POTENCY (MINIMUM ALVEOLAR ANESTHETIC CONCENTRATION) OF ISOFLURANE IS INDEPENDENT OF PERIPHERAL ANESTHETIC EFFECTS

Citation
Jf. Antognini et Nd. Kien, POTENCY (MINIMUM ALVEOLAR ANESTHETIC CONCENTRATION) OF ISOFLURANE IS INDEPENDENT OF PERIPHERAL ANESTHETIC EFFECTS, Anesthesia and analgesia, 81(1), 1995, pp. 69-72
Citations number
20
Categorie Soggetti
Anesthesiology
Journal title
ISSN journal
00032999
Volume
81
Issue
1
Year of publication
1995
Pages
69 - 72
Database
ISI
SICI code
0003-2999(1995)81:1<69:P(AACO>2.0.ZU;2-N
Abstract
The spinal cord is an important site where inhaled anesthetics suppres s movement in response to noxious stimuli. Inhaled anesthetics also ac t in peripheral tissues, although it is unclear whether these actions influence anesthetic requirements. In six isoflurane-anesthetized mong rel dogs, we placed Y cannulas in the lower aorta and vena cava, allow ing us to divert blood to, and infuse blood from, a bubble oxygenator/ roller pump system or to maintain normal blood flow. This technique pe rmits a greatly diminished isoflurane concentration at the site of the noxious stimulus (tail), while maintaining isoflurane in the remainde r of the body. After baseline minimum alveolar anesthetic concentratio n (MAC1) was determined, venous blood from the lower body was diverted to the bubble oxygenator and reinfused into the lower body via the ao rtic cannula; MAC2 was determined with isoflurane in the lower body at approximate to 0.2%, and MAC3 was determined with isoflurane in the l ower body matched to the end-tidal isoflurane. Bypass was terminated, the native circulation established, and MAC4 determined. MAC1, 2, 3, a nd 4 were (mean +/- SD) 1.3 +/- 0.3%, 1.2 +/- 0.1%, 1.2 +/- 0.2%, and 1.1 +/- 0.2%, respectively (P > 0.05). We conclude that the peripheral effects of isoflurane do not influence the response to a noxious stim ulus.