Novel Textbook Outcomes following emergency laparotomy: Delphi exercise.

BACKGROUND: Textbook outcomes are composite outcome measures that reflect the ideal overall experience for patients. There are many of these in the elective surgery literature but no textbook outcomes have been proposed for patients following emergency laparotomy. The aim was to achieve international consensus amongst experts and patients for the best Textbook Outcomes for non-trauma and trauma emergency laparotomy. METHODS: A modified Delphi exercise was undertaken with three planned rounds to achieve consensus regarding the best Textbook Outcomes based on the category, number and importance (Likert scale of 1-5) of individual outcome measures. There were separate questions for non-trauma and trauma. A patient engagement exercise was undertaken after round 2 to inform the final round. RESULTS: A total of 337 participants from 53 countries participated in all three rounds of the exercise. The final Textbook Outcomes were divided into 'early' and 'longer-term'. For non-trauma patients the proposed early Textbook Outcome was 'Discharged from hospital without serious postoperative complications (Clavien-Dindo ≥ grade III; including intra-abdominal sepsis, organ failure, unplanned re-operation or death). For trauma patients it was 'Discharged from hospital without unexpected transfusion after haemostasis, and no serious postoperative complications (adapted Clavien-Dindo for trauma ≥ grade III; including intra-abdominal sepsis, organ failure, unplanned re-operation on or death)'. The longer-term Textbook Outcome for both non-trauma and trauma was 'Achieved the early Textbook Outcome, and restoration of baseline quality of life at 1 year'. CONCLUSION: Early and longer-term Textbook Outcomes have been agreed by an international consensus of experts for non-trauma and trauma emergency laparotomy. These now require clinical validation with patient data.

Fascial layers encountered in the lateral skull base region: A cadaveric and radiological analysis.

BACKGROUND: In our experience, the anterior carotid sheath forms an important plane of dissection when excising temporal bone region cancers. However, its anatomical composition, relationships, and radiological appearance remains unclear. METHODS: Eight sides of cadaveric heads were dissected. Anatomical findings were correlated with a high-resolution baseline T1 MRI. RESULTS: The anterior carotid sheath was formed by the tensor-vascular-styloid fascia, stylopharyngeal fascia, buccopharyngeal fascia (BPF), and longus capitis fascia (LCF), and appeared as a hypointense line on MRI. Not previously described, the glossopharyngeal nerve pierced the sheath 9.0 mm (SD 2.1 mm) below the skull base and traveled through its LCF and BPF layers to exit near the pharynx. CONCLUSION: Multiple fascial layers formed the anterior carotid sheath at the skull base, and this was radiologically identifiable. Further studies are required to validate findings and investigate the role this fascial plane has in forming an effective barrier to spread of malignancy.

Combat vascular injury: Influence of mechanism of injury on outcome.

BACKGROUND: Haemorrhage is the leading cause of death on the battlefield. Seventy percent of injuries are due to explosive mechanisms. Anecdotally, these patients have had poorer outcomes when compared to those with penetrating mechanisms of injury (MOI). We wished to test the hypothesis that outcomes following vascular reconstruction were worse in blast-injured than non blast-injured patients. METHODS: Retrospective cohort study. British and American combat casualties with arterial injuries sustained in Iraq or Afghanistan (2003-2014) were identified from the UK Joint Theatre Trauma Registry (JTTR). Eligibility included explosive or penetrating MOI, with follow-up to UK hospital discharge, or death. Outcomes were mortality, amputation, graft thrombosis, haemorrhage, and infection. Statistical analysis was performed using Pearson Chi-Square test, t-tests, ANOVA or non-parametric equivalent, and survival analyses. RESULTS: One hundred and fifteen patients were included, 80 injured by explosive and 35 by penetrating mechanisms. Evacuation time, ISS, number of arterial injuries, age and gender were comparable between groups. Seventy percent of arterial injuries resulted from an explosive MOI. The explosive injuries group received more blood products (p = 0.008) and suffered more regions injured (p < 0.0001). Early surgical interventions in both were ligation (n = 36, 31%), vein graft (n = 33, 29%) and shunting (n = 9, 8%). Mortality (n = 12, 10%) was similar between groups. Differences in limb salvage rates following explosive (n = 17, 53%) vs penetrating (n = 13, 76.47%) mechanisms approached statistical significance (p = 0.056). Nine (28%) vein grafted patients developed complications. No evidence of a difference in the incidence of vein graft thrombosis was found when comparing explosive with non-explosive cohorts (p = 0.154). CONCLUSIONS: The recorded numbers of vein grafts following combat arterial trauma in are small in the JTTR. No statistically-significant differences in complications, including vein graft thrombosis, were found between cohorts injured by explosive and non-explosive mechanisms.

