M. Curatolo et al., A direct search procedure to optimize combinations of epidural bupivacaine, fentanyl and clonidine for postoperative analgesia, ANESTHESIOL, 92(2), 2000, pp. 325-337
Citations number
31
Categorie Soggetti
Aneshtesia & Intensive Care","Medical Research Diagnosis & Treatment
Background The authors applied an optimization model (direct search) to fin
d the optimal combination of bupivacaine dose, fentanyl dose, clonidine dos
e, and infusion rate for continuous postoperative epidural analgesia.
Methods: One hundred ninety patients undergoing 48-h thoracic epidural anal
gesia after major abdominal surgery were studied Combinations of the variab
les of bupivacaine dose, fentanyl dose, clonidine dose, and infusion rate w
ere investigated to optimize the analgesic effect (monitored by verbal desc
riptor pain score) under restrictions dictated by the incidence and severit
y of side effects. Six combinations were empirically chosen and investigate
d. Then a stepwise optimization model was applied to determine subsequent c
ombinations until no decrease in the pain score after three consecutive ste
ps was obtained.
Results: Twenty combinations were analyzed. The optimization procedure led
to a reduction in the incidence of side effects and in the mean pain scores
. The three best combinations of bupivacaine dose (mg/h), fentanyl dose (mu
g/h), clonidine dose (mu g/h), and infusion rate (ml/h) were: 9-21-5-7, 8-
30-0-9, and 13-25-0-9, respectively.
Conclusions: Given the variables investigated, the aforementioned combinati
ons may be the optimal ones to provide postoperative analgesia after major
abdominal surgery. Using the direct search method, the enormous number of p
ossible combinations of a therapeutic strategy can be reduced to a small nu
mber of potentially useful ones. This is accomplished using a scientific ra
ther than an arbitrary procedure.