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Statistical analysis in anesthesia


Selina Knöpfli

Semester/Bachelor Thesis, WS 04/05

This study deals with the problem of measuring pain in anesthetized volunteers during surgery. Since pain cannot be measured directly, the reaction of several clinical end-points to extended sural nerve stimulations are analyzed using different statistical methods. Principally, the influence of the anesthetic drugs on the measured parameters is examined using the following methods:

• Linear regression on the pulse wave (PW) curve during phases of no stimulation.

• Product-moment correlation and rank correlation between the different measured parameters and between drug concentrations and the parameters.

• Fisher’s discriminant analysis of the variability of heart rate (HR) and bispectral index (BIS).

• Analysis of variance on the variations of the PW values during stimulations.

From Fisher’s discriminant analysis follows, that HR and BIS values show significantly different distributions before and after a stimulus. Regression analysis leads to third order models that approximate PW for most subjects. Analysis of variance suggests a dependency of the PW variations on levels of alfentanil concentration.
Possible further steps include finding models for the PW values of the remaining subjects, or even finding one common model for all subjects, also taking into account a stimulus vector. Additional investigations of the clustering seen in the analysis of variability could lead toward a definition of a pain indicator.

Supervisors: V. Sartori, E. Zanderigo, Prof. M. Morari


Type of Publication:

(13)Semester/Bachelor Thesis

M. Morari

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% Autogenerated BibTeX entry
@PhdThesis { Xxx:2005:IFA_2768
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