Published in:
Open Access
01-04-2012 | Original
Peripheral vasoconstriction influences thenar oxygen saturation as measured by near-infrared spectroscopy
Authors:
Alexandre Lima, Michel Egide van Genderen, Eva Klijn, Jan Bakker, Jasper van Bommel
Published in:
Intensive Care Medicine
|
Issue 4/2012
Login to get access
Abstract
Purpose
Near-infrared spectroscopy has been used as a noninvasive monitoring tool for tissue oxygen saturation (StO2) in acutely ill patients. This study aimed to investigate whether local vasoconstriction induced by body surface cooling significantly influences thenar StO2 as measured by InSpectra model 650.
Methods
Eight healthy individuals (age 26 ± 6 years) participated in the study. Using a cooling blanket, we aimed to cool the entire body surface to induce vasoconstriction in the skin without any changes in central temperature. Thenar StO2 was noninvasively measured during a 3-min vascular occlusion test using InSpectra model 650 with a 15-mm probe. Measurements were analyzed for resting StO2 values, rate of StO2 desaturation (RdecStO2, %/min), and rate of StO2 recovery (RincStO2, %/s) before, during, and after skin cooling. Measurements also included heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), stroke volume (SV), capillary refill time (CRT), forearm-to-fingertip skin-temperature gradient (Tskin-diff), perfusion index (PI), and tissue hemoglobin index (THI).
Results
In all subjects MAP, CO, SV, and core temperature did not change during the procedure. Skin cooling resulted in a significant decrease in StO2 from 82% (80–87) to 72% (70–77) (P < 0.05) and in RincStO2 from 3.0%/s (2.8–3.3) to 1.7%/s (1.1–2.0) (P < 0.05). Similar changes in CRT, Tskin-diff, and PI were also observed: from 2.5 s (2.0–3.0) to 8.5 s (7.2–11.0) (P < 0.05), from 1.0°C (−1.6–1.8) to 3.1°C (1.8–4.3) (P < 0.05), and from 10.0% (9.1–11.7) to 2.5% (2.0–3.8), respectively. The THI values did not change significantly.
Conclusion
Peripheral vasoconstriction due to body surface cooling could significantly influence noninvasive measurements of thenar StO2 using InSpectra model 650 with 15-mm probe spacing.