Comparative evaluation of transcutaneous oxygen tension and ankle-brachial index as predictors of reoperation following below-knee amputation.

OBJECTIVE: Decision-making regarding level of lower extremity amputation is sometimes challenging. Selecting an appropriate anatomic level for major amputation requires consideration of tradeoffs between postoperative function and risk of wound complications that may require additional operations, including debridement and/or conversion to above-knee amputation (AKA). We evaluated the utility of common, non-invasive diagnostic tests used in clinical practice to predict the need for reoperations among patients undergoing primary, elective, below knee-amputations (BKAs) by vascular surgeons. METHODS: Patients undergoing elective BKA over a 5-year period were identified using Current Procedural Terminology codes. Medical records were reviewed to characterize demographics, pre-amputation testing transcutaneous oxygen tension (TcPO2), and ankle-brachial index (ABI). The need for ipsilateral post-BKA reoperation (including BKA revision and/or conversion to AKA) regardless of indication was the primary outcome. Associations were evaluated using univariable and multivariable logistic regression models. Cutpoints for TcPO2 values associated with amputation reoperation were evaluated using receiver operating characteristic curves. RESULTS: We identified 175 BKAs, of which 46 (26.3%) required ipsilateral reoperation (18.9% BKA revisions and 14.3% conversions to AKA). The mean age was 63.3 ± 14.8 years. Most patients were male (65.1%) and White (72.0%). Mean pre-amputation calf TcPO2 was 40.0 ± 20.5 mmHg, and mean ABI was 0.64 ± 0.45. In univariable models, post-BKA reoperation was associated with calf TcPO2 (odds ratio [OR], 0.97; 95% confidence interval [CI], 0.94-0.99; P = .013) but not ABI (OR, 0.53; 95% CI, 0.19-1.46; P = .217). Univariable associations with reoperation were also identified for age (OR, 0.97; 95% CI, 0.94-0.990; P = .003) and diabetes (OR, 0.43; 95% CI, 0.21-0.87; P = .019). No associations with amputation revision were identified for gender, race, end-stage renal disease, or preoperative antibiotics. Calf TcPO2 remained associated with post-BKA reoperation in a multivariable model (OR, 0.97; 95% CI, 0.94-0.99; P = .022) adjusted for age (OR, 0.98; 95% CI, 0.94-1.01; P = .222) and diabetes (OR, 0.98; 95% CI, 0.94-1.01; P = .559). Receiver operating characteristic analysis suggested a TcPO2 ≥38 mmHg as an appropriate cut-point for assessing risk for BKA revision (area under the curve = 0.682; negative predictive value, 0.91). CONCLUSIONS: Reoperation after BKA is common, and reoperation risk was associated with pre-amputation TcPO2. For patients undergoing elective BKA, higher risk of reoperation should be discussed with patients with an ipsilateral TcPO2 <38 mmHg.

Non-therapeutic laparotomies in military trauma (2009-2014).

BACKGROUND: Combat casualties are frequently injured in austere settings where modern imaging modalities are unavailable. Exploratory laparotomies are often performed in these settings when there is suspicion for intra-abdominal injury. Prior studies of combat casualties reported non-therapeutic laparotomy (NTL) rates as high as 32%. Given improvements in combat casualty care over time, we evaluated NTLs performed during later years of the wars in Iraq and Afghanistan. METHODS: Military personnel with combat-related injuries (6/1/2009-12/31/2014) who underwent exploratory laparotomy based on concern for abdominal injury (i.e. not performed for proximal vascular control or fecal diversion) and were evacuated to Landstuhl Regional Medical Center (Germany) before being transferred to participating U.S. military hospitals were assessed. An NTL was defined as a negative laparotomy without substantial intra-abdominal injuries requiring repair. Characteristics, indications for laparotomy, operative findings, and outcomes were examined. RESULTS: Among 244 patients who underwent laparotomies, 41 (16.8%) had NTLs and 203 (83.2%) had therapeutic laparotomies (i.e. positive findings). Patients with NTLs had more computed tomography scans concerning for injury (48.8% vs 27.1%; p = 0.006), less penetrating injury mechanisms (43.9% vs 71.9%; p < 0.001), and lower Injury Severity Scores (26 vs 33; p = 0.003) compared to patients with therapeutic laparotomies. Patients with NTLs were also less likely to be admitted to the intensive care unit (70.7 vs 89.2% for patients with therapeutic laparotomies; p = 0.007). No patients with NTLs developed abdominal surgical site infections (SSI) compared to 16.7% of patients with therapeutic laparotomies (p = 0.002). There was no significant difference in mortality between the groups (p = 0.198). CONCLUSIONS: Our proportion of NTLs was lower than reported from earlier years during the wars in Iraq and Afghanistan. No infectious complications from NTLs (i.e. abdominal SSIs) were identified. Nevertheless, surgeons should continue to have a low threshold for exploratory laparotomy in military patients in austere settings with concern for intra-abdominal injury.

