The aim of this study is to evaluate the effect of circumferential negative pressure therapy (CNPT) on distal O2 saturation in healthy volunteers.~Design and Methodology:~Design: This is a randomized controlled non-inferiority study.~Recruitment: Volunteers will be recruited through advertisement in King Faisal Specialist Hospital & Research Centre and other hospitals in Riyadh.~Pre-study procedures: After obtaining a well documented medical history each volunteer will undergo a full physical examination as well as an in-depth upper limb examination and comprehensive evaluation (including a pre-study index finger O2 saturation and upper limbs circumference measurements), the following data will be also collected: age, sex, height&weight, body mass index, and vital signs.~Procedures: CNPWT foam and dressing (in accordance to manufacturer's instructions) 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 by pulse oximetry drops below 92% at any study time.~Statistical analysis: The area under the curve (AUC) of O2 saturation will be compared between the 2 arms using ANCOVA.~Randomization schedule: a randomization schedule will be generated by an online program (www.randomization.com). Block randomization will be used.~Sample size: Fourteen adult volunteers will be invited to participate in the study.~The sample size for the study 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.
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.