Poor microcirculatory flow dynamics are associated with endothelial cell damage and glycocalyx shedding after traumatic hemorrhagic shock.

BACKGROUND: Endothelial cell damage and glycocalyx shedding after trauma can increase the risk of inflammation, coagulopathy, vascular permeability, and death. Bedside sublingual video-microscopy may detect worse flow and perfusion associated with this endotheliopathy. We compared markers of endotheliopathy with physical flow dynamics after traumatic hemorrhagic shock. METHODS: Sublingual incident dark field video-microscopy was performed at three time points after injury (<10 hours, 10-30 hours, and 30-50 hours). Values for microcirculatory flow index (MFI), Point Of carE Microcirculation assessment (POEM) score, proportion of perfused vessels (PPV), microcirculatory heterogeneity index (MHI), perfused vessel density (PVD), and total vessel density (TVD) were obtained. ELISAs were performed to measure concentrations of thrombomodulin and syndecan-1 as biomarkers of endothelial cell damage and glycocalyx shedding respectively. Flow parameters were dichotomized to above and below average, and biomarkers compared between groups; below average MFI, POEM, PPV, PVD, and TVD, and above average MHI were considered poor microcirculatory flow dynamics. RESULTS: A total of 155 sublingual video-microscopy clips corresponding to 39 time points from 17 trauma patients were analyzed. Median age was 35 (IQR 25-52); 16/17 were men. Within 10 hours of injury, syndecan-1 concentrations were significantly higher compared to 17 age- and sex-matched healthy controls (30 [IQR 20-44] ng/mL) for worse TVD (78 [IQR 63-417] ng/mL), PVD (156 [IQR 63-590] ng/mL), PPV (249 [IQR 64-578] ng/mL), MFI (249 [IQR 64-578] ng/mL), MHI (45 [IQR] 38-68) ng/mL), and POEM scores (108 [IQR 44-462] ng/mL) (all p < 0.01). Thrombomodulin was also raised within 10 hours of injury when compared to healthy controls (2.9 [IQR 2.2-3.4] ng/mL) for worse PPV (4.1 [IQR 3.4-6.2] ng/mL) and MFI (4.1 [IQR 3.4-6.2] ng/mL) (both p < 0.05). CONCLUSIONS: Endothelial cell damage and glycocalyx shedding are associated with worse flow, density, and heterogeneity within microvessels after traumatic hemorrhagic shock. The clinical utility of these biomarkers and flow parameters at the bedside are yet to be elucidated. LEVEL OF EVIDENCE: Prognostic study, level III.

An adapted Clavien-Dindo scoring system in trauma as a clinically meaningful nonmortality endpoint.