Outcomes of Exploratory Laparotomy and Abdominal Infections Among Combat Casualties.

BACKGROUND: Abdominal injuries historically account for 13% of battlefield surgical procedures. We examined the occurrence of exploratory laparotomies and subsequent abdominal surgical site infections (SSIs) among combat casualties. METHODS: Military personnel injured during deployment (2009-2014) were included if they required a laparotomy for combat-related trauma and were evacuated to Landstuhl Regional Medical Center, Germany, before being transferred to participating US military hospitals. RESULTS: Of 4304 combat casualties, 341 (7.9%) underwent laparotomy. Including re-explorations, 1053 laparotomies (median, 2; interquartile range, 1-3; range, 1-28) were performed with 58% occurring within the combat zone. Forty-nine (14.4%) patients had abdominal SSIs (four with multiple SSIs): 27 (7.9%) with deep space SSIs, 14 (4.1%) with a deep incisional SSI, and 12 (3.5%) a superficial incisional SSI. Patients with abdominal SSIs had larger volume of blood transfusions (median, 24 versus 14 units), more laparotomies (median, 4 versus 2), and more hollow viscus injuries (74% versus 45%) than patients without abdominal SSIs. Abdominal closure occurred after 10 d for 12% of the patients with SSI versus 2% of patients without SSI. Mesh adjuncts were used to achieve fascial closure in 20.4% and 2.1% of patients with and without SSI, respectively. Survival was 98% and 96% in patients with and without SSIs, respectively. CONCLUSIONS: Less than 10% of combat casualties in the modern era required abdominal exploration and most were severely injured with hollow viscus injuries and required massive transfusions. Despite the extensive contamination from battlefield injuries, the SSI proportion is consistent with civilian rates and survival was high.

Utility of the Mangled Extremity Severity Score in Predicting Amputation in Military Lower Extremity Arterial Injury.

BACKGROUND: Effective amputation prediction may help inform appropriate early limb salvage efforts in military lower extremity (LE) arterial injury. The Mangled Extremity Severity Score (MESS) is the most commonly applied system for early amputation prediction but its utility in military trauma is unknown. METHODS: Retrospective cohort study of Iraq and Afghanistan casualties with LE arterial injury who underwent a vascular limb salvage attempt. Retrospectively assessed MESS was statistically explored as an amputation predictor and MESS component surrogates (mechanism, vascular injury characteristics, tourniquet use, and transfusion volume) were used to characterize limb injuries by presenting characteristics and evaluated for amputation prediction. RESULTS: A total of 439 limbs were included with 99 (23%) amputations, 29 (7%) within 48 hr of injury. Median MESS was 5 (interquartile range 4-6) among salvaged limbs and 7 (5-9) among amputations (P < 0.0001). An MESS cutoff of ≥7 had a better receiver operating characteristic sensitivity/specificity profile (area under the curve 0.696 overall, 0.765 amputation within 48 hr) than MESS ≥8 (0.593, 0.621), but amputation rates were only 43% for MESS ≥7 and 50% for ≥8. MESS ≥7 was significantly associated with age, polytrauma, blast or crush mechanism, fracture, tourniquet use, distal (popliteal/tibial) and multiple arterial injuries, and massive transfusion. Amputation was significantly associated with polytrauma, blast or crush mechanism, fracture, and massive transfusion; however, 83 casualties had all 4 characteristics with an amputation rate of only 46%. CONCLUSIONS: In combat casualties with arterial injury, LE amputation after attempted vascular limb salvage is inadequately predicted by existing scoring systems or the presenting characteristics available in this registry. Limb loss is predominantly late and likely because of factors not projectable at initial presentation.

