EFFECTIVE OBSTETRIC PARACERVICAL-BLOCK WITH REDUCED DOSE OF BUPIVACAINE - A PROSPECTIVE RANDOMIZED DOUBLE-BLIND-STUDY COMPARING 25 MG (0.25-PERCENT) AND 12.5 MG (0.125-PERCENT) OF BUPIVACAINE

Background. To study whether paracervical block (PCB) with 12.5 mg (0. 125 %) of bupivacaine is as effective as with 25 me (0.25 %) and if th ere are differences in fetal heart rate (FHR) patterns between the dos es. Methods. A prospective, randomized double-blind study. Fifty-two p atients received PCB with 25 mg and 45 patients with 12.5 mg of bupiva caine. Pain intensity was assessed by the patients on a horizontal vis ual analog scale (VAS). Fetal heart rates of the fetuses were analyzed visually concerning basal rate, variability, accelerations, bradycard ia, silent pattern and decelerations. Results. The pain relief was sta tistically significant in both groups up to 120 min after PCB. The VAS -values were similar in both groups both before and after PCB. Fetal h eart rate changes appeared in both groups more frequently after than p rior to PCB. In patients receiving 25 mg of bupivacaine there appeared to be more FHR changes than in those receiving 12.5 mg. Conclusions. Paracervical block with 12.5 mg of bupivacaine is an effective method to relieve pain during labor. Fetal heart rate changes seemed to appea r less frequently with this reduced dose. It seems that by lowering th e dose of bupivacaine it is possible to reduce fetal side-effects with out losing analgesic effect.