BACKGROUND: There is no consensus on reporting nonmortality trauma complications in a graded manner. The Clavien-Dindo scale of complications was originally for elective surgery and requires adaptation to provide meaningful data for trauma patients. In particular, the original score does not account for those treated without surgery. We report an adapted Clavien-Dindo in trauma (ACDiT) scale and apply it to patients managed operatively and nonoperatively. METHODS: A combined prospective and retrospective international multicenter observational study was undertaken to apply the ACDiT scale to 484 trauma patients at three university teaching hospitals (Birmingham, England (n = 303); Houston, Texas (n = 113); and Glasgow, Scotland (n = 68)). These included both intensive care unit (ICU) and non-ICU-managed patients. The Clavien-Dindo scoring system was adapted for trauma patients based on consensus amongst an international collaboration of trauma specialists at these sites. Data included whether initial patients were managed operatively or nonoperatively. Complication grades were compared with hospital-free and ICU-free days as other outcome measures of patient morbidity. RESULTS: Two hundred seventeen (44.8%) of 484 patients experienced complications, of whom 61 (28.1%) of 217 died (grade V). The remainder consisted of grades I (n = 20), II (n = 60), III (n = 24), and IV (n = 52). There was a strong association between higher ACDiT grade category and lower number of hospital-free and ICU-free days (p < 0.01). Eighty-eight patients with complications did not require surgery, validating the score's usefulness in patients managed nonoperatively. CONCLUSION: The ACDiT scale can be used to grade the severity of posttrauma complications in patients managed both operatively and nonoperatively. It provides clinically meaningful data for morbidity and mortality meetings and other quality improvement exercises. LEVEL OF EVIDENCE: Prognostic, level IV.

Prehospital point-of-care lactate following trauma: A systematic review.

BACKGROUND: Serum lactate serves as a surrogate marker for global tissue hypoxia following traumatic injury and has potential to guide resuscitation. Portable, handheld point-of-care monitoring devices enable lactate values to be readily available in the prehospital environment. The current review examines the utility of prehospital lactate (pLa) measurement in the management of trauma. METHODS: MEDLINE and EMBASE databases were searched using predefined criteria (pLa measurement, trauma patients) until March 10, 2016. Studies were examined for lactate measurement as an intervention, prognostic indicator, and utilization in the guidance of goal-directed therapy. The Newcastle-Ottawa Scale was used to assess risk of bias, and quality of evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation system. Data were unsuitable for meta-analysis and are presented in narrative form. RESULTS: Of 2,415 articles of interest, seven met the inclusion criteria, all of which were observational studies, including 2,085 trauma patients. Lactate sampling techniques, timings, and thresholds were heterogeneous. No studies used pLa to guide intervention. Elevated pLa may be an independent prognostic marker of critical illness in trauma patients, particularly in blunt trauma. Prehospital lactate measurement may be more sensitive than systolic blood pressure in determining need for resuscitative care. Early lactate measurement may be particularly useful in the detection of occult hypoperfusion, with elevated pLa detectable within 30 minutes of injury. All current studies were assessed as being of "low" or "very low" quality and were at risk of bias. Considerable logistical barriers to pLa measurement exist. CONCLUSIONS: Prehospital point-of-care lactate monitoring for trauma has been variably performed. There is a paucity of evidence relating to its use. The limited data available show feasibility and potential clinical utility, and further investigation is warranted to establish whether lactate might give meaningful guidance during prehospital triage and trauma patient resuscitation. LEVEL OF EVIDENCE: Systematic review, level IV.

Improved survival in UK combat casualties from Iraq and Afghanistan: 2003-2012.

