O2 - Controller

• US 20080314385A1
• Filed: 01/30/2007
• Published: 12/25/2008
• Est. Priority Date: 01/30/2006
• Status: Active Grant

• Current Assignee: Hamilton Medical AG (Hamilton Company)
• Original Assignee: Hamilton Medical AG (Hamilton Company)
• Inventors: Laubscher, Thomas, Wysocki, Marc, Brunner, Josef
• Granted Patent: US 10,561,810 B2
• Time in Patent Office: Days
• US Class Current: 128/204.23
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/202 partial carbon oxide pressure, e.g. partial dioxide pressure (P-CO2)
• CPC Class Codes: A61M 2230/205 partial oxygen pressure (P-O2)
• CPC Class Codes: A61M 2230/30 Blood pressure A61M2230/04 takes precedence
• CPC Class Codes: A61M 2230/432 partial CO2 pressure (P-CO2)

Abstract

The invention relates to a device for the regulation of PEEP and FiO₂ of a ventilator for achieving an arterial oxygen partial pressure in the blood of a mechanically ventilated patient. At reading which is representative of the success of the oxygen supply, i.e. the oxygen saturation of the blood is measured with the device, and assigned to one of three regions, which are defined by two characteristic lines. A first control loop is designed to optimise PEEP and FiO₂ on assigning a reading to a region which demands a change of the settings, or to retaining the settings with an assignment to the normal region between the characteristic lines. This first control loop carries out such an optimisation at predefined temporal intervals on account of the representative reading (SaO₂^REP) and a predefined necessary supply intensity. The ventilator is subsequently activated accordingly. Therebetween, if necessary only FiO₂ is increased or reduced with a second control loop, if between optimisations by way of the first control loop, the current representative value (SaO₂^REP) falls below a limit value (characteristic line) which is dependent on the supply intensity, which demands an immediate increase of the oxygen supply.

Claims

1. A device for the regulation of PEEP- and FiO₂-settings of a ventilator for achieving an adapted, arterial oxygen level in the blood of a patient mechanically ventilated with the ventilator, comprising:

an input means for delivering at least one reading representative of the success of the oxygen supply derived from a continuous measurement or from a measurement in temporal intervals, and

a programmed computer in order to determine values for PEEP and FiO₂, wherein the programmed computer;

is designed in order to determine a necessary supply intensity,

is designed with a first electronic control loop, in order to weigh up PEEP and FiO₂ against one another and optimize them on account of the representative reading and the necessary supply intensity, and is programmed in a manner such that the first control loop is repeated in temporal intervals and the ventilator in each case is activated accordingly, and

is designed with a second electronic control loop, in order between the optimizations by way of the first control loop, if necessary, to increase FiO₂ in the short-term, on account of a current representative reading alone.

2. The device according to claim 1, wherein the supply intensity is a function of the PEEP.

3. The device according to claim 1, wherein the supply intensity is a function of FiO₂.

4. The device according to claim 1, wherein the oxygen sensor is a pulsoximeter.

5. The device according to claim 1, wherein the first control loop contains two algorithms, specifically

a first algorithm, in order to compute a necessary supply intensity on account of the current representative reading and the current supply intensity, and

a second algorithm, in order to evaluate the individual values for PEEP and FiO₂ on account of the necessary supply intensity.

6. The device according to claim 5, wherein an input possibility for a patient parameter characterising the lung condition of the patient, and by way of the fact that the patient parameter is taken into account in the second algorithm, so that a change of this patient parameter leads to a different optimization of PEEP and FiO₂.

7. The device according to claim 1, with which the first control loop in each case assigns the representative reading to one of three regions which are defined by a characteristic line pair, and only carries out a change of the parameters FiO₂ and/or PEEP when the reading lies outside a middle normal region, wherein the characteristic line pair has a first characteristic line which assigns in each case different minimal representative values to different, quantified supply intensities, and a second characteristic line which assigns in each case different maximal representative values to different quantified supply intensities, said both characteristic lines being distanced to one another and between them defining the normal region for the representative value, and the second control loop assigns the representative reading in each case to one of two regions which are defined by a single characteristic line, and only carries out a change of the parameter FiO₂ when the reading lies below the characteristic line, wherein the characteristic line in each case assigns different minimal representative values to the different, quantified supply intensities, and wherein the characteristic line used in the second control loop lies below the lower characteristic line of the characteristic line pair used in the first control loop, and the normal region which is used with the first control loop falls completely within the normal region present above the characteristic line with the second control loop.

