herein, a breathing gas flow coupler includes: a device connector having a female receptacle or a male nipple, wherein the female receptacle or the male nipple of the device connector includes a lateral leakage path; and a patient accessory connector having a male nipple or a female receptacle adapted to be connected to the female receptacle or the male nipple of the device connector. When the patient accessory connector is connected to the device connector, the patient accessory connector seals the lateral leakage path of the female receptacle or the male nipple of the device connector. The lateral leakage path is disposed at a position along the female receptacle such that when an incompatible patient accessory connector having a shorter male nipple than the male nipple of the patient accessory connector is connected to the device connector, the shorter male nipple of the incompatible patient accessory connector does not seal the lateral leakage path.

[0006] In some embodiments disclosed herein, a respiratory gas analyzer includes: a device connector having a female socket or a male connector, wherein the female socket or the male connector includes a lateral leakage path, and wherein the female socket or the male connector is suitable for connection with an associated patient accessory connector, wherein the connected associated patient accessory connector seals the lateral leakage path; a respiratory gas measurement unit; and a pump operably connected to draw a gas flow from the device connector and from the lateral leakage path through the respiratory gas measurement unit.

[0007] In some embodiments disclosed herein, a respiratory gas analysis method includes: connecting a patient accessory to a respiratory gas analyzer using a patient accessory connector of a patient accessory and a device connector of the respiratory gas analyzer, wherein the device connector has a lateral leakage path that is sealed by the connection between the patient accessory connector and the device connector; operating a pump to draw an airflow from the patient accessory into the respiratory gas analyzer via the connected patient accessory connector and the device connector; detecting whether the patient accessory is connected to the respiratory gas analyzer based on a measurement result of the airflow; and using the respiratory gas analyzer, performing a respiratory gas analysis on the drawn airflow under the condition that the patient accessory is detected as being connected to the respiratory gas analyzer.

[0008] One advantage resides in providing detection of an operative connection of a patient accessory to a capnograph or other respiratory gas analyzer.

[0009] Another advantage resides in providing detection of an operative connection of a patient attachment of a recommended type to a capnograph or other respiratory gas analyzer.

[0010] Another advantage resides in providing detection of an airtight connection of a patient attachment to a capnograph or other respiratory gas analyzer.

[0011] Another advantage resides in providing detection of the type of patient accessories connected to a capnograph or other respiratory gas analyzer.

[0012] A given embodiment may provide none of the foregoing advantages, may provide one, two, more, or all of the foregoing advantages, and / or may provide other advantages as will become apparent to one of ordinary skill in the art upon reading and understanding the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The invention may take form in various components and arrangements of components, and in various steps and arrangements of steps.The drawings are only for the purpose of illustrating the preferred embodiments and are not to be construed as limiting the invention.

[0014] Figure 1 A capnography machine and associated patient accessories are diagrammatically illustrated.

[0015] Figure 2 It shows diagrammatically Figure 1 Capnograph female connector.

[0016] Figure 3 Diagram showing the Figure 1 The capnograph has a female connector and the patient accessory has a male connector.

[0017] Figure 4 Diagram showing the connection of Figure 1 The capnograph has a female connector and the patient accessory has a male connector.

[0018] Figure 5 Diagram showing the Figure 1 The capnography device has a female connector and a male connector for compatible patient accessories.

[0019] Figure 6 Diagram showing the connection of Figure 1 The female connector of the capnography and Figure 5 Patient accessory compatible male connector.

[0020] Figure 7 The flow chart shows Figure 1 Proper operation of the patient attachment interlock device of the capnography machine.

[0021] Figure 8 Diagram showing the Figure 1 The capnography device has a female connector and a specific type of male connector for compatible patient accessories.

[0022] Fig. 9 Diagram showing the connection of Figure 1 The female connector of the capnography and Figure 8 A male connector of a specific type of compatible patient accessory.

