Ketamine has no effect on oxygenation indices following elective coronary artery bypass grafting under cardiopulmonary bypass

Cardiopulmonary bypass is known to elicit systemic inflammatory response syndrome and organ dysfunction. This can result in pulmonary dysfunction and deterioration of oxygenation after cardiac surgery and cardiopulmonary bypass. Previous studies have reported varying results on anti-inflammatory strategies and oxygenation after cardiopulmonary bypass. Ketamine administered as a single dose at induction has been shown to reduce the pro-inflammatory serum markers in patients undergoing cardiopulmonary bypass. Therefore we investigated if ketamine can result in better oxygenation in these patients. This was a prospective randomized blinded study. Eighty consecutive adult patients undergoing elective coronary artery bypass grafting under cardiopulmonary bypass were included in the study. Patients were divided into two groups. Patients in ketamine group received 1mg/kg of ketamine intravenously at induction of anesthesia. Control group patients received an equal volume of saline. All patients received standard anesthesia, operative and postoperative care.Paired t test and independent sample t test were used to compare the inter-group and between group oxygenation indices respectively. Oxygenation index and duration of ventilation were analyzed. Deterioration of oxygenation index was noted in both the groups after cardiopulmonary bypass. However, there was no significant difference in the oxygenation index at various time points after cardiopulmonary bypass or the duration of ventilation between the two groups. This study shows that the administered as a single dose at induction does not result in better oxygenation after cardiopulmonary bypass.