N-acetylcysteine for prevention of acute renal failure in patients with chronic renal insufficiency undergoing cardiac surgery: a prospective, randomized, clinical trial.

OBJECTIVE: To assess the preventive effect of the antioxidant N-acetylcysteine on postoperative acute renal failure in patients with renal insufficiency undergoing cardiac surgery. DESIGN: Randomized, placebo-controlled, prospective study. SETTING: University cardiology center. PATIENTS: Two hundred fifty-four consecutive patients with chronic renal insufficiency (estimated creatinine clearance < or = 60 mL/min) undergoing elective cardiac surgery. INTERVENTIONS: Patients were randomized to receive N-acetylcysteine (n = 129) or placebo (n = 125). Patients of the N-acetylcysteine group received four boluses of intravenous N-acetylcysteine (1200 mg every 12 hrs, starting immediately before cardiac surgery). MEASUREMENTS AND MAIN RESULTS: The incidence of postoperative acute renal failure (> 25% increase in serum creatinine from baseline) and the in-hospital clinical course were evaluated. Acute renal failure occurred in 46% of patients and was associated with increased in-hospital mortality (7% vs. 0.7%; p = .024). It occurred in 52% of control patients and 40% of N-acetylcysteine-treated patients (p = .06). In-hospital mortality and need for renal replacement therapy were not affected by N-acetylcysteine, but a lower percentage of N-acetylcysteine-treated patients required mechanical ventilation prolonged for > 48 hrs (3% vs. 18%; p < .001) and had an intensive care unit stay > 4 days (13% vs. 33%; p < .001). CONCLUSIONS: Intravenous administration of N-acetylcysteine does not clearly prevent postoperative acute renal failure in patients with renal insufficiency undergoing cardiac surgery.

Comparison of on pump and off pump coronary surgery: risk factors for neurological outcome.

OBJECTIVE: Cerebrovascular accidents (CVA) are devastating complications after coronary artery bypass grafting (CABG). The reported incidence of neurological complications after conventional CABG (CCABG) is 3-6%. Off-pump coronary bypass grafting (OPCAB) has been associated in recent studies to a decreased morbidity and risk of perioperative stroke. Nevertheless, uncertainty still surrounds the relative benefits of OPCAB. We investigated whether, in our experience, OPCAB was associated with lower neurological morbidity than conventional CABG approach. METHODS: Eight thousand and two patients underwent isolated CABG at our institution between January 1998 and January 2005. OPCAB operation was performed on 1415 patients. Data were prospectively collected. A multiple logistic regression analysis was used to evaluate the influence of the two different surgical techniques on the neurological outcomes. RESULTS: Patients in the OPCAB group were significantly older (66.2 vs 63.5%, p<0.0001), had a higher incidence of renal injury (5.4 vs 2.4%, p<0.0001), and were more redo interventions (6.95 vs 1.53%, p<0.0001). The CCABG patients were more urgent at operation (5.46 vs 3.26, p=0.0007), were less hypertensive (57.6 vs 63% of the patients, p=0.0003) more diabetics (22 vs 20.6%, NS), and had an ejection fraction less than 0.40 (10.4 vs 9.6%, NS). CVA incidence was similar in both groups (Type I outcome: OPCAB=0.70% vs CCABG=0.68%, p=0.91; Type II outcome OPCAB=0.70% vs CCABG=0.83%, p=0.63). CONCLUSIONS: In our experience patients undergoing CCABG were not exposed to a greater risk of neurological adverse events when compared to OPCAB patients.

Oxygen metabolism during and after cardiac surgery: role of CPB.

