Combination of cardiac and thoracic pump theories in rodent cardiopulmonary resuscitation: a new method of three-side chest compression

Abstract Background High-quality cardiopulmonary resuscitation (HQ-CPR) is of paramount importance to improve neurological outcomes of cardiac arrest (CA). The purpose of this study was to evaluate chest compression methods by combining two theories: cardiac and thoracic pumps. Methods Male Sprague-Dawley rats were used. Three types of chest compression methods were studied. The 1-side method was performed vertically with 2 fingers over the sternum. The 2-side method was performed horizontally with 2 fingers, bilaterally squeezing the chest wall. The 3-side method combined the 1-side and the 2-side methods. Rats underwent 10 min of asphyxial CA. We examined ROSC rates, the left ventricular functions, several arterial pressures, intrathoracic pressure, and brain tissue oxygen. Results The 3-side group achieved 100% return of spontaneous circulation (ROSC) from asphyxial CA, while the 1-side group and 2-side group achieved 80% and 60% ROSC, respectively. Three-side chest compression significantly shortened the time for ROSC among the groups (1-side, 105 ± 36.0; 2-side, 141 ± 21.7; 3-side, 57.8 ± 12.3 s, respectively, P < 0.05). Three-side significantly increased the intrathoracic pressure (esophagus, 7.6 ± 1.9, 7.3 ± 2.8, vs. 12.7 ± 2.2; mmHg, P < 0.01), the cardiac stroke volume (the ratio of the baseline 1.2 ± 0.6, 1.3 ± 0.1, vs. 2.1 ± 0.6, P < 0.05), and the common carotid arterial pressure (subtracted by femoral arterial pressure 4.0 ± 2.5, 0.3 ± 1.6, vs. 8.4 ± 2.6; mmHg, P < 0.01). Three-side significantly increased the brain tissue oxygen (the ratio of baseline 1.4±0.1, 1.3±0.2, vs. 1.6 ± 0.04, P < 0.05). Conclusions These results suggest that increased intrathoracic pressure by 3-side CPR improves the cardiac output, which may in turn help brain oxygenation during CPR.

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

Circulation ◽

10.1161/circ.140.suppl_2.358 ◽

2019 ◽

Vol 140 (Suppl_2) ◽

Author(s):

Yu Okuma ◽

Koichiro Shinozaki ◽

Tsukasa Yagi ◽

Kota Saeki ◽

Tai Yin ◽

...

Keyword(s):

Cardiac Arrest ◽

Arterial Pressure ◽

Cardiac Function ◽

Chest Compression ◽

Cerebral Oxygenation ◽

Intrathoracic Pressure ◽

Spontaneous Circulation ◽

Left Ventricular ◽

Sprague Dawley ◽

Targeted Interventions

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.

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Levosimendan improves brain tissue oxygen levels after cardiopulmonary resuscitation independent of cardiac function and cerebral perfusion

10.21203/rs.2.19573/v1 ◽

2019 ◽

Author(s):

Andreas García-Bardon ◽

Jens Kamuf ◽

Alexander Ziebart ◽

Tanghua Liu ◽

Nadia Krebs ◽

...

Keyword(s):

Cardiac Arrest ◽

Cardiac Output ◽

Cardiopulmonary Resuscitation ◽

Brain Tissue ◽

Cerebral Perfusion ◽

Cerebral Oxygenation ◽

Cerebral Microcirculation ◽

Tissue Oxygen ◽

Oxygen Levels ◽

Brain Tissue Oxygen

Abstract Background: Prompt reperfusion is essential to rescue ischemic tissue, but in itself represents a key pathomechanism contributing to poor outcome after cardiac arrest. Experimental data suggest levosimendan as a therapeutic drug to limit ischemia-reperfusion injury by improving cerebral microcirculation and thereby reducing neuronal injury. However, recent studies question its effect on cardiac output and cerebral microcirculation in normally pumping hearts. The present study was designed to investigate the influence of levosimendan on hemodynamic parameters, cerebral perfusion, and cerebral oxygenation after cardiac arrest and resuscitation.Methods: Ventricular fibrillation was induced in anesthetized juvenile male pigs for 7 min, followed by cardiopulmonary resuscitation. After return of spontaneous circulation (ROSC) animals were randomly assigned to levosimendan (12µg/kg, followed by 0.3µg/kg/min) or vehicle (normal saline) treatment for 6 hours. Cerebral oxygen saturation and brain tissue oxygen levels were determined with near-infrared spectroscopy (NIRS) and fluorescence quenching tissue PbtO 2 probes. Cerebral and kidney perfusion were quantified by fluorescent-labeled microspheres and laser-doppler flowmetry. Results: Compared to vehicle, levosimendan treated animals showed significantly higher brain tissue oxygen levels after ROSC. This effect was not accompanied by changes in cardiac output, cardiac preload and afterload, arterial blood pressure, nor cerebral microcirculation, indicating a local levosimendan-mediated effect in the brain.Conclusions: Cerebral oxygenation is key to minimizing neurological damage during and after cardiac arrest. Therefore, current concepts aim at improving impaired cardiac output or cerebral perfusion pressure. In the present study we provide evidence that NIRS fails to reliably detect low brain tissue oxygen levels and that levosimendan improves brain oxygen content. Levosimendan may therefore present a promising therapeutic approach to rescue brain tissue at risk in patients after cardiac arrest or other causes of cerebral ischemia or malperfusion such as stroke or traumatic brain injury.

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