BACKGROUND: The United Kingdom was at war in Iraq and Afghanistan for more than a decade. Despite assertions regarding advances in military trauma care during these wars, thus far, no studies have examined survival in UK troops during this sustained period of combat. The aims of this study were to examine temporal changes of injury patterns defined by body region and survival in a population of UK Military casualties between 2003 and 2012 in Iraq and Afghanistan. METHODS: The UK Military Joint Theatre Trauma Registry was searched for all UK Military casualties (survivors and fatalities) sustained on operations between January 1, 2003, and December 31, 2012. The New Injury Severity Score (NISS) was used to stratify injury severity. RESULTS: There were 2,792 UK Military casualties sustaining 14,252 separate injuries during the study period. There were 608 fatalities (22% of all casualties). Approximately 70% of casualties injured in hostile action resulted from explosive munitions. The extremities were the most commonly injured body region, involved in 43% of all injuries. The NISS associated with a 50% chance of survival rose each year from 32 in 2003 to 60 in 2012. CONCLUSION: An improvement in survival during the 10-year period is demonstrated. A majority of wounds are a result of explosive munitions, and the extremities are the most commonly affected body region. The authors recommend the development of more sophisticated techniques for the measuring of the performance of combat casualty care systems to include measures of morbidity and functional recovery as well as survival. LEVEL OF EVIDENCE: Epidemiologic study, level III.

Prehospital blood transfusion in the en route management of severe combat trauma: a matched cohort study.

BACKGROUND: The value of prehospital blood transfusion (PHBTx) in the management of severe trauma has not been established. This study aimed to evaluate the effect of PHBTx on mortality in combat casualties. METHODS: This is a retrospective cohort study of casualties admitted to the field hospital at Camp Bastion, Afghanistan, by the Medical Emergency Response Team from May 2006 to March 2011. Participants were divided into two consecutive cohorts by the introduction of PHBTx. Paired groups of patients were chosen by combining propensity score methodology with detailed matching of injury profile. Thus recipients of PHBTx were matched with nonrecipients who would have received it had it been available. RESULTS: A total of 1,592 patients were identified. Of the 1,153 patients to whom PHBTx was potentially available, 310 received it (26.9%). The rate of severe injury (Injury Severity Score [ISS] > 15) rose from 28% before PHBTx was available to 43% thereafter (p < 0.001). Mortality in the latter group was higher (14% vs. 10%, p = 0.013) but not in the severely injured patients (32% vs. 28%, p = 0.343). Ninety-seven patients were paired. The mortality of matched patients who received PHBTx, compared with those with similar injury patterns who did not, was less than half (8.2% vs. 19.6%, p < 0.001). However, matched recipients had more prehospital interventions, reached hospital more quickly, and had lower heart rate at admission (all p < 0.05). Matched recipients received more red blood cells within 24 hours (median, 4 U; interquartile range [IQR], 2-10 U) than nonrecipients (median 0 U; IQR, 0-3.5 U) and more fresh frozen plasma (median, 2 U; IQR, 2-9 U vs. median, 0 U; IQR, 0-1 U) (both p < 0.001). CONCLUSION: An aggressive approach to damage control resuscitation including the use of PHBTx was associated with a large improvement in mortality. However, because of confounders resulting from changes in practice, the isolated contribution of PHBTx cannot be determined from this study. LEVEL OF EVIDENCE: Therapeutic study, level IV.

Prospective evaluation of the correlation between torso height and aortic anatomy in respect of a fluoroscopy free aortic balloon occlusion system.

BACKGROUND: To report the lengths of key torso vascular and to develop regression models that will predict these lengths, based on an external measure of torso height (EMTH, sternum to pubis) in the development of a fluoroscopy-free balloon occlusion system for hemorrhage control. METHODS: We conducted a prospective, observational study at a Combat Support Hospital in Southern Afghanistan using adult male patients undergoing computed tomography (CT). EMTH was recorded using a tape measure and intra-arterial distance was derived from CT imaging. Regression models to predict distance from the common femoral artery (CFA) into the middle of aortic zone I (left subclavian artery to celiac trunk) and zone III (infrarenal aorta) were developed from a random 20% of the cohort and validated by the remaining 80%. RESULTS: Overall, 177 male patients were included with a median (interquartile range [IQR]) age of 23 (8) years. The median (IQR) lengths of aortic zone I and III were 222 (24), 31 (9), and 92 (15) mm. The mid-zone distance from the left and right CFA to zone I were 423 (27) and 418 (29) and for zone III 232 (21) and 228 (22). Linear regression models demonstrated an accuracy between 99.3% to 100% at predicting the insertion distance required to place a catheter within the middle of each aortic zone. CONCLUSION: This study demonstrates the use of morphometric analysis in the development of a fluoroscopy-free balloon occlusion system for torso hemorrhage control. Further study in a larger population of mixed gender is required to further validate insertion models.

