Effect of Body Position, Leg and Neck Extension, and Sedation on Lung Volume in Red-Eared Slider Turtles (Trachemys scripta elegans)
Pneumonia is a common problem in turtles and tortoises, which is typically diagnosed radiographically.1,3 An impact of body position and extension of extremities and neck on lung volume has been suggested,2,4,5 but has not been systematically described and quantified. Therefore, we investigated the effect of body position (vertical vs. horizontal) and leg and neck position (extended vs. withdrawn) on lung volume in conscious and sedated red-eared slider turtles (Trachemys scripta elegans) (six female and eight male) using computed tomography. While sedation with dexmedetomidine (Pfizer Animal Health, New York, NY, USA; 0.1 mg/kg, SC), midazolam (Hospira Inc, Lake Forest, IL, USA; 1 mg/kg, SC) and ketamine (Fort Dodge Animal Health, Fort Dodge, IA, USA; 2 mg/kg, SC) had no significant effect on total lung volume, leg and neck extension resulted in a significant increase in total lung volume (p<0.001) in sedated turtles. Left and right lateral and cranio-caudal vertical positioning had no significant effect on total lung volume, but resulted in a shift of coelomic organs ventrally, compressing and significantly reducing the volume of the dependent lung tissue (p<0.01). No significant gender differences were found in lung volume and position. Based on these results, horizontal radiographic positioning of chelonian patients is recommended in order to avoid compression of lung tissue by shifting coelomic organs. Extension of the extremities and neck will lead to an increase in lung volume and, therefore, potentially improve the diagnostic value of imaging of turtles and tortoises suffering from diseases of the lower respiratory tract.
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