Selected cardiopulmonary values and baroreceptor reflex in conscious green iguanas (Iguana iguana)

Sonia M. Hernandez
Juergen Schumacher, University of Tennessee, Knoxville
Stephen J. Lewis
Agricola Odoi, University of Tennessee, Knoxville
Stephen J. Divers

Abstract

Objective-To determine selected cardiopulmonary values and baroreceptor response in conscious green iguanas (Iguana iguana) and to evaluate the use of blood gas analysis and pulse oximetry in this species.

Animals-15 healthy juvenile green iguanas.

Procedures-Baseline cardiopulmonary values were determined in 15 conscious iguanas breathing room air. Effects of 100% O(2) inspiration were also measured (n = 6), and the baroreceptor reflex was characterized by exponential sigmoidal curve fitting analysis.

Results-Conscious iguanas had a mean +/- SD resting heart rate of 52 +/- 8 beats/min, respiratory rate of 28 +/- 6 breaths/min, and systolic, mean, and diastolic arterial blood pressures of 69 +/- 10 mm Hg, 62 +/- 12 mm Hg, and 56 +/- 13 mm Hg, respectively. Mean arterial pH at 37 degrees C was 7.29 +/- 0.11, Pao(2) was 81 +/- 10 mm Hg, and Paco(2) was 42 +/- 9 mm Hg; corrected for a body temperature of 30 degrees C, mean arterial pH at 37 degrees C was 7.382 +/-0.12, Pao(2) was 54 +/- 15 mm Hg, and Paco(2) was 32 +/- 7 mm Hg. Inspiration of 100% O(2) did not change heart and respiratory rates but increased Pao(2) to 486 +/- 105 mm Hg (corrected value, 437 +/- 96 mm Hg). A baroreceptor reflex was evident, with mean heart rates ranging from 30 +/- 3 beats/min to 63 +/- 5 beats/min and mean arterial blood pressures ranging from 42 +/- 3 mm Hg to 58 +/- 3 mm Hg.

Conclusions and Clinical Relevance-This study provided needed information on cardiopulmonary values in healthy green iguanas, the application and limitation of arterial and venous blood gas analysis, and the accuracy of pulse oximetry.