Finding the 'ideal' regimen for fentanyl-based intravenous patient-controlled analgesia: how to give and what to mix?

PURPOSE

This analysis was done to investigate the optimal regimen for fentanyl-based intravenous patient-controlled analgesia (IV-PCA) by finding a safe and effective background infusion rate and assessing the effect of adding adjuvant drugs to the PCA regimen.

MATERIALS AND METHODS

Background infusion rate of fentanyl, type of adjuvant analgesic and/or antiemetic that was added to the IV-PCA, and patients that required rescue analgesics and/or antiemetics were retrospectively reviewed in 1827 patients who underwent laparoscopic abdominal surgery at a single tertiary hospital.

RESULTS

Upon multivariate analysis, lower background infusion rates, younger age, and IV-PCA without adjuvant analgesics were identified as independent risk factors of rescue analgesic administration. Higher background infusion rates, female gender, and IV-PCA without additional 5HT₃ receptor blockers were identified as risk factors of rescue antiemetics administration. A background infusion rate of 0.38 μg/kg/hr [area under the curve (AUC) 0.638] or lower required rescue analgesics in general, whereas, addition of adjuvant analgesics decreased the rate to 0.37 μg/kg/hr (AUC 0.712) or lower. A background infusion rate of 0.36 μg/kg/hr (AUC 0.638) or higher was found to require rescue antiemetics in general, whereas, mixing antiemetics with IV-PCA increased the rate to 0.37 μg/kg/hr (AUC 0.651) or higher.

CONCLUSION

Background infusion rates of fentanyl between 0.12 and 0.67 μg/kg/hr may safely be used without any serious side effects for IV-PCA. In order to approach the most reasonable background infusion rate for effective analgesia without increasing postoperative nausea and vomiting, adding an adjuvant analgesic and an antiemetic should always be considered.