Research

500 ml of blood loss does not decrease non-invasive tissue oxygen saturation (StO₂) as measured by near infrared spectroscopy - A hypothesis generating pilot study in healthy adult women

Victor Jeger¹ , Stephan M Jakob² , Stefano Fontana³ , Martin Wolf⁴ , Heinz Zimmermann¹ and Aristomenis K Exadaktylos¹

¹  Department of Emergency Medicine, University and University Hospital of Berne (Inselspital), Berne, Switzerland

²  Department of Intensive Care Medicine, University and University Hospital of Berne (Inselspital), Berne, Switzerland

³  Blood Donation Service SRK, Berne, Switzerland

⁴  Biomedical Optics Research Laboratory, Clinic of Neonatology, University Hospital Zurich, Switzerland

author email corresponding author email

Journal of Trauma Management & Outcomes 2010, 4:5doi:10.1186/1752-2897-4-5

Published:	13 May 2010

Abstract

Background

The goal when resuscitating trauma patients is to achieve adequate tissue perfusion. One parameter of tissue perfusion is tissue oxygen saturation (StO₂), as measured by near infrared spectroscopy. Using a commercially available device, we investigated whether clinically relevant blood loss of 500 ml in healthy volunteers can be detected by changes in StO₂ after a standardized ischemic event.

Methods

We performed occlusion of the brachial artery for 3 minutes in 20 healthy female blood donors before and after blood donation. StO₂ and total oxygenated tissue hemoglobin (O₂Hb) were measured continuously at the thenar eminence. 10 healthy volunteers were assessed in the same way, to examine whether repeated vascular occlusion without blood donation exhibits time dependent effects.

Results

Blood donation caused a substantial decrease in systolic blood pressure, but did not affect resting StO₂ and O₂Hb values. No changes were measured in the blood donor group in the reaction to the vascular occlusion test, but in the control group there was an increase in the O₂Hb rate of recovery during the reperfusion phase.

Conclusion

StO₂ measured at the thenar eminence seems to be insensitive to blood loss of 500 ml in this setting. Probably blood loss greater than this might lead to detectable changes guiding the treating physician. The exact cut off for detectable changes and the time effect on repeated vascular occlusion tests should be explored further. Until now no such data exist.