8. The device according to claim 7, wherein different characteristic line pairs for the first control loop and different characteristic single lines for the second control loop are stored in a memory and are selectable.

9. The device according to claim 8, wherein a strategic goal is selectable, and the computer, depending on the selected strategic goal, selects different characteristic line pairs and single lines corresponding to the strategic goal.

10. The device according to claim 1, wherein a controller is present, which on account of the current PEEP and at least one value indicating the haemodynamics of the patient, the at least one value including the blood pressure or a reading which is a measure of the peripheral circulation, decides whether a PEEP-increase demanded by the first control loop is carried out, or FiO₂ is increased instead of the suggested PEEP-increase, or the decision is left to the user of the device.

11. The device according to claim 5, wherein an input possibility for a haemodynamic input value which characterises the haemodynamic stability of the patient, and by way of the fact that the haemodynamics input value is taken into account in the second algorithm on optimizing FiO₂ and PEEP.

12. The device according to claim 5, wherein different functions, which may be represented diagrammatically, are stored in a memory and in each case assign a value for PEEP to a value for FiO₂, and by way of the fact that the second algorithm determines the current values for PEEP and FiO₂ on account of one of these functions.

13. The device according to claim 12, wherein the second algorithm is programmed such that the function on which the algorithm is based is selected depending on an input representing the haemodynamic status of the patient, and on the current patient parameter.

14. The device according to claim 11, wherein a function which is applied with unstable haemodynamics, said function assigning FiO₂ and PEEP to one another independently of whether the supply intensity is increased or reduced.

15. The device according to claim 13, wherein a function which is applied with stable haemodynamics, said function forming a loop and assigning FiO₂ and PEEP to one another, depending on whether the supply intensity is increased or reduced.

16. The device according to claim 1, wherein the computer is programmed such that a recruitment maneuver is carried out before an increase of the PEEP.

17. The device according to claim 12, wherein the different functions are programmed in a manner configurable by a human operator.

18. A device for the regulation of the settings of a ventilator, with sensors for monitoring the success of the ventilation and the oxygen supply, with a programmable computer for activating the ventilator with the purpose of controlling the ventilation and the oxygen supply on account of the sensor signals, comprising:

a first ventilation control loop programmed in order to set the target frequency (RR^sp) and the inspiration pressure (P_insp) in accordance with the patient, and thus achieve a target value for the intensity of the ventilation, and a target value for the arterial CO₂-partial pressure of the patient which corresponds to the present intensity of the ventilation,

a second ventilation control loop programmed, in order, should the total respiratory frequency exceed the computed target frequency by a certain value, to reduce the target value for the arterial CO₂-partial pressure and to increase the target value for the ventilation intensity, in a temporally limited manner,

a first supply control loop programmed, in order to set the oxygen concentration of the ventilation gas (FiO₂) and the end-expiratory pressure (PEEP) and thus to achieve a target value for the oxygen supply of the patient, and

a second supply control loop programmed, in order to increase merely the oxygen concentration in the ventilation gas (FiO₂) until a renewed setting of FiO₂ and PEEP by way of the first supply control loop, as soon as a representative reading for the success of the oxygen supply falls below a certain limit value.

19. The device according to claim 18, wherein the ventilator includes a device for the regulation of the settings of the ventilator, a sensor for checking the success of the oxygen supply, and a computer with input possibilities for the haemodynamic stability of the patient, for the input of a patient parameter, as well as a strategic goal, said computer being programmed in order to automatically compute PEEP and FiO₂ on account of sensor values and the input values, and to regulate the settings of the ventilator accordingly.

20. A method for the regulation of PEEP- and FiO₂-settings of a ventilator for achieving an arterial oxygen partial pressure in the blood of a patient mechanically ventilated with the ventilator, comprising:

measuring at least one reading which is representative of the success of the oxygen supply continuously or at intervals,

optimizing the values of PEEP and FiO₂ with a first control loop in temporal intervals on account of the reading representative of the success of the oxygen supply and a predefined, necessary supply intensity necessary, and the ventilator is activated accordingly, and

increasing therebetween, if necessary, only FiO₂ with a second control loop on account of the current representative reading.

