Retrograde coronary blood flow during cardiopulmonary resuscitation in swine: intracoronary Doppler evaluation.

Cardiopulmonary resuscitation-generated coronary perfusion pressure and intracoronary flow velocity was studied with high-fidelity pressure transducers and an intracoronary Doppler catheter in 11 swine undergoing closed-chest manual cardiopulmonary resuscitation. Retrograde coronary blood flow in the mid left anterior descending coronary artery was documented during the compression (systolic) phase of chest compression. Techniques to enhance coronary perfusion pressure gradients, such as increasing the chest compression rate or increasing the force of compression, did not improve antegrade coronary blood flow velocity. Even when the aortic minus right atrial pressure gradient was raised throughout the cardiac cycle of closed-chest manual cardiopulmonary resuscitation, antegrade coronary flow occurred only during the relaxation phase of chest compressions. This study indicates that coronary blood flow during ventricular fibrillation and closed-chest cardiopulmonary resuscitation occurs only during diastole or the release phase of chest compression and supports the use of diastolic coronary perfusion pressure as a reflection of myocardial blood flow during closed-chest manual cardiopulmonary resuscitation.