UK specialist cardiothoracic management of thoracic injuries in military casualties sustained in the wars in Iraq and Afghanistan.

OBJECTIVES: Outcomes of casualties with thoracic wounding at the deployed UK military field hospital (Role 3(R3)) have been previously described. The level of cardiothoracic specialist input required on repatriation to the UK is less clear. This study aimed to assess the outcomes of casualties with thoracic injuries repatriated to the UK (Role 4 (R4)) and evaluate the impact of specialist cardiothoracic care. METHODS: Casualties were identified through the UK Joint Theatre Trauma Registry. Casualties coded for pulmonary contusions and/or thoracotomy between March 2006 and March 2011 were identified and case-notes reviewed. Subgroup analysis was performed for patients with a documented thoracic abbreviated injury score ≥3. RESULTS: One hundred and eighty-two UK patients were admitted to UK R4 coded to have a thoracic injury; overall mortality 4.9%. Ninety-three were classified as a thoracic AIS of ≥3; mortality 6.5%. Sixty-four were coded for pulmonary contusions and/or thoracotomy; mortality 1.6, and 66% had thoracic AIS ≥3. Improvised explosive devices injured 54 and 62% had a penetrating injury. Pulmonary contusions were present in 70%; 43% developed a chest infection. Thoracotomy/sternotomy was performed in 13 casualties in R3; 3 re-explored in R4. Oscillatory ventilation and extracorporeal membrane oxygenation was required in 1 case. Cardiothoracic surgery was involved in managing 39% (n = 24) of cases; 11 (45%) required surgical intervention and 19 (79%) had cardiothoracic outpatient follow-up. CONCLUSION: Morbidity and mortality associated with significant thoracic injury is low at UK R4. Follow-up is required to assess long-term outcomes. Specialist cardiothoracic support and intervention was required in the management of complex thoracic trauma. Early specialist support at R4 may improve morbidity and outcomes associated with life-threatening thoracic injury.

Use and complications of operative control of arterial inflow in combat casualties with traumatic lower-extremity amputations caused by improvised explosive devices.

BACKGROUND: Proximal traumatic lower-extremity amputation has become the signature injury of the war in Afghanistan. Casualties present in extremis and often require immediate operative control of arterial inflow to prevent exsanguination. This study evaluated the use of this strategy and its complications. METHODS: This is a retrospective analysis of case notes of UK service personnel, identified from the UK Joint Theatre Trauma Registry, who sustained traumatic lower-extremity amputation requiring suprainguinal vascular control, following improvised explosive device injury in Afghanistan, between July 2008 and December 2010. RESULTS: Fifty-one casualties were identified with a median Injury Severity Score (ISS) of 30. In 10 casualties, control was obtained via an extraperitoneal approach, and in 41, control was obtained via midline laparotomy and intraperitoneal (IP) approach. The most commonly controlled vessel in extraperitoneal control was the external iliac artery, and in IP control, the common iliac artery. Within the 41 patients who had IP control, 13 also required a therapeutic laparotomy, and 9 patients had bilateral injuries at the level of the proximal femur or higher. One patient, who had undergone IP control, experienced an injury to the common iliac vein, which was repaired. There were no other immediate complications recorded, and 39 casualties survived to discharge. CONCLUSION: This is the first study to characterize the methods of proximal control in high wartime lower-extremity amputees. Although some casualties will have abdominal injuries that necessitate laparotomy, the majority in our study did not; however, in the critically ill casualty, rapid proximal control is required. Novel methods of temporary hemorrhage control may reduce the need for, and burden of, cavity surgery. LEVEL OF EVIDENCE: Epidemiologic study, level III; prognostic study, level IV.

