Anesthesia and analgesia
-
Anesthesia and analgesia · Jul 2001
Comparative StudySodium nitroprusside compared with isoflurane-induced hypotension: the effects on brain oxygenation and arteriovenous shunting.
We compared sodium nitroprusside (SNP)-induced hypotension with 3% isoflurane-induced hypotension with regard to brain tissue oxygen pressure (PtO(2)), middle cerebral artery (MCA) blood flow, and cerebral arteriovenous shunting. Eight dogs were anesthetized with 1.5% isoflurane. After a craniotomy, a probe was inserted into the left frontoparietal brain cortex to mea-sure tissue gases and pH. Blood flow was measured in a secondary branch of the MCA by a flowprobe. Measurements were made during baseline 1.5% isoflurane, during 1.5% isoflurane and SNP-induced hypotension or 3% isoflurane-induced hypotension to a mean pressure of 60-65 mm Hg, and during continued treatment with SNP or 3% isoflurane with blood pressure support to baseline levels with phenylephrine. Shunting was calculated from arterial, sagittal sinus, and tissue (indicating capillary) oxygen content. During hypotension with SNP, PtO(2) decreased 50%, and shunting increased 50%. During hypotension with 3% isoflurane, PtO(2) and shunting did not change. Blood pressure support increased PtO(2) and MCA flow during both SNP and 3% isoflurane treatment. These results show that SNP is a cerebrovasodilator but that hypotension will decrease PtO(2), probably because of an increase in arteriovenous shunting and a decrease in capillary perfusion. ⋯ We measured brain arteriovenous shunting and tissue oxygen pressure(PtO(2))during a 40% decrease in blood pressure induced by sodium nitroprusside (SNP)or 3% isoflurane. Large-dose isoflurane maintainedPtO(2) with no change in shunting. SNP infusion decreasedPtO(2) 50%and increased shunting 50%. This suggests that SNP-induced hypotension decreases PtO(2) because of a decrease in capillary perfusion.
-
Anesthesia and analgesia · Jul 2001
Randomized Controlled Trial Clinical TrialNalbuphine versus propofol for treatment of intrathecal morphine-induced pruritus after cesarean delivery.
In this prospective, randomized, double-blinded study, we compared the efficacy of nalbuphine and propofol for treating intrathecal morphine-induced pruritus after cesarean delivery. One-hundred-eighty-one parturients who developed moderate to severe pruritus after the administration of intrathecal morphine were randomly allocated into two groups. One group received 3 mg IV nalbuphine (n = 91), and the other received 20 mg IV propofol (n = 90). The improvement of pruritus and other adverse effects was determined at 10 min after study drug administration. The treatment success rate was higher in the Nalbuphine group than in the Propofol group (83% vs 61%; P < 0.001). Among the successfully treated patients, recurrence rates of moderate to severe pruritus within 4 h were not significantly different (nalbuphine 9% versus propofol 7%; P = 0.76). Other side effects, such as decreased analgesia, increased nausea, vomiting, increased sedation, pain on injection, and dizziness, were not significantly different between groups. Sedation and pain on injection, which were the two most common side effects, were minor and clinically inconsequential. ⋯ Nalbuphine was superior to propofol for the treatment of intrathecal morphine-induced pruritus after cesarean delivery.