Intraoperative red blood cell transfusion during coronary artery bypass graft surgery increases the risk of postoperative low-output heart failure.

BACKGROUND: Hemodilutional anemia during cardiopulmonary bypass (CPB) is associated with increased mortality during coronary artery bypass graft (CABG) surgery. The impact of intraoperative red blood cell (RBC) transfusion to treat anemia during surgery is less understood. We examined the relationship between anemia during CPB, RBC transfusion, and risk of low-output heart failure (LOF). METHODS AND RESULTS: Data were collected on 8004 isolated CABG patients in northern New England between 1996 and 2004. Patients were excluded if they experienced postoperative bleeding or received > or = 3 units of transfused RBCs. LOF was defined as need for intraoperative or postoperative intra-aortic balloon pump, return to CPB, or > or = 2 inotropes at 48 hours. Having a lower nadir HCT was also associated with an increased risk of developing LOF (adjusted odds ratio, 0.90; 95% CI, 0.82 to 0.92; P=0.016), and that risk was further increased when patients received RBC transfusion. When adjusted for nadir hematocrit, exposure to RBC transfusion was a significant, independent predictor of LOF (adjusted odds ratio, 1.27; 95% CI, 1.00 to 1.61; P=0.047). CONCLUSIONS: In this study, we observed that exposure to both hemodilutional anemia and RBC transfusion during surgery are associated with increased risk of LOF, defined as placement of an intraoperative or postoperative intra-aortic balloon pump, return to CPB after initial separation, or treatment with > or = 2 inotropes at 48 hours postoperatively, after CABG. The risk of LOF is greater among patients exposed to intraoperative RBCs versus anemia alone.

Cortisol antiinflammatory effects are maximal at postoperative plasma concentrations.

OBJECTIVE: To determine the plasma concentration of cortisol that is needed for maximal suppression of the systemic inflammatory response to cardiac surgery with cardiopulmonary bypass. DESIGN: Prospective, randomized, double-blind clinical study of cardiac surgical patients. SETTING: Operating room and inpatient care facility of a university medical center. SUBJECTS: Sixty elective cardiac surgical patients scheduled for coronary artery bypass graft, cardiac valve replacement, or both. INTERVENTIONS: Patients were randomized to receive one of three different hydrocortisone doses, by intravenous infusion, for 6 hrs before, during, and immediately after surgery while also receiving etomidate to suppress endogenous cortisol production. MEASUREMENTS AND MAIN RESULTS: Serial determinations of plasma interleukin-6 were studied as a marker of systemic inflammation. Measurements of interleukin-10 were used as a marker of the compensatory antiinflammatory response. Plasma cortisol concentrations in an untreated control group rose from 17 microg/dL before surgery to a mean of 43 microg/dL by 4 hrs after surgery. A dose of hydrocortisone (4 microg/kg/min for 6 hrs) that maintained plasma cortisol between 40 and 50 microg/dL, starting 60-90 mins before surgery, significantly suppressed plasma interleukin-6 after surgery compared with control while significantly increasing plasma interleukin-10 during surgery. Plasma interleukin-6 after surgery was not suppressed further by increasing the dose of hydrocortisone to 8 microg/kg/min, although the mean peak plasma interleukin-10 concentration increased further compared with the group that received the 4 microg/kg/min hydrocortisone dose. CONCLUSIONS: At the doses studied, cortisol-induced suppression of plasma interleukin-6 during and after cardiac surgery appears to be a saturable phenomenon at the concentration of plasma cortisol that is normally achieved after surgery in untreated patients.

The association between heart rate and in-hospital mortality after coronary artery bypass graft surgery.

UNLABELLED: Avoidance of tachycardia is a commonly described goal for anesthetic management during coronary artery bypass graft (CABG) surgery. However, an association between increased intraoperative heart rate and mortality has not been described. We conducted an observational study to evaluate the association between preinduction heart rate (heart rate upon arrival to the operating room) and in-hospital mortality during CABG surgery. Data were collected on 5934 CABG patients. Fifteen percent of patients had an increased preinduction heart rate > or =80 bpm. Crude mortality was significantly more frequent among patients with increased preinduction heart rate (P(trend) = 0.002). After adjustment for baseline differences among patients, preinduction heart rate > or =80 bpm remained associated with increased mortality (P(trend) < 0.001). The increased heart rate may be a cause of the observed mortality. Alternatively, faster heart rate may be either a marker of patients with irreversible myocardial damage, or a marker of patients with limited cardiac reserve at risk for further injury. Lastly, faster heart rate may be a marker for under-use of beta-adrenergic blockade. Because the use of preoperative beta-adrenergic blockade in CABG patients is associated with improved in-hospital survival, further investigation concerning the effect of intraoperative treatment of increased heart rate with beta-adrenergic blockers on mortality after CABG surgery is warranted. IMPLICATIONS: We conducted an observational study to evaluate the association between heart rate upon arrival to the operating room (preinduction heart rate) and in-hospital mortality during coronary artery bypass graft surgery. After adjustment for baseline differences among patients, preinduction heart rate > or =80 bpm was associated with an increased in-hospital mortality after coronary artery bypass graft surgery.