[0023] Fig.10 A male embodiment of a device connector is diagrammatically shown. DETAILED DESCRIPTION

[0024] refer to Figure 1 , the respiratory gas analyzer 8 includes a gas flow path, which includes a respiratory gas measurement unit 10, a flow meter 12, a pump 14, and a scavenging system 16. The respiratory gas measurement unit 10 is designed to detect and measure one or more respiratory gases. In the illustrative example, the respiratory gas analyzer 8 is a capnograph 8 and the respiratory gas measurement unit 10 is designed to detect and measure the flow of CO 2 The carbon dioxide (CO) in the respiratory gas of the measuring unit 10 2 ) concentration or partial pressure. 2 For example, by measuring the narrowband light emitted by CO 2 The transmittance at a strongly absorbed wavelength (e.g., in the infrared) is optically measured, typically corrected for the absorption of nitrous oxide in the respiratory gas. The light source emits light on a spectrum covering the desired measurement band (e.g., 4.26 microns in some embodiments). If appropriate spectral filtering is used, the light can extend spectrally beyond the detection spectral range. In some embodiments, the light source may include an optical chopper, a pulse power supply, etc., so as to deliver the emitted light as a light pulse. By another illustrative example, the respiratory gas measurement unit can measure the partial pressure or concentration of oxygen in the respiratory gas, etc. The pump 14 draws the respiratory gas through the measuring unit 10, and the flow meter 12 measures the flow. The flow meter 12 can use any flow measurement technology suitable for breathing air, and can optionally take the form of a differential pressure meter, a flow resistance meter, etc. The scavenging system 16 is optional, but is typically used in a medical environment, where an inhaled anesthetic or analgesic or an inhaled drug can be administered to the patient-the scavenging system 16 scrubs or removes these from the air flow before discharge. The capnograph or other respiratory gas analyzer also typically includes processing electronics 20, for example implemented as a microprocessor or microcontroller 22, which is programmed to execute instructions stored in an EEPROM, ROM or other memory (not shown) to read the CO from the measurement unit 10. 2 or other gas measurements and process these measurements to generate clinical data such as capnography waveforms, etCO 2 or PETCO 2 values, etc. The patient respiratory gas data may be displayed on a built-in display 24 and / or may be transmitted via a wired and / or wireless electronic data network to a bedside patient monitor, a nurse's station, an electronic medical record or health record (EMR or EHR), etc.

[0025] Continue to refer Figure 1 And also refer to Figure 2 , the respiratory gases exhaled by the patient 26 are input to the respiratory gas analyzer 8 through a patient accessory 28 (e.g., an illustrative nasal cannula 28, a T-connection to a mechanical ventilator circuit or endotracheal tube, etc.). In order to connect the patient accessory 28 to the respiratory gas analyzer 8, a device connector 30 is provided on or connected to the respiratory gas analyzer 8, and a mating patient accessory connector 32 is provided at the distal end of the respiratory gas circuit 34 of the patient accessory 28. The two connectors 30, 32 form a mating male / female pair, wherein one connector has a female socket and the other connector has a male nozzle that fits into the female socket. Specifically, in Figure 2-4 In the illustrative embodiment of the present invention, the device connector 30 has a female receptacle 40 with a lumen 42; at the same time, the illustrative mating patient accessory connector 32 has a male connector 44, which is sized and shaped to fit into the female receptacle 40, such as Figure 3 (before connection) and Figure 4 (after connection) is best seen in the figure. The connection can be made using a variety of fixing mechanisms such as friction fit, threaded engagement, etc. Figure 2-4 In the illustrative example of , the securing mechanism is a threaded engagement in which an externally threaded collar 46 of the patient accessory connector 32 engages a nub or ring or external threads 48 on an outer surface of the device connector 30. Figure 2-4 In the illustrative example of FIG. , the device connector 30 also includes a mounting thread 50, such as Figure 1 As diagrammatically indicated in FIG. 1 , mounting threads 50 enable the device connector 30 to be screwed into a mating threaded mounting opening 52 of the capnography machine 8. However, other arrangements are contemplated; as another example, the capnography machine may include a length of gas tubing extending away from the capnography machine and terminating in the device connector. In another contemplated variation, it is contemplated that the device connector 30 may be threaded into a mating threaded mounting opening 52 of the capnography machine 8. 2 The measuring unit is integrated to form a modular CO 2 Sampling unit box.

[0026] like Figure 2 and Figure 3 As best seen, the device connector 30 includes a flow path 54 in fluid communication with the lumen 42 of the female receptacle 40; meanwhile, the patient fitting connector 32 includes a flow path 56 that passes through the male connector 44. Figure 1 and Figure 4As best seen, when the two connectors 30, 32 are connected together, these flow paths 54, 56 are in fluid communication to allow breathing gas to flow from the tubing 34 of the patient attachment 28 via the flow path 56, through the connector 44, and then into and through the device connector 30 via the flow path 54, and then into the CO 2 Measuring unit 10. Figure 4 Arrow F is shown indicating the direction of gas flow through flow path 56 through male connector 44 and then through flow path 54 through device connector 30. As previously described, in the illustrative sidestream configuration, this flow of breathing gas F is drawn by operation of pump 14, although positive pressure applied by the patient and / or by operation of a mechanical ventilator during the exhalation phase of the breathing cycle may also drive such flow. (Negative pressure from the patient and / or mechanical ventilator during the withdrawal phase can slow or completely interrupt the flow of breathing gas).

