Does Circumferential Negative Pressure Therapy Impair Distal O2 Saturation?
Condition: Negative Pressure Wound Therapy; Wound
MeSH terms: Wounds and Injuries
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): Negative Pressure System
Intervention type(s): Device
Intervention description(s): Negative Pressure System is a non-invasive system that applies sub-atmospheric(Negative) pressure, through a foam and an air-tight film dressing which is connected by suction tubes to a controller unit by which the primary negative pressure can be adjusted.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: 2 groups: intervention and control (both are in each arm of the same participant).
Intervention will be applied at one arm (chosen randomly) with using the contralateral arm as a control.
Masking: Single (Participant)
Primary purpose: Other
Keywords: negative pressure therapy; negative pressure; Wound therapy; NPWT; Vacuum therapy; VAC