The use of sodium nitrite during active resuscitation did not significantly improve survival to hospital admission or to discharge among patients who suffered out-of-hospital cardiac arrest, according to late-breaking trial results presented Sunday at the American College of Cardiology Scientific Sessions 2020 virtual conference.
The results of this randomized clinical trial were presented by Francis Kim, MD, of the University of Washington.
Previous animal models demonstrated that therapeutic delivery of sodium nitrite during resuscitation in a cardiac arrest scenario improved absolute survival by 30%. The aim of this current trial was to determine whether sodium nitrite given intravenously or intraosseously by paramedics during attempted resuscitation from out-of-hospital cardiac arrest (OHCA) improves survival to hospital admission and survival to discharge. In the trial, patients with OHCA from ventricular fibrillation (VF), asystole or pulseless electrical activity (PEA) were randomly allocated to 45 mg of sodium nitrite (96 VF, 220 asystole, 154 PEA), 60 mg of sodium nitrite (126 VF, 219 asystole, 136 PEA); or placebo (119 VF, 205 asystole, 147 PEA). The medication was given by bolus injection by paramedics in the field. Five EMS agencies and 10 receiving hospitals in Seattle and King County, Washington, participated. The primary outcomes were survival to hospital admission and survival to discharge with an 80% power to detect an absolute increase in hospital admission rates of 8%.
The results demonstrated that the baseline characteristics were similar across the three groups, with approximately 43% having a witnessed arrest, the time from call to randomization being 22 minutes and no difference in terms of return of spontaneous circulation sustained on emergency department arrival. In terms of the primary outcomes, there was no difference in survival to admission and survival to discharge among the three groups. In addition, there was no difference in survival to discharge in a secondary analysis looking specifically at VF versus non-VF patients.
The authors concluded that the use of sodium nitrite during active resuscitation did not significantly improve survival to hospital admission or to discharge among patients who suffered OHCA. Improving outcomes in OHCA patients remains challenging, and ongoing trials are needed.