A novel tamponade agent for management of post partum hemorrhage: adaptation of the Xstat mini-sponge applicator for obstetric use

BACKGROUND Although uterine tamponade is an effective treatment for postpartum hemorrhage (PPH), current methods have key limitations in their use, particularly in low resource settings. The XStat™ Mini Sponge Dressing (MSD) is approved for the management of non-compressible wounds in the battlefield/trauma setting. The MSD applies highly compressed medical sponges capable of stopping high-flow arterial bleeding within seconds. The objective of our study was to adopt the MSD for use in managing PPH. METHODS We performed desktop testing using a uterine model with pressure sensors to compare key design elements of the obstetrical prototype MSD (fundal pressure achieved, reduction in fluid loss, time to deploy, and time to remove) with alternativetechniques (uterine packing, balloon tamponade). To evaluate safety, we delivered the fetus of pregnant ewes by cesarean section and used the prototype to deliver the MSD into one uterine horn, and closed the hysterotomy. We followed the clinical recovery of animals (n = 3) over 24 h, and then removed the reproductive tract for histologic evaluation. To evaluate late effects, we surgically removed the MSDs after 24 h, and followed the clinical recovery of animals (n = 6) for an additional seven days before tissue removal. RESULTS The obstetrical prototype has a long tapered delivery system designed to be deployed during vaginal examination, and administers three times the volume of the approved MSD trauma bandage. The MSD are deployed within a mesh bag to facilitate removal by vaginaltraction. On desktop testing, the MSD resulted in the highest average fundal pressure (113 mmHg), followed by the MSD bag device (85.8 mmHg), gauze packing (15.5 mmHg), and the uterine balloon (8.2 mmHg). The MSD bag test group achieved the largest fluid flow reduction of -74%, followed by gauze packing (-55%), MSD (-35%), and uterine balloon (-19%). Animal testing demonstrated good uterine fill with no evidence of adverse clinical recovery, uterine trauma or infection at 24 h, or up to 7 days following device removal. CONCLUSION We adapted a highly effective trauma dressing and applicator for use in the treatment of severe PPH. Preliminary desktop and animal testing provide a basis for initial clinical trials in women.