[Comparative study of single-dose intradural anesthesia and continuous intradural anesthesia with or without fentanyl].

OBJECTIVE: To compare the hemodynamic effects, level of anesthetic blockade and advantages of single-dose versus continuous intrathecal anesthesia with hyperbaric bupivacaine with and without fentanyl. PATIENTS AND METHOD: Prospective study in 45 patients under 65 who were scheduled for elective surgery of the lower abdomen, randomly divided into 3 groups. Group 1 and 2 received continuous intrathecal anesthesia with 10 mg hyperbaric bupivacaine; group 2 also received 25 mcg fentanyl. Patients in group 3 were given a single intrathecal dose of 15 mg hyperbaric bupivacaine. Mean arterial pressure and heart rate were recorded at baseline and 10, 20 and 30 minutes after the start of anesthesia. The level of block achieved was recorded after 10, 30 and 60 minutes. Hemodynamic changes, differences in blockade and side effects were analyzed. RESULTS: Hemodynamic changes were greater in group 2 (fentanyl) than in groups 1 and 3 (p < 0.05), with group 3 showing the greatest degree of hemodynamic stability. Level of blockade was always higher in group 2, with significant differences at 30 min (p < 0.05). Seven and 5 reinjections by catheter were necessary in groups 1 and 2, respectively. Two patients in group 3 required general anesthesia when blockade was inadequate. Apart from pruritus in group 2 (40%), no side effects due to anesthesia were observed. CONCLUSIONS: A single dose intrathecal anesthesia, produces less hemodynamic changes than a continuous intrathecal block. Nevertheless, continuous intrathecal block, allows the maintenance of the block as long as required. The association of fentanyl enhances the hemodynamic changes with no other beneficial effects.