Remifentanil consumption in septoplasty surgery under general anesthesia. Association with humane mu-opioid receptor gene variants.

OBJECTIVES: To evaluate the influence of the ORM1 variants in codon 118 on the intra-operative remifentanil consumption under general anesthesia. Methods: A prospective gene association study, performed at the Jordan University Jordan, Amman, Jordan from September 2013 to August 2014. It includes patients who underwent septoplasty surgery under general anesthesia. All patients received standard intravenous anesthesia. Anesthesia maintained with fixed dose of Sevoflurane and variable dose of Remifentanil to keep the systolic blood pressure between 90-100 mm Hg. The Remifentanil dose was calculated and correlated with ORM1 genotype variance. Results: Genotype and clinical data were available for 123 cases. The A118A genotype was seen in 96 patients (78%), the A118G genotype was seen in 25 patients (20.3%), and only 2 patients had genotype G118G (1.6%). The G118G variant was removed from the statistical analysis due to small sample size. There was a significant effect of ORM1 genotype variant and the amount of remifentanil consumed. The A118A genotype received 0.173 ± 0.063 µg kg-1 min-1 and the A118G genotype received 0.316 ± 0.100 µg kg-1 min-1 (p less than 0.0001). Conclusion: The ORM1 gene has a role in intra-operative remifentanil consumption in patients who underwent septoplasty surgery under general anesthesia. The A118G gene required higher dose of remifentanil compared with the A118A genotype.

The impact of long-lasting preemptive epidural analgesia before total hip replacement on the hormonal stress response. A prospective, randomized, double-blind study.

UNLABELLED: Recent studies suggest that preemptive analgesia may be effective in reducing postoperative pain. One physiologic explanation may be interference with the endogenous opioid response. We investigated whether long-lasting preoperative preemptive analgesia may have an effect on the hormonal stress response after total hip replacement. METHODS: 42 patients scheduled for elective hip replacement for coxarthrosis were randomized to receive, on the day before the operation, either 5 ml*h(-1) ropivacaine 0.2% (study group, n = 21) or 5 ml*h(-1) saline (control group, n = 21). Postoperative analgesia was achieved in both groups by patient-controlled epidural analgesia (PCEA) with ropivacaine 0.2%. The main outcome measure was the concentration of authentic beta-endorphin [1-31] in plasma up to 4 days after surgery. Additional parameters included concentrations of adrenocorticotrope hormone and cortisol. RESULTS: Both groups were comparable concerning preoperative parameters and pain scores. Epidural blocks were sufficient in all patients for operative analgesia. Preemptive analgesia was performed for 11-20 hours in both groups and led to significantly decreased pain scores before surgery. Preemptive analgesia with epidural ropivacaine did not lead to decreased concentrations of beta-endorphin [1-31] before the start of surgery or in the postoperative period. Furthermore, no differences could be detected in the time course of beta-endorphin and adrenocorticotrope hormone after surgery. However, cortisol concentrations differed significantly between groups before the operation, but showed a comparable rise after surgery. CONCLUSION: Differences in postoperative pain after preemptive analgesia do not seem to be due to an altered endogenous opioid response.

Intraoperative administration of dexmedetomidine reduces the analgesic requirements for children undergoing hypospadius surgery.

BACKGROUND: The present study was designed to assess whether an intraoperative administration of dexmedetomidine would decrease the intraoperative and postoperative analgesic requirements for paediatric patients undergoing hypospadius surgery. METHODS: Forty-eight children (American Society of Anesthesiologists-1) aged 1-12 years undergoing hypospadius repair under general anaesthesia were randomly assigned into dexmedetomidine or placebo groups, D and P, respectively. Group D received a loading dose of dexmedetomidine 1 microg kg(-1) after induction of anaesthesia, followed by a continuous infusion at a rate of 0.7 microg kg(-1) h(-1). Group P received a volume-matched 0.9% saline. Both groups received fentanyl for intraoperative analgesia and intravenous morphine and oral paracetamol for postoperative analgesia. For both groups, heart rate, blood pressure and fentanyl requirements were recorded intraoperatively. During their stay for 2 h in the recovery room, heart rate, blood pressure, pain scores, behaviour scores and total morphine requirements were recorded. After discharge from postanaesthesia care unit, paracetamol requirements over 24 h were also recorded. RESULTS: Intraoperatively, the dexmedetomidine-treated group had significantly fewer fentanyl requirements, slower heart rate and lower mean arterial blood pressure (P < 0.001). In the postanaesthesia care unit, this group also consumed significantly less morphine, had lower pain scores, lower behaviour score in the immediate postoperative period, lower heart rates and mean arterial blood pressures when compared with the placebo group (P < 0.001). Group D consumed significantly less paracetamol than group P in the ward over 24 h. CONCLUSION: Intravenous administration of dexmedetomidine intraoperatively during hypospadius repair in children reduces intraoperative and postoperative analgesic requirements and lowers heart rate and blood pressure.

Anesthesia and electrocorticography for epilepsy surgery: a Jordanian experience.

OBJECTIVE: Electrocorticography (ECoG) may be used to guide epilepsy surgery. However, anesthetics can suppress epileptiform activity or induce confounding burst-suppression patterns and the relationship between ECoG results and seizure outcome is controversial. In this study, we evaluated the ECoG activity under several different anesthetics and examined the relationship between ECoG and outcome. METHODS: We retrospectively studied 44 patients who had ECoG during epilepsy surgery. Anesthesia was with fentanyl and isoflurane (n = 19), fentanyl and sevoflurane (n = 9), remifentanil and sevoflurane (n = 5), remifentanil and propofol (n = 9), and fentanyl with propofol sedation during local anesthesia (n = 2). Pre-resection ECoG was considered satisfactory if epileptiform activity was present and there was no burst-suppression. Post-resection ECoG was graded according to residual epileptiform activity: A (none), B (mild), C (moderate). Seizure outcome was graded: I (seizure free without medication), II (seizure free with medication), III (> 50% seizure reduction) or IV (< 50% seizure reduction). Grades I-III were considered beneficial. RESULTS: ECoG was satisfactory in 43 of the 44 surgeries, but one of the 11 recordings during propofol showed no epileptiform activity. Thirty-six of 37 patients (97%) with ECoG grade A or B and five of seven patients (71%) with ECoG grade C benefited from epilepsy surgery. Chi-squared, p > 0.05. CONCLUSIONS: Satisfactory ECoG is possible using isoflurane or sevoflurane with nitrous oxide and fentanyl or remifentanil or using propofol and remifentanil. However, one of eleven ECoGs under propofol was negative for epileptiform activity. The amount of post-resection ECoG epileptiform activity does not significantly correlate with seizure outcome.