First Results of Our Local Practice Guide Used During the Late Phase of Resuscitation in Patients with Refractory VF in Out of Hospital Cardiac Arrest.

Objective: Treatment of refractory ventricular fibrillation (rVF) is a clinical challenge. If rVF is still present after standard advanced life support (ALS) guideline care, including amiodaron administration, other therapeutic options might be necessary. Based on the available evidence and expertise, our Helicopter Emergency Medical Service (HEMS) team developed a local practice guide for the prolonged resuscitation of patients in rVF and implemented this as standard HEMS care in March 2022.

Methods: This database study contains all patients treated with our local practice guide during out of hospital cardiac arrest (OHCA) with rVF beyond the fifth regular ALS shock-block. This local practice HEMS treatment algorithm consisted of, among others, cessation of epinephrine and alternating administration of esmolol and norepinephrine combined with enoximone. Data were derived from the HEMS database and the treating hospitals. Primary outcome was the return of spontaneous circulation. Secondary outcome was defined as survival to hospital discharge and cerebral performance. This outcome was compared to the literature to analyze for inferiority of treatment.

Results: In a 21-month period, HEMS was 761 times deployed for OHCA. Nineteen patients were treated with the local practice guide, nine patients (47%) were admitted to hospital with return of spontaneous circulation. Median resuscitation time was 22min. Hospital survival with good neurology was achieved in 42% vs 17% as expected. Exact Clopper-Pearson and logistic regression analysis revealed non-inferiority of the local practice guide. Withholding epinephrine was achieved in 84% of patients. A total of 79% and 90% of patients received esmolol and norepinephrine/enoximone mixture, respectively. Alternative defibrillation positions were indicated in 18 patients but applied in only 6 (33%).

Conclusion: In patients with persisting VF despite prolonged advanced life support care, a multifaceted bundle of care approach shows promising results and warrants further research. Alternative drug administrations were found to be substantially easier to achieve compared to alternative defibrillation positions.