[0027] Continue to refer Figure 1-4 , the female receptacle 40 of the device connector 30 includes a lateral leakage path 60. As shown, the lateral leakage path 60 includes a channel through the wall of the female receptacle 40. The channel has a first open end in fluid communication with the lumen 42 of the female receptacle 40 and a second open end in fluid communication with ambient air. When the patient accessory connector 32 is not connected to the device connector 30 ( Figure 3 ), the air flow through the flow path 54 includes a leakage contribution L, which flows into the lumen 42 of the socket 40 of the device connector 30. This leakage flow contribution L contributes to the flow through the flow path 54 under the pull of the pump 14. Figure 4 As can be seen, when the patient accessory connector 32 is connected to the device connector 30 , the patient accessory connector 32 seals against a lateral leakage path 60 of the female receptacle 40 of the device connector 30 .

[0028] Therefore, the method for detecting whether the patient accessory connector 32 is connected to the device connector 30 (so that the patient accessory 28 is operatively connected to the capnograph 8) is obvious. If a constant leakage flow is observed in response to operating the pump 14, the patient accessory connector 32 is not connected to the device connector 30. The leakage flow includes the leakage flow L coming in through the lateral leakage path 60 and the leakage flow coming in from the open end of the lumen 42 of the device connector 30.

[0029] On the other hand, if the patient accessory connector 32 is connected to the device connector 30, there should be time intervals where little or no leak flow is observed. These intervals will occur during inhalation when no gas flows into the flow path 56 through the male connector 44 of the patient accessory connector 32.

[0030] However, only considering Figure 3-4, it is not obvious that the lateral leakage path 60 serves a useful purpose. This is because if the patient accessory connector 32 is not connected to the device connector 30, there will be a leakage flow coming in from the open end of the lumen 42 of the device connector 30. Moreover, this leakage flow from the open end of the lumen 42 is expected to be greater than the leakage flow L coming in via the lateral leakage path 60, simply due to the larger orifice of the open end of the lumen 42.

[0031] Reference now Figure 5 and Figure 6 , illustrating the purpose of the lateral leak path 60. In this example, the patient accessory connector 32 associated with the device connector 30 is replaced by a different patient accessory connector 32s having a shorter connector 44s than the connector 44 of the associated patient accessory connector 32. Figure 5 The device connector 30 and the shorter connector patient accessory connector 32s are shown prior to connection; Figure 6 The connectors 30, 32s are shown connected. Figure 6 As can be seen in FIG. 4 , due to the shorter connector 44s, the patient accessory connector 32s cannot seal the lateral leakage path 60 of the device connector 30. Therefore, even if the two connectors 30, 32s are Figure 6 If connected as shown, the leakage flow L will be Figure 6 42 of the device connector 30 is now blocked by the connected patient accessory connector 32s. Thus, the lateral leak path 60 can be used to detect whether Figure 4 The correct (eg, associated) patient accessory connector 32 is shown connected, or whether an incorrect patient accessory connector 32s having a shorter connector 44s is connected instead.

[0032] By way of non-limiting illustration, in one embodiment, the capnography device 8 is designed to be used when used with appropriate accessories (e.g., Figure 4 The lateral leakage path 60 should therefore have a large enough aperture to allow the pump to be operated at a flow rate of 50 ± 10 ml / min when connected (as shown). Therefore, a flow rate greater than 60 ml / min will be detected as a leak. Therefore, the lateral leakage path 60 should have a large enough aperture to allow the pump to be operated at a flow rate of 50 ± 10 ml / min when connected (as shown). Therefore, a flow rate greater than 60 ml / min will be detected as a leak. Figure 6 In the case of a 10 ml / min leak, a flow rate of 50 ml / min can be drawn using the correct connector ( Figure 4 shown).

[0033] It will be appreciated that flow measurements may alternatively be measured and processed as unit pressure measurements. In the above non-limiting illustrative examples, when used with appropriate accessories (e.g., Figure 4When connected to the capnograph 8 (as shown), the capnograph 8 is designed to work with a unit pressure of -3 ± 5 mmHg. Therefore, a flow rate measured as a pressure less than + 2 mmHg will be detected as a leak.