Endovascular Embolization Techniques in a Novel Swine Model of Fatal Uncontrolled Solid Organ Hemorrhage and Coagulopathy.

BACKGROUND: Endovascular embolization is increasingly used in treating traumatic hemorrhage and other applications. No endovascular-capable translational large animal models exist and coagulopathy's effect on embolization techniques is unknown. We developed a coagulation-adaptable solid organ hemorrhage model in swine for investigation of embolization techniques. METHODS: Anesthetized swine (n = 26, 45 ± 3 kg) had laparotomy and splenic externalization. Half underwent 50% isovolemic hemodilution with 6% hetastarch and cooling to 33-35°C (COAG group). All had controlled 20 mL/kg hemorrhage and endovascular access to the proximal splenic artery with a 4F catheter via a right femoral sheath. Splenic transection and 5 min free bleeding were followed by treatment (n = 5/group) with 5 mL gelfoam slurry, three 6-mm coils, or no treatment (n = 3, control). Animals received 15 mL/kg plasma resuscitation and were monitored for 6 hr. Splenic blood loss was continuously measured and angiograms were performed at specified times. RESULTS: Coagulopathy was successfully established in COAG animals. Pre-treatment blood loss was greater in COAG (11 ± 6 mL/kg) than non-COAG (7 ± 3 mL/kg, P = 0.04) animals. Splenic hemorrhage was universally fatal without treatment. Non-COAG coil survival was 4/5 (326 ± 75 min) and non-COAG Gelfoam 3/5 (311 ± 67 min) versus non-COAG Control 0/3 (82 ± 18 min, P < 0.05 for both). Neither COAG Coil (0/5, 195 ± 117 min) nor COAG Gelfoam (0/5, 125 ± 32 min) treatment improved survival over COAG Control (0/3, 56 ± 19 min). Post-treatment blood loss was 4.6 ± 3.4 mL/kg in non-COAG Coil and 4.6 ± 2.9 mL/kg in non-COAG Gelfoam, both lower than non-COAG Control (18 ± 1.3 mL/kg, P = 0.05). Neither COAG Coil (8.4 ± 5.4 mL/kg) nor COAG Gelfoam (15 ± 11 ml/kg) had significantly less blood loss than COAG Control (20 ± 1.2 mL/kg). Both non-COAG treatment groups had minimal blood loss during observation, while COAG groups had ongoing slow blood loss. In the COAG Gelfoam group, there was an increase in hemorrhage between 30 and 60 min following treatment. CONCLUSIONS: A swine model of coagulation-adaptable fatal splenic hemorrhage suitable for endovascular treatment was developed. Coagulopathy had profound negative effects on coil and gelfoam efficacy in controlling bleeding, with implications for trauma and elective embolization procedures.

Differing Resuscitation With Aortic Occlusion in a Swine Junctional Hemorrhage Polytrauma Model.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) and Abdominal Aortic and Junctional Tourniquet (AAJT) have received much attention in recent as methods for temporary control of junctional hemorrhage. Previous studies typically used the animal's shed blood for resuscitation. With current interest in moving REBOA to prehospital environment, this study aimed to evaluate the hemodynamic and metabolic responses to different resuscitation fluids used with these devices. METHODS: In swine (Sus scrofa), shock was induced using a controlled hemorrhage, femur fracture, and uncontrolled hemorrhage from the femoral artery. Infrarenal REBOA or AAJT was deployed for 60 min during which the arterial injury was repaired. Animals were resuscitated with 15 mL/kg of shed whole blood (SWB) or fresh frozen plasma (FFP) or 30 mL/kg of a balanced crystalloid (PlasmaLyte). RESULTS: Animals in the AAJT and REBOA groups did not show any measurable differences in hemodynamics, metabolic responses, or survival with AAJT or REBOA treatment; hence, the data are pooled and analyzed among the three resuscitative fluids. SWB, FFP, and PlasmaLyte groups did not have a difference in survival time or overall survival. The animals in the SWB and FFP groups maintained higher blood pressure after resuscitation, (P < 0.001) and required significantly less norepinephrine to maintain blood pressure than those in the PlasmaLyte group (P < 0.001). The PlasmaLyte resuscitation prolonged prothrombin time and decreased thromboelastography maximum amplitude. CONCLUSIONS: After 60 min, infrarenal REBOA or AAJT aortic occlusion SWB and FFP resuscitation provided better blood pressure support with half of the resuscitative volume of PlasmaLyte. Swine resuscitated with SWB and FFP also had a more favorable coagulation profile. These data suggest that whole blood or component therapy should be used for resuscitation in conjunction with REBOA or AAJT, and administration of these fluids should be considered if prehospital device use is pursued.