Injury pattern and mortality of noncompressible torso hemorrhage in UK combat casualties.

BACKGROUND: Hemorrhage following traumatic injury is a leading cause of military and civilian mortality. Noncompressible torso hemorrhage (NCTH) has been identified as particularly lethal, especially in the prehospital setting. METHODS: All patients sustaining NCTH between August 2002 and July 2012 were identified from the UK Joint Theatre Trauma Registry. NCTH was defined as injury to a named torso axial vessel, pulmonary injury, solid-organ injury (Grade 4 or greater injury to the liver, kidney, or spleen) or pelvic fracture with ring disruption. Patients with ongoing hemorrhage were identified using either a systolic blood pressure of less than 90 mm Hg or the need for immediate surgical hemorrhage control. Data on injury pattern and location as well as cause of death were analyzed using univariate and multivariate analyses. RESULTS: During 10 years, 296 patients were identified with NCTH, with a mortality of 85.5%. The majority of deaths occurred before hospital admission (n = 222, 75.0%). Of patients admitted to hospital, survivors (n = 43, 14.5%) had a higher median systolic blood pressure (108 [43] vs. 89 [46], p = 0.123) and Glasgow Coma Scale (GCS) (14 [12] vs. 3 [0], p < 0.001) compared with in-hospital deaths (n = 31, 10.5%). Hemorrhage was the more common cause of death (60.1%), followed by central nervous system disruption (30.8%), total body disruption (5.1%), and multiple-organ failure (4.0%). On multivariate analysis, major arterial and pulmonary hilar injury are most lethal with odds ratio (95% confidence interval) of 16.44 (5.50-49.11) and 9.61 (1.06-87.00), respectively. CONCLUSION: This study demonstrates that the majority of patients sustaining NCTH die before hospital admission, with exsanguination and central nervous system disruption contributing to the bulk cause of death. Major arterial and pulmonary hilar injuries are independent predictors of mortality.

Association of cryoprecipitate and tranexamic acid with improved survival following wartime injury: findings from the MATTERs II Study.

OBJECTIVE: To quantify the impact of fibrinogen-containing cryoprecipitate in addition to the antifibrinolytic tranexamic acid on survival in combat injured. DESIGN: Retrospective observational study comparing the mortality of 4 groups: tranexamic acid only, cryoprecipitate only, tranexamic acid and cryoprecipitate, and neither tranexamic acid nor cryoprecipitate. To balance comparisons, propensity scores were developed and added as covariates to logistic regression models predicting mortality. SETTING: A Role 3 Combat Surgical Hospital in southern Afghanistan. PATIENTS: A total of 1332 patients were identified from prospectively collected U.K. and U.S. trauma registries who required 1 U or more of packed red blood cells and composed the following groups: tranexamic acid (n = 148), cryoprecipitate (n = 168), tranexamic acid/cryoprecipitate (n = 258), and no tranexamic acid/cryoprecipitate (n = 758). MAIN OUTCOME MEASURE: In-hospital mortality. RESULTS: Injury severity scores were highest in the cryoprecipitate (mean [SD], 28.3 [15.7]) and tranexamic acid/cryoprecipitate (mean [SD], 26 [14.9]) groups compared with the tranexamic acid (mean [SD], 23.0 [19.2]) and no tranexamic acid/cryoprecipitate (mean [SD], 21.2 [18.5]) (P < .001) groups. Despite greater Injury Severity Scores and packed red blood cell requirements, mortality was lowest in the tranexamic acid/cryoprecipitate (11.6%) and tranexamic acid (18.2%) groups compared with the cryoprecipitate (21.4%) and no tranexamic acid/cryoprecipitate (23.6%) groups. Tranexamic acid and cryoprecipitate were independently associated with a similarly reduced mortality (odds ratio, 0.61; 95% CI, 0.42-0.89; P = .01 and odds ratio, 0.61; 95% CI, 0.40-0.94; P = .02, respectively). The combined tranexamic acid and cryoprecipitate effect vs. neither in a synergy model had an odds ratio of 0.34 (95% CI, 0.20-0.58; P < .001), reflecting nonsignificant interaction (P = .21). CONCLUSIONS: Cryoprecipitate may independently add to the survival benefit of tranexamic acid in the seriously injured requiring transfusion. Additional study is necessary to define the role of fibrinogen in resuscitation from hemorrhagic shock.

