Does Circumferential Negative Pressure Therapy Impair Distal O2 Saturation? A Randomized Controlled Study

Abstract:

Background: Circumferential negative pressure wound therapy (CNPWT) is commonly used to manage wounds and enhance the healing process. A theoretical concern was recently raised that CNPWT may have a negative effect on perfusion distally. Objectives: We aim to evaluate the effect of circumferential negative pressure therapy (CNPT) on distal O2 saturation in healthy volunteers. Design: Randomized controlled non-inferiority study. Methods: Fourteen healthy adult volunteers with O2 saturation ≥95% (by index finger pulse oximetry) will be invited to participate in the study. After obtaining a written informed consent, CNPWT foam/dressing will be applied in a sandwich-like manner on the middle third of each arm and a negative intermittent pressure of 125 mmHg will be applied to one arm chosen randomly, using the contralateral arm as control. The pressure will be applied 5 minutes on and 2 minutes off for 9 hours. Individual's participation will be terminated if O2 saturation drops below 92% at any study time. The outcome measure is index finger O2 saturation and will be checked every 30 minutes using a pulse oximetry. The area under the curve (AUC) of O2 saturation in the 2 arms will be compared using ANCOVA. Sample size was calculated to have 90% power, assuming a type one error of 5%, non-inferiority margin of 24 (mean AUC difference), SD of 20, and drop out of 2 participants. Importance: The study is expected to provide conclusive evidence on the effect of intermittent CNPT on distal O2 saturation. The results would have direct implications for CNPWT.