Myocardial protection during off pump coronary artery bypass surgery: A comparison of inhalational anesthesia with sevoflurane or desflurane and total intravenous anesthesia.

Aims and Objectives: The objective of the study was to evaluate the myocardial protective effect of volatile agents-sevoflurane and desflurane versus total intravenous anesthesia (TIVA) with propofol in offpump coronary artery bypass surgery (OPCAB) by measuring cardiac troponin-T (cTnT) as a marker of myocardial cell death. Materials and Methods: The study was conducted on 139 patients scheduled to undergo elective OPCAB surgery. The patients were randomly allocated to receive anesthesia with sevoflurane, desflurane or TIVA with propofol. The cTnT levels were measured preoperatively, at arrival in postoperative intensive care unit, at 8, 24, 48 and 96 hours thereafter. Results: The changes in cTnT levels at all time intervals were comparable in the three groups. Conclusion: The study did not reveal any difference in myocardial protection after OPCAB with either sevoflurane or desflurane or TIVA using propofol as assessed by measuring serial cTnT values.

A randomized prospective analysis of alteration of hemostatic function in patients receiving tranexamic acid and hydroxyethyl starch (130/0.4) undergoing off pump coronary artery bypass surgery.

Postoperative hemorrhagic complications is still one of the major problems in cardiac surgeries. It may be caused by surgical issues, coagulopathy caused by the side effects of the intravenous fluids administered to produce plasma volume expansion such as hydroxyl ethyl starch (HES). In order to thwart this hemorrhagic issue, few agents are available. Fibrinolytic inhibitors like tranexamic acid (TA) may be effective modes to promote blood conservation; but the possible complications of thrombosis of coronary artery graft, precludes their generous use in coronary artery bypass graft surgery. The issue is a balance between agents that promote coagulation and those which oppose it. Therefore, in this study we have assessed the effects of concomitant use of HES and TA. Thromboelastogram (TEG) was used to assess the effect of the combination of HES and TA. With ethical committee approval and patient's consent, 100 consecutive patients were recruited for the study. Surgical and anesthetic techniques were standardized. Patients fulfilling our inclusion criteria were randomly allocated into 4 groups of 25 each. The patients in group A received 20 ml/kg of HES (130/0.4), 10 mg/kg of T.A over 30 minutes followed by infusion of 1 mg/kg/hr over the next 12 hrs. The patients in group B received Ringer's lactate + TA at same dose. The patients in the Group C received 20 ml/kg of HES. Group D patients received RL. Fluid therapy was goal directed. Total blood loss was assessed. Reaction time (r), α angle, maximum amplitude (MA) values of TEG were assessed at baseline, 12, 36 hrs. The possible perioperative myocardial infraction (MI) was assessed by electrocardiogram (ECG) and troponin T values at the baseline, postoperative day 1. Duration on ventilator, length of stay (LOS) in the intensive care unit (ICU) were also assessed. The demographical profile was similar among the groups. Use of HES increased blood loss significantly (P < 0.05). Concomitant use of TA reduced blood loss when used along with HES. r value was prolonged at 12 hours in all the groups and α angle was reduced at 12 hours in all the groups, where as MA value was reduced at 12 th hour in the HES group compared to the baseline and increased in TA + HES group. These findings were statistically significant. No significant change in Troponin T values/ ECG, duration of ventilation and LOS ICU was observed. No adverse events was noticed in any of the four groups. HES (130/0.4) used at a dose of 20 ml/kg seems to produce coagulopathy causing increased blood loss perioperatively. Hemodilution produced by fluid therapy seems to produce Coagulopathy as observed by TEG parameters. Concomitant use of TA with HES appears to reverse these changes without causing any adverse effects in patients undergoing OPCAB surgery.

Effect of thoracic epidural anesthesia on oxygen delivery and utilization in cardiac surgical patients scheduled to undergo off-pump coronary artery bypass surgery: A prospective study.

To evaluate the effect of thoracic epidural anesthesia (TEA) on tissue oxygen delivery and utilization in patients undergoing cardiac surgery. This prospective observational study was conducted in a tertiary referral heart hospital. A total of 25 patients undergoing elective off-pump coronary artery bypass surgery were enrolled in this study. All patients received thoracic epidural catheter in the most prominent inter-vertebral space between C7 and T3 on the day before operation. On the day of surgery, an arterial catheter and Swan Ganz catheter (capable of measuring cardiac index) was inserted. After administering full dose of local anesthetic in the epidural space, serial hemodynamic and oxygen transport parameters were measured for 30 minute prior to administration of general anesthesia, with which the study was culminated. A significant decrease in oxygen delivery index with insignificant changes in oxygen extraction and consumption indices was observed. We conclude that TEA does not affect tissue oxygenation despite a decrease in arterial pressures and cardiac output.