US-12616809-B2 - Method for carrying out a P/V maneuver which automatically prevents an overdilation of the lungs, and ventilation device designed to carry out the method

US12616809B2US 12616809 B2US12616809 B2US 12616809B2US-12616809-B2

Abstract

A ventilation device for artificially ventilating a patient, having a controller to actuate a flow modifying device for a P/V maneuver while wherein the pressure of respiratory gas is increased during an inspiration phase, wherein respiratory gas passively flows out of the patient during an expiration phase after the pressure increase is terminated, for a plurality of respiratory gas pressures, the respective maneuver respiratory gas volume in the patient from the P/V maneuver is ascertained in connection with the respiratory gas pressure during inspiration and expiration phases; the controller ascertaining a sequence of lung compliance values during the inspiration phase, ascertain a reference compliance value, based on the reference compliance value, determine a termination compliance value in the form of a threshold value as a termination criterion for the inspiration phase, and—terminate the inspiration phase if the termination compliance value is reached or exceeded.

Inventors

Sascha Reidt
Christoph Schranz
Dominik Novotni

Assignees

HAMILTON MEDICAL AG

Dates

Publication Date: 20260505
Application Date: 20201028
Priority Date: 20191031

Claims (19)

1 . A ventilation device for artificial ventilation of a patient, comprising: a respiratory gas source arrangement which provides an inspiratory respiratory gas for artificial ventilation the patient, a flow modification device which is configured to produce and quantitatively modify an inspiratory respiratory gas flow, a respiratory gas line arrangement with a proximal longitudinal end which during operation lies nearer to the patient and with a distal longitudinal end which during operation lies further away from the patient, in order to convey the inspiratory respiratory gas flow from the respiratory gas source arrangement towards the patient, a flow sensor arrangement which is configured to acquire quantitatively both the inspiratory respiratory gas flow and an expiratory respiratory gas flow, a pressure sensor arrangement which is configured to acquire a pressure both of the inspiratory respiratory gas and of the expiratory respiratory gas in the respiratory gas line arrangement, a control device with a data memory, where the control device is connected for signal transmission with the data memory, with the flow sensor arrangement, and with the pressure sensor arrangement and which is configured to control the operational output of the flow modification device for modifying the inspiratory respiratory gas flow, where the control device is configured to actuate the flow modification device for performing a P/V maneuver in which in an inspiration phase, respiratory gas is supplied to a patient under elevated respiratory gas pressure which in an expiration phase after completion of the pressure elevation flows passively out of the patient, where both during the inspiration phase and during the expiration phase, for a plurality of respiratory gas pressures, the respective maneuver respiratory gas volume present in the patient due to the P/V maneuver is determined in correlation with the prevailing respiratory gas pressure, wherein the control device is configured to determine during the inspiration phase, on the basis of signals of the flow sensor arrangement and of the pressure sensor arrangement, a sequence of compliance values each of which represents a pulmonary compliance of the lung of the patient, to determine a reference compliance value in accordance with the sequence of compliance values, to determine as termination criterion for the inspiration phase, starting from the reference compliance value, a termination compliance value quantitatively different from the reference compliance value as threshold value, and to terminate the inspiration phase when the termination compliance value is reached or crossed.
2 . The ventilation device according to claim 1 , wherein the control device is configured to calculate the sequence of compliance values from i) a ratio of a volume change value associated with a respiratory gas pressure and a pressure change value associated with the same respiratory gas pressure, where the volume change value represents a temporal change in the maneuver respiratory gas volume and where the pressure change value represents a temporal change in the respiratory gas pressure, and/or ii) a ratio of a flow value associated with a respiratory gas pressure and the pressure change value associated with the same respiratory gas pressure, where the flow value represents the inspiratory respiratory gas flow.
3 . The ventilation device according to claim 2 , wherein the control device is configured to select, from a sequence of compliance values which first become quantitatively larger and subsequently smaller, the quantitatively largest compliance value as reference compliance value.
