Effectiveness of negative pressure wound therapy in the prevention of surgical wound complications in the cesarean section at-risk population: a parallel group randomised multicentre trial-the CYGNUS protocol.

INTRODUCTION: Caesarean delivery is steadily becoming one of the more common surgical procedures in Australia with over 100 000 caesarean sections performed each year. Over the last 10 years in Australia, the caesarean section rate has increased from 28% in 2003 to 33% in 2013. On the international stage, the Australian caesarean delivery rates are higher than the average for the Organisation for Economic Co-operation and Development, Australia ranked as 8 out of 33 and is second to the USA. Postoperative surgical site infections (SSIs) and wound complications are the most common and costly event following a caesarean section. Globally, complication rates following a caesarean delivery vary from 4.9% to 9.8%. Complications such as infection and wound breakdown affect the postpartum mother's health and well-being, and contribute to healthcare costs for clinical management that often spans the acute, community and primary healthcare settings. Published level one studies using advanced wound dressings in the identified 'at-risk' population prior to surgery for prophylactic intervention are yet to be forthcoming.

METHODS AND ANALYSIS: A parallel group randomised control trial of 448 patients will be conducted across two metropolitan hospitals in Perth, Western Australia, which provide obstetric and midwifery services. We will recruit pregnant women in the last trimester, prior to their admission into the healthcare facility for delivery of their child. We will use a computer-generated block sequence to randomise the 448 participants to either the interventional (negative pressure wound therapy (NPWT) dressing, n=224) or comparator arm (non-NPWT dressing, n=224). The primary outcome measure is the occurrence of surgical wound dehiscence (SSWD) or SSI. The Centres for Disease Control reporting definition of either superficial or deep infection at 30 days will be used as the outcome measure definition. SWD will be classified as per the World Union of Wound Healing Societies grading system (grade I-IV). We will assess recruitment rate, and adherence to intervention and follow-up. We will assess the potential effectiveness of NPWT in the prevention of postpartum surgical wound complications at three time points during the study; postoperative days 5, 14 and 30, after which the participant will be closed out of the trial. We will use statistical methods to determine efficacy, and risk stratification will be conducted to determine the SWD risk profile of the participant. Follow-up at day 30 will assess superficial and deep infection, and wound dehiscence (grade I-IV) and the core outcome data set for wound complications. This study will collect health-related quality of life (European Quality of Life 5-Dimensions 5-Level Scale), mortality and late complications such as further surgery with a cost analysis conducted. The primary analysis will be by intention-to-treat. This clinical trial protocol follows the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) and the Consolidated Standards of Reporting Trials guidelines.

ETHICS AND DISSEMINATION: Ethics approval was obtained through St John of God Health Care (HREC1409), Western Australia Department of Health King Edward Memorial Hospital (HREC3111). Study findings will be published in peer-reviewed journals and presented at international conferences. We used the SPIRIT checklist when writing our study protocol.

TRIAL REGISTRATION NUMBER: Australian and New Zealand Clinical Trials Registry (ACTRN12618002006224p).