Comparison of Sevoflurane with Isoflurane for Rapid Mask Induction in Midazolam and Butorphanol‐sedated Dogs

Abstract

Rapid mask induction can be a useful induction technique for veterinary patients, although it is often accompanied by exaggerated excitement responses in unpremedicated animals (Mutoh et al.: Jpn. J. Vet. Anesth. Surg. 26, 109-116; J. Vet. Med. Sci. 57, 1007-1013; J. Vet. Med. Sci. 57, 1121-1124; 1995). The aim of this study was to compare sevoflurane with isoflurane for rapid mask induction in six dogs sedated by a combination of midazolam (0.1 mg/kg) and butorphanol (0.2 mg/kg). Induction with sevoflurane (5%, 2.4 minimum alveolar concentration [MAC]) in O2 resulted in shorter time to loss of the palpebral reflex, negative tail clamp response, and successful intubation than with isoflurane (3%, 2.4 MAC) in O2. There were no changes in heart rate or mean arterial blood pressure during induction with sevoflurane, whereas an increase in heart rate was observed in dogs induced with isoflurane. A decrease in respiratory rate compared with the pre-induction rate was observed during induction, and associated mild respiratory acidosis, characterized by an increase in arterial PCO2, was measured at the end of the induction period in both induction groups. None of the animals had episodes of induction-related complications. These results suggest that both sevoflurane and isoflurane produce a smooth onset of induction in midazolam and butorphanol-sedated dogs. Sevoflurane is a more suitable for rapid mask induction than isoflurane since it provides faster induction associated with a lower blood/gas partition coefficient.

Comparison of the arterial blood gas, arterial oxyhaemoglobin saturation and end-tidal carbon dioxide tension during sevoflurane or isoflurane anaesthesia in rabbits

“…The adverse effects of halogenated volatile anaesthetics associated with mask induction, as experienced clinically in animals, are characterised by apnoea, breath-holding, laryngospasm, bronchoconstriction or body movements [7,9,10]. Some of these induction-related complications (e.g., struggling) also accompany mask induction in rabbits [2,4] and dogs [8].…”

Clinical effects of isoflurane and sevoflurane in lambs

“…The rate of induction of anaesthesia in veterinary subjects is commonly monitored using the TLPR (Johnson et al. 1998; Mutoh et al. 2001), the time to successful tracheal intubation (Pottie et al.…”

“…In unsedated and sedated (midazolam and butorphanol) dogs, TLPR was less after sevoflurane compared to isoflurane (Johnson et al. 1998; Mutoh et al. 2001).…”

“…The rate of induction of anaesthesia in veterinary subjects is commonly monitored using the TLPR (Johnson et al 1998;Mutoh et al 2001), the time to successful tracheal intubation (Pottie et al 2008), the time at loss of withdrawal reflexes or unresponsiveness to toe -tail -pinching (Lerche et al 2002), and the time at loss of the righting reflex (Flecknell et al 1999). Intubation of the small ruminant's trachea is challenging even when swallowing reflexes are absent and so this index of induction rate can produce more variable results.…”

Sevoflurane and its use in veterinary practice

“…5 %), είναι ταχΰτερη και καλΰτερη ποιοτικά σε σΰγκριση με το ισοφλουράνιο, το εν φλουράνιο και το αλοθάνιο (Johnson et al 1998, Mutoh et al 2001b, ενώ η αΰξηση της καρδιακής συχνότητας και του όγκου παλμοΰ είναι χωρίς κλινική σημασία (Mutoh et al 1995). Η εφαρμογή προαναισθητικής αγωγής, όπως για παράδειγμα με μεδετομιδίνη και μιδαζολάμη, καθιστά την εγκατάσταση της αναισθησίας με σεβοφλουράνιο ομαλό τερη (Polis et al 2001b, Mutoh et al 2002.…”