Diagnostic value of gasp frequency combined with echocardiography for assessing cardiac arrest and myocardial function during cardiopulmonary resuscitation in rats

Gasping occurring spontaneously during cardiac arrest (CA) may be associated with resuscitation outcomes, but the quantitative characteristics and the underlying mechanisms of its association with myocardial injury are still unclear. This study utilized a rat model to jointly explored the association between gasping frequency monitored during cardiopulmonary resuscitation (CPR) and echocardiography parameters, evaluating their diagnostic efficacy for CA and cardiac function. The CA model was established in 45Sprague-Dawley (SD) rats, and the rats were assigned to CA 4, 8, and 12 min groups (AG, BG, CG). Gasping parameters and echocardiographic parameters were dynamically monitored after CPR. The relationship between the peak frequency of gasping (Fmax) and cardiac function indicators was analyzed. Longer periods of CA lead to the lower Fmax. The return of spontaneous circulation (ROSC) success rate in the AG was 86.7%, visibly higher than the 26.7% in the BG and CG (P < 0.05). In the AG, ejection fraction (EF), cardiac output (CO), Tei index, systolic peak velocity (S’), and strain rates (SRs) were restored to baseline levels within 60 min after ROSC, while these parameters remained below baseline in the BG and CG (P < 0.05). Fmax was positively correlated with EF%, CO, S’, and SRs (r = 0.58–0.69), and negatively correlated with the Tei index (r = -0.75). The peak gasp frequency (Fmax) monitored during the no-flow phase of CA and the initial phase of CPR demonstrated significant correlation with high-frequency echocardiographic parameters (Tei index, strain rate). In the rat model, Fmax may serve as a non-invasive predictor for CA duration and the risk of post-resuscitation myocardial dysfunction.