Factors influencing MAC reduction after cardiopulmonary bypass in dogs

Neumeister, Michael W.; Li, Gefeng; Williams, G. R.; Doak, Greg J.; Sullivan, John A.; Hall, Richard

doi:10.1007/bf03019237

Cited by 8 publications

(3 citation statements)

References 31 publications

(3 reference statements)

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“…27 Within a single species, the variability in MAC is generally small. In our study, the MAC value for ISO was in agreement with other reported values of 1.41, 28 1.39, 29 and 1.28% 30 for dogs. The MAC value for each dog was consistent between test periods.…”

Section: Discussionsupporting

confidence: 93%

“…The noxious stimulus used in this study is similar to that used to determine MAC values for inhalant anesthetics. 28,40,41 The response to the tail clamp is the end result of a multiple-step process of nociception and integration that causes a gross purposeful movement. It should be emphasized that any drug-induced effects that interfere with an animal's ability to purposefully move (eg, neuromuscular junction blockers) could potentially decrease the MAC value when measured by gross response to a tail clamp.…”

Section: Discussionmentioning

confidence: 99%

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Duration of nonresponse to noxious stimulation after intramuscular administration of butorphanol, medetomidine, or a butorphanol-medetomidine combination during isoflurane administration in dogs

Grimm

Tranquilli²,

Jc³

et al. 2000

ajvr

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Duration of nonresponse to noxious stimulation after intramuscular administration of butorphanol, medetomidine, or a butorphanol-medetomidine combination during isoflurane administration in dogs

Grimm

Tranquilli²,

Jc³

et al. 2000

ajvr

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“…Takizawa et al reported that the anesthetic effect of propofol increased significantly during CPB without any alteration in the total drug concentration. 5 This mechanism has already been validated for volatile anesthetics in experimental models 19 , 20 and clinical contexts, 6 , 17 where the minimum alveolar concentration (MAC) was decreased after CPB.…”

Section: Discussionmentioning

confidence: 88%

Effects of Cardiopulmonary Bypass on Propofol Pharmacokinetics and Bispectral Index During Coronary Surgery

Barbosa¹,

Santos²,

White³

et al. 2009

Clinics

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Barbosa RAG, Santos SRCJ, White PF, Pereira VA, Silva Filho CR, Malbouisson LMS. Effects of cardiopulmonary bypass on propofol pharmacokinetics and bispectral index during coronary surgery. Clinics. 2009;64(3):215-21. PURPOSE:Cardiopulmonary bypass is known to alter propofol pharmacokinetics in patients undergoing cardiac surgery. However, few studies have evaluated the impact of these alterations on postoperative pharmacodynamics. This study was designed to test the hypothesis that changes in propofol pharmacokinetics increase hypnotic effects after cardiopulmonary bypass. METHODS: Twenty patients scheduled for on-pump coronary artery bypass graft (group, n=10) or off-pump coronary artery bypass graft (group, n=10) coronary artery bypass grafts were anesthetized with sufentanil and a propofol target controlled infusion (2.0 µg/mL). Depth of hypnosis was monitored using the bispectral index. Blood samples were collected from the induction of anesthesia up to 12 hours after the end of propofol infusion, at predetermined intervals. Plasma propofol concentrations were measured using high-performance liquid chromatography, followed by a non-compartmental propofol pharmacokinetic analysis. Data were analyzed using ANOVA, considering p<0.05 as significant. RESULTS: After cardiopulmonary bypass, despite similar plasma propofol concentrations in both groups, bispectral index values were lower in the on-pump coronary artery bypass graft group. Time to extubation after the end of propofol infusion was greater in the on-pump coronary artery bypass graft group (334 ± 117 vs. 216 ± 85 min, p = 0.04). Patients undergoing cardiopulmonary bypass had shorter biological (1.82 ± 0.5 vs. 3.67 ± 1.15h, p < 0.01) and terminal elimination (6.27 ± 1.29 vs. 10.5h ± 2.18, p < 0.01) half-life values, as well as higher total plasma clearance (28.36 ± 11.40 vs.18.29 ± 7.67 mL/kg/min, p = 0.03), compared to patients in the off-pump coronary artery bypass graft group. CONCLUSION: Aside from the increased sensitivity of the brain to anesthetics after cardiopulmonary bypass, changes in propofol pharmacokinetics may contribute to its central nervous system effects.

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