4 . The ventilation device according to claim 1 , wherein the control device is configured to select, from a sequence of compliance values which first become quantitatively larger and subsequently smaller, the quantitatively largest compliance value as reference compliance value.
5 . The ventilation device according to claim 1 , wherein the control device is configured to determine, from a sequence of value-pairs of an inspiratory respiratory gas pressure and the maneuver respiratory gas volume associated with the respective inspiratory respiratory gas pressure, an inflection point between sections curved in different directions of curvature of a graph representing the sequence of value-pairs, and to select the compliance value associated with the respiratory gas pressure at the inflection point as reference compliance value.
6 . The ventilation device according to claim 1 , wherein the control device is configured to calculate the termination compliance value through multiplying the reference compliance value by a predetermined factor or through adding the reference compliance value to a predetermined summand.
7 . The ventilation device according to claim 6 , wherein the termination compliance value equals 75% to 95% of the reference compliance values.
8 . The ventilation device according to claim 7 , wherein the termination compliance value equals 85% to 91% of the reference compliance values.
9 . The ventilation device according to claim 1 , wherein the control device is configured to calculate a volume ratio value from the quantitatively greatest difference occurring during the P/V maneuver for a respiratory gas pressure between the expiratory and the inspiratory maneuver respiratory gas volume and a difference between a maneuver respiratory gas volume value in an upper end-region and a maneuver respiratory gas volume value in a lower end-region of the respiratory gas pressure range traversed during the P/V maneuver, where the lower end-region contains a start respiratory gas pressure and extends up to 1.05 times the start respiratory gas pressure, and where the upper end-region contains a termination respiratory gas pressure with which the termination compliance value is associated and begins at 95% of the termination respiratory gas pressure.
10 . The ventilation device according to claim 9 , wherein the control device is configured to generate, when the volume ratio value exceeds a predetermined first threshold value, an output which indicates that a recruitment procedure for recruiting the patient's lung has overwhelming prospects of success.
11 . The ventilation device according to claim 1 , wherein the control device is configured to calculate a hysteresis ratio value from the size of the hysteresis area which the graphs of the expiratory and of the inspiratory maneuver respiratory gas volumes as functions of the respiratory gas pressure between a start respiratory gas pressure at which the P/V maneuver begins and a termination respiratory gas pressure with which the termination compliance value is associated, and the size of a rectangle enclosing the hysteresis area whose one corner is determined by a lower respiratory gas pressure value in a lower end-region of the respiratory gas pressure range traversed during the P/V maneuver and by the respiratory gas volume value associated with the lower respiratory gas pressure value, where the lower end-region contains the start respiratory gas pressure and extends up to 1.05 times the start respiratory gas pressure, and whose diagonally opposite corner is determined by an upper respiratory gas pressure value in an upper end-region and by the respiratory gas volume value associated with the upper respiratory gas pressure value, where the upper end-region contains a termination respiratory gas pressure with which the termination compliance value is associated and begins at 95% of the termination respiratory gas pressure.
12 . The ventilation device according to claim 11 , wherein the control device is configured to generate, when the hysteresis ratio value exceeds a predetermined second threshold value, an output which indicates that a recruitment procedure for recruiting the patient's lung has overwhelming prospects of success.
13 . A method for performing a P/V maneuver on a patient's lung, in particular for establishing data for assessing the recruitability of pulmonary tissue, where the method comprises the following steps: Performing a P/V maneuver and while supplying inspiratory respiratory gas to a patient in an inspiration phase under elevated respiratory gas pressure, During the inspiration phase: Determining an inspiratory maneuver respiratory gas volume supplied during the inspiration phase or an inspiratory maneuver volume flow of inspiratory respiratory gas and determining the respiratory gas pressure, Determining a sequence of compliance values each of which represents a pulmonary compliance of the lung of the patient, Determining a reference compliance value in accordance with the sequence of compliance values, Determining, starting from the reference compliance value, a termination compliance value quantitatively different from the reference compliance value as a termination threshold value, and Terminating the inspiration phase when the termination compliance value is reached or crossed.
