Air Medical Transport System Research Articles

Increasing Variability of Blood Pressure During Air Medical Transport Is Associated With Early Mortality in Patients with Ruptured Abdominal Aortic Aneurysm

The aim of this study is to evaluate the prehospital care during air medical transport of patients presenting with ruptured abdominal aortic aneurysm (RAAA). This was a retrospective study from 2001 through 2019 analyzing the prehospital care of patients with RAAA presenting to a single institution. Our integrated air medical transport system provides critical-care capability on each aircraft and has expanded over the study period with 15 helicopter bases in the region. We analyzed blood product utilization, key time components, and vital sign changes over time with vitals collected every five minutes while in transit. Outcomes included 30-day, early (48-hour) mortality. We excluded patients that did not receive an operation at the receiving facility. Three-hundred eight patients (mean age, 74 ± 9.65 years; 75.3% male) out of 537 total RAAA had available prehospital data. Most (92%, n = 282) were transferred from a referring hospital and by air in 88% (n = 272). The majority received crystalloid at the referring facility (88.3%, n = 272) with 25.3% (n = 78) receiving packed red blood cells (PRBCs). During transport, 35% of patients received PRBCs with an average of 1.8 ± 1.1 units transfused. The mean ratio of crystalloid to total resuscitative volume given during transport decreased over time while the PRBC to total volume ratio increased (Figure). Total transport duration was 68.2 ± 36.4 minutes: 23.9 ± 17.3 minutes from dispatch to referring facility, 14.6 ± 8.3 minutes at the referring facility for patient pickup, and 29.8 ± 17.3 minutes en route to the final receiving facility. Transport duration did not appreciably increase over this period despite expansion of the coverage area over time. Average mean systolic blood pressure (SBP) during transport was 115 ± 26 mm Hg. Sixteen percent (n = 48) of patients had sustained hypotension with a mean SBP of <90 mm Hg during transport. Standard deviation of SBP over the transport period was used as a measure of blood pressure variability. On multivariate logistic regression analysis, no transfusion product ratios or transport durations were significantly associated with any mortality when adjusted for Harborview criteria and repair modality. However, increasing variability of SBP during transport was associated with increased early mortality, especially in the sustained hypotensive cohort (odds ratio, 1.10; 95% confidence interval, 1.01-1.20 P = .03). Decreasing crystalloid and increasing PRBC usage over time reflect evolving prehospital treatment of hemorrhage but have not affected perioperative mortality in RAAA. Increasing SBP variability during transport was associated with increased early mortality especially in those with sustained hypotension.

Prevalence and Predictors of Post-Intubation Hypotension in Prehospital Trauma Care

Prehospital care of severe trauma patients often involves endotracheal intubation (ETI), which has complications. The frequency and predictors of post-ETI hypotension and cardiac arrest are not well defined in this population. We sought to derive and validate a scoring system that predicts post-ETI hypotension in prehospital patients and to describe the impact of hypotension on outcome. We performed an observational cohort study including normotensive adult trauma patients requiring ETI, treated from 2001 to 2018 by critical care transport providers in a regional air medical transport system. We divided eligible patients into a derivation cohort (2001–2010) and validation cohort (2011–2018) for analysis. We identified predictors of new systolic hypotension (<90 mmHg) or cardiac arrest within 15 minutes of ETI then developed and validated a scoring system that stratified patients into low, moderate and high risk. We included 4,866 subjects, 3,127 in the derivation and 1,739 in the validation cohort. Post-ETI hypotension occurred in 11% and 21%, respectively; 5% of each cohort experienced post-ETI cardiac arrest. Major independent predictors of post-ETI hypotension were age, pre-ETI systolic blood pressure and pre-ETI oxygen saturation. We developed a well-calibrated scoring system based on these major and several minor risk factors. Applying our system, 890 (33%) derivation patients and 550 (37%) validation patients were higher risk for post-ETI adverse outcomes. Of these, 21% and 33% respectively experienced post-ETI hypotension and 6% and 4%, respectively suffered post-ETI cardiac arrest. Patients at high risk for post-ETI hypotension or arrest are common and identifiable in prehospital trauma care.

