Air Medical Transport of a 12-Year-Old Girl With Cerebral Gas Embolism Due to Helium Inhalation.

This case report describes the initial care and transport considerations of a pediatric patient who suffered from cerebral gas embolism sustained after inhalation of helium from a pressurized tank. The patient demonstrated neurologic symptoms necessitating hyperbaric oxygen therapy and required fixed wing air transport across a mountain range from a rural community hospital to a tertiary center for the treatment. We review the pathophysiology of cerebral gas embolism and strategies for transporting patients with cerebral gas embolism and other trapped gas.

THE COMPENSATORY RESERVE INDEX FOR PREDICTING HEMORRHAGIC SHOCK IN PREHOSPITAL TRAUMA.

ABSTRACT: Background: The compensatory reserve index (CRI) is a noninvasive, continuous measure designed to detect intravascular volume loss. CRI is derived from the pulse oximetry waveform and reflects the proportion of physiologic reserve remaining before clinical hemodynamic decompensation. Methods: In this prospective, observational, prehospital cohort study, we measured CRI in injured patients transported by emergency medical services (EMS) to a single Level I trauma center. We determined whether the rolling average of CRI values over 60 s (CRI trend [CRI-T]) predicts in-hospital diagnosis of hemorrhagic shock, defined as blood product administration in the prehospital setting or within 4 h of hospital arrival. We hypothesized that lower CRI-T values would be associated with an increased likelihood of hemorrhagic shock and better predict hemorrhagic shock than prehospital vital signs. Results: Prehospital CRI was collected on 696 adult trauma patients, 21% of whom met our definition of hemorrhagic shock. The minimum CRI-T was 0.14 (interquartile range [IQR], 0.08-0.31) in those with hemorrhagic shock and 0.31 (IQR 0.15-0.50) in those without ( P = <0.0001). The positive likelihood ratio of a CRI-T value <0.2 predicting hemorrhagic shock was 1.85 (95% confidence interval [CI], 1.55-2.22). The area under the ROC curve (AUC) for the minimum CRI-T predicting hemorrhagic shock was 0.65 (95% CI, 0.60-0.70), which outperformed initial prehospital HR (0.56; 95% CI, 0.50-0.62) but underperformed EMS systolic blood pressure and shock index (0.74; 95% CI, 0.70-0.79 and 0.72; 95% CI, 0.67-0.77, respectively). Conclusions: Low prehospital CRI-T predicts blood product transfusion by EMS or within 4 hours of hospital arrival but is less prognostic than EMS blood pressure or shock index. The evaluated version of CRI may be useful in an austere setting at identifying injured patients that require the most significant medical resources. CRI may be improved with noise filtering to attenuate the effects of vibration and patient movement.

Prolonged Use of an Extraglottic Airway During Air Medical Transport From a Remote Alaskan Island.

Extraglottic devices (EGDs) are important tools for airway management in the prehospital and transport medicine environment. EGDs may be used as either a primary airway or rescue device depending on the provider skill level or patient circumstances. Although EGDs do not provide a definitive airway, they can facilitate oxygenation and ventilation in select patients. This is particularly important in the remote or austere environment when difficult airways are infrequently encountered. This case report details the prolonged use of an EGD during air medical transport from a rural Alaskan medical clinic to a large academic tertiary receiving facility, with the total time until definitive airway placement of approximately 9 hours. We review the prehospital coordination and evaluation, in-flight management, and successful transfer of care of the patient to the receiving tertiary center for definitive intervention.

A cost-aware framework for the development of AI models for healthcare applications.

Accurate artificial intelligence (AI) for disease diagnosis could lower healthcare workloads. However, when time or financial resources for gathering input data are limited, as in emergency and critical-care medicine, developing accurate AI models, which typically require inputs for many clinical variables, may be impractical. Here we report a model-agnostic cost-aware AI (CoAI) framework for the development of predictive models that optimize the trade-off between prediction performance and feature cost. By using three datasets, each including thousands of patients, we show that relative to clinical risk scores, CoAI substantially reduces the cost and improves the accuracy of predicting acute traumatic coagulopathy in a pre-hospital setting, mortality in intensive-care patients and mortality in outpatient settings. We also show that CoAI outperforms state-of-the-art cost-aware prediction strategies in terms of predictive performance, model cost, training time and robustness to feature-cost perturbations. CoAI uses axiomatic feature-attribution methods for the estimation of feature importance and decouples feature selection from model training, thus allowing for a faster and more flexible adaptation of AI models to new feature costs and prediction budgets.