21. The method according to claim 20, further comprising continuously measuring the at least one reading, the at least one reading representative of the oxygen saturation of the blood.

22. The method according to claim 20, further comprising computing a necessary supply intensity with a first algorithm of the first control loop on account of the current representative reading and the current supply intensity, and evaluating the individual values for PEEP and FiO₂ with a second algorithm of the first control loop on account of the necessary supply intensity.

23. The method according to claim 22, further comprising taking into account a patient parameter, which characterizes the lung condition, in the first algorithm.

24. The method according to claim 22, wherein the first algorithm assigns the representative reading and the current supply intensity in each case to one of three regions, said regions being defined by two characteristic lines distanced to one another, which in each case determine for a given supply intensity a minimal and maximal representative value, and between them define a normal region for the representative value.

25. The method according to claim 24, further comprising forming the first algorithm on the basis of different characteristic line courses according to the patient parameter and strategic goal.

26. The method according to claim 22, further comprising taking into account in the second algorithm a haemodynamics input value which characterizes the haemodynamic stability of the patient.

27. The method according to claim 22, wherein the second algorithm determines the current values for PEEP and FiO₂ on account of a diagrammatically representable function, said function in each case assigning a value for PEEP to a value for FiO₂.

28. The method according to claim 27, wherein the second algorithm uses different functions depending on the current haemodynamics input value, on a reading indicating the haemodynamics of the patient, and on the current patient parameter.

29. The method according to claim 28, wherein, with unstable haemodynamics, the applied function assigns FiO₂ and PEEP to one another independently of whether the supply intensity is increased or reduced.

30. The method according to claim 28, wherein, with stable haemodynamics, the applied function forms a loop and therefore assigns FiO₂ and PEEP to one another depending on whether the supply intensity is increased or reduced.

31. The method according to claim 20, further comprising carrying out a recruitment maneuver before a PEEP-increase.

32. The method according to claim 27, further comprising modifying at least one diagrammatically representable function and the newly configured function forming the basis of the second algorithm.

33. A method for the regulation of the settings of a ventilator, comprising:

setting a target frequency (RR^sp) and a inspiration pressure (P_insp) with a first ventilation control loop, in order to fulfill target values for an arterial CO₂-partial-pressure in a patient blood and for a ventilation intensity, in accordance with a patient,

reducing a target value for the arterial CO₂-partial-pressure by way of a second ventilation loop, in a temporally limited manner, and increasing a target value for the ventilation intensity, in the case that the total respiratory frequency exceeds the computed target frequency by a certain value,

setting an oxygen concentration of the respiratory gas (FiO₂) and the end-expiratory pressure (PEEP) with a first O₂-supply control loop, in order to fulfill target values for the supply intensity and an oxygen concentration in the patient blood, in accordance with the patient, and

increasing the oxygen concentration in the respiratory gas (FiO₂) by way of a second O₂-supply control loop until a renewed setting of FiO₂ and PEEP by way of the first O₂ supply control loop, as soon as a representative reading for the oxygen concentration in the patient blood falls below a certain limit value.

34. A device for regulating settings of a ventilator for achieving an adapted mechanical ventilation of a patient, comprising:

at least one sensor for the continuous measurement or for the measurement in temporal intervals at least of one reading representative of the success of the O₂-supply, and/or at least one sensor for the continuous measurement or measurement in temporal intervals of at least one reading representative of the success of the ventilation,

a programmed computer,

provided with at least one first electronic control loop functioning in a long-term manner, specifically a control loop in order to optimize PEEP and FiO₂, and/or a control loop in order to optimize P_insp and RR_IMV on account of the representative reading and a predefined necessary ventilation intensity and said computer being programmed in a manner such that the ventilator in each case is activated according to the current optimization, and

equipped with at least one second electronic control loop functioning in a short-term manner, specifically a control loop, in order between the optimizations by way of the first control loop, if necessary to increase the FiO₂ on account of the current representative value, and/or a control loop, in order between the optimizations by way of the first control loop, if necessary, to increase the ventilation on account of the current representative value.

35. The device according to claim 34, further comprising an oxygen sensor for checking the oxygen supply of the patient, in particular of the oxygen saturation in the blood of the patient, and a CO₂-sensor for checking the ventilation, in particular the arterial CO₂-partial-pressure of the patient and the control loops, are present.