Assessment of Pain Management During Interfacility Air Medical Transport of Intubated Patients

ObjectiveThe management of pain is an important component of care in the prehospital and transport setting. However, recent evidence suggests that pain control is infrequently achieved in these settings. The objective of the current study was to determine the proportion and frequency of opioid analgesia provided to intubated patients during interfacility transport by an air medical transport system. MethodsThis was a health records review examining electronic records of intubated patients transported by Ornge from July 2015 to November 2015. Cases were identified using Ornge database, and intubated patients were selected based on the inclusion criteria. A standardized data extraction form was piloted and used by a single trained data extractor. The primary outcome was whether analgesia was provided. Secondary outcomes included the frequency of administration and dose adequacy of an opioid analgesia; the analgesic used; adverse events; and the impact of age, sex, past medical history of chronic pain, or reason for transfer on pain management. ResultsOf the 500 potential patient transports, 448 met our inclusion criteria. Among the 448 patients, 295 (65.8%) were men, 327 (73.0%) received analgesia, and 211 (64.3%) received more than 1 dose during transport (median frequency of 2 doses, interquartile range = 1 to 3). The average transport time was 135 minutes, and repeated dosing (> 1 repeat dose) occurred primarily (45.5%) in transports of over 180 minutes. Fentanyl was the most commonly used analgesic (97.9%), and the most common dose was 50 µg (51.8%). Adverse events occurred in 8 patients (2.5%), most commonly new hypotension (mean arterial pressure < 65 mm Hg, n = 5). There was no significant difference in the administration of analgesia based on the patient's age or sex (68.0% of female patients and 75.6% of male patients received analgesia). Interestingly, only 30.8% of patients repatriated to their originating hospital received analgesia compared with 72.3% of patients undergoing their initial transfer to a higher level of care. ConclusionSeventy-three percent of intubated patients transported by Ornge received an opioid analgesic, most commonly fentanyl. We found no clinically relevant difference in the administration of analgesics based on age, sex, past medical history of chronic pain, or reason for transfer other than repatriation to the originating hospital.

Dispatch Decision Making in an Air Medical Transport System

Air medical transport relies on effective dispatching of air and land vehicles to provide the fastest and best care possible for patient transfers. These difficult dispatch decisions are characterized by high time pressure, uncertainty, and the dynamic and complex environment of medical transportation. This paper describes a preliminary study of the decision making processes that occur during dispatch decisions at Ornge, the air medical transportation system in Ontario, Canada. We drew upon the Critical Decision Method and the structured data analysis approach to understand the major decision points faced by Ornge’s dispatchers, and the cues and sources of information attended to in those situations. We found that the decision points deal with three main goals: maintain situation awareness, match resource to transfer, and plan logistics of transfer. Furthermore, we found that time estimation might play an important role in helping dispatchers coordinate within the dispatch team and with their external partners. These findings may help improve the design of computer aided dispatch software to better support the goals of the dispatchers.

Air medical transport system

We describe the importance of establishing air medical transport systems linked to emergency medical services in Sri Lanka.

Successful Airtraq Use in an Air Medical Transport System

IntroductionThere is a large body of literature that shows that the AirTraq device achieves equal or superior rates of successful intubation in all classes of user. A recent prospective human trial of the device questioned the first pass success rate and whether effective training could occur outside the Operating Room (OR). The purpose of this study was to investigate the first pass success rate for intubation with the AirTraq (AT) device utilizing only mannequin training in an air ambulance setting from Aug. 1 2009 to Aug. 1 2012 and compare it to direct laryngoscopy (DL). HypothesisWe hypothesize that the AirTraq device will be as effective overall as direct laryngoscopy, and that this requires no OR training to achieve. MethodsA retrospective chart review of 161 intubations by air ambulance flight nurses from Aug. 1, 2009 to Aug. 1, 2012 was conducted. Data regarding date of service, devices used, number of attempts, rescue device use, and complications was gathered and analyzed. The generalized estimating equation and the chi-squared test were used to evaluate the data. Results161 intubations were reviewed. 135 met inclusion criteria. Overall first pass success rate for AT was 82% (68/83) and DL was 74% (35/47). Overall first use success rate for AT was 79% (71/90) and DL was 70% (43/61). The overall success rate of intubation for any patient in which either AT or DL was attempted is 96% (130/135). ConclusionAirTraq was shown to be as effective as direct laryngoscopy. All air crew training for the AirTraq device was performed on mannequins. The successof the device compared to DL shows that mannequin training is sufficient to implement the AirTraq device for pre-hospital intubation.

