Comparison of antihypertensives after coronary artery surgery.

Hypertension following coronary artery bypass grafting is a common problem that may result in postoperative myocardial infraction or bleeding, Hemodynamic effects were compared in 45 hypertensive coronary bypass patients randomized to receive either diltiazem, nitroglycerin, or sodium nitroprusside. Diltiazem was administered as an intravenous bolus of 0.3 mg.kg-1 within 5 min, followed by infusion of 0.1-0.8 mg.kg-1.h-1 in group 1. Nitroglycerin was infused at a rate of 1-3 microg.kg.h-1 in group 2, and sodium nitroprusside was given at a rate of 1-3 microg.kg-1.min-1 in group 3. Hemodynamic measurements were carried out before infusion (T1) and at 30 min (T2), 2 h (T3), and 12 h (T4) after initiation of treatment in the intensive care unit. Mean arterial pressure decreased significantly in all groups. There were no differences among groups at T1 and T2. At T3, heart rate in group 2 was significantly higher than group 1. At T3 and T4, the double product was highest in group 3 (group 1 vs. 3, p<0.001). These results suggest that the hemodynamic effects of the 3 drugs are similar within the first 30 min. However, after 30 min, diltiazem affords better myocardial performance and more effective control of hypertension.

Clopidogrel does not increase bleeding and allogenic blood transfusion in coronary artery surgery.

OBJECTIVES: Platelet dysfunction is one of the major reasons of postoperative bleeding following coronary artery surgery. The aim of this study was to evaluate the effects of clopidogrel; a specific and potent irreversible inhibitor of platelet aggregation; on bleeding and use of blood and blood products after coronary artery bypass surgery (CABG). METHODS: Preoperative patient characteristics and perioperative and postoperative data were collected prospectively in 1628 consecutive patients undergoing isolated CABG performed by the same surgical and anesthesia team. Of these, 48 were receiving clopidogrel preoperatively. Of the 1628 patients, 1456 underwent elective and 172 (10.6%) underwent non-elective operation. Thirty-six (2.5%) of the elective patients and 12 (7%) of the non-elective patients were using clopidogrel, preoperatively. Baseline characteristics, chest tube output, and the need for reexploration or for blood and blood product transfusion of clopidogrel recipients and non-recipients were compared. The clopidogrel group had higher prothrombin time level (12.6+/-1.6; 11.5+/-1.7 s, (P=0.013), however comparable aPTT level (32.6+/-4.5 vs. 31.4+/-4.5 s), and platelet count (275,000+/-98,000 vs. 280,000+/-72,000 dl(-1)). RESULTS: The need for reexploration or for blood and blood product transfusion, chest tube output, ICU length of stay (20.1+/-2.9 vs. 21.9+/-13.5 h; P=NS), and hospital length of stay (5.5+/-1.7 vs. 5.4+/-2.1 days; P=NS) were similar in clopidogrel recipients and non-recipients, respectively. Further analysis demonstrated no significant difference in use of homologous blood or fresh frozen plasma, amount of postoperative bleeding and reoperation rates for bleeding as well as length of intensive care unit and hospital stay between the clopidogrel and the control groups both in elective and non-elective patients. CONCLUSIONS: The results of this study suggest that preoperative use of clopidogrel is not associated with increased bleeding and need for surgical exploration as well as risk of blood and blood product transfusion after CABG.

Fast track recovery of high risk coronary bypass surgery patients.

OBJECTIVE: Fast track recovery protocols on younger, low risk patients result in shorter hospital stays and decreased costs. However, data is lacking on the impact of these protocols on high risk patients based on an objective scoring system. METHODS: In this study, a high risk cohort of patients (EuroSCORE >or=6, n=158) was compared with a low risk cohort of patients (EuroSCORE <6, n=1004) to define the safety and efficacy of fast track recovery among high risk patients. A standard perioperative data is collected prospectively for every patient. RESULTS: Time to extubation was longer in the high risk group (299+/-253 vs. 232+/-256min; P=0.003), but intensive care unit (ICU) stay (25.6+/-28.7 vs. 21.5+/-9.4h; P=ns), and postoperative length of stay (5.8+/-2.4 vs. 5.6+/-2.7 days; P=ns) was similar when compared with the low risk group. Of the high risk patients 81% were extubated within 6h, 87% were discharged from the intensive care unit within 24h, and 67% were discharged from the hospital within 5 days. Multiple regression analysis showed that any red blood cell transfusion (P=0.02), and cross clamp time >60min (P=0.03) were the predictors of delayed extubation (>or=6h) in the high risk group. The predictors of extended ICU stay were any red blood cell transfusion (P=0.0001), and peripheral vascular disease (P=0.05). Any red blood cell transfusion was the only predictor for mortality (P=0.02) and readmission to the hospital within the first 30 days (P=0.02) in this cohort of patients. CONCLUSIONS: This study confirms the safety and efficacy of fast track recovery protocol among high risk patients undergoing coronary artery bypass surgery. All patients are basically suitable for fast track recovery and the preoperative risk factors are poor predictors of prolonged ventilation, increased ICU and hospital stay. Red blood cell transfusion is associated with delayed extubation and discharge from the ICU, and increased mortality and hospital readmission rate.

Adjustment of sweep gas flow during cardiopulmonary bypass.

Cardiopulmonary bypass (CPB) is one of the major tools of cardiac surgery. However, no clear data are available for the ideal value of sweep gas flow to oxygenator during CPB. The aim of this study was to determine the best value for sweep gas flow during CPB. Thirty patients undergoing isolated CABG were randomly and equally allocated into three groups. Sweep gas flow to oxygenator was kept at 1.35 l/min/m2 in group 1, 1.60 l/min/m2 in group 2, and 2.0 l/min/m2 in group 3. All patients were operated on under the same anaesthetic regime and surgical techniques. Samples for blood gas analysis were collected at T1: before CPB; T2: 5 min after the initiation of CPB; T3: just before rewarning; and T4: at the end of rewarming. Five minutes after the initiation of CPB (T2), pCO2 decreased significantly in groups 2 and 3 compared to group 1 (p < 0.02). With the addition of hypothermia (T3), the changes in the pH and pCO2 became more profound and, in this period, the levels in group 3 patients outranged the physiologic limits, with pCO2 and pH values being 28 +/- 3 mmHg and 7.50 +/- 0.04, respectively. At the end of the rewarming period (T4), in spite of increased carbon dioxide production, pCO2 values were below the physiologic limits in groups 2 and 3. We conclude that sweep gas flow to the oxygenator should be kept between 1.35 and 1.60 l/min/m2 during CPB to avoid hypocapnia, which results in alkalosis and has hazardous effects on lung mechanics, cerebral blood flow, and the cardiovascular system.