Evaluation of Doppler ultrasonography for the measurement of blood flow in young loggerhead sea turtles (Caretta caretta)

The use of echocardiography as a health assessment tool in green sea turtles (Chelonia mydas)

There are limited techniques available to assess the health of sea turtles as physical examination has little correlation to clinical findings, and blood reference intervals are broad and provide limited prognostic significance. Advances in the portability of ultrasound machines allow echocardiography to be increasingly used in the health assessments of wild animals. This study performed blood analysis and echocardiograms on 11 green sea turtles upon admission to a rehabilitation clinic and six animals before release. Significant differences were seen between groups, with admission animals having significantly smaller diameters of the cavum arteriosum at systole and diastole, smaller E-waves and an increased fractional shortening. Pre-release animals displayed significant increases in the maximum blood velocities of both the pulmonary artery and the left aorta. Significant negative correlations were seen between fractional shortening and uric acid and between the velocity time integral of the pulmonary artery and urea. The pulmonary artery velocity time integral was also significantly correlated to the E wave. Furthermore, there was asynchrony between the cavum arteriosum and the cavum pulmonale and the detection of a parasitic granuloma in the ventricular outflow tract of one animal. Overall, the results suggest that cardiac function in stranded green sea turtles is significantly impaired and that echocardiography has applications in the health assessments of green sea turtles.

Echocardiographic evaluation of four giant Aldabra tortoises (Aldabrachelys gigantea)

Objectives

In recent years echocardiography has become a good diagnostic tool in Zoo Medicine but in some cases, it is still a challenge. In Aldabra giant tortoise (Aldabrachelys gigantea) the big size of animals and the few individuals hosted in Zoo are critical points for the application of this diagnostic technique.The purposes of this research were: to evaluate the feasibility of the diagnostic imaging technique on big-sized turtles; to define the echographic parameters for this species; and to describe the morphofunctional and physiological echographic characteristics of their cardiovascular system.

Design

Repeated measures in vivo.

Setting

Ultrasonography systematic description and Doppler analysis of the cardiovascular system of Aldabra giant tortoise were carried out; B-mode examination allowed the evaluation of the kinetics of the ventricle, the atria and the atrioventricular valves.

Participants

4 Aldabra giant tortoises (two adult males and two young females) hosted in two zoological gardens.

Interventions

Echocardiography was performed placing the animals in ventral on a restraining platform raised from the floor, to provide adequate accessibility to the thoracic windows where the probe was placed. No chemical restraint was used.

Primary and secondary outcome measures

Heart rate, systolic and diastolic areas and volumes, vessel diameters and blood flow velocity were measured.

Results

Heart rate was 21±4 bpm (range 14-25 bpm). The averages of the diastolic and systolic area indexes linked to the subject weight were: 21±3 cm² and 9±1 cm².The aortic annulus diameter in female specimens measured 11.2±0.8 mm, while it measured 21.5±0.3 mm in male species.

Conclusion

Results confirm the effectiveness of echocardiography as a means to study and evaluate the cardiovascular system of this species even if more studies on a bigger number of patients would be necessary to develop the echocardiography technique.

INHALANT ANESTHETIC RECOVERY FOLLOWING INTRAMUSCULAR EPINEPHRINE IN THE LOGGERHEAD SEA TURTLE ( CARETTA CARETTA)

