RESUMEN
To determine whether adding blood to a cardioplegic solution affects myocardial preservation, a randomized prospective study was carried out in 60 patients undergoing coronary revascularization to compare the effects of crystalloid potassium cardioplegics (group C) and potassium cardioplegic solutions to which blood has been added (group B) on markers of myocardial metabolism (lactate, inorganic phosphate, base deficit release, glucose and lactate uptake, oxygen extraction), myocardial damage (creatine kinase [CK]-MB levels), and cardiac performance (cardiac index and left atrial pressure). The solution with added blood had a significantly (p less than .05) greater oxygen content, a lower pH, and higher concentrations of potassium, calcium, sodium, and glucose. In group B patients there was a suggestion (p less than .06) of greater uptake of oxygen during the beginning of the initial cardioplegic infusion. During reperfusion there was no evidence of differential release of the metabolites of anaerobiosis and myocardial oxygen extraction and glucose and lactate uptake were similarly depressed in both groups. Likewise, CK-MB release after bypass was the same in both groups. Prompt, adequate functional recovery of cardiac index and left atrial pressure was observed in both groups. It was concluded that although there may be more oxygen available from the blood-containing solution during early infusion, there is no evidence that under the conditions of this investigation adding blood to cardioplegic solution improves myocardial preservation.
Asunto(s)
Sangre , Puente de Arteria Coronaria , Circulación Coronaria/efectos de los fármacos , Miocardio/metabolismo , Compuestos de Potasio , Potasio , Creatina Quinasa/metabolismo , Femenino , Corazón/fisiopatología , Humanos , Isoenzimas , Masculino , Miocardio/enzimología , Estudios Prospectivos , Distribución AleatoriaRESUMEN
Cardiopulmonary bypass (CPB) alters systemic hemodynamics and affects several biochemical systems involved in cardiovascular regulation. We investigated the changes in levels of circulating epinephrine (E) and norepinephrine (NE) and related them to events during CPB. Twenty-eight patients undergoing various surgical procedures were studied. Plasma E and NE were determined by radioenzymatic assay at eight stages of the operation. A ninefold increase in arterial E (from 75 +/- 13 to 708 +/- 117.3 pg/ml) occurred from prebypass (stage 1) measurements to the end of aortic cross-clamping (stage 4). The values at stage 4 were significantly higher (p less than 0.05) than at all other stages. E decreased rapidly, to 360 +/- 84.3 pg/ml, after myocardial and pulmonary reperfusion (stage 5). Arterial NE increased twofold from stage 1 to stage 4 (from 426 +/- 66.9 to 825 +/- 84.2, p less than 0.05). The increase in NE from initial CPB values (stage 2) to 30 minutes of aortic cross-clamping (stage 3) was associated with an increase in mean blood pressure (r = 0.51, p = 0.02). The peak increases in catecholamines occurred when the heart and lungs were excluded from the circulation, which suggests that either or both contributed to the increase. Because the increase in E was markedly greater than that in NE, the predominant humoral response to CPB appears to be adrenomedullary release of E. This significant increase in catecholamines could jeopardize myocardial protective measures during CPB.