Hemostatic Resuscitation of Pediatric Trauma Patients During Air Medical Transport: A Retrospective Matched Cohort Study.

OBJECTIVE: The objective of this study was to examine an academic air ambulance service's experience with prehospital transfusion of plasma and red blood cells in pediatric trauma for evidence of efficacy on the treatment of shock and coagulopathy. METHODS: All trauma patients < 18 years old transfused during transport by the University of Washington Airlift Northwest (Airlift) air medical transport service to Harborview Medical Center, Seattle, WA, were identified. Controls were matched 1:1 from pediatric trauma patients transported by Airlift before transfusion support became available. Demographics, injury scores, emergency department admission and interval laboratory values, blood product use, and hospital outcome measures were registered. RESULTS: Seventeen cases met the inclusion criteria and were matched by age and Injury Severity Score to 17 control patients (mean age = 10.5 vs. 10.9 years; New Injury Severity Score, 37 vs. 40.7). No significant differences in vital signs, shock index, or mortality were observed. Cases received less in-flight crystalloid (4.3 mL/kg vs. 16.9 mL/kg, P = .004), had higher admission fibrinogen levels (238 vs. 148mg/dL, P = .007), and shorter time to normalization of the international normalized ratio (6.4 vs. 19.1 hours, P = .04). CONCLUSIONS: In this small series, hemostatic resuscitation during air medical transport was associated with less crystalloid administration and better support of coagulation indices.

Cardiac Arrest in Flight: A Retrospective Chart Review of 92 Patients Transported by a Critical Care Air Medical Service.

OBJECTIVE: The purpose of this study was to describe the incidence, characteristics, and outcomes of cardiac arrest in the air medical environment so that we can begin to understand predictors of in-flight cardiac arrest and identify opportunities to improve care. METHODS: This retrospective observational study was undertaken at Airlift Northwest from 2013 to 2017. Descriptive statistics of adult patients with medical and traumatic etiologies of cardiac arrest were analyzed and compared. RESULTS: Of the 13,915 adult patients transported during the study period, fewer than 1% (N = 92) had a cardiac arrest during transport. Of those, 42% in the overall cohort had return of spontaneous circulation on arrival at the destination hospital. Medical etiologies of cardiac arrest were more common than traumatic (65% vs. 35%), more likely to have an initial shockable rhythm (30% vs. 3%, P = .004), and more frequently arrived at the receiving hospital with return of spontaneous circulation (57% vs. 31%, P = .03). Rearrest in transport occurred frequently (39%). Most patients were hypotensive before cardiac arrest, and peri-intubation cardiac arrest occurred in 12% of patients. CONCLUSION: Cardiac arrest during air medical transport is a rare event that requires a high level of critical care to treat refractory cardiac arrests, hemodynamic instability, and airway compromise.

Economical provision of blood components for critical patient transport across a large geographic area.

BACKGROUND: Rapid air transport of critically injured patients to sites of appropriate care can save lives. The provision of blood products on critical care transport flights may save additional lives by starting resuscitation earlier. METHODS: Our regional trauma center transfusion service provided 2 units of O-negative red blood cells and 2 units of A low-titer anti-B liquid plasma in an internally monitored and sealed eutectic box weighing 10.4 pounds to eight air bases once weekly. Flight crews were instructed to transfuse plasma units first. Unused blood was returned to the transfusion service. Total blood use and wastage were recorded. RESULTS: Over a 6-year period, ≈ 7400 blood components were provided, and >1000 were used by the air transport service in patient care. Plasma units were 57% of all units given. Unused units were returned to the providing transfusion service and used in hospital patient care with <3% loss. Estimated cost of providing blood per mission was $63 and per patient transfused was $1940. CONCLUSIONS: With appropriate attention to detail, it is possible to provide life-saving blood components to aeromedical transport services across a large geographic area with efficient blood component usage, minimal blood wastage, and low cost.

Suspected Succinylcholine-Induced Masseter Muscle Rigidity During Rapid Sequence Intubation in the Air Medical Setting.

