Damage control surgery in weightlessness: A comparative study of simulated torso hemorrhage control comparing terrestrial and weightless conditions Andrew W. Kirkpatrick, MD, MHSC, Jessica Lynn McKee, MSc, Homer Tien, MD, Anthony J. LaPorta, MD, Kit Lavell, Tim Leslie, MSc, David R. King, MD, Paul B. McBeth, MD, Susan Brien, MD, Derek J. Roberts, MD, PhD, Reginald Franciose, MD, Jonathan Wong, Vivian McAlistair, MD, Danielle Bouchard, and Chad G. Ball, MD, MSC, Alberta, Canada BACKGROUND: Torso bleeding remains the most preventable cause of post-traumatic death worldwide. Remote damage control resuscitation (RDCR) en- deavours to rescue the most catastrophically injured, but has not focused on prehospital surgical torso hemorrhage control (HC). We exam- ined the logistics and metrics of intraperitoneal packing in weightlessness in Parabolic flight (0g) compared to terrestrial gravity (1g) as an extreme example of surgical RDCR. METHODS: A surgical simulator was customized with high-fidelity intraperitoneal anatomy, a “blood” pump and flowmeter. A standardized HC task was to explore the simulator, identify “bleeding” from a previously unknown liver injury perfused at 80 mm Hg, and pack to gain hemo- stasis. Ten surgeons performed RDCR laparotomies onboard a research aircraft, first in 1g followed by 0g. The standardized laparotomy was sectioned into 20-second segments to conduct and facilitate parabolic flight comparisons, with “blood” pumped only during these time segments. A maximum of 12 segments permitted for each laparotomy. RESULTS: All 10 surgeons successfully performed HC in both 1g and 0g. There was no difference in blood loss between 1g and 0g (p = 0.161) or during observation following HC (p = 0.944). Compared to 1g, identification of bleeding in 0g incurred less “blood” loss (p = 0.032). Over- all surgeons rated their personal performance and relative difficulty of surgery in 0g as “harder” (median Likert, 2/5). However, conducting all phases of HC were rated equivalent between 1g and 0g (median Likert, 3/5), except for instrument control (rated slightly harder, 2.75/5). CONCLUSION: Performing laparotomies with packing of a simulated torso hemorrhage in a high-fidelity surgical simulator was feasible onboard a research aircraft in both normal and weightless conditions. Despite being subjectively “harder,” most phases of operative intervention were rated equivalently, with no statistical difference in “blood” loss in weightlessness. Direct operative control of torso hemorrhage is theoretically possible in extreme environments if logistics are provided. (J Trauma Acute Care Surg. 2017;82: 392–399. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.) KEY WORDS: Exsanguination; operational medicine; tactical medicine; telemedicine; damage control surgery; surgical simulation. W hether building a space habitat or engaging in military operations, in a hostile location, far from any established hospital, exsanguination is the most likely potentially treatable cause of death. 1,2 Eastridge reported that during Operations Iraqi Freedom and Enduring Freedom, 87% of all battlefield injury fatalities occurred before arrival at a medical treatment facility. 3 The single most common (67%) cause of potentially survivable deaths were related to noncompressible torso hemorrhage (NCTH). 3 Similarly traumatic injury sustained by a deployed astronaut has been deemed the most probable incident that will have the largest impact on astronaut health and subsequently the mission. 4 The ability to control hemorrhage, specifically torso hemorrhage after traumatic injury in space remains a critical limitation in astronaut health care. As in battlefield care, space medicine is conducted in a setting where the crew must continue its mission autonomously and where there are enormous difficul- ties with resupply, evacuation, and even communication. 5–7 For many such reasons, the crew of an Exploratory Class Space Mission (one leaving low Earth's orbit) will likely face many of the same challenges dealing with an exsanguinating team member as a small Special Forces unit. To date, there has never been more options to ameliorate torso exsanguination, including the earliest use of blood products including fresh warm whole blood and other component thera- pies, junctional compressive devices, tranexamic acid, balloon Submitted: August 30, 2016, Revised: September 30, 2016, Accepted: October 4, 2016, Published online: October 25, 2016. From the Canadian Forces Health Services (A.W.K., J.W., V.M.A.); Departments of Surgery (A.W.K., P.B.M.B., D.J.R., C.G.B.), Critical Care Medicine (A.W.K., P.B.M.B), the Regional Trauma Services (A.W.K., P.B.M.B, C.G.B.), Foothills Medical Centre; University of Calgary (A.W.K., P.B.M.B, D.J.R., D.B., C.G.B.), Calgary, Alberta; Innovative Trauma Care (J.L.M.), Edmonton, Alberta; Sunnybrook Health Sciences Centre (C.H.T.), Toronto, Ontario, Canada; Rocky Vista (A.J.L.P.), University School of Medicine, Parker, Colorado; Strategic Operations (K.L.), San Diego, California; Flight Research Laboratory (T.L.), National Research Council of Canada, Ottawa, Ontario, Canada; Harvard Medical School (D.R.K.), Boston, Massachusetts; Royal College of Physicians and Surgeons (S.B.), Ottawa, Ontario, Canada; Denver Health (R.F.), Denver, Colorado; Vail Valley Medical Center (R.F.), Vail, Colorado; and University of Western Ontario (V.M.A.), London, Ontario, Canada. For the Damage Control Surgery in Austere Environments Research Group (DCSAERG). Trial Registration: ID ISRCTN/77929274. Supplemental digital content is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML text of this article on the journal’s Web site (www.jtrauma.com). This study was presented as a quick shot at the 75th annual meeting of the American Association for the Surgery of Trauma, September 14–17, 2016, in Waikaloa, Hawaii. Address for reprints: Andrew W. Kirkpatrick, MD, MHSC, EG23 Foothills Medical Centre, Calgary, Alberta, T2N 2T9 Andrew; email: Andrew.kirkpatrick@albertahealthservices.ca. DOI: 10.1097/TA.0000000000001310 ORIGINAL ARTICLE 392 J Trauma Acute Care Surg Volume 82, Number 2 Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.