Effect of three different doses of ketamine prior to general anaesthesia on postoperative pain following Caesarean delivery: a prospective randomized study.

BACKGROUND: Ketamine is an analgesic suitable for the induction of anesthesia during Caesarean delivery. This double blind, randomized trial examined the effect of intravenous ketamine used before the induction of general anesthesia on morphine consumption, immediate and long term postoperative pain after Cesarean delivery. METHODS: One hundred and forty term pregnant women undergoing elective Cesarean delivery were randomized into four groups (N.=35 each), placebo (0.9% normal saline), ketamine 0.25, 0.5, or 1 mg kg(-1) intravenously. In all patients 2-2.5 mg kg(-1) propofol was used for the induction of anesthesia, 0.6 mg kg(-1) rocuronium to facilitate the tracheal intubation and 50% oxygen in N2O and sevoflurane (end-tidal concentration of 1.2-1.3 %) for the maintenance of anesthesia. Postoperative analgesia was provided with intravenous morphine chloride patient-controlled analgesia (PCA) and rescue analgesia with intramuscular diclofenac sodium in the postoperative period. Apgar scores of the neonates and hemodynamic variables of the mothers were recorded during anaesthesia. Groups were compared regarding the cumulative morphine consumption and pain scores assessed with a numerical rating (0-10) scale at 2, 6, 12, 18, 24, and 48 h postoperatively. Postoperative side effects were recorded. Patients were evaluated for persistent postoperative pain at 2 weeks, 1 and 6 months, and 1 year. RESULTS: The cumulative morphine consumption at 48 hours after the surgery was the primary outcome of the study. There was no significant difference in terms of acute pain at 2 (P=0.3), 6 (P=0.7), 12 (P=0.4), 18 (P=0.4), 24 (P=0.8), and 48 (P=0.5) hours postoperatively. Cumulative morphine consumption obtained at 2 (P=0.9), 6 (P=0.5), 12 (P=0.4), 18 (P=0.4), 24 (P=0.1), and 48 (P=0.2) hours was also similar among the groups. Prolonged postoperative pain evaluated 2 weeks (P=0.3), 1 month (P=0.7), 6 months (P=0.1) and 1 year (P=0.3) after the operation was also similar among the groups. There was no significant difference in side effects among the groups during the postoperative 48 hours. Apgar scores at 1 min (P=0.5) and 5 mins (P=0.5) were similar among the groups. Maternal intraoperative hemodynamic parameters were similar among the groups. CONCLUSION: There was no difference regarding early and late postoperative pain and morphine consumption with ketamine at doses of 0.25, 0.5, and 1 mg kg(-1) in women undergoing Caesarean delivery under general anaesthesia, compared with the control group.

Gastric tonometer monitoring in infants undergoing repair of coarctation of the aorta.

OBJECTIVE: To evaluate gastric tonometer monitoring for splanchnic hypoperfusion in infants during surgical intervention for aortic coarctation, especially within aortic cross-clamp periods. DESIGN: A prospective study. SETTING: Cardiovascular intensive care unit in a university hospital. PARTICIPANTS: Fourteen infant patients after elective, uncomplicated repair of coarctation of the aorta. INTERVENTIONS: After the anesthesia induction, a 7F tonometry catheter was inserted into the stomach oropharyngeally. Gastric carbon dioxide, arterial blood gases, blood pressure of upper extremities, and hematocrit values were measured in 5 different time intervals. Time periods were as follows: T1 (after the anesthesia induction), T2 (before aortic cross-clamp), T3 (immediately after aortic cross-clamp removal), T4 (40 minutes after aortic cross-clamp removal), and T5 (as the patient reached the intensive care unit). Intramucosal pH was measured by means of the Henderson-Hasselbach equation. The mean values of all parameters were calculated. According to T1 time, T2, T3, T4, and T5 times were compared with Student's t-test. MEASUREMENTS AND MAIN RESULTS: Mean aortic cross-clamp time was 19.4 +/- 6.6 minutes. Intramucosal pH values of T3 (p < 0.001) and T4 (p < 0.01) were found to be lower than values of T1. The gastric carbon dioxide values of T3 were significantly higher than T1 (p < 0.01), and bicarbonate and arterial pH values of T3 were significantly lower (p < 0.01). There were no significant differences in other parameters over time intervals. CONCLUSION: Splanchnic hypoperfusion exists during aortic cross-clamping in infant aortic coarctation surgery, and the tonometric catheter is considered to be a safe method for monitoring this hypoperfusion.

Effects of phentolamine on tissue perfusion in pediatric cardiac surgery.

OBJECTIVE: To evaluate whether the deleterious effects of cardiopulmonary bypass (CPB) can be overcome by phentolamine-induced pharmacologic vasodilation in pediatric patients with congenital heart disease. DESIGN: Prospective, randomized, clinical study. SETTING: Single university hospital. PARTICIPANTS: Forty-three pediatric patients undergoing open cardiac surgery for repair of congenital heart disease. INTERVENTIONS: Patients were randomly allocated into two groups. Patients in group 1 (n = 22) received 0.2 mg/kg of phentolamine during the cooling and rewarming periods of CPB. Group 2 patients (n = 21) did not receive phentolamine. Temperature measurements (rectal [R], nasopharyngeal [N], and toe [P]) and serum lactate values were obtained before, during, and after CPB; systemic oxygen consumption was evaluated during CPB. MEASUREMENTS AND MAIN RESULTS: At the end of the CPB period and at the end of the operation, lactate values of group 1 (1.87+/-0.37 and 1.8+/-0.39 mmol/L, respectively) were significantly lower than values of group 2 (2.24+/-0.28 and 2.33+/-0.33 mmol/L; p < 0.05 and p < 0.05, respectively). At the beginning of the rewarming period N-R temperature gradients of group 1 (0.14 degrees C+/-0.92 degrees C) were lower than group 2 (-0.58 degrees C+/-1.84 degrees C) values (p < 0.05). Central-peripheral temperature gradients of group 1 obtained at the end of the CPB period (N-R = 2.18 degrees C+/-0.69 degrees C; N-P = 7.84 degrees C+/-1.54 degrees C; R-P = 5.66 degrees C+/-1.70 degrees C) were significantly lower than the values of group 2 (N-R = 2.80 degrees C+/-0.91 degrees C, N-P = 9.97 degrees C+/-2.02 degrees C; R-P = 7.18 degrees C+/-2.10 degrees C; p < 0.05; p < 0.001; p < 0.05). At the end of the operation values of group 1 (N-R = 0.48 degrees C+/-0.31 degrees C; N-P = 6.30 degrees C+/-1.23 degrees C; R-P = 5.82 degrees C+/-1.16 degrees C) were significantly lower than the values of group 2 (N-R = 0.94 degrees C+/-0.56 degrees C; N-P = 8.69 degrees C+/-0.28 degrees C; R-P = 7.75 degrees C+/-2.15 degrees C; p < 0.05; p < 0.001; p < 0.001). The systemic oxygen consumption values of group 1 were higher than group 2 (6.26+/-1.82 v 5.17+/-1.05 mL/min/kg; p < 0.05) after complete rewarming. Mean arterial pressure (MAP) values of group 1 (58.9+/-6.4 mmHg) were lower than group 2 (63.4+/-6.7 mmHg) at the period after CPB (p = 0.03). CONCLUSION: The results suggest that the use of phentolamine during CPB is associated with limited systemic anaerobic metabolism and more uniform body perfusion.