Method and an apparatus for pulse plethysmograph based detection of nociception during anesthesia or sedation
First Claim
1. A method for monitoring a condition of a patient under anesthesia or sedation, the method comprising the steps of:
- acquiring a pulse wave signal representing peripheral cardiovascular flow in the patient;
detecting individual heart beat pulses in said signal;
measuring predetermined pulse wave parameters of said signal within said individual heart beat pulses;
repeating the measuring of said pulse wave parameters in the successive heart beat pulses;
recording said measured pulse wave parameters;
calculating a reference value over a predetermined time period or over a predetermined number of heart beat pulses by deriving values of at least one predefined pulse wave parameter from said recorded pulse wave parameters;
quantifying change(s) between one or several prevailing predefined pulse wave parameter(s) and said reference value; and
displaying and/or recording said change(s) in said at least one pulse wave parameter.
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Abstract
The invention concerns a method and an apparatus for monitoring a condition of a patient under anesthesia or sedation. For this purpose there is a sensor for acquiring a signal that represents peripheral cardiovascular flow in the patient. Successive heart beat pulses are detected and predetermined pulse wave parameters are measured repeatedly in said signal, and predefined pulse wave parameters within said heart beat pulses are measured, too. At first, said predetermined pulse wave parameters in a number of successive heart beat pulses are compared in respect to possible occurrence of a substantial alteration. At second, if the alteration is noticed, a statistical reference value is calculated by deriving values from at least said predefined pulse wave parameters, and the change(s) between at least one predefined pulse wave parameter and said reference value is quantified. The results and/or intermediate results are finally displayed and/or recorded.
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Citations
32 Claims
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1. A method for monitoring a condition of a patient under anesthesia or sedation, the method comprising the steps of:
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acquiring a pulse wave signal representing peripheral cardiovascular flow in the patient; detecting individual heart beat pulses in said signal; measuring predetermined pulse wave parameters of said signal within said individual heart beat pulses; repeating the measuring of said pulse wave parameters in the successive heart beat pulses; recording said measured pulse wave parameters; calculating a reference value over a predetermined time period or over a predetermined number of heart beat pulses by deriving values of at least one predefined pulse wave parameter from said recorded pulse wave parameters; quantifying change(s) between one or several prevailing predefined pulse wave parameter(s) and said reference value; and displaying and/or recording said change(s) in said at least one pulse wave parameter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for monitoring a condition of a patient under anesthesia or sedation, the method comprising the steps of:
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acquiring a pulse wave signal representing peripheral cardiovascular flow in the patient; detecting successive heart beat pulses in said signal; measuring predetermined pulse wave parameters repeatedly in said signal within said successive heart beat pulses; comparing said predetermined pulse wave parameters in a number of successive heart beat pulses, and if a substantial alteration is occurred; calculating a statistical reference value by deriving values from at least said predefined pulse wave parameters; quantifying change(s) between at least one predefined pulse wave parameter and said reference value; and displaying and/or recording said change(s) or lack of change(s) respectively in said at least one predefined pulse wave parameter. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. An apparatus for monitoring a condition of a patient under anaesthesia or sedation, the apparatus comprising:
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a photoplethysmographic or a pulse oximeter sensor for receiving a substantially continuous electrical signal representing a cardiovascular flow of the patient; time measuring means and a voltage/current dependent circuit connected with said sensor means; first memory means storing criteria of predetermined pulse wave parameter(s); first calculation means and/or selection means connected to said first memory means, said voltage/current dependent circuit for detecting predefined pulse wave parameter(s) of said predetermined pulse wave parameter(s) in said signal; quantifying means providing quantified change(s) of at least one predefined pulse wave parameter in respect to values of said predefined pulse wave parameter prior to the present moment; and a display and/or connections into other possible devices. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32)
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Specification