Revascularization of acute inferior vena cava thrombosis and atresia in an adolescent.

Inferior vena cava (IVC) anomalies will remain silent until collateralized venous drainage has been lost. The initial signs can be subtle, including back pain, and are often missed initially until progressive changes toward motor weakness, phlegmasia cerulea dolens, and/or renal impairment have occurred. We have presented a case of acute occlusion of an atretic IVC and infrarenal collateral drainage in an adolescent patient, who had been treated with successful thrombolysis, thrombectomy, and endovascular revascularization for IVC stenting and reconstruction.

Anastomotic Outcomes in Military Exploratory Laparotomies in the Modern Combat Era.

BACKGROUND: Intestinal anastomoses in military settings are performed in severely injured patients who often undergo damage control laparotomy in austere environments. We describe anastomotic outcomes of patients from recent wars. METHODS: Military personnel with combat-related intra-abdominal injuries (June 2009-December 2014) requiring laparotomy with resection and anastomosis were analyzed. Patients were evacuated from Iraq or Afghanistan to Landstuhl Regional Medical Center (Germany) before being transferred to participating U.S. military hospitals. RESULTS: Among 341 patients who underwent 1053 laparotomies, 87 (25.5%) required ≥1 anastomosis. Stapled anastomosis only was performed in 57.5% of patients, while hand-sewn only was performed in 14.9%, and 9.2% had both stapled and hand-sewn techniques (type unknown for 18.4%). Anastomotic failure occurred in 15% of patients. Those with anastomotic failure required more anastomoses (median 2 anastomoses, interquartile range [IQR] 1-3 vs. 1 anastomosis, IQR 1-2, P = .03) and more total laparotomies (median 5 laparotomies, IQR 3-12 vs. 3, IQR 2-4, P = .01). There were no leaks in patients that had only hand-sewn anastomoses, though a significant difference was not seen with those who had stapled anastomoses. While there was an increasing trend regarding surgical site infections (SSIs) with anastomotic failure after excluding superficial SSIs, it was not significant. There was no difference in mortality. DISCUSSION: Military trauma patients have a similar anastomotic failure rate to civilian trauma patients. Patients with anastomotic failure were more likely to have had more anastomoses and more total laparotomies. No definitive conclusions can be drawn about anastomotic outcome differences between hand-sewn and stapled techniques.

Performance of a novel temporary arterial shunt in a military-relevant controlled hemorrhage swine model.

BACKGROUND: In military trauma, temporary vascular shunts restore arterial continuity until delayed vascular reconstruction, often for a period of hours. A novel US Air Force-developed trauma-specific vascular injury shunt (TS-VIS) incorporates an accessible side port for intervention or monitoring, which may improve patency under adverse hemodynamic conditions. Our objective was to evaluate TS-VIS patency in the setting of volume-limited resuscitation from hemorrhagic shock. METHODS: Female swine (70-90 kg) underwent 30% hemorrhage and occlusion of the left external iliac artery for 30 minutes. Animals were allocated to one of three groups (n = 5 per group) by left external iliac artery treatment: Sundt shunt (SUNDT), TS-VIS with arterial pressure monitoring (TS-VIS), or TS-VIS with heparin infusion (10 µ/kg per hour, TS-VISHep). Animals were resuscitated with up to 3 U of whole blood to maintain a mean arterial pressure (MAP) of >60 mm Hg and were monitored for 6 hours. Bilateral femoral arterial flow was continuously monitored with transonic flow probes, and shunt thrombosis was defined as the absence of flow for greater than 5 minutes. RESULTS: No intergroup differences in MAP or flow were observed at baseline or following hemorrhage. Animals were hypotensive at shunt placement (MAP, 35.5 ± 7.3 mm Hg); resuscitation raised MAP to >60 mm Hg by 26.5 ± 15.5 minutes. Shunt placement required 4.5 ± 1.8 minutes with no difference between groups. Four SUNDT thrombosed (three before 60 minutes). One SUNDT thrombosed at 240 minutes, and two TS-VIS and one TS-VISHep thrombosed between 230 and 282 minutes. Median patency was 21 minutes for SUNDT and 360 minutes for both TS-VIS groups (p = 0.04). While patent, all shunts maintained flow between 60% and 90% of contralateral. CONCLUSION: The TS-VIS demonstrated sustained patency superior to the Sundt under adverse hemodynamic conditions. No benefit was observed by the addition of localized heparin therapy over arterial pressure monitoring by the TS-VIS side port.