Glucocorticoid effects on the inflammatory and clinical responses to cardiac surgery.

OBJECTIVE: To measure the effects of glucocorticoids on the systemic inflammatory response and clinical recovery after cardiac surgery. DESIGN: Randomized, prospective, double-blind, placebo-controlled clinical trial with concurrent comparison groups. SETTING: University medical center. PARTICIPANTS: Patients scheduled for elective coronary artery bypass graft surgery using normothermic cardiopulmonary bypass (CPB) and a standardized anesthetic. INTERVENTIONS: Participants randomly received either methylprednisolone, 15 mg/kg intravenously 1 hour before surgery and 0.3 mg/kg intravenously every 6 hours x 4 doses, or placebo. Comparison groups included cardiac surgical patients who received etomidate to lower endogenous cortisol during surgery and healthy volunteers who received methylprednisolone only. MEASUREMENTS AND MAIN RESULTS: Patients who received methylprednisolone had a significant reduction in circulating interleukin (IL)-6 at 60 minutes after CPB (p < 0.05) and on the morning of the 1st (p < 0.01) and 3rd (p < 0.05) postoperative days and a significant increase in circulating IL-10 at 60 minutes after CPB (p < 0.01) compared with the placebo group. Etomidate, given to lower cortisol during surgery, was associated with significantly decreased IL-6 and IL-10 responses to surgery compared with the placebo group, whereas methylprednisolone alone, given to healthy nonsurgical volunteers, had no effect on these cytokines. After adjusting for age, there were no significant differences in postoperative length of hospital stay between the methylprednisolone-treated (4.6 days) and placebo (6.1 days) groups or in the duration of mechanical ventilation (9.9 hours and 15.6 hours). No patient treated with methylprednisolone had nausea and vomiting on the 1st postoperative day compared with 33% of placebo-treated patients (p = 0.02). Glucose was significantly higher after methylprednisolone treatment at 1 hour after CPB (276 mg/dL v 210 mg/dL; p = 0.001) and at 2 hours (289 mg/dL v 213 mg/dL; p = 0.009) and 8 hours (247 mg/dL v 196 mg/dL; p = 0.02) after surgery. There were no differences in pain scores and no significant intergroup differences in lung peak expiratory flow rate or alveolar-arterial oxygen gradients after surgery. CONCLUSION: This study shows significant effects of glucocorticoids on the production of IL-6 and IL-10 in response to cardiac surgery but only minor effects on clinical recovery.

Epidural anesthesia and analgesia: effects on recovery from cardiac surgery.

OBJECTIVE: To measure predefined clinical effects resulting from the use of epidural anesthesia and analgesia during and after cardiac surgery. DESIGN: Prospective, randomized, nonblinded clinical trial. SETTING: Single academic medical center. PARTICIPANTS: Sixty patients scheduled for elective cardiac surgery with cardiopulmonary bypass. INTERVENTIONS: Sixty participants were randomly assigned to 1 of 2 study groups: (1) A control group received general anesthesia during surgery and intravenous opiate analgesia after surgery. (2) A treatment group received thoracic epidural anesthesia combined with general anesthesia during surgery and epidural analgesia for the first 24 postoperative hours. MEASUREMENTS AND MAIN RESULTS: Primary study measurements were planned to evaluate recovery from surgery and included time to tracheal extubation, duration of postoperative intensive care unit stay, duration of postoperative hospitalization, pain control, urinary free cortisol, cardiopulmonary complication rate, and total hospital charges. No statistically significant differences between the 2 study groups were found in these main measurements. CONCLUSIONS: The clinical course of elective cardiac surgical patients who receive epidural anesthesia during surgery and epidural analgesia after surgery is comparable to that of patients managed with general anesthesia alone during surgery followed by parenteral opiate analgesia after surgery.