Please see Bibliography of References for a list of abstracts, manuscripts and posters.

Other Studies

Adaptability of muscle tissue oxygenation (StO₂) to repeated vascular occlusion

Thomson SJ, Al-Subaie N, Hamilton M, Cowan ML, Musa S, Grounds RM, Rahman TM. Crit Care. 2009;13(Suppl 1):P240.

Introduction: Dynamic testing of muscle tissue oxygenation (StO₂) with near infrared spectroscopy and vascular occlusion (VOT) is a developing area of research in critical care. VOT is often performed multiple times during analysis. We report the impact of repeated VOT on StO₂ parameters.

Methods: Twenty five healthy subjects were studied with the InSpectra 650 monitor & 15mm probe. VOT was set at systolic blood pressure +50mHg for three minutes in triplicate. Each VOT was separated by a five minute rest period. StO₂ data are reported for baseline (BL)%, downslope (DS) & upslope (US)%/min, overshoot %, area over ischaemic curve (AOC Isch) & area under recovery curve (AUC Rec)%/min and recovery time (Rec Time) min. Data was compared by analysis of variance (ANOVA).

Results: See Table (1)

Conclusions: It is important to understand the impact of serial VOT. We have observed sequential change in rates of StO₂ decline during ischaemia (reduced DS gradients, total drop and AOC Isch). Although the overshoot was unchanged, AUC Rec and Rec time demonstrated increases approaching significance. These patterns imply a ‘preconditioned’ adaptation to repeated VOT and an exaggerated hyperaemic response. Further studies are required to determine acceptable rest periods between VOT to ameliorate these changes.

References:

Table 1:

Population StO₂ means (+/- SD) for consecutive VOT and significance