Influence of PEEP Ventilation Immediately after Cardiopulmonary Bypass on Right Ventricular Function: Conclusion

Rabinovitch et al concluded from their studies that the right side of the heart should not be neglected to achieve optimal myocardial protection during cardiac operations. High-grade RCA lesions can prevent the cold cardioplegia solution from reaching the right ventricular myocardium at a sufficient rate. Moreover, the right heart is not as well submerged as the left ventricle in the pericardial cold saline solution bath used for supplementary topical cooling due to its ventral location. Therefore, the right ventricle seems to be the most vulnerable aspect of an ischemic heart. Therefore, overall right ventricular dysfunction after CPB is not determined by the loading conditions alone. Local myocardial and septal involvement is suspected to be an important determinant of right ventricular function as well. xalatan generic

Forty-five min after weaning from CPB, a sufficient reperfusion of the myocardium with an improvement in myocardial 02 supply may have contributed in our patients to the fact that there was no more difference in right ventricular function between the two groups during the second period of PEEP application, and MAP and Cl could be maintained in this situation. On the other hand, volume expansion (eg, by infusion of washed erythrocytes) is thought to be an important mechanism by which CO (and MAP) can be restored when it is reduced as a result of increased right ventricular afterload or depressed contractility This mechanism, however, is limited because increasing right ventricular volume may have some adverse effects such as increased wall tension with an augmented myocardial oxygen demand, decreased left ventricular compliance and possible tricuspid regurgitation.
It can be concluded that application of PEEP is followed by complex hemodynamic changes. An increase in right ventricular afterload is tolerated by the right ventricle provided there is no factor concomitantly limiting the right ventricular contractility such as a high grade RCA stenosis. The present data suggest that right ventricular dysfunction secondary to ineffective myocardial preservation or to reduced blood flow may also result in significant impairment in global cardiac performance when PEEP is applied. Thus, the right ventricle seems to play an important role and might be the limiting factor in weaning from CPB. Precise monitoring of pulmonary and right ventricular hemodynamics are of greatest importance in this situation.

Category: Cardiopulmonary Bypass

Tags: cardiopulmonary bypass, coronary artery, ventricular function