Reproducibility of transcutaneous oxygen pressure measurements in persons with spinal cord injury

Abstract

Objectives: To assess the reproducibility and the effects of the subjects' characteristics on the reproducibility of transcutaneous oxygen pressure (TcPO2) measurements in the sacral area in persons with spinal cord injury during loading in the supine position.

Design: Test-retest study.

Setting: Physical medicine and rehabilitation center.

Participants: Thirty spinal cord-injured American Spinal Injury Association grade A subjects.

Main outcome measures: Two TcPO2 monitoring sessions in the sacral area during loading in the supine position were performed at 24-hour intervals, including the measurement of absolute resting sacral and chest TcPO2 values and the calculation of regional perfusion index (RPI) and delta from rest oxygen pressure, taking into account systemic TcPO2 changes.

Results: The intraclass coefficient of the sacral TcPO2 absolute resting value, RPI, and delta from rest oxygen pressure was .787 and .798, .704 and .635, .760 and .465, respectively, at 20 and 40 minutes. The only characteristic with an influence on RPI reproducibility was the subject's smoking status, whereas age, weight, time since injury, lesion level, and presence of pressure ulcer showed no influence.

Conclusions: TcPO2 measurement is a reproducible method for assessing cutaneous microcirculation during loading over 20-minute monitoring sessions, with RPI exhibiting better reproducibility than delta from rest oxygen pressure at 40 minutes.