Combining isoflurane anesthesia with midazolam and butorphanol in rats

Abstract

Representative inhalant anesthetic agent, isoflurane is commonly used during surgery in rats. However, isoflurane mediates relatively strong respiratory depression. In human and veterinary medicine, sedatives and analgesics are co-administered to complement the anesthetic action of inhalant anesthesia. The present study aimed to establish the novel balanced anesthesia that combines midazolam and butorphanol with isoflurane (MBI) in rats. Male Sprague Dawley rats were divided into 2 groups, and administered either isoflurane monoanesthesia or isoflurane with midazolam (2.5 mg/kg, ip) and butorphanol (2.0 mg/kg, ip). The minimum alveolar concentration (MAC) in each group was evaluated. Induction and recovery times were measured in each group. Adverse reactions during induction were also recorded. In each group, vital signs were assessed for 1 h under 1.5×MAC of isoflurane. Instability of vital signs was assessed under each anesthesia by calculating coefficient of variance. Compared with isoflurane monoanesthesia, MBI anesthesia caused 32% MAC reduction (isoflurane monoanesthesia: 1.30 ± 0.09%, MBI 0.87 ± 0.08%, P<0.05). MB premedication mediated smooth sedating action with low incidence of adverse reactions such as urination and defecation. Isoflurane monoanesthsesia remarkably decreased respiratory rate and saturation O2 (SPO2). In contrast, MBI anesthesia resulted in a relatively stable respiratory rate without decreases in SPO2 during the anesthetic period. In summary, MB premedication is effective for attenuating respiratory depression induced by isoflurane, and achieving smooth induction. This anesthetic protocol serves as a novel option for appropriate anesthesia in rats.

Different sensitivity to the suppressive effects of isoflurane anesthesia on cardiorespiratory function in SHR/Izm, WKY/Izm, and Crl:CD (SD) rats

“…After the recording under the set at 5%, the rat was relieved from anesthesia by removing the nose mask and observed until awakening. Endotracheal intubation in rats requires a certain amount of skill and endoscope for the successful intubation [20] and there were many reports using nose mask for isoflurane anesthesia in rats even in recent years [1, 2, 7, 40]. For practical data using nose mask, we used nose mask instead of endotracheal intubation in maintenance of isoflurane anesthesia.…”

Pharmacological properties of various anesthetic protocols in 10-day-old neonatal rats

“…This concentration corresponds to MAC × 1.5, which is commonly used for standard surgery. In adult rats, MAC was reported as 1.3–1.4% [ 11 , 26 ], whereas it is reported as 2% in neonatal rats [ 20 ]; this is suggestive of a lower drug sensitivity in neonates. In adult rats, isoflurane mediated sufficient anesthetic depth with rapid induction and awakening [ 11 ], demonstrating a wide safety margin and accomplishing sufficient anesthetic depth with reduced cardiac and metabolic influence [ 7 , 14 , 19 ].…”

“…To date, several general anesthetic protocols have been applied to rodents [ 5 , 11 , 14 , 26 ]. General anesthesia is mainly classified into injection anesthesia and inhalation anesthesia.…”

Effects of Thioxanthene Containing Anti-Psychotic and Anti-Platelet Drug Combination on Mean Platelet Volume and Platelet Distribution Width in Rats

“…Rats were anesthetized by using the Isoflurane [14]. Blood samples were collected at 0, 7 th , 14 th and 21 st days during experiment.…”