Anesthesia and analgesia
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Anesthesia and analgesia · Oct 1999
Randomized Controlled Trial Clinical TrialHemodynamic responses induced by dopamine and dobutamine in anesthetized patients premedicated with clonidine.
To test the hypothesis that the pharmacological effects of dopamine (DOA) and dobutamine (DOB) are altered when there is inhibition of the release of norepinephrine from nerve endings, we examined the hemodynamic responses to DOA and DOB in anesthetized patients premedicated with oral clonidine. Seventy adult patients were assigned to one of two groups (oral premedication with clonidine 5 microg/kg or no premedication). After the induction of general anesthesia, heart rate and systemic blood pressure (BP) were measured for 10 min after each of five IV infusions (3 and 5 microg x kg(-1) x min(-1) of DOA; 0.5, 1, and 3 microg x kg(-1) x min(-1) of DOB) in a randomized, double-blind manner. In patients given clonidine, the mean BP increases induced by DOA 5 microg x kg(-1) x min(-1) were significantly attenuated (P < 0.01), whereas the mean BP increases induced by DOB-0.5, 1, or 3 microg x kg(-l) x min(-1) were significantly enhanced (P < 0.01 or 0.05). The heart rate responses to DOA and DOB did not differ between patients with or without clonidine. Premedication with clonidine alters the effects on BP to both DOA and DOB. When small doses of DOA or DOB are used in clonidine-premedicated patients, differences of pharmacological profiles need to be considered for perioperative management. ⋯ Our randomized, double-blind study suggests that premedication with clonidine may enhance the effect on blood pressure response to a small dose of dobutamine (direct-acting) and attenuate that to a small dose of dopamine (mixed direct-and indirect-acting) in patients anesthetized with fentanyl and nitrous oxide.
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Anesthesia and analgesia · Oct 1999
Review Comparative StudyAmbulatory anesthesia experience with remifentanil.
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Anesthesia and analgesia · Oct 1999
Review Comparative StudyExperience with remifentanil in neurosurgical patients.
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Anesthesia and analgesia · Oct 1999
Comparative StudyThe effect of a sciatic nerve block on the development of inflammation in carrageenan injected rats.
Neurogenic inflammation may participate in postoperative inflammatory pain. We evaluated, in the rat, the influence of a short and prolonged sciatic nerve block on carrageenan-induced inflammation, the time course of which may be compared to postoperative inflammation. A catheter was placed on the right sciatic nerve and injected with 0.5% bupivacaine with epinephrine (0.2 mL): one injection in the Short Block Group, and four injections performed at 90-min intervals in the Prolonged Block Group. In all groups, the two hind paws were then injected with carrageenan. The development of inflammation was evaluated in both hind paws by measurement of paw circumference (PC) before, and 1, 2, 3, 4, 6, and 24 h after carrageenan injection. Temperature of both hind paws was evaluated at the same time points. The vocalization threshold to paw pressure test (VTPP) of both hind paws was evaluated at 6, 8, 10, 12, and 24 h after carrageenan injection. The left hind paw was used for the Control Group. A Sham Group had a catheter placed on the sciatic nerve and injected with normal saline. Inflammation developed in the Control Group with a maximum increase of PC (32%) and temperature (14%) 4 h after carrageenan injection and a maximal reduction of VTPP (44%) at 6 h, reflecting mechanical allodynia. A similar evolution was observed in the Sham Group. In the Short Block Group, the nerve block did not influence the PC, the paw temperature, or the VTPP when compared with the Control Group. In the Prolonged Block Group, when compared with the Control Group, the increased PC was reduced throughout the 24 h (P < 0.0001). The maximal increase in PC at 4 h was limited to 23%, as compared with the precarrageenan value. This effect on PC did not persist at 24 h. Paw temperature was increased (P = 0.07) throughout the study in the Prolonged Block Group, as compared with the Control Group. The VTPP reduction was still limited in the Prolonged Block Group at 24 h, as compared with the Control Group (P < 0.0001). We conclude that a prolonged sciatic nerve block limits carrageenan-induced increase in PC and, subsequently, mechanical allodynia at 24 h in rats. ⋯ Our study has shown that a prolonged (6 h) but not a short sciatic nerve block (90 min) can limit edema and related pain after carrageenan-induced inflammation in rat.