Association between case volume and mortality in pre-hospital anaesthesia management: a retrospective observational cohort

Abstract

Background: Pre-hospital anaesthesia is a core competency of helicopter emergency medical services (HEMS). Whether physician pre-hospital anaesthesia case volume affects outcomes is unknown in this setting. We aimed to investigate whether physician case volume was associated with differences in mortality or medical management. Methods: We conducted a registry-based cohort study of patients undergoing drug-facilitated intubation by HEMS physician from January 1, 2013 to August 31, 2019. The primary outcome was 30-day mortality, analysed using multivariate logistic regression controlling for patient-dependent variables. Case volume for each patient was determined by the number of pre-hospital anaesthetics the attending physician had managed in the previous 12 months. The explanatory variable was physician case volume grouped by low (0e12), intermediate (13e36), and high (!37) case volume. Secondary outcomes were characteristics of medical management, including the incidence of hypoxaemia and hypotension. Results: In 4818 patients, the physician case volume was 511, 2033, and 2274 patients in low-, intermediate-, and highcase-volume groups, respectively. Higher physician case volume was associated with lower 30-day mortality (odds ratio 0.79 per logarithmic number of cases [95% confidence interval: 0.64e0.98]). High-volume physician providers had shorter on-scene times (median 28 [25the75th percentile: 22e38], compared with intermediate 32 [23e42] and lowest 32 [23e43] case-volume groups; P<0.001) and a higher first-pass success rate for tracheal intubation (98%, compared with 93% and 90%, respectively; P<0.001). The incidence of hypoxaemia and hypotension was similar between groups. Conclusions: Mortality appears to be lower after pre-hospital anaesthesia when delivered by physician providers with higher case volumes.

Association between physician's case volume in prehospital advanced trauma care and 30-day mortality: A registry-based analysis of 4,032 patients

“…A survey of nonphysician emergency medical services personnel in Northern Finland reported a mean annual frequency of 1.1 drug-assisted intubations among providers licensed to perform the procedure 21 . In our previous studies, we found the median to be 11 per year among Finnish HEMSs physicians and a higher annual number to be associated lower mortality 10,16 . However, the volume-outcome relationship in prehospital critical care does not seem to be universal, as more active treatment for patients resuscitated from out-of-hospital cardiac arrest by physicians with high case volumes did not lead to higher survival rates 22 .…”

“… 21 In our previous studies, we found the median to be 11 per year among Finnish HEMSs physicians and a higher annual number to be associated lower mortality. 10 , 16 However, the volume-outcome relationship in prehospital critical care does not seem to be universal, as more active treatment for patients resuscitated from out-of-hospital cardiac arrest by physicians with high case volumes did not lead to higher survival rates. 22 To better understand the sorts of prehospital emergencies benefiting from centralization warrants studies like this one.…”

“…Recently, an association between the case volume of HEMSs physicians and mortality after prehospital anesthesia was found. 10 For patients with major trauma, dedicated teams are allocated in the emergency department, and the most severe cases are transported to dedicated trauma centers. 11 , 12 Trauma centers with higher case volumes have been shown to achieve better outcomes, which has led to minimum volume standards being implemented in many countries.…”

“…However, the literature on the relationship between case volume and outcome in prehospital critical care is limited. Recently, an association between the case volume of HEMSs physicians and mortality after prehospital anesthesia was found 10 . For patients with major trauma, dedicated teams are allocated in the emergency department, and the most severe cases are transported to dedicated trauma centers 11,12 .…”

A scenario based approach to optimizing cost-effectiveness of physician-staffed Helicopter Emergency Medical Services compared to ground-based Emergency Medical Services in Finland

“…In the modelling, a service needs assessment forecast was created, integrating data from completed HEMS missions, the entirety of EMS missions coordinated by the emergency center, specific risk classifications on a municipal level, road network information, and population statistics. The modelling incorporated findings that centralizing advanced prehospital care with specialized teams lowers patient mortality, informed by literature and HEMS experts [ 12 , 13 ].…”