80 patients (ASA I-III, mean age 40-50 years, mean weight 59-68 kg) recovering from major gynaecological surgery (170-200 min) under balanced anaesthesia were randomly assigned to four groups to self-administer intravenous fentanyl during the early postoperative period. PCA devices were ODAC and Prominject with fentanyl demand doses of 34.5 or 34 micrograms, respectively, and lockout times of 1 or 5 min. Concurrent fentanyl infusion was none (group Prom), fixed-rate with 4 micrograms/h (group ODACf), tail-dose, i.e., a fixed-rate infusion with 17 mg/h for a maximum of 60 minutes following a valid demand (group Prom(t)), or adaptive, starting with 4 micrograms/h and being adapted to individual needs depending on total fentanyl consumption in the latest 60-minute period (group ODACa). Data were collected for fentanyl consumption, venous fentanyl serum concentrations in fixed intervals, actual and retrospective verbal rating pain scores (0-5), haemodynamic variables, respiratory rate, side effects and patients' acceptance. Mean duration of patient-controlled analgesia (PCA) was 15-17 hrs. During this period, an average of 12-18 demands were administered per patient, resulting in an average fentanyl consumption of 36-52 micrograms/h (0.57-0.94 micrograms/kg/h). Analgesic efficacy was good in all groups, mean pain scores ranging from 0.4 to 1.1 (actual) and 1.7 to 2.2 (retrospective). Mean duration of a single fentanyl bolus dose was highly variable, ranging from 58 to 90 min if calculated for the total observation period. Statistically significant differences were found for none of the above mentioned PCA parameters. As a trend, the adaptive-rate infusion strategy was favoured (lowest demand rate, best retrospective pain scores).(ABSTRACT TRUNCATED AT 250 WORDS)
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.