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Objective: The effect of pre-emptive milrinone without bolus during off-pump coronary artery bypass surgery (OPCAB) was evaluated in two groups of patients with low and normal pre-graft cardiac index., Methods: Eighty-two patients were divided into two groups based on their pre-graft cardiac index. Each group was randomly subdivided into two groups to receive either milrinone or normal saline. After the internal mammary artery was harvested, the infusion of milrinone, or normal saline was started and maintained until the end of the anastomosis. The haemodynamic variables were measured: just before the start of milrinone or normal saline after pericardiotomy (baseline value); 10 min after the tissue stabilizer had been applied for the anastomosis of left anterior descending artery, left circumflex artery and right coronary artery; and after the sternal closure., Results: Milrinone reduced the extent of the decrease in cardiac index and stroke volume as well as the extent of the increase in systemic and pulmonary vascular resistance. The extent of the decrease in cardiac index and mixed venous oxygen saturation were greater in normal pre-graft cardiac index group than in low pre-graft cardiac index group regardless of milrinone infusion during anastomoses. The effect of milrinone on haemodynamics showed no significant difference between low and normal pre-graft cardiac index groups., Conclusions: Pre-emptive milrinone infusion without bolus effectively improved cardiac performance during OPCAB and was especially useful for patients with low pre-graft cardiac index to prevent the decrease in cardiac index and stroke volume index below the critical level.

Objective: This study was designed to evaluate the serial haemodynamic changes during coronary artery anastomoses using two deep pericardial stay sutures and octopus tissue stabilizer in patients undergoing initial experiences of off-pump coronary artery bypass graft surgery (OPCAB) using continuous cardiac output and mixed venous oxygen saturation (SvO(2)) monitoring., Methods: With IRB approval, thirty patients undergoing OPCAB were studied. Pulmonary artery catheter (PAC) for continuous cardiac output and SvO(2) monitoring was inserted before anaesthesia. Haemodynamic measurements were recorded after pericardiotomy for baseline value. During each coronary artery anastomosis, haemodynamic variables were measured at 1,3,5,10, and 15 min after the application of tissue stabilizer and after the removal. Vasopressors were used to maintain mean arterial pressure (MAP) higher than 60 mmHg., Results: MAP and heart rate (HR) were maintained without significant change during the anastomoses of all three arteries. Cardiac index (CI), and SvO(2) decreased significantly after stabilizer application in all three arteries. CI was below 2.5 l/min/m(2) and SvO(2) was under 70% during left circumflex artery (LCX) anastomosis. The decrease in CI and SvO(2) were significantly greater during LCX anastomosis. The increase in mean pulmonary artery pressure (MPAP) and pulmonary capillary wedge pressure (PCWP) was significant only in left anterior descending artery (LAD). Central venous pressure (CVP) increased significantly during the anastomosis of all three coronary arteries. The differences in MPAP, PCWP and CVP among the three coronary arteries were not statistically significant. The highest dose of vasoconstrictor was used during LCX anastomosis., Conclusions: When the coronary anastomoses were performed with two deep pericardial stay sutures and octopus tissue stabilizer on the beating heart, CI and SvO(2) decreased significantly during all coronary artery anastomoses immediately after the stabilizer application and the degree of reduction in CI and SvO(2) increased with time, though MAP was maintained constantly. CI and SvO(2) during LCX anastomosis were consistently below normal values. Therefore close monitoring and proper managements are needed during graft anastomoses.

Objectives: Hemodynamic derangement during displacement of beating heart in off-pump coronary artery bypass graft (OPCAB) surgery might be related with right ventricular (RV) dysfunction. We evaluated RV function and hemodynamic alterations using a thermodilution pulmonary artery catheter., Methods: The study included 30 patients undergoing OPCAB, using single pericardial suture and tissue stabilizer. A thermodilution pulmonary artery catheter for continuous monitoring of the cardiac output (CO), right ventricular ejection fraction (RVEF) and RV volume was inserted before anesthesia. The hemodynamic variables were measured after the induction of anesthesia, 5 min after the heart was positioned for each coronary anastomosis and after the sternum was closed., Results: There was no significant change in the RVEF and cardiac index during anastomosis of the left anterior descending artery and right coronary artery. However, the significantly reduced RVEF accompanied by an increase in RV afterload and decrease in the CO was observed during anastomosis of the obtuse marginal (OM) artery. RV volumes did not significantly change during anastomoses, though the right atrial pressure increased during anastomoses of all coronary arteries., Conclusions: The displacement of beating heart for positioning during anastomosis of the graft to OM artery caused significant derangement of RV function and decrease in CO. A thermodilution catheter continuously measuring the CO and RVEF was useful to monitor the change in RV function and volume during OPCAB.

The haemodynamic effects of a continuous infusion of milrinone without an initial bolus dose were evaluated in patients undergoing off-pump coronary artery bypass graft surgery. After internal mammary artery harvest, milrinone 0.5 microg.min(-1).kg(-1) (29 patients) or a normal saline infusion (33 patients) was started and continued until all graft anastomoses were completed. Haemodynamic variables were recorded before application of the tissue stabiliser, at 1, 3, 5 and 10 min after the application of the stabiliser, and after its removal. The administration of a milrinone infusion was associated with a smaller decrease in cardiac output and mixed venous oxygen saturation during all the coronary artery anastomoses, with no severe complications and a decreased dose of norepinephrine infused to maintain systemic arterial pressure.

In this study the effect of phenylephrine and norepinephrine for the treatment of systemic hypotension were evaluated in patients with chronic pulmonary hypertension. When systemic hypotension (systolic arterial pressure < 100 mmHg) occurred following induction of anaesthesia, either phenylephrine or norepinephrine were infused in a random manner to raise the systolic blood pressure by 30% and 50% above baseline values. Norepinephrine decreased the ratio of pulmonary arterial pressure to systemic blood pressure without a change in cardiac index. However, phenylephrine did not increase arterial blood pressure by more than 30% from baseline in one-third of patients and decreased cardiac index without a significant decrease in ratio of pulmonary arterial pressure to systemic blood pressure. These vasoconstrictors showed different systemic and pulmonary haemodynamic effects in patients with chronic pulmonary hypertension as compared to acute pulmonary hypertension. Norepinephrine was considered to be preferable to phenylephrine for the treatment of hypotension in patients with chronic pulmonary hypertension.