Prehospital Care of Trauma Patients in Los Angeles County During the Early COVID-19 Pandemic

Abstract

Early in the coronavirus disease 2019 (COVID-19) pandemic, emergency medical services (EMS) personnel encountered significant changes in the volume and nature of activations. 1 Similar to the inpatient setting, reports suggest that prehospital care practices by EMS also changed during this period, most notably for patients with various cardiovascular conditions. 2,3 It remains unclear whether this also occurred in trauma patients, as data are lacking for this population. The aim of this study was to assess whether the prehospital care of trauma patients in Los Angeles County (LAC) changed during the early stage of the pandemic. We hypothesized that prehospital field interventions involving exposure to the airway were performed less frequently while transport times also decreased. The study was reviewed by the Institutional Review Board and deemed exempt. De-identified data were obtained from the LAC EMS Agency including the EMS Provider and Trauma Registries. The LAC EMS Agency is responsible for all EMS and inpatient data for trauma patients within the county of 10.5 million residents. All trauma-related EMS activations from March 1 to June 30 in 2019 and 2020 were analyzed. Patients who were not transported to any facility or who were missing all variables in the EMS Provider registry were excluded. Field interventions were selected based on the likelihood of exposure to the airway and included bag-valve-mask (BVM) ventilation, placement of a cervical collar, wound dressing placement, needle thoracostomy, oropharyngeal or nasopharyngeal airway, and administration of supplemental oxygen. A comparison of field interventions between study periods was performed using multivariable binary logistic regression while adjusting for age, sex, mechanism of injury (blunt, penetrating, other), dichotomized Injury Severity Score (ISS: ≥16 vs <16), dichotomized Glasgow Coma Scale (GCS: <9 vs ≥9), and field vital signs (heart rate, respiratory rate, and systolic blood pressure). Models were assessed for linearity using the Box-Tidwell test for each regressor that was not an indicator variable. The resulting models were evaluated for multicollinearity by examining the variance inflation factor for each regressor, for each fitted model. With regard to EMS response and transport times, specific timepoints were extracted from the EMS Provider registry for each transport and compared using the Mann-Whitney test. These variables were reported as medians with interquartile ranges (IQRs). Multiple imputation was used to account for missing data. Unadjusted P-value less than or equal to .01 were considered significant. Statistical analysis was performed using Stata version 17.0 (StataCorp, College Station, TX, USA) and R version 4.0.4. A total of 9 055 EMS encounters met our inclusion criteria for analysis, of which 4 517 occurred in the 2020 period. The patients in 2020 were older (median (IQR), 43 (28-61) vs 41 (28-59) years; P = .01), and sustained a higher proportion of penetrating injuries (18.8% vs 16.5%; P = .01). Along these lines, the proportion of blunt injuries in 2020 was lower (74.0% vs 77.4%; P < .001), as was the median Injury Severity Score (5 (2-13) vs 6 (3-13); P = .004). There were no significant differences in Glasgow Coma Scale or field vital signs. On multivariable logistic regression, field interventions that occurred less frequently during the pandemic period included BVM ventilation, placement of a cervical collar, use of an oropharyngeal or nasopharyngeal airway, and administration of supplemental oxygen (Figure 1). No significant differences were observed in the placement of wound dressings or needle thoracostomy. On evaluation of EMS response times, the duration between dispatch and EMS arrival on scene was similar between years (median (IQR), 6 (4-8) vs 6 (4-8) min; P = .07). On the other hand, the transport time between departure from the scene and arrival at a facility was shorter in 2020 (median (IQR), 9 (6-13) vs 10 (6-15) min; P < .01) along with overall time from dispatch to facility. Figure 1. Forest plot demonstrating logistic regression analysisa for field interventions performed by emergency medical services in 2020 vs 2019. Abbreviations: OPA, oropharyngeal airway; NPA, nasopharyngeal airway. Multivariable binary logistic regression adjusting for age, sex, mechanism of injury (blunt, penetrating, other), injury severity score ≥16, traumatic brain injury, heart rate, respiratory rate, and systolic blood pressure. The delivery of prehospital care in the COVID-19 era continues to evolve. The present study analyzed over 4500 EMS patient transports in the country’s most populous county during a 4-month period in the first half of 2020. When compared to the same pre-pandemic calendar period, transport times were shorter, and significant changes were noted in the performance of EMS field interventions. To our knowledge, this is the first pre- and post-pandemic comparison study of prehospital interventions for trauma patients. The reason for our findings is likely multifactorial. The 2020 study period encompassed the initial rise in cases and represented a time of uncertainty regarding the severity and transmissibility of the virus. Given the close interaction with individuals of unknown viral status in confined spaces, first responders were at high risk of exposure. In order to help protect EMS personnel and preserve availability of resources, the LAC EMS Agency drafted a series of policy changes, the first of which was implemented in March 2020. These centered around identifying low-acuity patients with COVID-19 symptoms who did not warrant immediate transport to a facility as well as treatment and safety protocols for patients with known or suspected COVID-19. Other guidelines specifically related to field interventions were later instituted; however, these unlikely influenced our results as they were implemented beyond our study period. Similar prehospital treatment protocols geared toward protecting EMS personnel were developed across the country. In Western Pennsylvania, where health system directors recommended avoiding aerosol generating procedures, Satty et al 3 found an increase in the use of advanced airways over a similar period to the present study. Contrary to our results, they showed a slight increase in the use of supplemental oxygen. The timing of the updated recommendations in relation to their study period and how that could have impacted their findings is unclear. In addition to EMS policy changes, traffic volume was diminished early in the pandemic, and this likely contributed to the changes seen in transport times. The longer on-scene time in 2020 could reflect additional time spent donning personal protective equipment. Despite the overall quicker arrival to a trauma facility, the clinical significance of this slight improvement is difficult to discern, especially for those without life-threatening injuries. Along these lines, and in the setting of the differences observed in field interventions, it is important to note that a prior analysis of trauma patients in LAC showed no difference in 30-day mortality during the first half of 2020 when compared to the year prior. 4 The pandemic has provided all levels of the health care system with a foundation upon which we can prepare for future outbreaks of infectious disease, especially those with airborne transmission. Guidelines for the prehospital care of trauma patients in these settings should continue to focus on ensuring the safety of EMS providers while providing necessary interventions. Limitations of the study include its use of retrospective data, reliance on accurate data recording, and focus on patients within a specific county which may limit its applicability to other regions. In addition, we did not include endotracheal intubation in our analysis of field interventions given that it is performed exceedingly rare by EMS in LAC. Similar studies from other parts of the country are warranted to further inform EMS policies and assess for changes in outcomes.