Can pulse oximetry detect raised intracompartmental pressure?
Pulse oximetry has been advocated as a simple noninvasive investigation of vascular compromise. Its usefulness in aiding diagnosis of microvascular compromise in a developing compartment syndrome is questioned. This study investigates the reproducibility of pulse oximetry and the effect on arterial haemoglobin saturation of raising limb intracompartmental pressure by compression bandaging. In 32 out of 50 normal subjects there was a difference in percentage saturation between right and left arms, with a 2% difference in 6 people (12%). Percentage saturation fell significantly at average bandage pressures of 80 mmHg (P < 0.0001) and 60 mmHg (P < 0.001). At clinically relevant pressures, the test had a sensitivity of 40.4%. With a greater than 50% risk of a false-negative result, pulse oximetry is not an appropriate additional investigation in the detection of raised intracompartmental pressure.
Mars
M
M
Department of Physiology, University of Natal, Durban.
Maseko
S
S
Thomson
S
S
Rout
C
C
D000328:Adult; D003161:Compartment Syndromes / Q000175:diagnosis*; D006801:Humans; D008297:Male; D010092:Oximetry; D012016:Reference Values; D015203:Reproducibility of Results