Prehospital care for traumatic cardiac arrest in the US: A cross-sectional analysis and call for a national guideline

"Dead or Alive?" Assessment of the Binary End-of-Event Outcome Indicator for the NEMSIS Public Research Dataset

OBJECTIVES

The National Emergency Medical Services Information System (NEMSIS) provides a robust set of data to evaluate prehospital care. However, a major limitation is that the vast majority of the records lack a definitive outcome. This study aimed to evaluate the performance of a recently proposed method ("MLB" method) to impute missing end-of-EMS-event outcomes ("dead" or "alive") for patient care reports in the NEMSIS public research dataset.

METHODS

This study reproduced the recently published method for patient outcome imputation in the NEMSIS database and replicated the results for years 2017 through 2022 (n = 686,075). We performed statistical analyses leveraging an array of established performance metrics for binary classification from the machine learning literature. Evaluation metrics included overall accuracy, true positive rate, true negative rate, balanced accuracy, precision, F1 score, Cohen's Kappa coefficient, Matthews' coefficient, Hamming loss, the Jaccard similarity score, and the receiver operating characteristic/area under the curve.

RESULTS

Extended metrics show consistently good imputation performance from year-to-year but reveal weakness in accurately indicating the minority class: e.g., after adjustments for conflicting labels, "dead" prediction accuracy is 77.7% for 2018 and 61.8% over the six-year NEMSIS sub-sample, even though overall accuracy is 98.8%. Slight over-fitting is also present.

CONCLUSIONS

This study found that the recently published MLB method produced reasonably good "dead" or "alive" indicators. We recommend reporting of True Positive Rate ("dead" prediction accuracy) and True Negative Rate ("alive" prediction accuracy) when applying the imputation method for analyses of NEMSIS data. More attention by EMS clinicians to complete documentation of target NEMSIS elements can further improve the method's performance.

Emergency Medical Services Protocols for Assessment and Treatment of Patients with Ventricular Assist Devices

BACKGROUND

Patients with ventricular assist devices (VADs) represent a growing population presenting to Emergency Medical Services (EMS), but little is known about their prehospital care. This study aimed to characterize current EMS protocols in the United States for patients with VADs.

METHODS

States with state-wide EMS protocols were included. Protocols were obtained from the state EMS website. If not available, the office of the state medical director was contacted. For each state, protocols were analyzed for patient and VAD assessment and treatment variables.

RESULTS

Of 32 states with state-wide EMS protocols, 21 had VAD-specific protocols. With 17 (81%) states noting a pulse may not be palpable, protocols recommended assessing alternate measures of perfusion and mean arterial pressure (MAP; 15 [71%]). Assessment of VAD was advised through listening for pump hum (20 [95%]) and alarms (20 [95%]) and checking the power supply (15 [71%]). For treatment, EMS prehospital consultation was required to begin chest compression in three (14%) states, and mechanical (device) chest compressions were not permitted in two (10%) states. Contact information for VAD coordinator was listed in a minority of five (24%) states. Transport of VAD equipment/backup bag was advised in 18 (86%) states.

DISCUSSION

This national analysis of EMS protocols found VAD-specific EMS protocols are not universally adopted in the United States and are variable when implemented, highlighting a need for VAD teams to partner with EMS agencies to inform standardized protocols that optimize these patients' care.

Traumatic Cardiac Arrest-A Narrative Review

A paradigm shift in traumatic cardiac arrest (TCA) perception switched the traditional belief of futility of TCA resuscitation to a more optimistic perspective, at least in selected cases. The goal of TCA resuscitation is to rapidly and aggressively treat the common potentially reversible causes of TCA. Advances in diagnostics and therapy in TCA are ongoing; however, they are not always translating into improved outcomes. Further research is needed to improve outcome in this often young and previously healthy patient population.

