Comparison of the effectiveness of two CPR techniques through the use of predictive metrics and the measurement of regional blood flows
Abstract
Bystander CPR has been recognized as an important link in improving the survival rate for out-of-hospital cardiac arrest. One potential CPR technique for use by bystanders is rhythmic only abdominal compression CPR (OAC-CPR). However, little is known about its strengths and weaknesses relative to continuous chest compression CPR (CC-CPR). In this study, intrasubject comparisons between OAC-CPR and CC-CPR were made during two minute intervals of fibrillation. Predictive metrics of survival and neurological outcome were monitored. No significant difference in the cardiac output between the two techniques was found, while OAC-CPR produced greater blood oxygenation and no abdominal damage over short periods of application. However, OAC-CPR also produced lower carotid flow, and resulted in a greater time from a successful defibrillation until strong heartbeats were observed. End-tidal CO2 measurements suggest that this rate and force combination creates arterial hypocapnia, perhaps causing coronary and cerebral vasoconstriction. For a more detailed observation of the techniques, regional blood flow measurements using a microsphere deposition technique were made. This indicated that OAC-CPR produced lower coronary and cerebral blood flows. As such, OAC-CPR is not recommended for use by bystanders in its current form. Future work will need to center on the refinement of a mathematical model of the technique that incorporates all relevant cardiovascular effects that the technique may experience. From this refined model, a more optimal form of OAC-CPR may be able to be developed and tested in-vivo. As a low risk of regurgitation and abdominal damage was observed for OAC-CPR in this study, its use as circulatory support during cardiac arrest in patients that have recently undergone open heart surgery remains promising.
Degree
M.S.B.M.E.
Advisors
Rundell, Purdue University.
Subject Area
Biomedical engineering|Medicine
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