Introduction: Prehospital ultrasound (PHUS) assessments by physicians and non-physicians are performed on medical and trauma patients with increasing frequency. Prehospital ultrasound has been shown to be of benefit by supporting interventions.Problem: Which patients may benefit from PHUS has not been clearly identified.Methods: A multi-variable logistic regression analysis was performed on a previously created retrospective dataset of five years of physician- and non-physician-performed ultrasound scans in a Canadian critical care Helicopter Emergency Medical Service (HEMS). For separate medical and trauma patient groups, the a-priori outcome assessed was patient characteristics associated with the outcome variable of “PHUS-supported intervention.”Results: Both models were assessed (Likelihood Ratio, Score, and Wald) as a good fit. For medical patients, the characteristics of heart rate (HR) and shock index (SI) were found to be most significant for an intervention being supported by PHUS. An extremely low HR was found to be the most significant (OR=15.86 [95% confidence interval (CI), 1.46-171.73]; P=.02). The higher the SI, the more likely that an intervention was supported by PHUS (SI 0.9 to<1.3: OR=9.15 [95% CI, 1.36-61.69]; P=.02; and SI 1.3+: OR=8.37 [95% CI, 0.69-101.66]; P=.09). For trauma patients, the characteristics of Prehospital Index (PHI) and SI were found to be most significant for PHUS support. The greatest effect was PHI, where increasing ORs were seen with increasing PHI (PHI 14-19: OR=13.36 [95% CI, 1.92-92.81]; P=.008; and PHI 20-24: OR=53.10 [95% CI, 4.83-583.86]; P=.001). Shock index was found to be similar, though, with lower impact and significance (SI 0.9 to<1.3: OR=9.11 [95% CI, 1.31-63.32]; P=.025; and SI 1.3+: OR=35.75 [95% CI, 2.51-509.81]; P=.008).Conclusions: In a critical care HEMS, markers of higher patient acuity in both medical and trauma patients were associated with occurrences when an intervention was supported by PHUS. Prospective study with in-hospital follow-up is required to confirm these hypothesis-generating results. O’Dochartaigh D , Douma M , Alexiu C , Ryan S , MacKenzie M . Utilization criteria for prehospital ultrasound in a Canadian critical care Helicopter Emergency Medical Service: determining who might benefit. Prehosp Disaster Med. 2017;32(5):536–540.

Introduction: Following life-threatening junctional trauma, the goal is to limit blood loss while expediting transfer to operative rescue. Unfortunately, life-threatening abdominal-pelvic or junctional hemorrhage is often not amenable to direct compression and few temporizing strategies are available beyond hemostatic dressings, hypotensive resuscitation, and balanced transfusion. Objectives: In this study, we evaluated proximal external aortic compression to arrest blood flow in healthy adult men. Methods: This was a simulation trial of proximal external aortic compression, for life-threatening abdominal-pelvic and junctional hemorrhage, in a convenience sample of healthy adult male volunteers. The primary end points were cessation of femoral blood flow as assessed by pulse wave Doppler ultrasound at the right femoral artery, caudal to the inguinal ligament. Secondary end points were discomfort and negative sequelae. Results: Aortic blood flow was arrested in 12 volunteers. Median time to blood flow cessation was 12.5 seconds. Median reported discomfort was 5 out of 10. No complications or negative sequelae were reported. Conclusion: This trial suggests that it may be reasonable to attempt temporization of major abdominal-pelvic and junctional hemorrhage using bimanual proximal external aortic compression. In the absence of immediate alternatives for this dangerous and vexing injury pattern, there appear to be few downsides to prehospital proximal external aortic compression while concomitantly expediting definite care.

Introduction: Non-invasive positive pressure ventilation (NIPPV) is used to treat severe acute respiratory distress. Prehospital NIPPV has been associated with a reduction in both in-hospital mortality and the need for invasive ventilation.Hypothesis/Problem: The authors of this study examined factors associated with NIPPV failure and evaluated the impact of NIPPV on scene times in a critical care helicopter Emergency Medical Service (HEMS). Non-invasive positive pressure ventilation failure was defined as the need for airway intervention or alternative means of ventilatory support.Methods: A retrospective chart review of consecutive patients where NIPPV was completed in a critical care HEMS was conducted. Factors associated with NIPPV failure in univariate analyses and from published literature were included in a multivariable, logistic regression model.Results: From a total of 44 patients, NIPPV failed in 14 (32%); a Glasgow Coma Scale (GCS) <15 at HEMS arrival was associated independently with NIPPV failure (adjusted odds ratio 13.9; 95% CI, 2.4-80.3; P=.003). Mean scene times were significantly longer in patients who failed NIPPV when compared with patients in whom NIPPV was successful (95 minutes vs 51 minutes; 39.4 minutes longer; 95% CI, 16.2-62.5; P=.001).Conclusion: Patients with a decreased level of consciousness were more likely to fail NIPPV. Furthermore, patients who failed NIPPV had significantly longer scene times. The benefits of NIPPV should be balanced against risks of long scene times by HEMS providers. Knowing risk factors of NIPPV failure could assist HEMS providers to make the safest decision for patients on whether to initiate NIPPV or proceed directly to endotracheal intubation prior to transport. Lee JS , O’Dochartaigh D , MacKenzie M , Hudson D , Couperthwaite S , Villa-Roel C , Rowe BH . Factors associated with failure of non-invasive positive pressure ventilation in a critical care helicopter Emergency Medical Service. Prehosp Disaster Med 2015; 30(2): 1–5

AIM Low overhead height can negatively affect chest compression performance. An adapted compression technique has been proposed by paramedic H. Koch (pron. “Cook”). This study compares conventional to Koch technique in a height-restricted aeromedical helicopter. METHODS Eighteen clinicians were randomized to two minutes of conventional or Koch compressions, then crossed-over. Koch technique uses a forearm/elbow instead of overlapping hands. Compression quality was assessed with a Skill Reporting Laerdal Resusci-Anne manikin. Quality variables were: the number and rate of compressions, compression depth, release, land marking, and overall aggregate quality score. Participant feedback was collected using the Borg Scale of Perceived Exertion, and compression difficulty using a zero-to-ten scale. Furthermore, we solicited open-ended descriptive responses. RESULTS The average overall quality score was 63% for conventional compressions versus 79% for Koch compressions (p = 0.04). On average, the Koch compression method increased compression depth by 5mm (95% CI 4.3 to 5.7) and the proportion of compressions at the correct depth by 17% (95% CI 7.55 to 26.45), although these were not statistically significant. Correct release and land marking showed no statistically significant difference between techniques. Koch compressions resulted in statistically significant reductions in physical exertion and difficulty (p < 0.001). Qualitative feedback described modified compressions as easier and more sustainable. CONCLUSIONS In a height-restricted aeromedical helicopter, the average overall quality score improved using Koch compressions, although the mean rate, mean depth, correct release and land marking were found to be similar between techniques. Qualitative feedback described Koch compressions as easier and more sustainable. In settings where the compressor is affected by reduced overhead working height, Koch compressions may be an advisable alternative.