Introduction: Cardiac surgery using cardiopulmonary bypass (CPB) and cardioplegic arrest is often associated with a hyperdynamic circulatory response and an impairment of myocardial function after CPB . We therefore tested the effects of beating heart surgery (BHS) on cardiopulmonary performance after CPB. BHS was assisted by a simplified bypass system (SBS) consisting of only a blood pump and the oxygenator.
Method: 46 patients (age 63 ± 9 years) undergoing coronary artery bypass grafting were studied. 16 patients (group H) were randomized to a conventional CPB circuit (HL-20, Jostra, Germany). Cardiac arrest was induced by 2000mL of crystalloid cardioplegic solution. 30 patients underwent BHS with assistance of a SBS: 15 patients (group D) were randomized to the DeltaStreamTM-system (Medos, Germany) and 15 patients (group C) to the CORxTM-system (CardioVention, USA). Haemodynamic monitoring consisted of transpulmonary thermodilution for assessment of stroke volume index (SVI), systemic vascular resistance index (SVRI) and intrathoracic blood volume index (ITBI). Fractional area change of the left resp. right ventricle (LV-resp. RV-FAC) was determined by transoesophageal echocardiography. Measurements were performed after induction of anaesthesia (IND), before (PRE) and after (POST) CPB and at end of surgery (EOS).
Results: Data (mean ± SD) are presented in the table:
Discussion: BHS using SBS offered only few advantages with regard to haemodynamic stability after CPB. Pulmonary gas exchange was less impaired in one SBS-group.
1 McBride WT, Elliott P. Advances in cardiopulmonary bypass circuitry. Curr Opin Anaesth