title: Long-term effects of Combat Ready Clamp application to control junctional hemorrhage in swine.
abstract: BACKGROUND
  Groin application of Combat Ready Clamp (CRoC) in pigs elicits an acute inflammation in underlying ischemic tissues. This study examined functional recovery of pigs' hind leg(s) following 2 hours of CRoC application.
  
  
  METHODS
  Left femoral arteries were isolated and injured in anesthetized pigs. Following 25% hemorrhage, CRoC was applied on the inguen for 2 hours (n = 6), and wounds were covered with combat gauze (CG). Bleeding was treated in the control animals (n = 5) with CG only. Next, CRoC and CG were removed, arteries were repaired and reflowed, and animals were recovered. The legs' mobility was scored daily, and their neuromuscular functions were measured on Days 7 and 14. Computed tomographic angiography and blood analysis were performed on Days 0, 2, 7, and 14. Pigs were then euthanized, and tissues were collected for histology. Umbilicus application of CRoC was also tested in four pilot experiments.
  
  
  RESULTS
  Inguinal application of CRoC with 524 ± 12 mm Hg pressure occluded iliac arteries and collateral circulation. Following surgical repair, blood flow to the arteries was restored, and five of six CRoC-applied legs recovered full mobility within 9 days. Control-treated legs recovered full function in 3 days (p = 0.001). At 2 weeks, muscle strength of CRoC-applied legs was diminished (p < 0.05 vs. baselines or controls). Injury biomarkers in the CRoC group increased severalfold compared with the controls on Day 2 but returned to baseline afterward. Histologic changes were mostly mild and indicative of ischemia in the CRoC group. Umbilical application of CRoC required higher pressure (625 ± 8 mm Hg) and caused gross ischemic necrosis of lumbar muscles with significant disabilities.
  
  
  CONCLUSIONS
  Two-hour inguinal application of CRoC caused mild and reversible ischemic injuries, which delayed full recovery of the limb function by a few days. In contrast, 2-hour umbilicus application of CRoC resulted in extensive muscle necrosis with functional disabilities. While CRoC seems safe and effective for inguinal application, other tourniquets should be evaluated for treating bilateral junctional bleeding.
authors.affiliation: From the US Army Institute of Surgical Research, JBSA Fort Sam Houston, San Antonio, Texas.
authors.forename: Bijan S
authors.initials: BS
authors.lastname: Kheirabadi
authors.forename: Irasema B
authors.initials: IB
authors.lastname: Terrazas
authors.forename: Nahir
authors.initials: N
authors.lastname: Miranda
authors.forename: J Scot
authors.initials: JS
authors.lastname: Estep
authors.forename: Benjamin T
authors.initials: BT
authors.lastname: Corona
authors.forename: John F
authors.initials: JF
authors.lastname: Kragh
authors.forename: Michael A
authors.initials: MA
authors.lastname: Dubick
mesh_terms: D000818:Animals; D005260:Female; D005263:Femoral Artery / Q000293:injuries*; D006119:Groin; D006470:Hemorrhage / Q000628:therapy*; D006489:Hemostatic Techniques / Q000295:instrumentation*; D007511:Ischemia / Q000209:etiology / Q000503:physiopathology; D035002:Lower Extremity / Q000098:blood supply / Q000293:injuries* / Q000503:physiopathology; D013552:Swine; D014111:Tourniquets / Q000009:adverse effects