Near-infrared spectroscopy measured cerebral tissue and thenar muscle oxygen saturation poorly correlate with central venous oxygen saturation during heart surgery.

Berg, J.P. van den (2013) Near-infrared spectroscopy measured cerebral tissue and thenar muscle oxygen saturation poorly correlate with central venous oxygen saturation during heart surgery. thesis, Medicine.

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Abstract

Study type: Post-hoc analysis of data obtained from a prospective randomized observational trial. Introduction: ScvO2 (central venous oxygen saturation) represents the balance between systemic oxygen demand (VO2) and oxygen delivery (DO2). It is effective to guide therapy on the value of ScvO2 in both critically ill patients and patients undergoing high risk surgery. In clinical practice a central venous catheter (CVC) is used to measure ScvO2. The use of CVC is considered standard practice in anesthesiology for high risk surgery. However, CVC insertion is an invasive procedure with potentially serious complications. Therefore, a non-invasive alternative is of interest. A non-invasive method for tissue oxygenation (StO2) measurement has become available using near infrared light spectroscopy (NIRS). Aim of the study is to determine if there is a good correlation between invasively measured ScvO2 and the non-invasively, NIRS measured oxygen saturation of thenar muscle (StO2) and frontal cortex (ScO2). This in order to obtain an impression whether ScvO2 is interchangeable with a non-invasive alternative or not. Methods: For the primary prospective trial sixty patients scheduled for coronary artery bypass graft surgery (CABG) were randomized into two groups: on pump and off pump CABG. Non-invasively measured cerebral and peripheral muscle tissue oxygenation were measured continuously and compared with invasively measured ScvO2 (CVC). Two NIRS devices for cerebral oxygen saturation measurement were used simultaneously. Both absolute values and trends were compared and analyzed using Bland-Altman analysis for paired simultaneous measurements and polar plots for changes in sequential paired simultaneous measurements. Results: Correlation between ScvO2 and StO2 (thenar muscle), ScO¬2 (Cerebral tissue oxygenation using ForeSight®) and ScO2 (Cerebral tissue oxygenation using INVOS®) was rs = .45 (p<0,001) , rs = .37 (p<0,001) en rs = .23 (p<0,0001), respectively. Bland-Altman (BA) analyses showed wide 95% limits of agreement for all comparisons between ScvO2 tissue oxygenation values. Not all correlations according to fourquadrantplots for the differences of ScvO2 and StO2, ScO2 (FS) and ScO2 (INVOS®) were significant rs = -.20 (p=0,065), rs = .17 (p<0,01) and rs = .18 (p<0,001). In all cased less than 75% of the data points fell within the ±30o polar limits. Correlation between tissue oxygenation measured by Foresight (FS) and INVOS® was rs = .54 (p<0,001). BA analysis showed a bias of -2.67% with wide 95% limits of agreement while fourquadrantplots showed a correlation of rs = .23 (p<0,001) and 70.3% of the data fell within the polar limits. Conclusions: Both cerebral and thenar muscle saturations poorly correlate with ScvO2.

Item Type:	Thesis (Thesis)
Supervisor name:	Beest, P.A. van and Absalom, Prof. A.R.
Faculty:	Medical Sciences
Date Deposited:	25 Jun 2020 10:55
Last Modified:	25 Jun 2020 10:55
URI:	https://umcg.studenttheses.ub.rug.nl/id/eprint/1557

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