Trismus, or masseter muscle rigidity, is a rare but previously described complication of succinylcholine-induced neuromuscular blockade. We present a case report that details unique aspects of suspected masseter muscle rigidity in the prehospital setting air medical setting after attempted rapid sequence intubation with succinylcholine. We then discuss the need for knowledge base of this life-threatening and rarely described syndrome as well as the importance of working through a differential diagnosis and specific trismus-focused airway algorithm. Trismus, or masseter muscle rigidity (MMR), is a rare but previously described complication of succinylcholine-induced neuromuscular blockade. It has been cited in anesthesia and emergency medicine literature as a potentially life-threatening complication and requires prompt intervention. This case report details a unique case of suspected MMR in the prehospital setting after attempted rapid sequence intubation (RSI) with succinylcholine performed by an experienced aeromedical flight crew.

Management of Acute Aortic Dissection During Critical Care Air Medical Transport.

Acute aortic dissection is a time-critical emergency that air medical teams must be capable of transporting. Aortic dissections can manifest a myriad of complications in which prompt recognition and tailored treatments may mitigate additional physiological burden and limit dissection flap propagation. The purpose of this review is to discuss specific critical scenarios that air medical providers may be faced with and to equip them with a pathophysiological understanding of the disease and best practices for the management of acute aortic dissections.

Difficult Intubation due to Penetrating Trauma from a Crossbow Bolt.

We present the case of a patient with penetrating neck and craniofacial trauma from a self-inflicted crossbow bolt injury. This case highlights the challenges involved in prehospital airway management related to an in situ foreign object penetrating the oral cavity. We review the complications associated with such injuries and considerations for effective prehospital airway management.

A Comprehensive Course for Teaching Emergency Cricothyrotomy.

Audience: This curriculum was developed for emergency medicine (EM) residents at the post-graduate year (PGY) 1-4 level, and attending EM physicians. It may be adapted for training of any healthcare provider or learner who might be required to perform an emergency cricothyrotomy, including emergency medical technicians, senior medical students, and advanced practice providers (ie, nurse practitioners and physician assistants); however, we did not specifically validate it for these providers. Introduction: Emergency cricothyrotomy (EC) is a lifesaving surgical procedure, often the option of last resort, used to secure the airway when other methods of airway control have failed or are not feasible. It is a high-risk procedure since it is infrequently performed, but it is time-sensitive and critical for survival when needed.1,2 Time-sensitive procedural skills such as EC are subject to relatively rapid decay,3,4 and unlike other high-risk procedures, in which just-in-time training (JITT) may improve real time procedural performance, the extreme time sensitivity of cricothryotomy precludes JITT as a feasible educational intervention to improve EC performance.5 As such, clinicians must periodically review the essential concepts and practice the physical actions of the procedure in order to build and maintain familiarity with the steps involved and to develop and maintain the muscle memory necessary to perform it quickly and confidently. Previous studies have shown that simulation-based training improves both confidence and competence in the performance of the simulated procedures,6,7 and that small group learning situations are effective for procedural learning.8,9Commercially produced mannequins are available to simulate cricothyrotomy. However, being made of plastic materials, they suffer from unrealistic "tissue" feel that is radically different from that of biologic tissue.10,11 Additionally, because they are mass-produced, they tend to be fairly homogeneous in their anatomic representations, lacking the variability encountered in the human population.We developed an inexpensive procedure simulator using commercially available porcine byproduct that more closely mimics the feel of cricothyrotomy in real life, and a comprehensive curriculum for instruction in, or review of, EC, intended for implementation in a small-group format. This publication is intended to provide interested educators with a comprehensive suite of materials for teaching EC at their own institution. Included are instructions for how to construct the simulator, an EC case scenario with discussion points, a PowerPoint didactic module covering the fundamental concepts of EC, and sample course evaluation forms that may be implemented directly or adapted to meet institutional requirements. Educational Objectives: After completing this activity, the learner will be able to:correctly describe the indications for and contraindications to emergency cricothyrotomycorrectly describe and identify on the simulator the anatomic landmarks involved in emergency cricothyrotomycorrectly list the required equipment and the sequence of the steps for the "standard" and "minimalist" variations of the proceduredemonstrate proper technique when performing a cricothyrotomy on the simulator without prompts or pauses. Educational Methods: Small group activity combining didactic learning, case-based learning, and procedural simulation. The didactic component may be delivered in an asynchronous learning or "flipped classroom" format. Research Methods: The cricothyrotomy simulator was initially pilot-tested on a group of emergency medicine attending faculty, who were asked to evaluate the simulator, with results demonstrating that it was felt to be superior to typical plastic mannequin simulators. This simulator was then subsequently integrated into our airway workshops teaching EC, which include hands-on practice, didactic, and discussion components. The content and delivery of these workshops were assessed by the learners via standardized evaluation forms after completion of each workshop, and the overall clinical relevance, appropriateness of content, and satisfaction with the workshop format were highly rated (mean score 4.87 on a 5-point scale, with 5 denoted as "Excellent"). Discussion: The real-tissue model to simulate the procedure was well liked by course participants, and the learning environment was felt to be conducive to asking questions and discussion. Overall, the instructors and the learners felt that the workshops were effective in improving understanding of the procedure and increasing the comfort level and skill of the emergency physician learners in performing the procedure. Topics: Cricothyrotomy, cricothyroidotomy, emergency airway, surgical airway, failed airway, rescue airway, can't intubate can't ventilate, small group activity, simulation.