[0034] Return to reference Figure 1 And also refer to Figure 7 , showing that the appropriate Figure 1 The sequence of operations performed by the capnograph 8 of the present invention is shown in FIG. 70 . In operation 72 , the processing electronics 20 are programmed to determine whether a leak is detected using the flow meter 12 . This can be done in a variety of ways. Generally, a leak cannot be detected simply by detecting a flow rate greater than some threshold value because a high flow rate may be measured during exhalation even if the connector 30 , 32 is connected to the lateral leak path 60 blocked by the connector 44 of the patient accessory 32 . In one approach, the leak detection operation 72 monitors the flow rate over a period of time long enough to cover at least one breath, and the minimum flow rate detected during the period of time is used to assess whether a leak is detected. If the connector 30 , 32 is connected to the lateral leak path 60 blocked by the connector 44 of the patient accessory 32 , a minimum flow rate will occur during inhalation, when the flow rate will be substantially reduced or even zero. On the other hand, if the connector 30 , 32 is disconnected, the minimum flow rate will be high because leakage will occur both through the open end of the lumen 42 of the device connector 30 and through the lateral leak path 60 . Finally, if an incompatible patient accessory connector 32s having a shorter nipple 44s is connected to the device connector 30, the minimum airflow rate will be intermediate because leakage will only occur through the lateral leak path 60 and not through the open end of the lumen 42 of the device connector 30. Figure 7 In the example of FIG. 1 , if the minimum airflow rate is at or above the intermediate level corresponding to an incompatible patient accessory connector 32s being connected, then a note is given on the display 24 stating “PATIENT ACCESSORY NOT CONNECTED OR INCORRECT PATIENT FIT IS CONNECTED” 74. On the other hand, if operation 72 does not detect a leak (i.e., the minimum airflow rate is below the intermediate level corresponding to connection of an incorrect patient accessory connector 32s), then flow proceeds to operation 76 where the processing electronics 20 is programmed to process the leak caused by the CO. 2 The CO measured by the measuring unit 10 2 data, and displays etCO 2 and / or other capnographic data (and / or in monitoring oxygen or CO 2 in the case of a breathing gas monitor for some other breathing gas than the above, other breathing gas data).

[0035] In alternative embodiments of operations 72 and 74, different messages are displayed depending on the situation. For example, if the minimum airflow rate is at or above a high leak rate corresponding to a disconnection, "Patient accessory not connected" can be displayed; however, if the minimum airflow rate is at or above an intermediate level corresponding to a connection of an incorrect patient accessory connector 32s, but below a high leak rate corresponding to a disconnection, "Incorrect patient accessory connected" is displayed.

[0036] In further variations, if the minimum airflow rate is at or above an intermediate level corresponding to connection of an improper patient accessory connector 32s, but below a high leak rate corresponding to a disconnection, processing may transfer to operation 76 to process the CO flow rate with consideration given to the patient accessory connector 32s with a short connector 44s being connected. 2 For example, the patient accessory connector 32 may be provided in conjunction with a patient accessory connected to a breathing circuit or extending from an endotracheal tube, while the patient accessory connector 32s may be provided in conjunction with a patient accessory including a nasal cannula. In this case, CO measurement using a patient accessory having the patient accessory connector 32 is more convenient due to the airtight connection to the breathing circuit or endotracheal tube. 2 The measurement may be considered more reliable, whereas CO measurements performed using a patient accessory (here, a nasal cannula) having a patient accessory connector 32s 2 The measurement may be considered less reliable due to the potential leaky connection provided by the nasal cannula. 2 The data processing should take into account the leakage flow L through the lateral leakage path 60, for example, by expanding the upward etCO 2 To account for the negligible CO in the leakage flow component 2 level.

[0037] Notably, the cross-sectional area of ​​the lateral leak path 60 can be optimized to control the difference between an intermediate level of leakage through the leak path 60 alone (when an incorrect patient accessory connector 32s is connected) compared to a high level of leakage through both the leak path 60 and the open end of the lumen 42 (when no patient accessory connector is connected to the device connector 30). Likewise, the magnitude of the leakage flow L can be tailored by optimizing the cross-sectional area of ​​the lateral leak path 60, for example, to allow accurate accounting of the leakage flow L when using a patient accessory connector 32s that does not block the leakage flow L.