Prolonged anesthetic recovery time is a common complication of chelonian inhalant anesthesia and may be exacerbated by right-to-left intracardiac shunting of blood. Epinephrine may decrease intracardiac shunting, which may shorten anesthetic recovery time. The study objective was to assess inhalant anesthetic recovery time following intramuscular epinephrine compared with saline in the loggerhead sea turtle ( Caretta caretta). With the use of a prospective, randomized, blinded, crossover design with a 1-wk washout period, six turtles were anesthetized with intravenous (IV) alfaxalone 3 mg/kg, orotracheally intubated, manually ventilated with 3.5% isoflurane inhalant in 100% oxygen for 90 min, and administered either intramuscular (IM) epinephrine 0.1 mg/kg or IM saline 0.1 ml/kg. Isoflurane administration was immediately discontinued and turtles were manually ventilated with room air until extubation. Physiologic variables, sedation scores, end-tidal carbon dioxide (ET_CO2) and isoflurane (ET_ISO) concentrations, time to first movement, and time to extubation were recorded and two-time-point venous blood gas analyses performed. Data were compared with the use of paired t-tests and repeated-measures analyses of variance (ANOVA) ( P < 0.05). No morbidity, mortality, or adverse events occurred. ET_CO2 and ET_ISO did not significantly change over time during the isoflurane delivery period ( P = 0.990). Mean time to first movement was significantly faster following epinephrine (69.24 ± 12.28 min) compared with saline (87.71 ± 27.05 min, P = 0.047). Although differences were not statistically significant ( P = 0.133), time to extubation was at least 30 min faster (31-123 min) in 4/6 turtles following epinephrine compared with saline. Intramuscular epinephrine significantly reduces time to first movement during isoflurane anesthetic recovery in loggerhead sea turtles.

Contrast echocardiography for analysis of heart anatomy in tortoises

OBJECTIVE

The cardiac anatomy in tortoises depicted on B-mode and color-Doppler should be better differentiated by additional contrast-echocardiography.

MATERIAL AND METHODS

An intravenous contrast agent (INN-sulphur hexafluoride [SonoVue®]) was injected in four tortoises (three Testudo hermanni, one Agrionemys horsfieldii), via the coccygeal vein, with parallel B-mode echocardiographic examination. The results of the contrast-enhanced echocardiography were compared with the contrast-free B-mode recordings and color-Doppler ultrasound.

RESULTS

The use of SonoVue® enabled clearer distinction of the cardiac structures, differentiation of the arising major arteries, identification of wash-out-shunts, and visualization of blood flow patterns throughout the tortoise heart.

CONCLUSION AND CLINICAL RELEVANCE

This study enables the accurate depiction and differentiation of cardiac anatomy in tortoises through the use of a combination of B-mode, color-Doppler and contrast-echocardiography. Basic knowledge of blood flow in the reptile heart is essential to understand echocardiographic anatomy. Blood-flow-patterns and anatomy of the tortoise heart as found in this study will help to establish a basis for further echocardiographic examinations of these animals.

Evaluation of pulmonary function in European land tortoises using whole-body plethysmography

The aim of this study was to evaluate the use of whole-body plethysmography as a non-invasive method to determine the respiratory parameters and profiles in two tortoise species belonging to the genus Testudo. Pulmonary functions and volumetric parameters were determined in 10 adults of Testudo hermanni and in seven Testudo marginata animals, using whole-body plethysmography. A profile pattern was regularly observed: an inspiratory flow peak, an expiratory peak, an apnoea phase and a second expiratory peak, previous to the beginning of the next respiratory cycle. Positive and significant correlation was observed between the inspiratory time, weight and length of the tortoises. Larger tortoises showed a higher time of inhalation. The peak of inspiratory flow was correlated with the sex, being longer in the females. T. marginata had an inspiratory time longer than that of T. hermanii. In T. hermanii, differences related to the sex were observed in the tidal volume, peak inspiratory flow, peak expiratory flow, expiratory flow of 50 per cent and enhanced pause, which could be related to the smaller size of males. The results suggest that additional information on new technologies currently used in pet medicine or even in human medicine should be developed and adjusted as alternative ways to support the rehabilitation of turtles and tortoises.

Postmortem diagnostic investigation of disease in free-ranging marine turtle populations: a review of common pathologic findings and protocols

Over the past few decades, there have been increasing numbers of reports of diseases in marine turtles. Furthermore, in recent years, there have been documented instances of apparently new diseases emerging in these species of which the etiology and/or pathogenesis remain unknown. These instances i) raise concern for the survival of marine turtles, and ii) question the health and stability of the benthic marine environments in which turtles live. Knowledge of common disease processes and pathologic changes in lesions, along with a standardized approach to postmortem and sample collection are required to document and understand the host-agent-environment interactions in marine turtle health. This review combines, for the first time, a standardized approach to the postmortem of marine turtles for veterinary clinicians, with a concurrent descriptive review of the gross and microscopic pathologic changes in lesions commonly seen.