The value of spontaneous gasping associated with duration of cardiac arrest in predicting post-resuscitation myocardial dysfunction in a rat model

Abstract

Objective To analyze the timing and frequency of spontaneous gasping during cardiopulmonary resuscitation in a rat model,and evaluate its value bearing some relation to duration of cardiac arrest （CA ） in predicting the severity of post-resuscitation myocardial dysfunction.Methods Twenty-seven healthy Sprague-Dawley rats were randomly （random number）divided into 3 groups according to different durations of CA：CA 4 min （n=9）,CA 6 min （n=9）and CA 8 min （n=9）.CA of rats was electrically induced and untreated for 4,6 or 8 min respectively in the corresponding groups,and then cardiopulmonary resuscitation （CPR）was initiated and continued for 8 min in all animals.The emergence timing and frequency of spontaneous gasping during cardiopulmonary resuscitation and resuscitation outcomes were documented.Myocardial function such as cardiac output,ejection fraction and Tei index was measured by echocardiography prior to CA and at 1 h,2 h and 4 h post-resuscitation.Results The earliest appearance of gasping with highest frequency was observed in the CA 4 min group during CPR.Gasping appeared later with decreased frequency observed following longer duration of CA.There were statistically significant differences in the timing and frequency of gasping among the 3 groups.In the CA 4 min group with frequent gasping,all animals were successfully resuscitated with 8-min CPR with the least number of defibrillation,which was significantly better than that in the CA 8 min group.During the evaluation of post-resuscitation myocardial function,cardiac output,ejection fraction and myocardial work index （Tei index） were better in the CA 4 min group with frequent gasping,worse in the CA 6 min group and worst in the CA 8 min group, showing statistically significant differences in cardiac function among the 3 groups. Conclusions The spontaneous gasping appeared sooner with higher frequency during cardiopulmonary resuscitation indicated shorter duration of CA,and predicted better success of resuscitation and post-resuscitation myocardial function. Key words: Cardiac arrest; Cardiopulmonary resuscitation; Gasping; Myocardial dysfunction