[0038] refer to Figure 8 and Fig. 9As a further extension, it is contemplated to have two or more lateral leakage paths 60, 61 to provide further differentiation between different patient accessory connectors. In this example, the modified device connector 30' has the same components as the device connector 30 labeled using the same reference numerals. However, in addition to the lateral leakage path 60 already described, the modified device connector 30' also has a second lateral leakage path 61. Therefore, in this embodiment, the female socket 40 of the device connector 30' includes at least two lateral leakage paths 60, 61, which are spaced apart along the direction of airflow through the female socket 40. Figure 8 The modified device connector 30 ′ is illustrated prior to connection with a patient accessory connector 32 s having a shorter contact 44 s than the contact 44 of the associated patient accessory connector 32 . Fig. 9 A modified device connector 30' is shown connected to a patient accessory connector 32s having a shorter connector 44s. Fig. 9 As seen in FIG, the shorter connector 44s blocks the lateral leak path 61, but is not long enough to block the lateral leak path 60. Therefore, medial leakage will be observed through the lateral leak path 60, rather than through the lateral leak path 61. On the other hand, if a patient accessory connector 32 having a longer connector 44 is connected to a modified device connector 30' (connection not shown), both of these leak paths 60, 61 will be blocked thereby providing minimal (or no) leakage. Once again, if a patient accessory connector (again not shown) having a connector that is shorter than connector 44s of patient accessory connector 32s is employed, the shortest connector of such patient accessory connector may not be able to block either of the lateral leak paths 60, 61, thereby resulting in a shorter device connector than the one shown in FIG. Fig. 9 In this manner, multiple lateral leak paths 60, 61 designed to be sequentially blocked by progressively longer tabs of different patient accessory connector types provide a mechanism for distinguishing between different patient accessory connector types based on the amount of leakage.

[0039] In the embodiments described thus far, the device connector 30 is a female connector, i.e., has a female receptacle 40, and the patient accessory connector 32 or 32s is a male connector, i.e., has a male connector 44 or 44s that fits into the female receptacle 40. In addition, as disclosed herein, the female receptacle 40 has a lateral leakage path 60 for detecting connection with a patient accessory connector having a male connector 44 or 44s of a specific length. However, it will be appreciated that the "polarity" of the male-female connection can be reversed.

[0040] refer to Fig.10, shows an example of a device connector 30M having a male configuration. The device connector 30M includes a male connector 40M having a lateral leakage path 60M. Fig.10 In the embodiment of the present invention, the lateral leakage path 60M includes a channel through the wall of the male connector 40M, the channel having a first open end in fluid communication with the lumen 42M of the male connector 40M and a second open end in fluid communication with ambient air. The operation is similar to that of the patient accessory connector (not shown) except that in this case the patient accessory connector has a female receptacle that mates with the male connector 40M of the male device connector 30M. Figure 2-4 If the female socket of the patient accessory connector is long enough, it is used to seal the lateral leakage path 60M; however, if the female socket of the incorrect patient accessory connector is too short, it will not be able to seal the lateral leakage path 60M. Figure 7 Detecting leakage through the lateral leakage path 60M in the manner described can detect incorrect (eg, incompatible) patient accessory connector connection. Alternatively, similar to the combination of Figure 7 In the described variant embodiments, such leakage can be used to differentiate between the connection of different types of patient accessory connectors and to adjust the respiratory gas analysis depending on the type of patient accessory connected.

[0041] In a suitable method, the sealing of the lateral leakage paths 60, 60M is achieved by plastic-on-plastic sealing. For example, consider Figure 2-4 In the embodiment of the present invention, the female receptacle 40 of the device connector 30 is plastic, and the male connector 44 of the patient accessory connector 32 is plastic and (according to Figure 4 ) When the patient accessory connector 32 is connected to the device connector 30, the lateral leakage path 60 of the female socket 40 of the device connector 30 is sealed by a plastic-on-plastic seal.

[0042] The present invention has been described with reference to the preferred embodiments. Modifications and changes will occur to others after reading and understanding the foregoing detailed description. The exemplary embodiments are intended to be interpreted as including all such modifications and changes as long as they fall within the scope of the appended claims or their equivalents.

Claims

1. A breathing gas flow coupler, comprising: A device connector having a female receptacle (40), wherein the female receptacle of the device connector includes a lateral leakage path; and a patient accessory connector (32) having a male connector (44) adapted to connect to the female receptacle of the device connector; Wherein, when the patient accessory connector is connected to the device connector, the male connector of the patient accessory connector seals the lateral leakage path of the female socket of the device connector.

