Vasodilatory shock requiring treatment with catecholamines occurs in some patients following cardiopulmonary bypass. We investigated the use of vasopressin in the treatment of this syndrome. Forty patients with a left main coronary artery disease and a poor left ventricular function (ejection fraction <30%) were studied. Only those patients (n=12, 30%) in whom difficulty was experienced in maintaining a mean arterial pressure of > 60 mm Hg and a systemic vascular resistance of greater than 900 dynes.sec.cm5 on maximal doses of pharmacological and mechanical support were selected. Patients underwent a standard cardiac anaesthesia protocol. All patients had a Swan-ganz catheter inserted pre-operatively. Arginine vasopressin was administered as a bolus of 0.015 units/kg intravenously followed by an infusion of 0.03 units/kg/hour. This dose increased the mean arterial pressure from 67+/-7 to 95+/-5 mm Hg and the systemic vascular resistance from 860+/-55 to 1502+/-71 dynes.sec.cm-5. It was also associated with a decrease in pharmacological support. All subjects responded to vasopressin administration. Vasopressin is an effective pressor in vasodilatory shock after cardiopulmonary bypass.

Blood conservation is an important aspect of care provided to the patients undergoing cardiac operations with cardiopulmonary bypass (CPB). It is even more important in patients with anticipated prolonged CPB, redo cardiac surgery, patients having negative blood group and in patients undergoing emergency cardiac surgery. In prolonged CPB the blood is subjected to more destruction of important coagulation factors, in redo surgery the separation of adhesions leads to increased bleeding and difficulty in achieving the haemostasis and in patients with negative blood group and emergency operations, the availability of sufficient blood can be a problem. Harvesting the autologous platelet rich plasma (PRP) can be a useful method of blood conservation in these patients. The above four categories of patients were prospectively studied, using either autologous whole blood donation or autologous platelet rich plasma (PRP) harvest in the immediate pre-bypass period. Forty two patients were included in the study and randomly divided into two equal groups of 21 each, control group (Group I) in which one unit of whole blood was withdrawn, and PRP group (Group II) where autologous plateletpheresis was utilised. After reversal of heparin, autologous whole blood was transfused in the control group and autologous PRP was transfused in the PRP group. The chest tube drainage and the requirement of homologous blood and blood products were recorded. Average PRP harvest was 643.33 +/- 133.51 mL in PRP group and the mean whole blood donation was 333.75 +/- 79.58 mL in the control group. Demographic, preoperative and intra operative data showed no statistically significant differences between the two groups. The PRP group patients drained 26.44% less (p<0.001) and required 38.5% less homologous blood and blood products (p<0.05), in the postoperative period. Haemoglobin levels on day zero (day of operation) and day three were statistically not different between the two groups. We conclude that autologous plateletpheresis is a better method of blood conservation in terms of better haemostasis, and less requirement of blood and blood products in the postoperative period as compared with the autologous whole blood donation. This technique can be especially useful in the above-mentioned categories of patients.

The effects of antegrade and antegrade with retrograde delivery of cardioplegic solution were evaluated in 60 patients who underwent myocardial revascularisation. All patients had triple vessel coronary artery disease and underwent revascularisation using arterial and vein grafts. Myocardial protection consisted of administration of the St.Thomas' Hospital cardioplegic solution, topical slushed ice and systemic hypothermia (28 degrees C-30 degrees C). The patients were categorised into: group A (n=30), who received antegrade cardioplegia alone, and group B (n=30), who received antegrade and retrograde cardioplegia. With the exception of the total dose of cardioplegic solution ('p'=0.02), there was no significant difference between the two groups. Cardiac function was assessed before and after the patient was weaned from the cardio-pulmonary bypass. There was a significant increase in the right atrial pressure and a significant decrease in the mean arterial pressure from the baseline ('p'<0.05), 10 minutes after cardiopulmonary bypass in group A. All patients in-group B had a spontaneous return to sinus rhythm after release of the aortic cross clamp, whereas 3 patients in group A required defibrillation to restore sinus rhythm. Intra aortic balloon pump support was necessary in 4 patients in group A, as against 1 patient in group B to terminate the cardiopulmonary bypass. The clinical outcome was similar in both groups. We conclude that the use of a combination of retrograde and antegrade cardioplegia facilitates early recovery of left ventricular function after coronary artery bypass grafting.