Resuscitative thoracotomy following wartime injury.

BACKGROUND: The evidence for resuscitative thoracotomy (RT) in trauma patients following wartime injury is limited; its indications and timings are less defined in battle injury. The aim of this study was to analyze survival as well as the causes and times of death in patients undergoing RT within the context of modern battlefield resuscitation. METHODS: A retrospective cohort study was performed on consecutive admissions to a Field Hospital in Southern Afghanistan. All patients undergoing RT were identified using the UK Joint Theatre Trauma Registry. The primary outcome was 30-day mortality, and secondary outcomes included location of cardiac arrest, time from arrest to thoracotomy, and proportion achieving a return of spontaneous circulation. RESULTS: Between April 2006 to March 2011, 65 patients underwent RT with 14 survivors (21.5%). Ten patients (15.4%) had an arrest in the field with no survivors, 29 (44.6%) had an arrest en route with 3 survivors, and 26 (40.0%) had an arrest in the emergency department with 11 survivors. There was no difference in Injury Severity Scores (ISSs) between survivors and fatalities (27.3 [7.6] vs. 36.0 [22.1], p = 0.636). Survivors had a significantly shorter time to thoracotomy than did fatalities (6.15 [5.8] minutes vs. 17.7 [12.63] minutes, p < 0.001). CONCLUSION: RT following combat injury will yield survivors. Best outcomes are in patients who have an arrest in the emergency department or on admission to the hospital. LEVEL OF EVIDENCE: Epidemiologic/prognostic study, level III.

En-route care capability from point of injury impacts mortality after severe wartime injury.

OBJECTIVE: The objective of this study is to characterize modern point-of-injury (POI) en-route care platforms and to compare mortality among casualties evacuated with conventional military retrieval (CMR) methods to those evacuated with an advanced medical retrieval (AMR) capability. BACKGROUND: Following a decade of war in Afghanistan, the impact of en-route care capabilities from the POI on mortality is unknown. METHODS: Casualties evacuated from POI to one level III facility in Afghanistan (July 2008-March 2012) were identified from UK and US trauma registries. Groups comprised those evacuated by a medically qualified provider-led, AMR and those by a medic-led CMR capability. Outcomes were compared per incremental Injury Severity Score (ISS) bins. RESULTS: Most casualties (n = 1054; 61.2%) were in the low-ISS (1-15) bracket in which there was no difference in en-route care time or mortality between AMR and CMR. Casualties in the mid-ISS bracket (16-50) (n = 583; 33.4%) experienced the same median en-route care time (minutes) on AMR and CMR platforms [78 (58) vs 75 (93); P = 0.542] although those on AMR had shorter time to operation [110 (95) vs 117 (126); P < 0.001]. In this mid-ISS bracket, mortality was lower in the AMR than in the CMR group (12.2% vs 18.2%; P = 0.035). In the high-ISS category (51-75) (n = 75; 4.6%), time to operation was lower in the AMR than the CMR group (66 ± 77 vs 113 ± 122; P = 0.013) but there was no difference in mortality. CONCLUSIONS: This study characterizes en-route care capabilities from POI in modern combat. Conventional platforms are effective in most casualties with low injury severity. However, a definable injury severity exists for which evacuation with an AMR capability is associated with improved survival.