Abstract 358: Three-Sided Chest Compression is Beneficial to Rats Suffering From Cardiac Arrest

Abstract

Objective: Rat models are necessary to study targeted interventions to improve survivability in patients suffered from a cardiac arrest (CA). For translational researchers, increasing the rate of return of spontaneous circulation (ROSC) is important to reduce the number of rats being used to obtain sufficient data. Yet, few studies have demonstrated how to perform better chest compression on rats. Methods: Rats underwent 10 min of asphyxia to induce CA. All rats were placed in a supine position. Three types of chest compression were examined: 1-sided method (classic) with 2 fingers on the sternum; 2-sided method with 2 fingers on the chest from both sides; and the 3-sided method with 2 hands (2 fingers on the sternum and with 2 fingers on the chest). ROSC rates, cardiac function, arterial pressure(s), intrathoracic pressure, cerebral oxygenation, and end-tidal CO 2 (EtCO 2 ) were measured. In addition, survival after 14-min asphyxia was assessed. Results: Male Sprague-Dawley rats were used and there were no differences in chest compression rates among the three groups. The ROSC rate was 100% (8/8) with the 3-sided method, 80% (4/5) with the 1-sided method, and 60% (3/5) with the 2-sided method. The 3-sided group showed significantly shorter time to ROSC (105.0±36.0 sec for the 1-sided method vs.141.0±21.7 sec for the 2-sided method vs. 57.8±12.3 sec for the 3-sided method, p<.05). The 3-sided method significantly increased the left ventricular stroke volume (the ratio of baseline: 1.2±0.6, 1.3±0.1, vs. 2.1±0.6, p<.05) and pressure (24.0±5.5, 19.8±3.4, vs. 29.4±1.8 mmHg, p<.05), the difference of common carotid arterial pressure to femoral artery pressure (4.0±2.5, 0.3±1.6, vs. 8.4±2.6 mmHg, p<.01), intrathoracic pressure (esophagus: 7.6±1.9, 7.3±2.8, vs. 12.7±2.2 mmHg, p<.01), cerebral oxygenation (the ratio of baseline: 1.4±0.1, 1.3±0.2, vs. 1.6±0.04, p<.05) and EtCO 2 (the ratio of baseline: 12.4±2.0, 14.2±1.9, vs. 17.5±1.7 mmHg, p<.05). The 3-sided chest compression achieved 75% (3/4) ROSC from 14-min asphyxia CA. Conclusions: The 3-sided chest compression was associated with the most successful ROSC. It is likely that the 3-sided method increased intrathoracic pressure and stabilized cardiac function, which might be beneficial to the brain.