Background. Out-of-hospital cardiac arrest (OHCA) is associated with a high mortality rate in the elderly. Although most reports have investigated among elderly patients with OHCA until 1990s, non-invasive monitorings cannot presently predicted cerebral resuscitation during cardiopulmonary resuscitation (CPR). Findings of a previous study suggest that monitoring of middle latency auditory evoked potentials (MLAEP) during CPR could provide an indicator of effective post-resuscitation survival.
Objectives. We speculated that the MLAEP index (MLAEPi), measured in an emergency room, can predict post-resuscitation survival among elderly patients with OHCA.
Methods. This prospective study included 31 elderly patients aged ≥65 years with OHCA who received basic life support (BLS) and did not achieve restoration of spontaneous circulation (ROSC) until arrival at the emergency center between December 2010 and December 2011. All patients were administered advanced cardiac life support (ACLS) in the emergency room. Initial MLAEPi was measured using an MLAEP monitor (aepEX plus®, Audiomex, UK) during the first cycle of ACLS. Prediction of the post-resuscitation survival was investigated.
Results. Eight patients who achieved ROSC were admitted to our hospital and 23 did not achieve ROSC in the emergency room. Initial MLAEPi was significantly higher in patients with than without ROSC (median, 33 vs. 26, p = 0.02). Three survivors, among patients with ROSC, were discharged from our hospital (survivors) and 5 died during hospitalization (non-survivors). Initial MLAEPi was significantly higher in survivors than in non-survivors (median, 35 vs. 28, p = 0.03) or patients without ROSC (median, 35 vs. 26, p < 0.01).
Conclusions. MLAEPi satisfactorily denotes cerebral function and predicts post-resuscitation survival in elderly populations.
Key words: cardiopulmonary resuscitation, basic life support, advanced cardiac life support, age, monitoring, critical care