Management of Combat Casualties during Aeromedical Evacuation from a Role 2 to a Role 3 Medical Facility.

INTRODUCTION: Emergent clinical care and patient movements through the military evacuation system improves survival. Patient management differs when transporting from the point-of-injury (POI) to the first medical treatment facility (MTF) versus transporting from the Role 2 to the Role 3 MTF secondary to care rendered within the MTF, including surgery and advanced resuscitation. The objective of this study was to describe care provided to patients during theater inter-facility transports and compare with pre-hospital transports (POI to first MTF). MATERIALS AND METHODS: We performed a retrospective chart review of patients with the Role 2 to the Role 3 transports in Afghanistan and Iraq from 2007 to 2016. Data collected included procedures and events at the MTF and during transport. We compared the intra-theater transport data (Role 2 to Role 3) to data from a previous study evaluating pre-hospiital transports (POI to first MTF). RESULTS: We reviewed the records of 869 Role 2 to Role 3 transport patients. Role 2 to Role 3 transports were longer in duration compared to POI transports (39 minutes vs. 23 minutes) and were more likely to be staffed by advanced personnel (nurses, physician assistants, and physicians) (57% vs. 3%). The sample primarily consisted of military-aged males (mean age 27 years) who suffered from explosive or blunt force injuries. Procedures performed during each phase of care reflected the capabilities of the teams and locations. Pain and cardiac events were more common in POI evacuations compared to the Role 2 to Role 3 transports, but documentation of respiratory events, hemodynamic events, neurologic events, and equipment failure was more common during the Role 2 to Role 3 transports. Survival rates were slightly higher among the Role 2 to Role 3 cohort (98% vs. 95%, difference 3% [95% confidence interval of the difference 1-5%]). CONCLUSIONS: Inter-facility transports (Role 2 to Role 3) are longer in duration, transport more complex patients, and are staffed by more advanced level provider types compared to transports from POI.

A Descriptive Study of Casualties Evacuated Out of Afghanistan by Critical Care Air Transport Teams During the Withdrawal of U.S. Troops.

INTRODUCTION: The War in Afghanistan ended in August 2021. Evacuation from the country was a large effort during the last days of the conflict. During evacuation efforts at Kabul Hamid Karzai International Airport, a suicide bombing occurred necessitating emergent medical care for many injured troops and civilians. The U.S. Air Force Critical Care Air Transport Teams (CCATTs) played a role in the medical care provided during the operations in Afghanistan. We report on in-flight events and interventions that took place during the final days of the Afghanistan withdrawal. MATERIALS AND METHODS: We performed a retrospective chart review of patients requiring aeromedical evacuation from the Afghanistan theater of operations by CCATT from July 1 to August 30, 2021. From the CCATT patient care record, data abstractors collected patient characteristics, flight information, vital signs, laboratory values, in-flight interventions, and in-flight events in a study-specific electronic database. We performed descriptive analyses of patient characteristics and in-flight interventions. This study was approved by the San Antonio Institutional Review Board. RESULTS: Nine patients were included in this analysis. Seven out of nine patients were foreign nationals; the remaining two were U.S. Marines. Five patients suffered penetrating injuries from gunshot wounds and four suffered blast injuries. Six received intravenous narcotic analgesia. Four received intravenous sedatives, and four received antibiotics in flight. Two patients required chest tube management. One patient received blood. Three patients were in acute respiratory distress. CONCLUSIONS: Severe injuries were sustained during the withdrawal efforts at the end of the War in Afghanistan. Critical Care Air Transport Teams played a role in the care and evacuation of patients out of theater during this unique and unprecedented time. Even given the limitations associated with retrospective studies and a small sample size, information reported in this study can help inform future decisions, and aid in preparatory efforts for future operations, that may require medical care by CCATT.

Hemodynamic events during en route critical care for patients with traumatic brain injury.

