Prehospital Ground and Helicopter-Based Extracorporeal Cardiopulmonary Resuscitation (ECPR) Reduce Barriers to ECPR: A GIS Model.

INTRODUCTION: Evidence suggests that Extracorporeal Cardiopulmonary Resuscitation (ECPR) can improve survival rates for nontraumatic out-of-hospital cardiac arrest (OHCA). However, when ECPR is indicated over 50% of potential candidates are unable to qualify in the current hospital-based system due to geographic limitations. This study employs a Geographic Information System (GIS) model to estimate the number of ECPR eligible patients within the United States in the current hospital-based system, a prehospital ECPR ground-based system, and a prehospital ECPR Helicopter Emergency Medical Services (HEMS)-based system. METHODS: We constructed a GIS model to estimate ground and helicopter transport times. Time-dependent rates of ECPR eligibility were derived from the Resuscitation Outcome Consortium (ROC) database, while the Cardiac Arrest Registry to Enhance Survival (CARES) registry determined the number of OHCA patients meeting ECPR criteria within designated transportation times. Emergency Medical Services (EMS) response time, ECPR candidacy determination time, and on-scene time were modeled based on data from the EROCA trial. The combined model was used to estimate the total ECPR eligibility in each system. RESULTS: The CARES registry recorded 736,066 OHCA patients from 2013 to 2021. After applying clinical criteria, 24,661 (3.4%) ECPR-indicated OHCA were identified. When considering overall ECPR eligibility within 45 min from OHCA to initiation, only 11.76% of OHCA where ECPR was indicated were eligible in the current hospital-based system. The prehospital ECPR HEMS-based system exhibited a four-fold increase in ECPR eligibility (49.3%), while the prehospital ground-based system showed a more than two-fold increase (28.4%). CONCLUSIONS: The study demonstrates a two-fold increase in ECPR eligibility for a prehospital ECPR ground-based system and a four-fold increase for a prehospital ECPR HEMS-based system compared to the current hospital-based ECPR system. This novel GIS model can inform future ECPR implementation strategies, optimizing systems of care.

Association of Geographic Distance and Hospital Characteristics With Use of Interhospital Transfer by Air: A Multicenter Retrospective Study.

OBJECTIVE: Interhospital transfer by air (IHTA) represents the majority of helicopter air ambulance transports in the United States, but the evaluation of what factors are associated with utilization has been limited. We aimed to assess the association of geographic distance and hospital characteristics (including patient volume) with the use of IHTA. METHODS: This was a multicenter, retrospective study of helicopter flight request data from 2018 provided by a convenience sample of 4 critical care transport medicine programs in 3 US census regions. Nonfederal referring hospitals located in the home state of the associated critical care transport medicine program and within 100 miles of the primary receiving facility in the region were included if complete data were available. We fit a Poisson principal component regression model incorporating geographic distance, the number of emergency department visits, the number of hospital discharges, case mix index, the number of intensive care unit beds, and the number of general beds and tested the association of the variables with helicopter emergency medical services utilization. RESULTS: A total of 106 referring hospitals were analyzed, 21 of which were hospitals identified as having a consistent request pattern. Using the hospitals with a consistent referral pattern, geographic distance had a significant positive association with flight request volume. Other variables, including emergency department visit volume, were not associated. Overall, the included variables offered poor explanatory power for the observed variation between referring facilities in the use of IHTA (r2 = 0.09). Predicted flights based on the principal component regression model for all referring hospitals suggested the majority of referring hospitals used multiple flight programs. CONCLUSION: Geographic distance is associated with the use of IHTA. Unexpectedly, most basic hospital characteristics are not associated with the use of IHTA, and the degree of variation between referring facilities that is explained by patient volume is limited. The evaluation of nonhospital factors, such as the density and availability of critical care or advanced life support ground emergency medical services resources, is needed.

Factors Associated with Early Withdrawal of Life-Sustaining Treatments After Out-of-Hospital Cardiac Arrest: A Subanalysis of a Randomized Trial of Prehospital Therapeutic Hypothermia.