Risk factors for abdominal surgical site infection after exploratory laparotomy among combat casualties.

BACKGROUND: Surgical site infections (SSIs) are well-recognized complications after exploratory laparotomy for abdominal trauma; however, little is known about SSI development after exploration for battlefield abdominal trauma. We examined SSI risk factors after exploratory laparotomy among combat casualties. METHODS: Military personnel with combat injuries sustained in Iraq and Afghanistan (June 2009 to May 2014) who underwent laparotomy and were evacuated to participating US military hospitals were included. Log-binominal regression was used to identify SSI risk factors. RESULTS: Of 4,304 combat casualties, 341 patients underwent a total of 1,053 laparotomies. Abdominal SSIs were diagnosed in 49 patients (14.4%): 8% with organ space SSI, 4% with deep incisional SSI, and 4% with superficial SSIs (4 patients had multiple SSIs). Patients with SSIs had more colorectal (p < 0.001), small bowel (p = 0.010), duodenum (p = 0.006), pancreas (p = 0.032), and abdominal vascular injuries (p = 0.040), as well as prolonged open abdomen (p = 0.004) and more infections diagnosed before the SSI (or final exploratory laparotomy) versus non-SSI patients (p < 0.001). Sustaining colorectal injuries (risk ratio [RR], 3.20; 95% confidence interval [CI], 1.58-6.45), duodenum injuries (RR, 6.71; 95% CI, 1.73-25.58), and being diagnosed with prior infections (RR, 10.34; 95% CI, 5.05-21.10) were independently associated with any SSI development. For either organ space or deep incisional SSIs, non-intra-abdominal infections, fecal diversion, and duodenum injuries were independently associated, while being injured via an improvised explosive device was associated with reduced likelihood compared with penetrating nonblast (e.g., gunshot wounds) injuries. Non-intra-abdominal infections and hypotension were independently associated with organ space SSIs development alone, while sustaining blast injuries were associated with reduced likelihood. CONCLUSION: Despite severity of injuries and the battlefield environment, the combat casualty laparotomy SSI rate is relatively low at 14%, with similar risk factors and rates reported following severe civilian trauma. LEVEL OF EVIDENCE: Epidemiological, level III.

Abdominal aortic and junctional tourniquet versus zone III resuscitative endovascular balloon occlusion of the aorta in a swine junctional hemorrhage model.

BACKGROUND: Junctional hemorrhage is a leading contributor to battlefield mortality. The Abdominal Aortic and Junctional Tourniquet (AAJT) and infrarenal (zone III) resuscitative endovascular balloon occlusion of the aorta (REBOA) are emerging strategies for controlling junctional hemorrhage, with AAJT currently available in select forward deployed settings and increasing interest in applying REBOA in the military prehospital environment. This study compared the hemostatic, hemodynamic, and metabolic effects of these devices used for junctional hemorrhage control. METHODS: Shock was induced in anesthetized, mechanically ventilated swine with a controlled hemorrhage (20 mL/kg) and closed femur fracture followed by uncontrolled hemorrhage from a partial femoral artery transection (40% total hemorrhage volume). Residual femoral hemorrhage was recorded during 60-minute AAJT (n = 10) or zone III REBOA (n = 10) deployment, and the arterial injury was repaired subsequently. Animals were resuscitated with 15 mL/kg autologous whole blood and observed for 6 hours. RESULTS: One animal in each group died during observation. Both devices achieved hemostasis with mean residual femoral blood loss in the AAJT and REBOA groups of 0.38 ± 0.59 mL/kg and 0.10 ± 0.07 mL/kg (p = 0.16), respectively, during the 60-minute intervention. The AAJT and REBOA augmented proximal blood pressure equally with AAJT allowing higher distal pressure than REBOA during intervention (p < 0.01). Following device deflation, AAJT animals had transiently lower mean arterial blood pressure than REBOA pigs (39 ± 6 vs. 54 ± 11 mm Hg p = 0.01). Both interventions resulted in similar degrees of lactic acidemia which resolved during observation. Similar cardiac and renal effects were observed between AAJT and REBOA. CONCLUSION: The AAJT and REBOA produced similar hemostatic, resuscitative, and metabolic effects in this model of severe shock with junctional hemorrhage. Both interventions may have utility in future military medical operations.

