Tampere University of Technology

TUTCRIS Research Portal

Method and an apparatus for pulse plethysmograph based detection of nociception during anaesthesia or sedation

Research output: PatentScientific


Original languageEnglish
Patent numberUS2005143665
IPCA61B 5/ 11 A I
Priority date14/10/02
Publication statusPublished - 30 Jun 2005
Externally publishedYes
Publication typeH1 Granted patent


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.