BACKGROUND: The objective of this study is to describe incidence and factors associated with early withdrawal of life-sustaining therapies based on presumed poor neurologic prognosis (WLST-N) and practices around multimodal prognostication after out-of-hospital cardiac arrest (OHCA). METHODS: We performed a subanalysis of a randomized controlled trial assessing prehospital therapeutic hypothermia in adult patients admitted to nine hospitals in King County with nontraumatic OHCA between 2007 and 2012. Patients who underwent tracheal intubation and were unconscious following return of spontaneous circulation were included. Our outcomes were (1) incidence of early WLST-N (WLST-N within < 72 h from return of spontaneous circulation), (2) factors associated with early WLST-N compared with patients who remained comatose at 72 h without WLST-N, (3) institutional variation in early WLST-N, (4) use of multimodal prognostication, and (5) use of sedative medications in patients with early WLST-N. Analysis included descriptive statistics and multivariable logistic regression. RESULTS: We included 1,040 patients (mean age was 65 years, 37% were female, 41% were White, and 44% presented with arrest due to ventricular fibrillation) admitted to nine hospitals. Early WLST-N accounted for 24% (n = 154) of patient deaths and occurred in half (51%) of patients with WLST-N. Factors associated with early WLST-N in multivariate regressions were older age (odds ratio [OR] 1.02, 95% confidence interval [CI]: 1.01-1.03), preexisting do-not-attempt-resuscitation orders (OR 4.67, 95% CI: 1.55-14.01), bilateral absent pupillary reflexes (OR 2.4, 95% CI: 1.42-4.10), and lack of neurological consultation (OR 2.60, 95% CI: 1.52-4.46). The proportion of patients with early WLST-N among all OHCA admissions ranged from 19-60% between institutions. A head computed tomography scan was obtained in 54% (n = 84) of patients with early WLST-N; 22% (n = 34) and 5% (n = 8) underwent ≥ 1 and ≥ 2 additional prognostic tests, respectively. Prognostic tests were more frequently performed when neurological consultation occurred. Most patients received sedating medications (90%) within 24 h before early WLST-N; the median time from last sedation to early WLST-N was 4.2 h (interquartile range 0.4-15). CONCLUSIONS: Nearly one quarter of deaths after OHCA were due to early WLST-N. The presence of concerning neurological examination findings appeared to impact early WLST-N decisions, even though these are not fully reliable in this time frame. Lack of neurological consultation was associated with early WLST-N and resulted in underuse of guideline-concordant multimodal prognostication. Sedating medications were often coadministered prior to early WLST-N and may have further confounded the neurological examination. Standardizing prognostication, restricting early WLST-N, and a multidisciplinary approach including neurological consultation might improve outcomes after OHCA.

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.

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.

Targeted Temperature Management at 33 Versus 36 Degrees: A Retrospective Cohort Study.

OBJECTIVES: To determine the association between targeted temperature management goal temperature of 33°C versus 36°C and neurologic outcome after out-of-hospital cardiac arrest. DESIGN: This was a retrospective, before-and-after, cohort study. SETTING: Urban, academic, level 1 trauma center from 2010 to 2017. PATIENTS: Adults with nontraumatic out-of-hospital cardiac arrest who received targeted temperature management. INTERVENTIONS: Our primary exposure was targeted temperature management goal temperature, which was changed from 33°C to 36°C in April of 2014 at the study hospital. Primary outcome was neurologically intact survival to discharge. Secondary outcomes included hospital mortality and care processes. MEASUREMENTS AND MAIN RESULTS: Of 782 out-of-hospital cardiac arrest patients transported to the study hospital, 453 (58%) received targeted temperature management. Of these, 258 (57%) were treated during the 33°C period (targeted temperature management 33°C) and 195 (43%) were treated during the 36°C period (targeted temperature management 36°C). Patients treated during targeted temperature management 33°C were older (57 vs 52 yr; p < 0.05) and had more arrests of cardiac etiology (45% vs 35%; p < 0.05), but otherwise had similar baseline characteristics, including initial cardiac rhythm. A total of 40% of patients treated during targeted temperature management 33°C survived with favorable neurologic outcome, compared with 30% in the targeted temperature management 36°C group (p < 0.05). After adjustment for demographic and cardiac arrest characteristics, targeted temperature management 33°C was associated with increased odds of neurologically intact survival to discharge (odds ratio, 1.79; 95% CI, 1.09-2.94). Targeted temperature management 33°C was not associated with significantly improved hospital mortality. Targeted temperature management was implemented faster (1.9 vs 3.5 hr from 911 call; p < 0.001) and more frequently in the emergency department during the targeted temperature management 33°C period (87% vs 55%; p < 0.001). CONCLUSIONS: Comatose, adult out-of-hospital cardiac arrest patients treated during the targeted temperature management 33°C period had higher odds of neurologically intact survival to hospital discharge compared with those treated during the targeted temperature management 36°C period. There was no significant difference in hospital mortality.

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.

Inflammation, endothelial injury, and the acute respiratory distress syndrome after out-of-hospital cardiac arrest.

