Minimum Alveolar Concentration of Isoflurane and Arterial Blood Gas Values in Anesthetized Green Iguanas, Iguana iguana

Abstract

A b s t r a c t : The minimum alveolar concentration o f isoflurane ( M A C is o f lu r a n e ) was determined in seven green iguanas, Iguana iguana, using a standard double bracketing technique. Following chamber induction, anesthe sia was maintained with isoflurane in 100% O2 using mechanical ventilation o f 25 ml/kg body weight, at a rate o f two breaths per minute. Following an equilibration period o f 25 min at each percentage o f isoflurane tested, response to a supramaximal electrical stimulus applied to the ventral portion o f the tail was assessed. Arterial blood was collected from the right carotid artery for determining blood gas values in iguanas main tained at 1.5 times their individual M A C is o flu ra n e -As measured by time to loss o f righting reflex, chamber induction time was 23 ± 7 min (range 1 8 -3 5 min). M ean (±SD) M A C is o f lu ra n e was 1.62 ± 0.40%, median MAC was 1.60 %, with a range o f 1.10 to 2.15%. Values for pH, partial pressure o f carbon dioxide (PaC02) in kPa (mmHg), partial pressure o f oxygen (Pa02) in kPa (mmHg), bicarbonate concentration (HCO3') mmol L: * base excess (mmol L '1), oxygen saturation (%), concentrations o f sodium (Na+) (mmol L '1), calcium (Ca ) (mmol L_1), potassium (K+) (mmol L '1,), and chloride (C l') (mmol L '1), and anion Gap (mmol L_1) were 7.49 ± 0 .0 3 , 4.75 ± 0.13 (34.6 ± 2 .7 ), 14.2 ± 1 .6 (106.7 ± 12.0), 25.7 ± 1.2, 2.4 ± 1 .4 , 94.4 ± 5.2, 151.1 ± 2.6, 1.03 ± 0.15, 2.0 ± 0.6, 123.8 ± 4.4, and 3.6 ± 1.7 respectively. The MAC o f isoflurane was lower than minimum alveolar concentration values previously published for green iguanas. The pH, oxygen saturation, and Pa02 were higher than reported in prior publications in which blood was collected from the femoral artery or ventral coccygeal vessels, and the mean Pa02 was lower than in a previous publication in which blood was collected from the left carotid artery.K e y w o r d s : green iguana, Iguana iguana, minimum alveolar concentration, arterial blood gases, isoflurane.

Venous hematology, biochemistry, and blood gas analysis of free-ranging Eastern Copperheads (Agkistrodon contortrix) and Eastern Ratsnakes (Pantherophis alleghaniensis)

“…However, many of the blood gas components are influenced by temperature, so when applied to research involving reptiles and other poikilotherms, clinicians and researchers must decide whether to correct the results for ambient temperature. Temperature corrections may not always be warranted and instituting them can preclude comparison of data sets if the methods are not stated, vary among sources, or if the temperatures are different [44][45][46]. There are multiple formulae for manually performing temperature corrections, but none have been validated for snake blood gas analysis performed with portable point-of-care analyzers, such as the iSTAT (Abbott Point of Care, Princeton, NJ) Table 8.…”