Critical Care/Resuscitation
Abstracts
Raoul Daoust, MD, MSc
Université de Montréal/Hôpital du Sacré-Coeur de Montréal
Disclosure Relationship(s): Nothing to disclose
Background: Patients for whom the out-of-hospital cardiac arrest (OHCA) is not witnessed are generally not considered eligible for extracorporeal resuscitation (E-CPR) because the duration before the initiation of their resuscitation (no-flow) is uncertain. It has previously been proposed that an initial shockable rhythm (SR) strongly suggested a short period of no-flow. The objective of this study was to describe the association between the duration between the initiation of the prehospital resuscitation and the presence of a SR for patients suffering from an OHCA.
Methods: The present cohort study used a registry of adult OHCA between 2010 and 2015 in Montreal, Canada. Adult patients suffering from a non-traumatic OHCA for whom the OHCA was witnessed, who did not have by-stander cardiopulmonary resuscitation were included. Patients who had a paramedic-witnessed OHCA were also included as a control group (no-flow time = 0 minutes). Patients who experienced a return of spontaneous circulation (ROSC) before the paramedics’ arrival or for whom the initial rhythm was not known were excluded. The evolution of the proportion of SR was initially described and a multivariable logistic regression controlling for pertinent demographic and clinical variables (e.g. age, gender, time of the day).<
Results: A total of 1751 patients (male = 67%, mean age = 69 years [SD 16]) were included in the main analysis, of whom 603 (34%) had an initial shockable rhythm. A total of 663 other patients had their OHCA witnessed by paramedics. A shorter no-flow duration was associated with the presence of an initial SR (adjusted odds ratio = 0.97 [95%CI 0.94-0.99], p=0.016). However, this relation was not linear and the proportion of SR does not seem to lower until 15 minutes of no-flow duration (0 min = 35%, 1-5 min = 37%, 5-10 min = 35%, 10-15 min = 34%, more than 15 min = 16%).<
Conclusion: Although the proportion of patients with a SR decreases as the no-flow duration increase, this relationship does not appear to be linear. The main decline in the proportion of patients with SR seems to occur after the fifteenth minute of no-flow time.