Abstract P148: Patients Presenting with Initial Non-shockable Rhythms after Cardiac Arrest Do Not Have Inferior Outcome If They Progress to a Shockable Rhythm
Background: Cardiac arrest patients presenting with initial non-shockable rhythms have previously been reported to have inferior outcome if they progress to a shockable rhythm. We wanted to confirm this observation in our prospectively collected database, and assess whether differences in CPR quality could help explain any such difference in outcome.
Materials and methods: All out-of-hospital cardiac arrest cases in the Oslo EMS between May 2003 and April 2008 were retrospectively studied, and cases with initial asystole or pulseless Electrical Activity (PEA) were selected. Ambulance run sheets, Utstein forms, Hospital records and continuous ECGs were reviewed. Quality of CPR and outcome were compared for patients who progressed to a shockable rhythm and patients who remained in non-shockable rhythms.
Results: There were 738 cases with initial non-shockable rhythms; 508 (69%) with asystole and 230 (31%) with PEA. One hundred and fourteen (16%) patients progressed to a shockable rhythm, while 622 (85%) remained in a non-shockable rhythm during the entire resuscitation effort (two unknown). There were no significant demographic differences between the shockable and non-shockable group. Hands-off ratio was higher in the shockable than the non-shockable group, 0.20±0.12 vs. 0.16±0.10 (p<0.001) with no significant difference in compression and ventilation rates (118±9 vs. 116±10 and 11±4 vs. 11±4, respectively. Seven patients (6.1%) survived to hospital discharge in the shockable group and 15 (2.4%) in the non-shockable group (p=0.064).
Conclusion: Patients presenting with non-shockable rhythms who progress to a shockable rhythm do not have inferior outcome compared to the patients who remain in non-shockable rhythms during the resuscitation effort. This occurred despite more pauses in chest compressions in the shockable group, probably related to defibrillation attempts.