Supporting Air Versus Ground Vehicle Decisions for Interfacility Medical Transport Using Historical Data

Patients undergoing interfacility transfers are at potentially greater risk of adverse or critical events than those in hospital, and efficient transfers play a significant role in reducing mortality and morbidity. Medical dispatchers rely on accurate estimations of transfer time in determining the most appropriate method of transportation, often either a helicopter and/or land ambulance, in situations that are characterized by high time pressure and uncertainty. In this paper, we propose the design of a data-driven decision support tool to improve dispatcher transport mode decision making. We studied the dispatch process of the air and land medical transport system in Ontario, Canada through onsite observations and developed a tool which generates transfer time estimates based on historical data. We found that dispatchers have large estimation errors, and are biased toward higher degrees of underestimation for air transfers compared with land transfers. In contrast, the proposed tool produced estimates that had significantly less error than dispatcher estimates. The estimation error for the tool was on the average 21 min less: a practically significant difference in urgent patient care. Through onsite observations and the relevant literature, we also identified factors that may influence the collaboration between the dispatcher and the tool. This research is a first attempt to study how decisions are made for interfacility medical transfers and for evaluating the accuracy of human operator estimates of these transfer times. It is also the first to demonstrate a tool's utility in comparison to existing procedures for estimating transfer times.

Performance of Endotracheal Intubation and Rescue Techniques by Emergency Services Personnel in an Air Medical Service

Background. Literature spanning the last two decades has identified potential harm associated with out-of-hospital endotracheal intubation performed by ground paramedics. Previous researchers have reported intubation success rates of 66% to 97% in the air medical setting. Objective. To examine the success of endotracheal intubation and rescue techniques performed by air medical personnel during the first eight years of operation of the air ambulance service. Methods. This study was a retrospective survey of health records utilizing data from LifeFlight of Maine's airway procedure quality review database, covering the first eight years of system encounters. Results. During the study period, 369 intubation encounters occurred. Rapid-sequence intubation medications were administered in 345 (93.5%) cases. Flight personnel successfully performed endotracheal intubation in 340 (92.1%) encounters. Unsuccessful intubations were managed with an alternative definitive airway, rescue airway, or bag–valve–mask. Laryngeal mask airway (n = 11) was the most commonly used rescue airway device. Conclusions. During the first eight years of operation of this air medical transport system, flight personnel were able to successfully perform endotracheal intubation in 92.1% of cases.

U.S. army air ambulance operations in El Paso, Texas: A descriptive study and system review

Objectives. To analyze a high-volume military air ambulance unit and review the U.S. Army air medical transport system and Military Assistance to Safety and Traffic (MAST) program. Methods. The setting was a remote medical system with numerous ground emergency medical services. All patients transported between January 1, 1996, and February 28, 1998, were included. Patients who were dead on scene or for whom records were unavailable were excluded. A retrospective review of transport and available inpatient records was conducted. Results. Five hundred seventeen patients were transported during the study period; 461 patients met inclusion criteria (89%). Of these, 70% were classified as trauma; 30% possessed medical or other surgical diagnoses. Prehospital responses numbered 71.6%, while 28.4% were interhospital transfers. Missions averaged 23.4 minutes per flight, with no major aircraft mishaps. Prehospital utilization review showed appropriate use; 35% of interhospital trauma and 11% of interhospital nontrauma missions were staffed inadequately by these criteria. Time intervals, procedures, and program impact are discussed. Conclusion. This and similar units participating in the MAST program provide effective air transport in settings underserved by civilian programs. Quality and wartime readiness could be improved by centralized medical direction, treatment and transfer protocols, and enhanced training of medics. Further investigations of the clinical impact of advanced training and a two-medic aircrew model are warranted. PREHOSPITAL EMERGENCY CARE 2000;4:136-143

U.S. Army Air Ambulance Operations in E1 Paso, Texas: A Descriptive Study and System Review

Objective: Analysis of a high-volume military air ambulance unit and review of the U.S. Army air medical transport system and Military Assistance to Safety and Traffic (MAST) program. Setting: A remote medical system with numerous ground emergency medical services. Inclusion: All patients transported between January 1, 1996, and February 28, 1998. Exclusion: Patients who were dead on the scene or for whom records were unavailable. Methods: Retrospective review of transport and available inpatient records. Results: A total of 517 patients were transported during the study period; 461 patients met the inclusion criteria (89%). Of these, 70% were classified as trauma patients, and 30% had medical or other surgical diagnoses. Prehospital responses accounted for 71.6% of transports, and 28.4% were interhospital transfers. Missions averaged 23.4 minutes per flight, with no major aircraft mishaps. Prehospital utilization review showed appropriate use; 35% of interhospital trauma missions and 11% of interhospital nontrauma missions were staffed inadequately by our criteria. Time intervals, procedures, and program impact are discussed. Conclusion: This and similar units participating in the MAST program provide effective air transport in settings underserved by civilian programs. Quality and wartime readiness could be improved by centralized medical direction, treatment and transfer protocols, and enhanced training of medics. Further investigations of the clinical impact of advanced training and a two-medic aircrew model are warranted.