Background: Acute respiratory distress syndrome (ARDS) is often seen in patients resuscitated from out-of-hospital cardiac arrest (OHCA). We aim to test whether inflammatory or endothelial injury markers are associated with the development of ARDS in patients hospitalized after OHCA. Methods: We conducted a prospective, cohort, pilot study at an urban academic medical center in 2019 that included a convenience sample of adults with non-traumatic OHCA. Blood and pulmonary edema fluid (PEF) were collected within 12 hours of hospital arrival. Samples were assayed for cytokines (interleukin [IL]-1, tumor necrosis factor-α [TNF-α], tumor necrosis factor receptor1 [TNFR1], IL-6), epithelial injury markers (pulmonary surfactant-associated protein D), endothelial injury markers (Angiopoietin-2 [Ang-2] and glycocalyx degradation products), and other proteins (matrix metallopeptidase-9 and myeloperoxidase). Patients were followed for 7 days for development of ARDS, as adjudicated by 3 blinded reviewers, and through hospital discharge for mortality and neurological outcome. We examined associations between biomarker concentrations and ARDS, hospital mortality, and neurological outcome using multivariable logistic regression. Latent phase analysis was used to identify distinct biological classes associated with outcomes. Results: 41 patients were enrolled. Mean age was 58 years, 29% were female, and 22% had a respiratory etiology for cardiac arrest. Seven patients (17%) developed ARDS within 7 days. There were no significant associations between individual biomarkers and development of ARDS in adjusted analyses, nor survival or neurologic status after adjusting for use of targeted temperature management (TTM) and initial cardiac arrest rhythm. Elevated Ang-2 and TNFR-1 were associated with decreased survival (RR = 0.6, 95% CI = 0.3-1.0; RR = 0.5, 95% CI = 0.3-0.9; respectively), and poor neurologic status at discharge (RR = 0.4, 95% CI = 0.2-0.8; RR = 0.4, 95% CI = 0.2-0.9) in unadjusted associations. Conclusion: OHCA patients have markedly elevated plasma and pulmonary edema fluid biomarker concentrations, indicating widespread inflammation, epithelial injury, and endothelial activation. Biomarker concentrations were not associated with ARDS development, though several distinct biological phenotypes warrant further exploration. Latent phase analysis demonstrated that patients with low biomarker levels aside from TNF-α and TNFR-1 (Class 2) fared worse than other patients. Future research may benefit from considering other tools to predict and prevent development of ARDS in this population.

The association between arterial-end-tidal carbon dioxide difference and outcomes after out-of-hospital cardiac arrest.

AIM: We sought to determine if the difference between PaCO2 and ETCO2 is associated with hospital mortality and neurologic outcome following out-of-hospital cardiac arrest (OHCA). METHODS: This was a retrospective cohort study of adult patients who achieved return of spontaneous circulation (ROSC) after OHCA over 3 years. The primary exposure was the PaCO2-ETCO2 difference on hospital arrival. The primary outcome was survival to hospital discharge. The secondary outcome was favorable neurologic status at discharge. We used receiver operating characteristic (ROC) curves to determine discrimination threshold and multivariate logistic regression to examine the association between the PaCO2-ETCO2 difference and outcome. RESULTS: Of 698 OHCA patients transported to the hospitals, 381 had sustained ROSC and qualifying ETCO2 and PaCO2 values. Of these, 160 (42%) survived to hospital discharge. Mean ETCO2 was 39 mmHg among survivors and 43 mmHg among non-survivors. Mean PaCO2-ETCO2 was 6.8 mmHg and 9.0 mmHg (p < 0.05) for survivors and non-survivors. After adjustment for Utstein characteristics, a higher PaCO2-ETCO2 difference on hospital arrival was not associated with hospital mortality (OR 0.99, 95% CI: 0.97-1.0) or neurological outcome. Area under the ROC curve or PaCO2-ETCO2 difference was 0.56 (95% CI 0.51-0.62) compared with 0.58 (95% CI 0.52-0.64) for ETCO2. CONCLUSION: Neither PaCO2-ETCO2 nor ETCO2 were strong predictors of survival or neurologic status at hospital discharge. While they may be useful to guide ventilation and resuscitation, these measures should not be used for prognostication after OHCA.

The association between diabetes status and survival following an out-of-hospital cardiac arrest: A retrospective cohort study.

BACKGROUND: Sudden cardiac arrest (SCA), confirmed absence of cardiac mechanical activity, is the leading cause of heart-related death in the US. Almost 85% of SCA occur out-of-hospital (OHCA), with very poor rates of return of spontaneous circulation (ROSC) and survival to hospital discharge. We sought to determine if diabetes status was associated with survival or ROSC following an OHCA. METHODS: We completed a retrospective cohort study using data from the Toronto Regional RescuNet Epistry dataset, based upon data definitions defined by the Resuscitation Outcomes Consortium (ROC) Epistry-Cardiac Arrest and the Strategies for Post Arrest Resuscitation Care (SPARC) network datasets. Adults ≥18years of age who experienced an OHCA, had data on diabetes status, and were treated by Emergency Medical Services (EMS) between 2012-2014 were included in the analysis (n=10,097). We used bivariate analyses to examine relationships between diabetes status, Utstein elements and outcomes, and logistic regression to determine predictors of survival. RESULTS: Diabetes prevalence was 27.8% (95% CI: 27.0-28.7). A larger proportion of those with diabetes had a non-shockable initial rhythm (28.8% vs. 25.1%; p<0.01) and did not survive to hospital discharge (92.1% vs. 89.2%, p<0.001). Diabetes status is associated with a decrease in survival, independent from a number of Utstein elements (adjusted OR=0.76; 95% CI: 0.64-0.91, p=0.003). CONCLUSIONS: This is the first Canadian study to examine the association between diabetes status and OHCA outcomes. Our findings suggest that diabetes status prior to arrest is associated with decreased survival. The growing prevalence of diabetes globally suggests a future burden related to OHCAs.