14 . The method according to claim 13 , wherein an expiration phase temporally subsequent to the inspiration phase, in which respiratory gas flows passively out of the patient, where during the expiration phase both the expiratory respiratory gas pressure and an expiratory maneuver respiratory gas volume value are determined, where the expiratory maneuver respiratory gas volume value represents an expiratory maneuver respiratory gas volume present in the patient during the expiration phase due to the P/V maneuver.
15 . The method according to claim 14 , wherein determining the expiratory maneuver respiratory gas volume value comprises: Determining a volume of expiratory respiratory gas exhaled during the expiration phase, and/or Determining an expiratory maneuver volume flow of expiratory respiratory gas.
16 . The method according to claim 15 , wherein calculation of a volume ratio value from The quantitatively greatest difference occurring during the P/V maneuver for a respiratory gas pressure between the expiratory and the inspiratory maneuver respiratory gas volume, and A difference value between a maneuver respiratory gas volume value in an upper end-region and a maneuver respiratory gas volume value in a lower end-region of the respiratory gas pressure range traversed during the P/V maneuver, Where the lower end-region contains a start respiratory gas pressure and extends up to 1.05 times the start respiratory gas pressure, and where the upper end-region contains a termination respiratory gas pressure with which the termination compliance value is associated and begins at 95% of the termination respiratory gas pressure.
17 . The method according to claim 14 , wherein calculation of a volume ratio value from The quantitatively greatest difference occurring during the P/V maneuver for a respiratory gas pressure between the expiratory and the inspiratory maneuver respiratory gas volume, and A difference value between a maneuver respiratory gas volume value in an upper end-region and a maneuver respiratory gas volume value in a lower end-region of the respiratory gas pressure range traversed during the P/V maneuver, Where the lower end-region contains a start respiratory gas pressure and extends up to 1.05 times the start respiratory gas pressure, and where the upper end-region contains a termination respiratory gas pressure with which the termination compliance value is associated and begins at 95% of the termination respiratory gas pressure.
18 . The method according to claim 16 , wherein by calculation of a hysteresis ratio value from The size of the hysteresis area which the graph of the expiratory and of the inspiratory maneuver respiratory gas volumes as functions of the respiratory gas pressure between a start respiratory gas pressure at which the P/V maneuver begins and a termination respiratory gas pressure with which the termination compliance value is associated, and The size of a rectangle enclosing the hysteresis area whose one corner is determined by a lower respiratory gas pressure value in a lower end-region of the respiratory gas pressure range traversed during the P/V maneuver and by the respiratory gas volume value associated with the lower respiratory gas pressure value, Where the lower end-region contains the start respiratory gas pressure and extends up to 1.05 times the start respiratory gas pressure and whose diagonally opposite corner is determined by an upper respiratory gas pressure value in an upper end-region and by the respiratory gas volume value associated with the upper respiratory gas pressure value, where the upper end-region contains a termination respiratory gas pressure with which the termination compliance value is associated and begins at 95% of the termination respiratory gas pressure.
19 . The method according to claim 14 , wherein by calculation of a hysteresis ratio value from The size of the hysteresis area which the graph of the expiratory and of the inspiratory maneuver respiratory gas volumes as functions of the respiratory gas pressure between a start respiratory gas pressure at which the P/V maneuver begins and a termination respiratory gas pressure with which the termination compliance value is associated, and The size of a rectangle enclosing the hysteresis area whose one corner is determined by a lower respiratory gas pressure value in a lower end-region of the respiratory gas pressure range traversed during the P/V maneuver and by the respiratory gas volume value associated with the lower respiratory gas pressure value, Where the lower end-region contains the start respiratory gas pressure and extends up to 1.05 times the start respiratory gas pressure and whose diagonally opposite corner is determined by an upper respiratory gas pressure value in an upper end-region and by the respiratory gas volume value associated with the upper respiratory gas pressure value, where the upper end-region contains a termination respiratory gas pressure with which the termination compliance value is associated and begins at 95% of the termination respiratory gas pressure.

