The Efficacy of Intravenous Patient-Controlled Analgesia After Intracranial Surgery on the Posterior Fossa

Surgery of the posterior fossa often produces intense postoperative pain. However, this pain is infrequently treated because of concern that opioid administration may mask the postoperative neurologic examination and/or produce hypercarbia. In this prospective, randomized controlled trial, we sought to determine whether IV patient-controlled analgesia (PCA) would lead to reductions in postoperative pain after neurosurgical procedures of the posterior fossa compared with conventional IV nurse-administered as-needed (PRN) therapy.Eighty patients (age range, 18-82 years) undergoing elective posterior fossa surgery were randomized to receive postoperative IV fentanyl PRN 25 to 50 μg every 30 minutes or via PCA 0.5 μg/kg/dose, with a maximal dose limit of 50 μg, and 15-minute lockout (4 doses/hour). We measured pain (Numerical Rating Scale, 0-10), analgesic use, sedation (Ramsay Sedation Scale and Glasgow Coma Scale), respiration, hemodynamics, and adverse events hourly.Sixty-five patients completed the study. Thirty-one patients received IV PCA and 34 received PRN analgesia. Patient demographics did not differ between groups. Patients in the PCA group reported less pain at rest (mean [95% confidence interval]: 3.7 [3.0, 4.4] vs 5.2 [4.5, 5.8], P = 0.003) and received more fentanyl (mean [95% confidence interval]: 54.8 [42.1, 67.6] vs 29.9 [24.2, 35.7] μg/h, P = 0.002) than those in the PRN group. There were no differences in side effects and no adverse events related to analgesic therapy.IV PCA use resulted in reduction in postoperative pain compared with PRN analgesic therapy after surgery of the posterior fossa. Larger studies will be required to determine the safety of IV PCA in this patient population.