Predictors and timing of amputations in military lower extremity trauma with arterial injury.

INTRODUCTION: Military lower extremity arterial injuries present threats to life and limb. These injuries are common and limb salvage is a trauma system priority. Understanding the timing and predictors of amputation through the phases of casualty evacuation can help inform future limb salvage efforts. This study characterizes limbs undergoing amputation at different operationally relevant time points. METHODS: A retrospective cohort study of casualties with lower extremity arterial injuries undergoing initial vascular limb salvage in Iraq and Afghanistan was undertaken. Amputations were grouped as having been performed early (in theater at Role 2 or 3) or late (after evacuation to Role 4 or 5). Further distinction was made between late and delayed (after discharge from initial hospitalization) amputations. RESULTS: Four hundred fifty-five casualties met inclusion criteria with 103 amputations (23%). Twenty-one (20%) were performed in theater and 82 (80%) were performed following overseas evacuation. Twenty-one (26% of late amputations) were delayed, a median of 359 days from injury (interquartile range, 176-582). Most amputations were performed in the first 4 days following injury. Amputation incidence was highest in popliteal injuries (28%). Overall, amputation was predicted by higher incidence of blast mechanism and fracture and greater limb and casualty injury severity. Early amputations had higher limb injury severity than late amputations. Delayed amputations had greater incidence of motor and sensory loss and contracture than early amputations. CONCLUSION: Casualty and limb injury severity predict predictors and timing of amputation in military lower extremity arterial injury. Amputation following overseas evacuation was more common than in-theater amputation, and functional loss is associated with delayed amputation. Future limb salvage efforts should focus on postevacuation and rehabilitative care. LEVEL OF EVIDENCE: Epidemiologic study, level III.

Venovenous bypass using continuous renal replacement therapy and endovascular inferior vena cava reconstruction to treat bilateral massive iliocaval deep venous thrombosis.

Many inferior vena cava (IVC) anomalies remain asymptomatic because of collateral circulation, but thrombosis of these channels can cause acute deep venous thrombosis with serious sequelae. For those with threatened limbs, anticoagulation is the mainstay of treatment, with endovascular pharmacomechanical thrombolysis replacing open surgical thrombectomy. Described is a severe case of massive iliocaval deep venous thrombosis with bilateral lower extremity Rutherford IIb acute limb ischemia in a patient with congenital IVC atresia. After initial thrombolysis, endovascular IVC reconstruction was accomplished to decompress the lower extremities. The patient ultimately required a right through-knee amputation but remains ambulatory with a prosthetic.

Effect of partial and complete aortic balloon occlusion on survival and shock in a swine model of uncontrolled splenic hemorrhage with delayed resuscitation.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is accepted as a resuscitation adjunct and bridge to definitive hemostasis. The ischemic burden of REBOA may be mitigated by a partial REBOA (P-REBOA) strategy permitting longer occlusion times and military use for combat trauma. We evaluated REBOA and P-REBOA in a swine multiple trauma model with uncontrolled solid organ hemorrhage and delayed resuscitation and surgical hemostasis. METHODS: Anesthetized swine (51.9 ± 2.2 kg) had 20 mL/kg hemorrhage and closed femur fracture. Splenic transection was performed and free bleeding permitted for 10 minutes. Controls (n = 5) were hemorrhaged but had no REBOA, REBOA (n = 8) had 60 minutes complete zone 1 occlusion, P-REBOA (n = 8) had 15 minutes complete occlusion and 45 minutes 50% occlusion. Splenectomy was performed and plasma (15 mL/kg) resuscitation initiated 5 minutes prior to deflation. Resuscitation goal was 80 mm Hg systolic with epinephrine as needed. Animals were monitored for 6 hours. RESULTS: An initial study with 120-minute occlusion had universal fatality in three REBOA (upon deflation) and three P-REBOA animals (after 60 minutes inflation). With 60-minute occlusion, mortality was 100%, 62.5%, and 12.5% in the control, REBOA, and P-REBOA groups, respectively (p < 0.05). Survival time was shorter in controls (120 ± 89 minutes) than REBOA and P-REBOA groups (241 ± 139, 336 ± 69 minutes). Complete REBOA hemorrhaged less during inflation (1.1 ± 0.5 mL/kg) than Control (5.6 ± 1.5) and P-REBOA (4.3 ± 1.4), which were similar. Lactate was higher in the REBOA group compared with the P-REBOA group after balloon deflation, remaining elevated. Potassium increased in REBOA after deflation but returned to similar levels as P-REBOA by 120 minutes. CONCLUSION: In a military relevant model of severe uncontrolled solid organ hemorrhage 1-hour P-REBOA improved survival and mitigated hemodynamic and metabolic shock. Two hours of partial aortic occlusion was not survivable using this protocol due to ongoing hemorrhage during inflation. There is potential role for P-REBOA as part of an integrated minimally invasive field-expedient hemorrhage control and resuscitation strategy.