2. The breathing gas flow coupler according to claim 1, wherein: The lateral leakage path (60) includes a passage through the wall of the female socket (40), the passage having a first open end in fluid communication with the lumen (42) of the female socket and a second open end in fluid communication with ambient air.

3. The breathing gas flow coupler according to any one of claims 1 to 2, wherein: The lateral leakage path (60) is disposed at a position along the female socket (40) such that when an incompatible patient accessory connector (32s) having a shorter male connector (44s) shorter than the male connector (44) of the patient accessory connector (32) is connected to the device connector, the shorter male connector (44s) of the incompatible patient accessory connector (32s) does not seal the lateral leakage path.

4. A breathing gas flow coupler according to any one of claims 1-2, wherein: The female socket (40) of the device connector (30) is plastic; and The male connector (44) of the patient accessory connector (32) is plastic and seals the lateral leakage path (60) of the female receptacle of the device connector by a plastic-on-plastic seal when the patient accessory connector is connected to the device connector.

5. A breathing gas flow coupler according to any one of claims 1-2, wherein: The female socket (40) of the device connector includes at least two lateral leakage paths, and the at least two lateral leakage paths are spaced apart along the direction of air flow through the female socket.

6. A respiratory gas analyzer comprising: A device connector having a female receptacle (40), wherein the female receptacle includes a lateral leakage path, and wherein the female receptacle is adapted to be connected to an associated patient accessory connector (32), wherein the associated patient accessory connector has a male connector adapted to be connected to the female receptacle of the device connector, the male connector of the associated patient accessory connector sealing the lateral leakage path of the female receptacle of the device connector when the associated patient accessory connector is connected to the device connector; a respiratory gas measurement unit (10); and A pump (14) is operatively connected to draw a gas flow from the device connector through the respiratory gas measurement unit and from the lateral leak path.

7. The respiratory gas analyzer according to claim 6, further comprising: a flow meter (12) operatively connected to measure the flow of gas drawn by the pump (14); as well as A microprocessor or microcontroller (22) is programmed to determine whether the associated patient accessory connector (32) is connected to the device connector (30) based on the air flow measured by the flow meter.

8. The respiratory gas analyzer according to claim 7, wherein: The female socket (40) of the device connector comprises at least two lateral leakage paths, the at least two lateral leakage paths being spaced apart along a direction of airflow through the female socket (40); and The microprocessor or microcontroller (22) is also programmed to determine the type of the associated patient accessory connector to which the device connector is connected based on the air flow measured by the flow meter.

9. A respiratory gas analyzer according to any one of claims 7 and 8, wherein: The microprocessor or microcontroller (22) is also programmed to generate respiratory gas information based on respiratory gas measurements acquired by the respiratory gas measurement unit (10) only when a correct associated patient accessory connector (32) is connected to the device connector (30).

10. The respiratory gas analyzer according to any one of claims 6 to 8, wherein: The respiratory gas measurement unit (10) comprises a carbon dioxide measurement unit, and the respiratory gas analyzer comprises a capnograph (8).

11. A respiratory gas analysis method, comprising: connecting the patient accessory to the respiratory gas analyzer using a patient accessory connector (32) of the patient accessory (28) and a device connector (30) of the respiratory gas analyzer (8), wherein the device connector has a female socket (40) including a lateral leakage path (60), and the patient accessory connector has a male connector adapted to connect to the female socket of the device connector, wherein the male connector of the patient accessory connector seals the lateral leakage path of the female socket of the device connector when the patient accessory connector is connected to the device connector; operating a pump (14) to draw a flow of gas from the patient accessory into the respiratory gas analyzer via the connected patient accessory connector and device connector; detecting whether the patient accessory is connected to the respiratory gas analyzer based on the measurement of the airflow; and Using the respiratory gas analyzer, a respiratory gas analysis is performed on the extracted airflow under the condition that the patient accessory is detected as being connected to the respiratory gas analyzer.

12. The respiratory gas analysis method according to claim 11, wherein: The lateral leak path (60) comprises a passage through the wall of the female socket, the passage having a first open end in fluid communication with the lumen (42) of the female socket and having a second open end in fluid communication with ambient air, and the detecting comprises: Whether the patient accessory (28) is connected to the respiratory gas analyzer (8) is detected by detecting whether ambient air is flowing through the passage into the lumen of the female socket.

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