Lower limb peripheral NIRS parameters during a vascular occlusion test: an experimental study in healthy volunteers.

OBJECTIVES

The aim of the study was to compare NIRS parameters in combination with a vascular occlusion test (VOT) at a proximal (leg) and a distal (foot) site in male and female.

STUDY DESIGN

A prospective experimental study in healthy subjects.

PATIENTS AND METHODS

Twenty volunteers (10 male, 10 female, 28 ± 4 years) were investigated during 4 experimental steps: baseline, ischemia, reperfusion, and baseline. For each volunteer, 3 NIRS optodes were placed on right and left calves and the left arch of the foot. Blood pressure, heart rate and peripheral pulse oxymetry were monitored.

RESULTS

Significant differences were observed at baseline between regional oxygen saturation (rSO₂) values according to the site of measurement (proximal rSO₂ 81 ± 9% vs distal rSO₂ 60 ± 5%, P<0.001) but not according to gender. Both decreases in proximal and distal rSO₂ during ischemia and increases over baseline values during reperfusion depended on group membership (male or female). NIRS parameters during the VOT were significantly higher in male when compared with female at the proximal site: desaturation rate 5.6% (IQR: 5.5) vs 2.5% (IQR: 0.8), P=0.001; resaturation rate 40.7% (IQR: 6.6) vs 21.7% (IQR: 5.4), P=0.003; and ΔrSO₂ 10.0% (IQR: 7.0) vs 5.5% (IQR: 6.0), P=0.041.

CONCLUSIONS

Values of rSO₂ at the lower limb varied according to the anatomical site of measurement. A VOT induced major changes in rSO₂ that differed between male and female. These results should be taken into account in further clinical studies.