title: Remifentanil patient-controlled analgesia for labour: optimizing drug delivery regimens.
abstract: OBJECTIVE
  A pilot study was undertaken to compare the efficacy of two regimens of intravenous patient-controlled analgesia (PCA) with remifentanil for labour analgesia.
  
  
  METHODS
  Twenty term parturients requesting labour analgesia were randomized to receive one of two regimens of intravenous remifentanil. The initial settings in both groups consisted of an infusion of 0.025 μg·kg-1·min-1, a PCA bolus of 0.25 μg·kg-1and a lockout interval of two minutes. In Group A, the infusion was increased in a stepwise manner from 0.025 to 0.05, 0.075 and 0.1 μg·kg-1·min-1as required; the bolus was kept constant at 0.25 μg·kg-1. In Group B, the bolus was increased from 0.25 to 0.5, 0.75 and 1 μg·kg-1as necessary; the infusion was kept constant at 0.025 μg·kg-1·min-1. Maternal pain, satisfaction and sedation scores, remifentanil requirement, and side effects were recorded.
  
  
  RESULTS
  Mean pain and patient satisfaction scores, and cumulative doses of remifentanil were similar in the two groups. The overall incidence of side effects was greater in Group B (P = 0.0007), with drowsiness observed in 100% of patients, as compared to 30% in Group A (P = 0.003). The minimum oxygen saturation levels were 94.3% ± 2.6% and 92.2% ± 3.8% in Groups A and B respectively (P = 0.19).
  
  
  CONCLUSIONS
  Although pain and satisfaction scores were similar in both groups, the regimen used in Group A was associated with fewer side effects compared to the Group B dosing regimen. This pilot study suggests that remifentanil intravenous PCA is efficacious for labour analgesia as a bolus of 0.25 μg·kg-1, with a lockout interval of two minutes and continuous infusion of 0.025-0.1 μg·kg-1·min-1. The potential for respiratory depression mandates close respiratory monitoring. Large-scale trials to evaluate safety issues are warranted.
authors: Department of Anesthesia and Pain Management, Canada. mrinalini.balki@uhn.on.ca.
authors: Mrinalini
authors: M
authors: Balki
authors: Department of Anesthesia and Pain Management, Canada.
authors: Shilpa
authors: S
authors: Kasodekar
authors: Department of Anesthesia and Pain Management, Canada.
authors: Sudhir Dhumne
authors: SD
authors: Mbbs
authors: Department of Obstetrics & Gynecology, University of Toronto, Mount Sinai Hospital, 600 University Avenue, Room 781, M5G 1X5, Toronto, Ontario, Canada.
authors: Paul
authors: P
authors: Bernstein
authors: Department of Anesthesia and Pain Management, Canada.|Department of Obstetrics & Gynecology, University of Toronto, Mount Sinai Hospital, 600 University Avenue, Room 781, M5G 1X5, Toronto, Ontario, Canada.
authors: Jose C A
authors: JC
authors: Carvalho