BACKGROUND: Cardiopulmonary bypass (CPB) has been reported to increase oxygen metabolism and to influence the relation between oxygen consumption (VO(2)) and delivery (DO(2)) in the early hours after cardiac surgery. To investigate the role of CPB, we studied oxygen metabolism in coronary artery bypass procedures performed on-pump (CABG) and off-pump (OPCAB). METHODS: Twenty-five patients were randomized to undergo CABG (n = 14) or OPCAB (n = 11). All patients received the same anesthetic management. Oxygen metabolism variables were assessed before induction of anesthesia and up to 18-hours after surgery. RESULTS: At baseline, before induction of anesthesia, there were no differences between CABG and OPCAB in oxygen consumption (VO(2)), delivery (DO(2)), or extraction (ExO(2)). After surgery VO(2) and ExO(2) increased in both groups, while DO(2) decreased. No significant differences between CABG and OPCAB were detected in postoperative VO(2), DO(2), and ExO(2) levels. The relation between VO(2) and DO(2) was very similar in CABG and OPCAB patients throughout the study, and no significant differences were detected in slopes and intercepts of the regression lines between CABG and OPCAB at all time points. There was, however, a significant effect of time on the relation between VO(2) and DO(2): this relation was stronger in the postoperative period, and the slope of this relation increased over time as well. CONCLUSIONS: A hypermetabolic state and progressive and significant increases in the strength of the relationship between VO(2) and DO(2) and in the slope of this relationship occur after both CABG and OPCAB. Cardiopulmonary bypass is not responsible for these changes in oxygen metabolism.

High thoracic epidural anesthesia for off-pump coronary artery bypass surgery.

OBJECTIVE: To assess the feasibility of high thoracic epidural anesthesia combined with sevoflurane for off-pump coronary artery bypass surgery and to evaluate the postoperative pain control, side effects, and perioperative hemodynamics. DESIGN: Retrospective review of prospectively collected data. SETTING: A university teaching hospital. PARTICIPANTS: One hundred six consecutive patients receiving thoracic epidural combined with sevoflurane. INTERVENTION: From November 1999, the patients undergoing off-pump coronary artery bypass grafting were offered the epidural-inhalation anesthetic approach. MEASUREMENTS AND MAIN RESULTS: Insertion of the epidural catheter was successful in all but 2 patients; 1 bloody tap occurred and the dura was never punctured, although 1 patient presented with postoperative paraplegia. An emergency spinal cord nuclear magnetic resonance excluded signs of medullary compression caused by epidural or spinal hematoma. Visual analog scale scores for pain during the first 24-hour period were < 2 in all patients. Mean time to extubation was 4.6 +/- 2.9 hours. The average intensive care unit stay was 1.5 +/- 0.8 days. Incidences of perioperative myocardial infarction, myocardial ischemia, and atrial fibrillation were 2.8%, 7.5%, and 10.6%, respectively. Two patients died: 1 from multiorgan failure and the other from myocardial infarction. Heart rate, mean arterial pressure, cardiac index, and systemic vascular resistance were not affected by thoracic epidural alone. Mean arterial pressure and cardiac index decreased (p < 0.05) when general anesthesia was induced and remained stable thereafter. Neither heart rate nor systemic vascular resistance changed from baseline during operation. CONCLUSIONS: Thoracic epidural as an adjunct to general anesthesia is a feasible technique in off-pump coronary artery bypass surgery. It induces intense postoperative analgesia and does not compromise central hemodynamics.

Fenoldopam prophylaxis of postoperative acute renal failure in high-risk cardiac surgery patients.

BACKGROUND: Acute renal failure requiring replacement therapy occurs in 1% to 2% of patients who have undergone cardiac surgery with cardiopulmonary bypass and is associated with a very high mortality rate. The aim of this study was to determine if prophylactic treatment with fenoldopam mesylate of patients at high risk of postoperative acute renal failure reduced the incidence of this event. METHODS: This was a multicenter, prospective, cohort study in which 108 patients at high risk of postoperative acute renal failure and undergoing cardiac surgery with cardiopulmonary bypass were treated with fenoldopam mesylate (0.08 microg x kg(-1) x min(-1)) starting at the induction of anesthesia and throughout at least the next 24 hours. A homogeneous control group of 108 patients was created using a propensity-score analysis. RESULTS: Fenoldopam prophylaxis was significantly associated with a reduction in acute renal failure incidence (from 22% to 11%, p = 0.028), a less pronounced creatinine clearance decrease (p = 0.05), and a lower mortality rate (6.5% versus 15.7%, p = 0.03) by the univariate analysis, but these results were not confirmed by a multivariable analysis. Within the subgroup of patients who suffered a postoperative low output syndrome, fenoldopam prophylaxis was an independent protective factor for postoperative renal failure (odds ratio, 0.14; 95% confidence interval, 0.03 to 0.7; p = 0.017). CONCLUSIONS: Given the limitations of a nonrandomized prospective trial, our results support the hypothesis that fenoldopam may reduce the risk of acute renal failure in patients in whom endogenous and exogenous cathecolamines action may induce a renal vascular constrictive condition.