Despite Trauma Center Closures, Trauma System Regionalization Reduces Mortality and Time to Definitive Care in Severely Injured Patients.

The Northern Ohio Trauma System (NOTS), consisting of multiple hospital systems, was established in 2010 to improve trauma outcomes. This study assessed its impact on mortality and time to definitive care, focusing especially on the severely injured patients. NOTS trauma registry was queried for all trauma activations from 2008 to 2013. The years between 2008-2009 and 2011-2013 were designated as pre- and post-NOTS, respectively. Data from 2010 was excluded as a transitional year. Two trauma centers (TCs) closed in 2010. Predetermined patient subgroups were analyzed. A total of 27,843 patients were examined. Mean age was 46 and 64 per cent were male. Median Injury Severity Score (ISS) was five, and 87 per cent sustained blunt injuries. Of these, 10,641 patients were pre-NOTS and 17,202 were post-NOTS. Comparing the two groups, mortality decreased from 5 to 4 per cent post-NOTS (P < 0.001); median time to definitive care increased by 12 minutes post-NOTS. Multivariate logistic regression showed that NOTS implementation was an independent predictor for survival (P = 0.008), whereas time to definitive care was not. Subgroup analyses demonstrated mortality reductions post-NOTS for all subgroups except patients with penetrating injuries, where mortality remained the same despite an increase in ISS. Patients with ISS ≥15 had a 23 per cent relative reduction in mortality, and their median time to definitive care decreased by 12 minutes. Implementation of a collaborative, regional trauma system was associated with mortality reduction and shortened time to definitive care in the severely injured patients. These findings highlight the importance of collaboration in the future development of regional trauma systems.

Current Pneumonia Surveillance Methodology: Similar Underestimation in Trauma and Surgical Patients in the Intensive Care Unit.

BACKGROUND: In 2013, the Centers for Disease Control and Prevention (CDC) developed new surveillance definitions for ventilator-associated events (VAE), leading to concerns that hospitals may be underreporting the true incidence of ventilator-associated pneumonias (VAPs). We sought to compare rates of clinically diagnosed VAP with CDC defined possible VAPs (PVAPs) in patients with a VAE in the surgical/trauma intensive care unit (STICU). HYPOTHESIS: Significant difference exists between rates of clinical VAP and PVAP in patients with at least one VAE. PATIENTS AND METHODS: All STICU patients with ≥1 VAE, between 1/1/2013 and 10/31/2015 were identified. Age, length of stay (LOS), ICU and ventilator days were collected. RESULTS: There were 134 patients who had ≥1 VAE. Mean age was 54.3 (±17.1) years. Mean LOS, median ICU, and median ventilator days were 26.3 (±14.1), 21.0 (17.0-33.0), and 17.0 (12.8-24.0) days, respectively. There were 68 cases of clinically diagnosed VAP, but only 37% met PVAP criteria. We compared 43 cases of clinical VAP, not meeting PVAP criteria, with the 25 PVAPs. Both groups had similar outcomes. The PVAPs were more likely to have an abnormal temperature (48.0% vs. 14.0%, p = 0.004), abnormal white blood cell count (84.0% vs. 18.6%, p < 0.001), or new antibiotic agent initiated (100% vs. 18.6%, p < 0.001) as VAE triggers. Comparison of the 93 trauma and 41 surgical patients demonstrated trauma patients were younger (51.2 vs. 61.5 y, p = 0.001), but had similar outcomes and rates of clinical VAP (48.4% and 43.9%, p = NS). Only 20.4% of trauma and 14.6% of surgical patients, however, had a PVAP reported. For patients with at least one VAE, the sensitivity and specificity for PVAP detecting VAP was 36.8% and 96.0%, respectively. CONCLUSION: The new CDC definition for PVAP grossly underestimates the clinical diagnosis of VAP and reports less than a third of the patients treated for VAP. Reporting differences were similar for trauma and surgical patients.

