Epidemiology of out-of-hospital cardiac arrests that occur secondary to chemical asphyxiants: a retrospective series

Epidemiology of open limb fractures attended by ambulance clinicians in the out-of-hospital setting: A retrospective analysis

BACKGROUND

Open limb fractures are a time-critical orthopaedic emergency that present to jurisdictional ambulance services. This study describes the demographic characteristics and epidemiological profile of these patients METHODS: We undertook a retrospective analysis of all patients that presented to Queensland Ambulance Service with an open limb fracture (fracture to the humerus, radius/ulna, tibia/fibula or femur) over a two-year period (January 2018 - December 2019).

RESULTS

Overall, 1020 patients were included. Patients were mainly male (65.9%) and middle-aged (age 41 years, IQR 22-59). Fractures predominately occurred in the lower extremities (64.9%) with transport crashes the primary mechanism of injury (47.8%). The location of the fracture varied depending on the cause of injury, with femur fractures associated with motorcycle crashes, and fractures to the radius/ulna attributed to falls of greater than one metre (p = 0.001). The median prehospital episode of care was 83 min (IQR 62-144) with aeromedical air ambulance involvement and the attendance of a critical care paramedic or emergency physician, both independent factors that increased this time interval.

CONCLUSION

Open limb fractures are a relatively infrequent injury presentation encountered by ambulance clinicians. The characteristics of these patients is consistent with previously described national and international out-of-hospital trauma cohorts.

Epidemiology and survival outcomes of out-of-hospital cardiac arrest following volatile substance use in Queensland, Australia

INTRODUCTION

The deliberate inhalation of volatile substances for their psychotropic properties is a recognised public health issue that can precipitate sudden death. This study aimed to describe the epidemiological characteristics and survival outcomes of patients with out-of-hospital cardiac arrests following volatile substance use.

METHODS

We conducted a retrospective cohort analysis of all out-of-hospital cardiac arrest attended by the Queensland Ambulance Service over a ten-year period (2012-2021). Incidents were extracted from the Queensland Ambulance Service cardiac arrest registry, which collects clinical information using the Utstein-style guidelines and linked hospital data.

RESULTS

During the study period, 52,102 out-of-hospital cardiac arrests were attended, with 22 (0.04%) occurring following volatile substance use. The incidence rate was 0.04 per 100,000 population, with no temporal trends identified. The most commonly used product was deodorant cans (19/22), followed by butane canisters (2/22), and nitrous oxide canisters (1/22). The median age of patients was 15 years (interquartile range 13-23), with 14/22 male and 8/22 Indigenous Australians. Overall, 16/22 patients received a resuscitation attempt by paramedics. Of these, 12/16 were bystander witnessed, 10/16 presented in an initial shockable rhythm, and 9/16 received bystander chest compressions. The rates of event survival, survival to hospital discharge, and survival with good neurological outcome (Cerebral Performance Category 1-2) were 69% (11/16, 95% CI 41-89%), 38% (6/16, 95% CI 15-65%) and 31% (5/16, 11-59%), respectively. Eight patients in the paramedic-treated cohort that used hydrocarbon-based products were administered epinephrine during resuscitation. Of these, none subsequently survived to hospital discharge. In contrast, all six patients that did not receive epinephrine survived to hospital discharge, with 5/6 having a good neurological outcome.

CONCLUSION

Out-of-hospital cardiac arrest following volatile substance use is rare and associated with relatively favourable survival rates. Patients were predominately aged in their adolescence with Indigenous Australians disproportionately represented.