An Investigation of the Association Between Desflurane Inhalational Agent, Serum Brain Natriuretic Peptide (BNP) Levels and Clinical Outcomes During Coronary Artery Bypass Graft (CABG) Surgery

In a prospective, randomized, double-blinded study, desflurane inhalational anesthesia was administered either continuously or intermittently (Group 1; n=60 versus Group 2; n=62). The preoperative and postoperative BNP levels at 24, 48 and 72 hours after surgery were collected. Outcomes were recorded. Randomization into two groups was performed using sealed envelopes. The sequentially numbered assignments of participants were concealed in these envelopes during the study. The patients enrolled in the study receive an allocation to a group after anesthesia induction by health care personnel after the opening of the envelope. The observers were blinded to the anesthetic protocol. Caregivers were not blinded, but they did not participate in data collection or data interpretation. Therefore, the study protocol is considered double-blinded, masked to observers. Inclusion criteria include; 18 to 75 years of age, body mass index of 25 to 31, ejection fraction≥50%. Exclusion criteria include; repeat cardiac surgery, emergent surgery, preoperative coagulation disorder, preoperative congestive heart failure, ejection fraction <49%, preoperative renal dysfunction (serum creatinine>1.3 mg/dL), dialysis, preoperative hepatic dysfunction (serum aspartate/alanine amino transferase>40 U/L), preoperative electrolyte imbalance, history of pancreatitis or current corticosteroid treatment.The primary endpoint was to determine preoperative and postoperative BNP values 24, 48 and 72 hours after surgery. The secondary endpoint was the relation between BNP values and clinical outcomes such as; 1-Aortic cross-clamp time, 2-Cardiopulmonary bypass time, 3-The use of inotropic support, 4-Intra-aortic balloon pump, 5-Duration of mechanical ventilation (>48 hours), 6-Development of pneumonia, 7-Perioperative myocardial infarction, 8-Cerebrovascular event (stroke or transient ischemic attack), seizure, 9-Atrial fibrillation and other rhythm disturbances, 10-Need for renal replacement therapy (RRT), 11-Reoperation secondary to bleeding, 12-Intensive care unit stay (>3 days), 13-Hospital stay and, 14-Thirty-day mortality.

Statistical analysis. The sample size was calculated according to the comparison of serum BNP values in a previous study and a sample size of 58 patients per group would be required with 80% power and the conventional 2-sided type 1 error of 5%. A multiple logistic regression analysis was performed to assess the predictive factors for weaning failure from mechanical ventilation, and the significance level was set at a p-value of less than 0.10 in the univariate model. To determine the best cut-off for preoperative BNP value to predict the development of prolonged mechanical ventilation, we calculated the area under the receiver operating characteristic curve.