BACKGROUND: Exposure to stressors of flight may increase risk of secondary insults among critically injured combat casualties wounded with traumatic brain injury (TBI). The primary objective of this study was to describe the prevalence of hemodynamic events by phase of transport among patients with TBI transported by Critical Care Air Transport Teams (CCATT). METHODS: We performed a secondary analysis of a retrospective cohort of 477 adults with moderate to severe TBI, who required transport by CCATT to Germany from multiple hospitals in the Middle East between January 2007 and May 2014. We abstracted clinical data from handwritten CCATT medical records. Hemodynamic events included systolic blood pressure <100 mm Hg and cerebral perfusion pressure <60 mm Hg. We calculated the proportion of patients experiencing hemodynamic events for each phase of flight. RESULTS: We analyzed 404 subjects after exclusions for catastrophic brain injury (n = 39) and missing timestamps (n = 34). Subjects had high Injury Severity Scores (median, 29; interquartile range [IQR], 21-35) and a median flight time of 423 minutes (IQR, 392.5-442.5 minutes). The median of documented in-flight vital signs was 8 measurements (IQR, 6.5-8 measurements). Documented systolic blood pressure in-flight events occurred in 3% of subjects during ascent, 7.9% during early flight, 7.7% during late flight, and 2.2% during descent, with an overall in-flight prevalence of 13.9%. Among patients with intracranial pressure monitoring (n = 120), documented cerebral perfusion pressure events occurred in 5% of subjects during ascent, 23% during early flight, 17% during late flight, and 5.8% during descent, with an overall in-flight prevalence of 30.8%. CONCLUSION: Documented hemodynamic events occurred during each phase of flight in severely injured combat casualties wounded with TBI, and episodic documentation likely underestimated the actual in-flight frequency of secondary insults. LEVEL OF EVIDENCE: Prognostic and epidemiological; Level IV.

Descriptive Analysis of Coronavirus Disease 2019 Air Medical Evacuations by Critical Care Air Transport Teams.

OBJECTIVE: Preserving air medical evacuation capabilities for critically ill patients with coronavirus disease 2019 (COVID-19) required innovation for en route care logistics, training, and equipment. The aim of this study was to describe characteristics and in-flight interventions for patients with suspected COVID-19 requiring air medical evacuation by US Air Force critical care air transport teams (CCATTs). METHODS: We performed a retrospective chart review of patients with suspected COVID-19 requiring air medical evacuation by CCATT from April 2020 to February 2021. We included patients with an available CCATT medical record and transport with COVID-19 infection isolation precautions. CCATT medical records were the data source, and we performed descriptive analyses of patient characteristics and in-flight interventions. RESULTS: We reviewed 460 records and identified 16 patients for inclusion. The Transport Isolation System (50%) and Negatively Pressurized Conex (31%) were commonly used portable biocontainment units. The median patient age was 48.5 years, and 94% were male. All patients required oxygen supplementation, with 8 (50%) receiving mechanical ventilation. In-flight interventions among intubated patients (n = 8) included vasopressors (50%), paralytics (25%), and patient-ventilator asynchrony management (63%). CONCLUSION: Patients with COVID-19 requiring CCATT transport were older than prior military en route care cohorts, and in-flight interventions for patient-ventilator asynchrony were commonly required during mechanical ventilation.

Association of Hypocalcemia With Mortality of Combat Casualties With Brain Injury and Polytrauma Transported by Critical Care Air Transport Teams.

INTRODUCTION: Hypocalcemia at hospital presentation is associated with increased mortality in trauma patients with hemorrhagic shock. The 2019 updates to the Joint Trauma System Damage Control Resuscitation (DCR) Clinical Practice Guideline recommend calcium supplementation for ionized calcium (iCa) measurements <1.2 mmol/L. Ionized calcium goals for en route critical care (ERCC) following DCR are less defined, and the impact of in-flight hypocalcemia events among critically injured combat wounded is unknown. This study aimed to describe the association between hypocalcemia and mortality for combat-wounded with brain injury and polytrauma requiring transport by Critical Care Air Transport Teams (CCATT). METHODS: We performed a secondary analysis of a retrospective cohort of patients with moderate-to-severe traumatic brain injury transported by CCATT out of combat theater between January 2007 and May 2014. Additional inclusion criteria included polytrauma and at least one documented in-flight iCa measurement. We categorized exposures based on the minimum in-flight iCa measurement as severe hypocalcemia (iCa <0.9 mmol/L), hypocalcemia (iCa 0.9-1.11 mmol/L), and never hypocalcemic (iCa ≥1.12 mmol/L). The primary outcome measure was mortality. We calculated descriptive statistics and performed multivariate logistic regression to assess the association between hypocalcemia and mortality. RESULTS: We analyzed 190 subjects, with a median age of 24 years (interquartile range [IQR] 21 to 29 years) and 97.7% male gender. Explosive injuries (82.1%) and gunshot wounds (6.3%) were the most common mechanisms of injury. The median injury severity score was 34 (IQR 27 to 43). During the flight, 11.6% of patients had severe hypocalcemia, and 39.5% had hypocalcemia. Among patients with any hypocalcemia measurement in-flight (n = 97), 41.2% had hypocalcemia on pre-flight iCa, 28.9% received blood products in-flight, and 23.7% received in-flight calcium supplementation. Only 32.4% of patients with hypocalcemia or severe hypocalcemia in the setting of vasopressor administration received in-flight calcium supplementation. There was no significant difference in mortality between severe hypocalcemia (9.1%), hypocalcemia (5.3%), and never hypocalcemic (3.2%) patients even after controlling for pre-flight variables. CONCLUSION: In-flight hypocalcemia events were common among critically ill combat-wounded polytrauma patients transported by CCATT but were not associated with differences in mortality. Future training should emphasize the need for calcium correction among ERCC patients requiring vasopressors. Future studies with larger sample sizes of patients receiving ERCC are needed to assess the association between in-flight calcium supplementation with clinical outcomes.

