Minimum Anesthetic Concentration and Cardiovascular Dose–Response Relationship of Isoflurane in Cinereous Vultures (Aegypius monachus)

Abstract

This study aimed to determine the minimum anesthetic concentration (MAC) and dose-related cardiovascular effects of isoflurane during controlled ventilation in cinereous vultures (Aegypius monachus). The MAC was determined for 10 cinereous vultures as the midpoint between the end-tidal isoflurane concentration that allows gross purposeful movement and that which prevents the movement in response to clamping a pedal digit. Immediately after the MAC was determined, the cardiovascular effects of isoflurane at 1.0, 1.5, and 2.0 times the MAC were investigated in seven of the 10 birds. The MAC of isoflurane for 10 cinereous vultures during controlled ventilation was 1.06 +/- 0.07% (mean +/- SD). When the isoflurane concentration was increased to 1.5 and 2.0 times the MAC, there was significant dose-dependent decrease in the arterial blood pressure. However, the heart rate did not change over a range of 1.0 to 2.0 times the MAC.

Anaesthesia with sevoflurane in pigeons: minimal anaesthetic concentration (MAC) determination and investigation of cardiorespiratory variables at 1 MAC

“…The MAC value, however, may vary considerably among avian species (Mercado and others 2008) and can be influenced by many physiological factors (body temperature, metabolic rate, blood CO 2 tension and large variations in blood pressure; Quasha and others 1980). In the current study, as in several other studies determining MAC values in birds (Ludders and others 1989, Naganobu and Hagio 2000, Naganobu and others 2003, Kim and others 2011, Escobar and others 2012, Phair and others 2012), body temperature remained stable during all the anaesthetic procedures. Consequently, body temperature was unlikely to have influenced these results.…”

Cardiorespiratory parameters in the awake pigeon and during anaesthesia with isoflurane

“…During isoflurane anaesthesia, SAP was significantly lower (87 AE 11 mmHg), as previously reported in pigeons undergoing coelioscopy (Touzot-Jourde et al 2005). Isoflurane is known to be a vasodilator (Schnellbacher et al 2012) and the consequent decrease in systemic vascular resistance may represent the main cause of hypotension; the degree of hypotension has been correlated with depth of isoflurane anaesthesia in other avian species (Ludders et al 1989;Naganobu & Hagio 2000;Kim et al 2011).…”

“…), 1.45 ± 0.07% in red‐tailed hawks (Fitzgerald & Blais ) and 1.06 ± 0.07% in cinereous vultures (Kim et al. ). Our findings also differ from the isoflurane MAC value of 1.51 ± 0.15% measured in a study in 12 adult pigeons (Fitzgerald & Blais ).…”

“…This value is higher than those reported for other avian species. MAC values for isoflurane were reported to be 1.07% in thickbilled parrots (Mercado et al 2008), 1.34 AE 0.14% in sandhill cranes (Ludders et al 1989), 1.25 AE 0.13% in chickens (Naganobu & Hagio 2000), 1.30 AE 0.23% in Pekin ducks (Ludders et al 1990), 1.45 AE 0.07% in red-tailed hawks (Fitzgerald & Blais 1991) and 1.06 AE 0.07% in cinereous vultures (Kim et al 2011). Our findings also differ from the isoflurane MAC value of 1.51 AE 0.15% measured in a study in 12 adult pigeons (Fitzgerald & Blais 1991).…”

Physiological alteration, quality of anesthesia and economy of isoflurane in domestic chickens (Gallus domesticus)

“…In wild red kite ( Milvus milvus ), heart rate was maintained at 240-260 beats/min during coelioscopy under isoflurane anesthesia [24]. No significant changes of heart rate were observed in cinereous vulture [25]. …”