I NTUBATION S UCCESS R ATES BY A IR A MBULANCE P ERSONNEL DURING 12- VERSUS 24- HOUR S HIFTS : D OES F ATIGUE M AKE A D IFFERENCE ?

Objectives. To determine whether the skill performance and psychomotor agility, as measured by the endotracheal intubation success rate, of air ambulance medical personnel would be affected by the potential fatigue incurred when increasing the length of their shifts from 12 to 24 hours. Methods. This was a retrospective review of all flight and intubation records from a large air medical transport system from 1997, when 24-hour shifts were in place, and six months (March–August) of 1996, during which 12-hour shifts were scheduled. Records of all intubation efforts during both periods, including multiple attempts per patient, and outcomes of all attempts, were recorded. Results of successes and failures were tabulated for both ultimate intubation outcome per patient and all attempts per patient for each calendar day and for the 12 hours between 19:00 and 07:00 when fatigue might play a role. Results from the two study periods were compared using Fisher's exact test. Results. During the six months of 1996, 190 of 199 (95.5%) patients were ultimately successfully intubated. These patients required 237 attempts (80.1% successful). During 1997, 362 of 376 (96.3%) patients were successfully intubated, and required 438 attempts (82.6% successful). There was no statistically significant difference in the number of ultimately successful intubations (p = 0.66) or total intubation attempts (p = 0.37) between 1996 and 1997. Analysis of intubations between 19:00 and 07:00 revealed 81 of 84 (96.4%) patients successfully intubated in 1996, with 81 of 103 (78.6%) attempts successful. During 1997, 173 of 180 (96.1%) patients were ultimately successfully intubated, with 173 of 212 (81.6%) attempts successful. Again, there was no significant difference in the number of successful intubations (p = 0.99) or intubation attempts (p = 0.55) between 1996 and 1997. Conclusion. Psychomotor agility of air ambulance medical personnel, as measured by the success rate of endotracheal intubation, was not affected by the potential additional fatigue incurred as a result of increasing shift length from 12 to 24 hours.

U.S. A RMY A IR A MBULANCE O PERATIONS IN E L P ASO , T EXAS : A D ESCRIPTIVE S TUDY AND S YSTEM R EVIEW

Objectives. To analyze a high-volume military air ambulance unit and review the U.S. Army air medical transport system and Military Assistance to Safety and Traffic (MAST) program. Methods. The setting was a remote medical system with numerous ground emergency medical services. All patients transported between January 1, 1996, and February 28, 1998, were included. Patients who were dead on scene or for whom records were unavailable were excluded. A retrospective review of transport and available inpatient records was conducted. Results. Five hundred seventeen patients were transported during the study period; 461 patients met inclusion criteria (89%). Of these, 70% were classified as trauma; 30% possessed medical or other surgical diagnoses. Prehospital responses numbered 71.6%, while 28.4% were interhospital transfers. Missions averaged 23.4 minutes per flight, with no major aircraft mishaps. Prehospital utilization review showed appropriate use; 35% of interhospital trauma and 11% of interhospital nontrauma missions were staffed inadequately by these criteria. Time intervals, procedures, and program impact are discussed. Conclusion. This and similar units participating in the MAST program provide effective air transport in settings underserved by civilian programs. Quality and wartime readiness could be improved by centralized medical direction, treatment and transfer protocols, and enhanced training of medics. Further investigations of the clinical impact of advanced training and a two-medic aircrew model are warranted.

The epidemiology of pediatric air medical transports in utah

Objective. To describe the air-transported patients treated at Primary Children's Medical Center (PCMC), the sole pediatric tertiary care center in Utah and a referral center in the intermountain region. This study describes the patients who utilized the air medical transport system, the medical services provided in the prehospital setting, and the corresponding charges for transport and treatment. Methods. Participants were air-transported patients aged 17 years and less who were treated at PCMC during the calendar years 1991–1992. The study population excluded patients who were transported to other medical facilities, and newborns. Data were abstracted retrospectively from the patients' medical and transport records. Data collected included demographic information, patient diagnoses, and treatments performed during transport. Financial data were supplied by the hospital. Results. During the study period, 874 pediatric patients met the participant criteria. Helicopter and fixed-wing transports comprised 561 and 313, respectively, from nine states in the mountain and western regions. The majority (313, 56%) of the patients transported by helicopter were trauma patients, while the majority (195, 62%) of fixed-wing transports were for illness-related conditions. Scene transports accounted for 120 (21%) of helicopter transports. Children with special health care needs accounted for 171 (20%) of all transports. Conclusions. Injury severity scores indicate that, overall, air-transported patients were more severely injured than comparable ground-transported patients. However, it is apparent that some patients who were air-transported could have been transported by ground ambulance without detriment.