Evacuation Strategies for U.S. Casualties with Traumatic Brain Injury (TBI) with and without Polytrauma.

INTRODUCTION: According to the Military Health System Traumatic Brain Injury (TBI) Center of Excellence, 51,261 service members suffered moderate to severe TBI in the last 21 years. Moderate to severe TBI in service members is usually related to blast injury in combat operations, which necessitates medical evacuation to higher levels of care. Prevention of secondary insult, and mitigation of the unique challenges associated with the transport of TBI patients in a combat setting are important in reducing the morbidity and mortality associated with this injury. The primary goal of this study was a secondary analysis comparing the impact of time to transport on clinical outcomes for TBI patients without polytrauma versus TBI patients with polytrauma transported out of the combat theater via Critical Care Air Transport Teams (CCATT). Our secondary objective was to describe the occurrence of in-flight events and interventions for TBI patients without polytrauma versus TBI with polytrauma to assist with mission planning for future transports. MATERIALS AND METHODS: We performed a secondary analysis of a retrospective cohort of 438 patients with TBI who were evacuated out of theater by CCATT from January 2007 to May 2014. Polytrauma was defined as abbreviated injury scale (AIS) of at least three to another region in addition to head/neck. Time to transport was defined as the time (in days) from injury to CCATT evacuation out of combat theater. We calculated descriptive statistics and examined the associations between time to transport and preflight characteristics, in-flight interventions and events, and clinical outcomes for TBI patients with and without polytrauma. RESULTS: We categorized patients into two groups, those who had a TBI without polytrauma (n = 179) and those with polytrauma (n = 259). Within each group, we further divided those that were transported within 1 day of injury, in 2 days, and 3 or more days. Patients with TBI without polytrauma transported in 1 or 2 days were more likely to have a penetrating injury, an open head injury, a preflight Glascow Coma Score (GCS) of 8 or lower, and be mechanically ventilated compared to those transported later. Patients without polytrauma who were evacuated in 1 or 2 days required more in-flight interventions compared to patients without polytrauma evacuated later. Patients with polytrauma who were transported in 2 days were more likely to receive blood products, and patients with polytrauma who were evacuated within 1 day were more likely to have had at least one episode of hypotension en route. Polytrauma patients who were evacuated in 2-3 days had higher hospital days compared to polytrauma with earlier evacuations. There was no significant difference in mortality between any of the groups. CONCLUSIONS: In patients with moderate to severe TBI transported via CCATT, early evacuation was associated with a higher rate of in-flight hypotension in polytrauma patients. Furthermore, those who had TBI without polytrauma that were evacuated in 1-2 days received more in-flight supplementary oxygen, blood products, sedatives, and paralytics. Given the importance of minimizing secondary insults in patients with TBI, recognizing this in this subset of the population may help systematize ways to minimize such events. Traumatic Brain Injury patients with polytrauma may benefit from further treatment and stabilization in theater prior to CCATT evacuation.

Advancing Prehospital Combat Casualty Evacuation: Patients Amenable to Aeromedical Evacuation via Unmanned Aerial Vehicles.

INTRODUCTION: The U.S. military currently utilizes unmanned aerial vehicles (UAVs) for reconnaissance and attack missions; however, as combat environment technology advances, there is the increasing likelihood of UAV utilization in prehospital aeromedical evacuation. Although some combat casualties require life-saving interventions (LSIs) during medical evacuation, many do not. Our objective was to describe patients transported from the point of injury to the first level of care and characterize differences between patients who received LSIs en route and those who did not. MATERIALS AND METHODS: We conducted a retrospective review of the records of traumatically injured patients evacuated between January 2011 and March 2014. We compared patient characteristics, complications, and outcomes based on whether they had an LSI performed en route (LSI vs. No LSI). We also constructed logistic regression models to determine which characteristics predict uneventful flights (no en route LSI or complications). RESULTS: We examined 1,267 patient records; 47% received an LSI en route. Most patients (72%) sustained a blast injury and injuries to the extremities and head. Over 78% experienced complications en route; the LSI group had higher rates of complications compared to the No LSI group. Logistic regression showed that having a blunt injury or the highest abbreviated injury scale (AIS) severity score in the head/neck region are significant predictors of having an uneventful flight. CONCLUSION: Approximately half of casualties evaluated in our study did not receive an LSI during transport and may have been transported safely by UAV. Having a blunt injury or the highest AIS severity score in the head/neck region significantly predicted an uneventful flight.