Survival following Prehospital Traumatic Cardiac Arrest Resuscitation in the Israel Defense Forces: A Retrospective Study

BACKGROUND

Prehospital traumatic cardiac arrest (TCA) is associated with a poor prognosis and requires urgent interventions to address its potentially reversible causes. Resuscitative efforts of TCA in the prehospital setting may entail significant resource allocation and impose added tolls on caregivers. The Israel Defense Forces Medical Corps (IDF-MC) instructs clinicians to perform a set protocol in the case of TCA, providing prompt oxygenation, chest decompression and volume resuscitation. This study investigates the settings, interventions, and outcomes of TCA resuscitation by IDF-MC teams over 25 years in both combat and civilian settings.

METHODS

Retrospective study of the IDF-MC Trauma Registry between 1997-2022. Search criteria were applied to identify cases where the TCA protocol was initiated. A manual review of cases matching the search criteria was performed by two curators to determine the indications, interventions, and outcomes of casualties with prehospital TCA. Patients for whom interventions were performed outside of the TCA protocol, such as with measurable vital signs, were excluded. The primary outcome was survival to hospital admission, with the secondary outcome being return of vital signs in the prehospital setting.

RESULTS

Following case review, 149 patients with prehospital TCA were included, with a median age of 21 (interquartile range 19-27). Eighty-four (56.4%) presented with TCA in military or combat settings, with gunshot wounds and blast injuries being the most common mechanisms in this group. For 56 casualties (37.8%), all components of the protocol were performed (oxygenation, chest decompression, and volume resuscitation). Five (3.4%) casualties had return of vital signs in the prehospital setting, but none survived to hospital admission.

CONCLUSION

The prognosis of prehospital TCA is poor, and efforts to address its potentially reversible causes may often be futile. These notions may be further emphasized in military settings, where resources are limited, and extensive penetrating injuries are more common.

Emergency Medical Services Management of Bronchospasm in the United States: A Cross-Sectional Analysis and Nationwide Quality Assessment

Background/Objective: Bronchospasm, caused by asthma and other related conditions, is a significant cause of morbidity and mortality commonly managed by emergency medical services (EMS). We aimed to evaluate the quality of prehospital management of bronchospasm by EMS in the US.Methods: The National EMS Information System Public Release Research dataset, a nationwide convenience sample of prehospital patient care report data from 2018 to 2019, was used to capture 9-1-1 activations where patients aged ≥2 years were treated and transported by EMS for suspected bronchospasm. First, we described the extent to which EMS care met eight quality measures identified from available statewide EMS protocols, existing quality measures, and national guidelines. Second, we quantified the extent of risk-standardized agency-level variation in administration of inhaled beta agonists and systemic corticosteroids using logistic regression models, accounting for patient characteristics, severity, and clustering by agencies. Third, we compared rates of completed prehospital interventions between pediatric (age <18 years) versus adult patients using two-sample t-tests.Results: A total of 1,336,988 EMS encounters for suspected bronchospasm met inclusion criteria. Median age of patients was 66 years, with only 4% pediatric; 55% were female. Advanced life support (ALS) units managed 94% of suspected bronchospasm. Respiratory rate (98%) and pulse oximetry (96%) were documented in nearly all cases. Supplemental oxygen was administered to hypoxic patients by 65% of basic life support (BLS) and 73% of ALS units. BLS administered inhaled beta-agonist therapy less than half the time (48%), compared to 77% by ALS. ALS administered inhaled anticholinergic therapy in 38% of cases, and systemic corticosteroids in 19% of cases. Pediatric patients were significantly less likely to receive supplemental oxygen when hypoxic, inhaled beta-agonists, inhaled anticholinergics, or systemic corticosteroids.Conclusions: We found important gaps in recent EMS practice for prehospital care of suspected bronchospasm. We highlight three targets for improvement: inhaled beta-agonist administration by BLS, systemic corticosteroid administration by ALS, and increased interventions for pediatric patients. These findings indicate important areas for research, protocol modification, and quality improvement efforts to improve EMS management of bronchospasm.