Trauma system regionalization improves mortality in patients requiring trauma laparotomy.

INTRODUCTION: This study evaluates the impact of a regional trauma network (RTN) on patient survival, intensive care unit (ICU) length of stay, and hospital length of stay in patients who required trauma laparotomy. METHODS: Patients who required trauma laparotomy from January 2008 to December 2013 were analyzed. Patients admitted during 2008-2009 and 2011-2013 were designated as pre-RTN and RTN groups, respectively. The primary outcome was mortality. RESULTS: A total of 569 patients were analyzed, 231 patients were pre-RTN, and 338 were in the RTN group. Overall, mean age was 35.7 ± 17.1 and median Injury Severity Score was 16 (25th-75th percentile: 9-26). The two groups were similar with regard to age, Injury Severity Score, Abbreviated Injury Scale abdomen, sex, and mechanism. Overall, there was a 35% relative reduction in mortality from the pre-RTN to RTN group (p = 0.035), and 30% more patients were triaged to a Level 1 trauma center in the RTN group (p < 0.001). Logistic regression showed that being in the RTN group was an independent predictor for survival (p = 0.026) with odds ratio of 0.53 (95% confidence interval, 0.30-0.93). Patients with penetrating trauma had a nonsignificant decrease in mortality and a reduction of 1 day of ICU stay (p = 0.001). Patients with blunt trauma had a significant reduction in mortality from 38% in the pre-RTN group to 23% in the RTN group (p = 0.017). CONCLUSION: This study focused on the unique patient population that required trauma laparotomies. It showed that trauma system regionalization led to a significant increase in the number of patients triaged to a Level 1 trauma center and reduction of ICU length of stay. More importantly, it demonstrated the benefit of regionalization by showing a significant reduction of hospital mortality in this critically injured patient population. LEVEL OF EVIDENCE: Therapeutic study, level IV.

Leaving the Skin Incision Open May Not Be as Beneficial as We Have Been Taught.

BACKGROUND: Currently, various methods of skin closures are used in contaminated and dirty abdominal wounds without solid, evidence-based guidance. This study investigates whether closure methods affect surgical site infection (SSI) and other incisional complications. We hypothesize that open management of the skin would have the lowest complications, including SSI. PATIENTS AND METHODS: Patients age ≥18 who underwent trauma laparotomy (TL) or damage control laparotomy (DCL) from 2008-2013 and had class III/IV wounds were included. Demographic, injury, treatment, and outcome variables were compared based on skin closure methods: Primary closure, intermittently stapled with wicks, or open management. Subgroup analyses for TL, DCL, and high-risk patients with stomach, colon, or rectal injuries were performed. Bivariable and multivariable logistic regression (MLR) analyses were performed to identify risk factors for superficial/deep SSI and surgical incision complications. RESULTS: A total of 348 patients were included. The median age was 47 years; 14% were female; 21% had blunt injuries. Overall SSI was highest for open incisions (p < 0.05), but there was no difference in superficial/deep SSI. Primary closures healed a median of 20 days, compared with 68 and 71 days for the intermittently stapled and open groups, respectively (p < 0.001). Primary closure in TL and high-risk patients also had the lowest SSI rates (all p < 0.05), but there were no differences in superficial/deep SSI in any subgroup. In TL patients, diabetes mellitus and colon injuries were independently associated with the development of superficial/deep SSI and surgical incision complications; however, skin closure method was not. CONCLUSION: In class III and IV wounds, primary closure was associated with the lowest SSI, shortest length of stay and healing time. Method of skin closure, however, did not have an independent effect on the development of superficial/deep SSI or surgical incision complications. These suggest that primary skin closure in contaminated and dirty abdominal wounds may be performed more safely than commonly perceived.