Device and process for controlling the depth of sedation of a mechanically respirated patient

• US 8,206,341 B2
• Filed: 11/05/2008
• Issued: 06/26/2012
• Est. Priority Date: 01/04/2008
• Status: Expired due to Fees

• Current Assignee: Dragerwerk AG & Company KGaA (FPS Vermögensverwaltung GmbH)
• Original Assignee: Drager Medical GmbH (FPS Vermögensverwaltung GmbH)
• Inventors: Schmidt, Hartmut
• Primary Examiner(s): Sirmons, Kevin C
• Assistant Examiner(s): Scott, Brandy C
• Application Number:
  US12/265,147
• Publication Number:
  US 20090177181A1
• Time in Patent Office: 1,329 Days
• Field of Search: 604/65, 604/66, 604/67, 604/503, 128/204.18, 600/554
• US Class Current: 604/67
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/01 specially adapted for anaesthetising A61M16/104, A61M16/18 take precedence
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 2016/0033 electrical
• CPC Class Codes: A61M 2230/42 Rate
• CPC Class Codes: A61M 5/142 Pressure infusion, e.g. using pumps
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00

Abstract

A device is provided for controlling the depth of sedation of a respirated patient. The device includes a respirator (2) and a sensor array (1) for detecting the tidal volume and/or the respiration rate of the patient being respirated. A computing unit (5) is provided for calculating the measured values determined with the sensor array (1). A drug regulating unit (3), a drug dispensing unit (4), and a central control device (6) are provided. The central control device (6) has stored desired values for the drug concentration to be dispensed as a function of a preselected depth of sedation corresponding to the corresponding variability over time of the tidal volume and/or respiration rate. The drug regulating unit (3) sets the drug dispensing unit (4) as a function of the tidal volume detected and/or the respiration rate for a preselected depth of sedation of the patient.

Claims

1. A device for controlling the depth of sedation of a mechanically respirated patient, the device comprising:

a respirator;

a sensor array detecting a tidal volume and/or a respiration rate of the patient being respirated with said respirator;

a computing unit calculating measured values detected with the sensor array;

a drug regulating unit;

a drug dispensing unit for dispensing a drug to the patient being respirated; and

a central control device with stored desired values for a drug concentration to be dispensed as a function of a preselected depth of sedation corresponding to a corresponding variability over time of the tidal volume and/or the respiration rate, wherein the drug regulating unit sets the drug dispensing unit as a function of the detected tidal volume and/or the respiration rate for a preselected depth of sedation of the patient, wherein the measured values determined in the computing unit are calculated into parameters for the variability over time of the respiration rate and/or the tidal volume.

2. A device in accordance with claim 1, wherein classification or assessment rules for depths of sedation as a function of the measured variability over time of the respiration rate and/or tidal volume are stored in the central control device.

3. A device in accordance with claim 2, wherein the classification or assessment rules are based on scoring methods.

4. A device in accordance with claim 3, wherein the classification or assessment rules based on scoring methods comprise one of Ramsay Sedation Scale (RSS), Sedation Agitation Scale (SAS), Motor Activity Assessment Scale (MAAS), Vancouver Interaction and Calmness Scale (VICS), Richmond Agitation Sedation Score (RASS), and Cook-Palma Scale.

5. A device in accordance with claim 1, wherein therapy data corresponding to individual therapy protocols are additionally stored in the central control device with defined, prioritized depths of sedation for preset points in time.

6. A device in accordance with claim 1, wherein said sensor array is arranged in the respiration system of the respirator.

7. A device in accordance with claim 1, wherein said computing unit and said drug regulating unit comprise a single assembly unit.

8. A device in accordance with claim 1, wherein said drug dispensing unit is an infusion pump, said infusion pump dispensing said drug to the patient intravenously.

11. A device in accordance with claim 1, wherein said drug regulating increases said drug concentration with an increase in said variability over time of said tidal volume.

9. A process of controlling the depth of sedation of a mechanically respirated patient, the process comprising the steps of:

providing a respirator and respirating a patient with said respirator;

providing a sensor array for detecting the tidal volume and/or a respiration rate of the patient being respirated with said respirator;

providing a computing unit;

calculating measured values detected with said sensor array using said computing unit;

providing a drug regulating unit;

providing a drug dispensing unit;

providing a central control device with stored desired values for a drug concentration to be dispensed as a function of a preselected depth of sedation corresponding to a corresponding variability over time of the tidal volume and/or the respiration rate;

dispensing a drug with the drug dispensing unit to the patient being respirated for inducing sedation using a preset drug dispensing rate having a desired depth of sedation corresponding to the actual depth of sedation;

switching on the drug regulating unit, so that a time-dependent tidal volume flow and/or the respiration rate of the patient is measured;

calculating parameters that represent the variability over time of the tidal volume and/or the respiration rate from the measured values and determining corresponding depths of sedation by means of classification or assessment rules using the central control device; and

setting drug dispensing for a preset desired depth of sedation based on stored rules for the relationship between the depth of sedation and the drug concentration to be dispensed wherein the drug regulating unit sets the drug dispensing unit as a function of the parameters that represent the variability of the detected tidal volume and/or the respiration rate for the preselected depth of sedation of the patient.

10. A process in accordance with claim 9, wherein classification or assessment rules for depths of sedation as a function of the measured variability over time of the respiration rate and/or tidal volume are stored in the central control device, the classification or assessment rules are based on scoring methods comprise one of Ramsay Sedation Scale (RSS), Sedation Agitation Scale (SAS), Motor Activity Assessment Scale (MAAS), Vancouver Interaction and Calmness Scale (VICS), Richmond Agitation Sedation Score (RASS), and Cook-Palma Scale.

12. A process of controlling a depth of sedation of a patient, the process comprising the steps of:

predetermining a desired depth of sedation for the patient;

determining an initial drug dosage to place the patient at the desired depth of sedation;

administering the initial drug dosage to the patient;

measuring respiration of the patient over time after said administration of the initial drug dose;

calculating a respiration variability parameter representing how the respiration varies over time from said measuring step;

equating the respiration variability parameter with an actual depth of sedation;

comparing said desired depth of sedation with said actual depth of sedation;

selectively administering future drug dosages to the patient to minimize a difference between the desired depth of sedation and the actual depth of sedation.

13. A process in accordance with claim 12, wherein:

said measuring includes measuring one of a tidal volume and a respiration rate;

said respiration variability parameter is a variability of said one of the respiration rate and the tidal volume.

14. A process in accordance with claim 12, further comprising:

mechanically respirating the patient.

15. A process in accordance with claim 12, wherein:

said determining of the desired variability is performed by administering a sufficient amount of the drug to bring the patient to the desired depth of sedation according to a predetermined scoring method, measuring the variability of the tidal volume or respiration rate at the desired depth of sedation, and using the measured variability at the desired depth of sedation according to the predetermined scoring method as the desired variability.

16. A process in accordance with claim 12, further comprising:

changing the desired depth of sedation over time;

determining the desired variability of tidal volume or respiration rate corresponding to the changes in desired depth of sedation;

selectively administering the future drug dosages to the patient to minimize a difference between the desired variability at a present time and the actual variability.

17. A process in accordance with claim 12, wherein:

said selectively administering of the drug increases the drug dosage with an increase in the actual variability.