Advanced Paramedic Paralysis in ROSC (APPiR) study

Introduction: Some patients who have an out-of-hospital cardiac arrest (OHCA) achieve a return of spontaneous circulation (ROSC), but many will show no signs of awareness pre-hospital. For a subset of patients who begin to show signs of awareness and distress, advanced paramedic practitioners (APPs) in critical care can administer analgesia and sedation. Additionally, for patients who have already had an endotracheal tube (ETT) placed, APPs may administer a neuromuscular blockade (NMB) agent under a patient group direction (PGD) to paralyse respiratory muscles where there is poor tolerance to the ETT and ventilatory control is required. Methods: A retrospective cohort study with quantitative descriptive and inferential statistical analysis was conducted for all occasions where APPs within one ambulance service administered an NMB agent. The study period was one year, from 1 June 2024 to 31 May 2025. PGD compliance was assessed and data were collected that informed the circumstances in which NMB occurred. Furthermore, relevant patient vital signs were scrutinised for the 10-minute period before and after administration to establish possible physiological trends in oxygen saturations, end-tidal carbon dioxide, mean arterial pressure and heart rate. Results: APPs administered NMB to 99 patients. Of those, 85 (85.9%) patients were male and the mean age was 57.6 years. Most patients had a witnessed arrest and bystander CPR. Over half the group presented with a shockable rhythm. Median time to NMB was 71 minutes from OHCA, 40 minutes post ROSC and 28 minutes prior to the arrival at hospital. All APP endotracheal intubation occurred within two attempts. In all cases the PGD indication for NMB was met. There were no statistically significant adverse physiological trends identified in the oxygen saturations, end-tidal carbon dioxide, mean arterial pressure or heart rate. Conclusion: Despite the challenges involved in managing OHCA ROSC patients, APPs were able to administer NMB within PGD and without adversely affecting physiological measurements. Comparative pre-hospital systems may find this data useful to help inform their own critical care scope of practice.