US 8,998,808 B2 · System for identifying patient response to anesthesia infusion

Abstract

A generic model structure captures basic characteristics in BIS-based patients' responses to anesthesia and surgical stimulation, the model being used in combination with the insight of an anesthesiologist. The model structure represents the patient response with a time delay, a time constant for response speed, and a nonlinear function for drug sensitivity. Clinical data confirms the model structure and is used to establish parameters and function forms for individual patients. A feedback and predictive control strategy for anesthesia drug infusion is then introduced on the basis of the patient model. Feedback control alone cannot avoid large fluctuations in BIS values when significant surgical stimulation is imposed, as a result of time delays in a patient's response to drug infusion. Predictive control attenuates fluctuations of BIS levels from surgical stimulation.

Claims10

Dependent claims

An apparatus for assisting a human expert during the administration of a medical anesthesia drug to a patient, the apparatus comprising:

a computing machine having:
an input that receives data corresponding to a plurality of coefficients C1 , C2, C3, as well as time periods τp (initial time delay after infusion of the anesthesia drug) and Tp(time constant representing speed of response), the time periods being initially determined in response to an assessment of the patient by the human expert;
a memory that stores the plurality of coefficients C1, C2, C3, and the time periods τp and Tp;
a processor that solves the formula:
y
=
f
p
⁡
(
x
)
=
C
1
⁢
x
x
1
⁢
Φ
1
⁡
(
x
)
+
C
2
⁢
x
x
2
⁢
Φ
2
⁡
(
x
)
+
C
3
⁢
x
x
3
⁢
Φ
3
⁡
(
x
)
and
a display that displays resulting data to the human expert.

53 more elements

Apparatus for determining a predicted response of a patient to the administration of an anesthesia drug, the apparatus comprising:

a first memory for storing patient dynamics information relating to the infusion of a bolus dosage of anesthesia drug, said first memory having a first output for producing a first output signal corresponding to a first anesthesia level;
a second memory for storing patient dynamics information relating to the infusion of a titrated dosage of anesthesia drug, said second memory having a second output for producing a second output signal corresponding to a second anesthesia level;
a third memory for storing patient dynamics information relating to the patient's predicted response to events of surgical stimulation, said third memory having a third output for producing a third output signal corresponding to an anesthesia effect level;
a signal combiner arrangement for receiving the first and second output signals and the anesthesia effect level, and producing at an output thereof a combined anesthesia effect signal;
a limiter coupled to the output of said signal combiner for establishing maximum and minimum values of the combined anesthesia signal;
a processor for generating a virtual anesthesia monitor that produces an anesthesia value responsive to the combined anesthesia signal;
and
a display that displays resulting data.

5 more elements

Dependencies are inferred from the claim text.

System for identifying patient response to anesthesia infusion

Life of this patent

System for identifying patient response to anesthesia infusion

Life of this patent

Abstract

Claims10