Description

This application claims priority in PCT application PCT/EP2020/080328 filed on Oct. 28, 2020, which claims priority in German Patent Application DE 10 2019 129 549.1 filed on Oct. 31, 2019, which are incorporated by reference herein. The present invention concerns a ventilation device for artificial ventilation of a patient, comprising: A respiratory gas source arrangement which provides an inspiratory respiratory gas for artificial ventilation of the patient,A flow modification device which is configured to produce and quantitatively modify an inspiratory respiratory gas flow,A respiratory gas line arrangement with a proximal longitudinal end which during operation lies nearer to the patient and with a distal longitudinal end which during operation lies further away from the patient, in order to convey the inspiratory respiratory gas flow from the respiratory gas source arrangement towards the patient,A flow sensor arrangement which is configured to acquire quantitatively both the inspiratory respiratory gas flow and an expiratory respiratory gas flow,A pressure sensor arrangement which is configured to acquire a pressure both of the inspiratory respiratory gas and of the expiratory respiratory gas in the respiratory gas line arrangement,A control device with a data memory, where the control device is connected for signal transmission with the data memory, with the flow sensor arrangement, and with the pressure sensor arrangement and which is configured to control the operational output of the flow modification device for modifying the inspiratory respiratory gas flow, Where the control device is configured to actuate the flow modification device for performing a P/V maneuver in which in an inspiration phase, respiratory gas is supplied to a patient under elevated respiratory gas pressure which in an expiration phase after completion of the pressure elevation flows passively out of the patient, where both during the inspiration phase and during the expiration phase, for a plurality of respiratory gas pressures, the particular maneuver respiratory gas volume present in the patient due to the P/V maneuver is determined and assigned to the prevailing respiratory gas pressure. The present invention further concerns a method for performing a P/V maneuver on a patient's lung, preferably for the purpose of establishing data for assessing a recruitability and dilatability of pulmonary tissue of a patient's lung. BACKGROUND OF THE INVENTION A ventilation device of the type mentioned at the beginning and a method for performing a P/V maneuver on a patient's lung are known from EP 2 091 429 B1. This publication proposes to determine a positive end-expiratory pressure, hereunder referred to as ‘PEEP’ (for Positive End-Expiratory Pressure) in conformity with the professional world, for a particular patient by means of a P/V maneuver on the patient and/or the patient's lung, respectively. In this P/V maneuver known from EP 2 091 429 B1, beginning with a start respiratory gas pressure under continuous elevation of the respiratory gas pressure, inspiratory respiratory gas is supplied to the patient until a predetermined inspiratory respiratory gas end-pressure is reached. An inspiratory P-V curve is recorded during this process, representing the inspiratory respiratory gas volume supplied to the patient during the inspiration phase of the P/V maneuver, always in correlation with the respective prevailing respiratory gas pressure. Once the predetermined respiratory gas end-pressure is reached, as part of the still ongoing P/V maneuver the previously supplied respiratory gas is allowed to escape from the patient's lung as expiratory respiratory gas, once again under acquisition of the particular respiratory gas volume still present in the patient in correlation with the pressure of the expiratory respiratory gas prevailing during the respective acquisition. For this too, a P-V curve is recorded, this time as an expiratory P-V curve, representing the respiratory gas volume present in the patient during the expiration phase of the P/V maneuver in correlation with the expiratory respiratory gas pressure prevailing during the acquisition. The P/V maneuver ends at a predetermined end-pressure. The inspiratory and the expiratory P-V curve traverse a common respiratory gas pressure range, where the two curves exhibit hysteresis. The expiratory P-V curve exhibits, over a wide mid-level respiratory gas pressure range, higher volumes at the same respiratory gas pressure values. EP 2 091 429 B1 proposes to determine automatically, for the particular patient on whom the P/V maneuver is performed, a suitable PEEP as that pressure at which the expiratory and the inspiratory P-V curve exhibit the quantitatively greatest difference. Since due to the characteristics of the two P-V curves, once a quantitatively greatest volume difference between the two P-V curves was acquired then under further decreasing pressure of the expiratory respirat