REVISTA

Reducción de las necesidades de anestésicos inhalatorios por metadona en perros

Descripción: Una dosis de metadona 0,5 mg/kg reduce las necesidades de anestésicos inhalatorios en un 35% efectos cardiovasculares importantes

TITULO FUENTE ORIGINAL:

Effects of methadone on the minimum alveolar concentration of isoflurane in dogs.

AUTORES:

Credie RG, Teixeira Neto FJ, Ferreira TH, Aguiar AJ, Restitutti FC, Corrente JE.

REVISTA ABREV.:

Vet Anaesth Analg.

AÑO:

2010

REFERENCIA:

May;37(3):240-9.

DOI:

10.1111/j.1467-2995.2010.00528.x.

FECHA DE PUBLICACIÓN:

01/05/2010

RESUMEN ORIGINAL:

OBJECTIVE:
To investigate the effects of methadone on the minimum alveolar concentration of isoflurane (ISO(MAC)) in dogs.
STUDY DESIGN:
Prospective, randomized cross-over experimental study.
ANIMALS:
Six adult mongrel dogs, four males and two females, weighing 22.8 +/- 6.6 kg.
METHODS: + Leer más

OBJECTIVE:
To investigate the effects of methadone on the minimum alveolar concentration of isoflurane (ISO(MAC)) in dogs.
STUDY DESIGN:
Prospective, randomized cross-over experimental study.
ANIMALS:
Six adult mongrel dogs, four males and two females, weighing 22.8 +/- 6.6 kg.
METHODS:
Animals were anesthetized with isoflurane and mechanically ventilated on three separate days, at least 1 week apart. Core temperature was maintained between 37.5 and 38.5 degrees C during ISO(MAC) determinations. On each study day, ISO(MAC) was determined using electrical stimulation of the antebrachium (50 V, 50 Hz, 10 mseconds) at 2.5 and 5 hours after intravenous injection of physiological saline (control) or one of two doses of methadone (0.5 or 1.0 mg kg(-1)).
RESULTS:
Mean (+/-SD) ISO(MAC) in the control treatment was 1.19 +/- 0.15% and 1.18 +/- 0.15% at 2.5 and 5 hours, respectively. The 1.0 mg kg(-1) dose of methadone reduced ISO(MAC) by 48% (2.5 hours) and by 30% (5 hours), whereas the 0.5 mg kg(-1) dose caused smaller reductions in ISO(MAC) (35% and 15% reductions at 2.5 and 5 hours, respectively). Both doses of methadone decreased heart rate (HR), but the 1.0 mg kg(-1) dose was associated with greater negative chronotropic actions (HR 37% lower than control) and mild metabolic acidosis at 2.5 hours. Mean arterial pressure increased in the MET1.0 treatment (13% higher than control) at 2.5 hours.
CONCLUSIONS AND CLINICAL RELEVANCE:
Methadone reduces ISO(MAC) in a dose-related fashion and this effect is lessened over time. Although the isoflurane sparing effect of the 0.5 mg kg(-1) dose of methadone was smaller in comparison to the 1.0 mg kg(-1) dose, the lower dose is recommended for clinical use because it results in less evidence of cardiovascular impairment.

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