A Computer-based Study on the Effect of Sympathetic Activity during CPR

Alka Rachel John ,M Manivannan ,Natesan Damodaran

doi:10.31487/j.jicoa.2018.01.004

Abstract

Purpose: In spite of extensive studies, the mechanism of cardiopulmonary resuscitation (CPR) has not been properly understood and a proper comprehension of the role of regulatory mechanisms of the cardiovascular system during CPR is unavailable. Using computational methods, we try to study the influence of sympathetic activation on the cardiac output and mean arterial pressure (MAP) during CPR at different compression pressures and rates. Methods: A computer model was used to investigate the effect of sympathetic activation during CPR. The model has a detailed representation of the cardiopulmonary resuscitation system and sympathetic control. Sympathetic activation during CPR was achieved through vital cardiac parameters such as contractility and peripheral resistance. We compared the cardiac output and MAP during CPR in four scenarios, namely with; (1) sympathetic activation of heart alone, (2) sympathetic activation of the peripheral arteries alone, (3) sympathetic activation of both heart and peripheral arteries, and (4) no sympathetic activation; for different compression pressures and rates. Results: The results show that the cardiac output and MAP increases with increasing compression pressures and rates during CPR with sympathetic activation of peripheral arteries. The sympathetic activation of peripheral arteries during CPR at the AHA and ERC recommended chest compression pressures and rates resulted in an increased MAP, an augmented aortic diastolic pressure and a decreased cardiac output. The results also show that cardiac output and MAP pressure increases with increasing compression rate during CPR with sympathetic activation of heart. There is a slight increase in the MAP but no substantial improvement in cardiac output during CPR with sympathetic activation of heart at the AHA and ERC recommended pressures and rates. Conclusions: It is observed from the study that sympathetic activation of heart during CPR may not be beneficial at the AHA and ERC recommended chest compression rates as it gives very little improvement in cardiac output and MAP. However, performing CPR at higher compression rate may improve the chances of resuscitation when drugs are used to induce sympathetic activity in the heart. The augmented aortic diastolic pressure during CPR with sympathetic activation of peripheral arteries at the AHA and ERC recommended compression pressure and rates can improve the myocardial perfusion, but the reduced cardiac output is a cause of concern.

Highlights

Cardiopulmonary resuscitation (CPR) is an emergency lifesaving procedure that helps maintain life in a person whose heart has stopped beating
The cardiac output during CPR with SP and SHP was lesser than the cardiac output during CPR with no sympathetic activation of peripheral arteries for all compression pressures less than 130 compressions per minute (CPM)
As seen from figure 2, during CPR without any sympathetic activation of peripheral arteries, the maximal cardiac output is clearly distinguishable at a compression pressure of 100 mmHg

Summary

Introduction

Cardiopulmonary resuscitation (CPR) is an emergency lifesaving procedure that helps maintain life in a person whose heart has stopped beating. Redding and Pearson studied CPR in dogs and observed that while drugs inducing sympathetic activation of heart are not useful for resuscitation, the drugs inducing sympathetic activation of peripheral arteries are useful [4]. Yakaitis et al found that sympathetic activation of heart in dogs has little effect on successful resuscitation but the sympathetic activation of peripheral arteries during CPR improves the diastolic pressure, which is important for successful resuscitation [5]. Livesay et al studied the effect of drugs which cause the sympathetic activation of peripheral arteries during CPR in dogs and noted that the sympathetic activation of peripheral arteries results in an augmented aortic diastolic pressure, improving the coronary perfusion during CPR [6]. The work of Pearson and Redding worked on a dog model to show that drugs which cause a sympathetic activation of peripheral arteries during CPR improves the diastolic pressure, thereby improving the chances of spontaneous circulation [7]. The study of Micheal et al on dogs, noted that the drugs inducing sympathetic activation of heart improves the myocardial blood flow during CPR [9]

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Results

Conclusion