Mg. Richardson et al., INTRATHECAL HYPOBARIC VERSUS HYPERBARIC BUPIVACAINE WITH MORPHINE FORCESAREAN-SECTION, Anesthesia and analgesia, 87(2), 1998, pp. 336-340
Both hyper- and hypobaric solutions of bupivacaine are often combined
with morphine to provide subarachnoid anesthesia for cesarean section.
Differences in the baricity of subarachnoid solutions influence the i
ntrathecal distribution of anesthetic drugs and would be expected to i
nfluence measurable clinical variables. We compared the effects of hyp
er- and hypobaric subarachnoid bupivacaine with morphine to determine
whether one has significant advantages with regard to intraoperative a
nesthesia and postoperative analgesia in term parturients undergoing e
lective cesarean section. Thirty parturients were randomized to receiv
e either hyper- or hypobaric bupivacaine (15 mg) with morphine sulfate
(0.2 mg). Intraoperative outcomes compared included extent of sensory
block, quality of anesthesia, and side effects. Postoperative outcome
s, including pain visual analog scale scores, systemic analgesic requi
rements, and side effects, were monitored for 48 h. Sedation effects w
ere quantified and compared using Trieger and digit-symbol substitutio
n tests. We detected no differences in sensory or motor block, quality
of anesthesia, quality of postoperative analgesia, incidence of side
effects, or psychometric scores. Both preparations provide highly sati
sfactory anesthesia for cesarean section and effective postoperative a
nalgesia. Implications: Dextrose alters the density of intrathecal bup
ivacaine solutions and is thought to influence subarachnoid distributi
on of the drug. We randomized parturients undergoing cesarean section
to one of two often used spinal bupivacaine preparations, hypobaric an
d hyperbaric. We detected no differences in clinical outcomes between
groups.