METHODS: Patients (n = 94) scheduled for gynaecological laparotomy received i.v. fentanyl infusion (3 μg/kg/h) after induction of general anaesthesia. Post-operative fentanyl requirements were quantified by using a patient-controlled analgesia and the number of i.v. fentanyl rescue analgesia required were recorded. Pain control was assessed using visual analogue scores (VAS) and fentanyl's adverse effects were documented. CYP3A4*4, CYP3A4*5 and CYP3A4*18 alleles of cytochrome P450 3A4 were identified by polymerase chain reaction-restriction fragment length polymorphism. Differences in fentanyl requirements, VAS scores and adverse effects among the various genotypes were compared.
RESULTS AND DISCUSSION: No CYP3A4*4 and CYP3A4*5 alleles were detected. Eighty-nine patients (94·7%) were wild-type, five (5·3%) were heterozygous and none was homozygous. No significant difference was demonstrated between the genotype groups in terms of fentanyl consumption, pain control and adverse effects.
WHAT IS NEW AND CONCLUSION: CYP3A4*4 and CYP3A4*5 are rare in the Malaysian Malay population. Genetic polymorphism of CYP3A4*18 may not play an important role in influencing postoperative fentanyl requirements.
METHODS: The cold pressor pain responses of 148 opioid dependent patients receiving MMT were evaluated using the cold pressor test (CPT). DNA was extracted from whole blood and subjected to polymerase chain reaction (PCR)-genotyping.
RESULTS: Of the 148 subjects, 77 (52.0%) were carriers of CYP2B6*6 allele. CYP2B6*6 allele carriers had shorter cold pain threshold and pain tolerance times than non-carriers of CYP2B6*6 allele (21.05s vs 33.69s, p=0.036 and 27.15s vs 44.51s, p=0.020, respectively). Pain intensity scores of the CYP2B6*6 allele carriers was 67.55, whereas that of the CYP2B6*6 allele non-carriers was 64.86 (p=0.352).
CONCLUSION: Our study indicates that the CYP2B6*6 allele is associated with a lower pain threshold and lower pain tolerance among males with opioid dependence on MMT. The CYP2B6*6 allele may provide a mechanistic explanation for clinical observations of heightened pain sensitivity among opioid dependent patients receiving MMT.
METHODS: We used data from the AIDS Care Cohort to Evaluate Exposure to Survival Services (ACCESS) study, a long-running study of a community-recruited cohort of HIV-positive PWUD, linked to comprehensive HIV clinical records in Vancouver, Canada, a setting of no-cost, universal access to HIV care. The longitudinal relationship between MMT-ART dispensation at the same facility and the odds of ≥ 95% ART adherence was analysed using multivariable generalized linear mixed-effects modelling. We conducted a further analysis using a marginal structural mode with inverse probability of treatment weights as a sensitivity analysis.
RESULTS: This study included data on 1690 interviews of 345 ART- and MMT-exposed participants carried out between June 2012 and December 2017. In the final multivariable model, MMT-ART dispensation, compared with nondispensation at the same facility, was associated with greater odds of achieving ≥ 95% adherence [adjusted odds ratio (AOR) 1.56; 95% confidence interval (CI) 1.26-1.96]. A marginal structural model estimated a 1.48 (95% CI 1.15-1.80) greater odds of ≥ 95% adherence among participants who reported MMT-ART dispensation at the same facility compared with those who did not.
CONCLUSIONS: The odds of achieving optimal adherence to ART were 56% higher during periods in which MMT and ART medications were dispensed at the same facility, in a low-barrier setting. Our findings highlight the need to consider a simpler integrated approach with medication dispensation at the same facility in low-threshold settings.
AIMS: This study investigated the use of extraluminal bronchial blocker placement for one-lung ventilation and the effect of infusion of remifentanil in infants and small children undergoing video-assisted thoracoscopic surgery.
METHODS: We retrospectively reviewed the technique of one-lung ventilation and the hemodynamic effects of remifentanil infusion in 31 small children during elective video-assisted thoracoscopic surgery for congenital lung lesions under anesthesia with sevoflurane or isoflurane, oxygen, and air. Patients' heart rate, blood pressure, and endtidal carbon dioxide at baseline (after induction of anesthesia), immediately after one-lung ventilation, during carbon dioxide insufflation, and at the end of one-lung ventilation were extracted from the database and analyzed. The use of vasopressors or dexmedetomidine was also recorded and analyzed.
RESULTS: Extraluminal placement of a bronchial blocker alongside the tracheal tube was successfully performed in 90.3% of cases (28 patients) without any serious complications or arterial oxygen desaturation. There was no significant rise in blood pressure or heart rate even with the rise of endtidal carbon dioxide concentration during video-assisted thoracoscopic surgery. In 58% of patients (18 patients), phenylephrine was administered to maintain the blood pressure within 20% of the baseline value. There was no significant change in the heart rate of all patients at each time point.
CONCLUSION: One-lung ventilation with an extraluminal parallel blocker was used effectively in this series of young children undergoing thoracoscopic excision of congenital pulmonary lesions. Remifentanil infusion attenuated surgical stress effectively in infants and small children undergoing video-assisted thoracoscopic surgery.
METHODS: An open-label study was conducted to evaluate the effectiveness of the addition of 1.5 mcg/kg intranasal fentanyl to 2 mg/kg intravenous tramadol (fentanyl + tramadol arm, n = 10) as compared to the administration of 2 mg/kg intravenous tramadol alone (tramadol-only arm, n = 10) in adult patients with moderate to severe pain due to acute musculoskeletal injuries.
RESULTS: When analysed using the independent t-test, the difference between the mean visual analogue scale scores pre-intervention and ten minutes post-intervention was 29.8 ± 8.4 mm in the fentanyl + tramadol arm and 19.6 ± 9.7 mm in the tramadol-only arm (t[18] = 2.515, p = 0.022, 95% confidence interval 1.68-18.72 mm). A statistically significant, albeit transient, reduction in the ten-minute post-intervention mean arterial pressure was noted in the fentanyl + tramadol arm as compared to the tramadol-only arm (13.35 mmHg vs. 7.65 mmHg; using Mann-Whitney U test with U-value 21.5, p = 0.029, r = 0.48). There was a higher incidence of transient dizziness ten minutes after intervention among the patients in the fentanyl + tramadol arm.
CONCLUSION: Although effective, intranasal fentanyl may not be appropriate for routine use in adult patients, as it could result in a significant reduction in blood pressure.