Resuscitative Airway Management for Massive Gastrointestinal Hemorrhage.

Massive upper gastrointestinal hemorrhage represents a highly morbid, resource intensive disease entity that requires rapid diagnostic and therapeutic delivery in parallel with mobilization of in-hospital providers for definitive intervention. This report details a unique case demonstrating exceptional collaboration spanning multiple healthcare systems, a novel use of resuscitative endovascular balloon occlusion of the aorta, and a discussion on resuscitative airway management in the setting of massive upper gastrointestinal hemorrhage.

Development and Testing of a Neonatal Intubation Checklist for an Air Medical Transport Team.

OBJECTIVE: We developed a Neonatal Intubation Checklist for Airlift Northwest. Our goal was to improve the preparation, technical proficiency, and safety of neonatal intubation without increasing the time required to perform the procedure. METHODS: The Neonatal Intubation Checklist, a "call and response" checklist for neonatal intubation, was developed. Its effectiveness was evaluated during a baseline assessment and 2 practice sessions after a checklist orientation. Intubation proficiency was evaluated using a validated assessment tool that included a proficiency score, a global rating scale (GRS) score, and time to perform the procedure. RESULTS: Significant improvements in intubation proficiency and time to intubation were noted when teams used the intubation checklist (proficiency score: 29 [7] at baseline vs. 57 [1] with checklist, P < .001; GRS 2 [2, 2.5] at baseline vs. 5 [3, 5] with checklist, P < .001; baseline intubation time 626 [93] seconds vs. 479 (44) seconds with checklist, P < .001). These changes were associated with a large effect on proficiency (ƞ2 = 0.89), GRS (ƞ2 = 0.6), and time to successful intubation (ƞ2 = 0.52). CONCLUSION: The use of the Neonatal Intubation Checklist improved transport team performance during simulated neonatal intubations and decreased the time required to successfully perform the procedure.

Logistical Concerns for Prehospital Blood Product Use by Air Medical Services.

Over the past few decades, reports have described favorable results from transfusion of blood products in helicopter EMS (HEMS). Nevertheless, the initiation of a HEMS transfusion program requires consideration of many factors, some unique to each clinical site. This paper describes our experience developing a HEMS transfusion program in an urban non-hospital based HEMS program with a history of long transport times. When considering blood use away from the hospital, major consideration must be given to safe storage and monitoring of blood products both on the ground and while in flight. PRBCs have been shown to generally be resilient to helicopter transit and have a prolonged storage duration. Transfusion of other blood products, such as plasma, involves additional challenges but has been achieved by some HEMS sites. Flight protocols should be developed addressing when and how many blood products should be transported, potentially considering patient factors, scene factors, and the regional availability of blood products during interfacility transport. Quality assurance and documentation protocols must also be developed for blood product use in flight. In our center's experience, we have so far transfused a limited number of patients with generally good results. Patient outcomes are described as below.

Ruptured intercostal artery pseudoaneurysm: a rare cause of acute back pain.

A 63-year-old man with no relevant medical history presented with acute non-traumatic back pain and was found to have a T8 intercostal artery pseudoaneurysm associated with haemomediastinum on CT of the chest. He was taken to angiography with interventional radiology and the aneurysm was coiled without complication.