Cardiopulmonary effects of butorphanol in sevoflurane-anesthetized guineafowl (Numida meleagris)

Effects of a single intravenous bolus of fentanyl on the minimum anesthetic concentration of isoflurane in chickens (Gallus gallus domesticus)

“…In the second phase of the study, there were no significant changes in cardiopulmonary variables before and after administration of fentanyl (30 mg kg À1 ) IV over 1 minute. Other studies in birds have reported the cardiopulmonary effects of equipotent concentrations of inhalation anesthetics combined or not with opioids (Escobar et al 2014(Escobar et al , 2016. A combination of sevoflurane with butorphanol resulted in cardiopulmonary arrest in two guineafowl (Escobar et al 2014).…”

“…Other studies in birds have reported the cardiopulmonary effects of equipotent concentrations of inhalation anesthetics combined or not with opioids (Escobar et al 2014(Escobar et al , 2016. A combination of sevoflurane with butorphanol resulted in cardiopulmonary arrest in two guineafowl (Escobar et al 2014). Administration of isoflurane combined with methadone to chickens decreased the HR and increased sAP when compared with anesthesia using an equipotent concentration of isoflurane (Escobar et al 2016).…”

“…Although the PaCO 2 values after fentanyl administration were within the normal range for birds (24e40 mmHg; 3.2e5.3 kPa) (Powell 2000), inclusion of birds anesthetized only with isoflurane as a control group may have provided information about a change in the ventilatory pattern. In addition, administration of fentanyl over 1 minute in this study may have minimized subsequent cardiopulmonary changes in comparison with a rapid IV bolus administration in another study that induced cardiac arrest (Escobar et al 2014).…”

“…The duration of the anestheticsparing effect of opioids during inhalation anesthesia in birds is reported to be short. In the guineafowl, intravenous (IV) administration of butorphanol (4 mg kg À1 ) reduced the sevoflurane MAC at 15 and 30 minutes by 21% and 11%, respectively (Escobar et al 2012); however, this dosage was considered unsafe (Escobar et al 2014). Intramuscular (IM) administration of morphine (3 or 6 mg kg À1 ) in chickens reduced the isoflurane MAC at 15 minutes by 15% and 22%, respectively (Vela et al 2014).…”

Effects of Methadone on the Minimum Anesthetic Concentration of Isoflurane, and Its Effects on Heart Rate, Blood Pressure and Ventilation during Isoflurane Anesthesia in Hens (Gallus gallus domesticus)

“…The pharmacodynamics of opioids in avian patients are still understudied; most investigations on antinociceptive and immobilizing effects of opioids are with butorphanol or buprenorphine [ 1 – 5 ], which are not full agonist at μ-opioid receptors [ 6 ]. The butorphanol dosage that decreases the minimum anesthetic concentration (MAC) of sevoflurane is unsafe and has short-lived effects in guineafowl [ 7 ] and the analgesic effect of butorphanol in birds is controversial [ 2 , 3 ]. On the other hand, morphine and fentanyl, which are full agonists at μ-opioid receptors, reduced isoflurane MAC by more than 50% in chickens and red-tailed hawks, respectively [ 8 , 9 ].…”