Comparison of Isoflurane and Sevoflurane for Anesthesia in Beaver

Abstract

We compared the hemodynamic and respiratory effects, recovery time, and cost of two gas inhalants (isoflurane and sevoflurane) for anesthetic induction and maintenance of beaver (Castor canadensis) during surgery to implant radio transmitters in the peritoneal cavity. Heart rate, respiratory rate, relative hemoglobin saturation with oxygen (SpO 2 ), and body temperature were measured every 5 min for the first 45 min, and arterial blood gas was measured once, 25 min into the anesthetic procedure. Induction for either agent was smooth and rapid. Heart rate and respiratory rate both decreased during the procedure though neither was lower than baseline values reported in the literature for beaver. Relative hemoglobin saturation with oxygen, body temperature, and blood gas variables did not differ between each anesthetic regime. Both inhalants caused slight respiratory acidosis. Recovery time from anesthesia was highly variable (1-178 min) but did not differ statistically between drugs. Sevoflurane costs ($22.30/60 min) were much higher than isoflurane costs ($3.50/60 min). We recommend isoflurane or sevoflurane for anesthetic induction and maintenance of beaver because of the lack of physiologic differences.

Field Use of Isoflurane as an Inhalant Anesthetic in the American Marten (Martes Americana)

“…Nevertheless, because we used this vaporizer outside its recommended range of temperatures (15 C to 35 C), the reported settings of isoflurane are not necessary equal to the actual concentration delivered. Even though isoflurane has a slightly pungent and ethereal odor and can irritate the upper airways (Calvey and Williams, 2001), martens tolerated induction via face mask well; this is consistent with observations of Siberian polecats (Gaynor , 1997), sea lion pups (Heath et al, 1997), beavers (Breck and Gaynor, 2003), and ferrets (Lawson et al, 2006). Isoflurane is a volatile agent with a low blood:gas solubility coefficient (1.4 versus 2.4 for halothane) and low tissue solubility, resulting in extremely rapid induction and recovery (Calvey and Williams, 2001).…”

Differences in need for hemodynamic support in horses anesthetized with sevoflurane as compared to isoflurane

“…1998; Polis et al. 2001), beaver (Breck & Gaynor 2003), goats (Hikasa et al. 2002) and humans (Ebert et al.…”

Field Use of Isoflurane for Safe Squirrel and Woodrat Anesthesia

“…Portable anesthesia machines with isoflurane-specific vaporizers have been used in beavers (Castor canadensis; Breck and Gaynor 2003) and big brown bats (Eptesicus fuscus; Wimsatt et al 2005). However, these animals were easily and quickly transported to central processing facilities which facilitated the use of vaporizers.…”