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Updated: Aug 1, 2026
Electromechanical Assessment of Optogenetically Modulated Cardiomyocyte Activity
Published on: March 5, 2020
Cardiopulmonary effects of a medetomidine-ketamine combination administered intravenously in gopher tortoises
Patricia M Dennis1, Darryl J Heard
1Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610, USA.
Objective:
To determine whether IV administration of a combination of medetomidine and ketamine depresses cardiopulmonary function in healthy adult gopher tortoises.
Design:
Prospective study.
Animals:
3 adult male and 3 adult female nonreleasable gopher tortoises.
Procedure:
Prior to the study, carotid and jugular catheters were surgically placed in each tortoise for blood collection, direct arterial blood pressure monitoring, and drug administration. Heart rate, direct carotid arterial blood pressure, and body temperature were measured before and every 5 minutes for 45 minutes after IV injection of medetomidine (100 microg/kg [45.5 microg/lb]) and ketamine (5 mg/kg [2.3 mg/lb]). Carotid arterial blood samples were collected before and 5, 15, 30, and 45 minutes after medetomidine-ketamine administration to determine pH, PO2, and PCO2. Atipamezole (500 mg/kg [227 microg/lb], IV) was administered 30 minutes after administration of medetomidine-ketamine.
Results:
The medetomidine-ketamine combination caused a moderate increase in arterial blood pressure, and moderate hypercapnia and hypoxemia. There were no significant changes in heart rate or body temperature. Intravenous administration of atipamezole rapidly induced severe hypotension.
Conclusions And Clinical Relevance:
The combination of medetomidine and ketamine administered IV resulted in effective short-term immobilization adequate for minor diagnostic procedures in gopher tortoises. This combination also caused moderate hypoventilation, and it is recommended that a supplemental source of oxygen or assisted ventilation be provided. Atipamezole administration hastens recovery from chemical immobilization but induces severe hypotension. It is recommended that atipamezole not be administered IV for reversal of medetomidine in tortoises and turtles.
Insights
Medetomidine and ketamine provide short-term immobilization for gopher tortoises but cause hypoventilation. Supplemental oxygen is recommended, and intravenous atipamezole should be avoided due to severe hypotension.
Area of Science:
- Veterinary Medicine
- Wildlife Conservation
- Anesthesiology
Background:
- Gopher tortoises are a keystone species in their ecosystem.
- Effective chemical immobilization is crucial for veterinary procedures in wildlife.
- Assessing the cardiopulmonary effects of anesthetic combinations is vital for safe practice.
Purpose of the Study:
- To evaluate the cardiopulmonary effects of intravenous medetomidine-ketamine in gopher tortoises.
- To determine the efficacy and safety of this anesthetic combination for immobilization.
- To assess the impact of atipamezole as a reversal agent.
Main Methods:
- A prospective study involving 6 adult gopher tortoises.
- Surgical placement of carotid and jugular catheters for monitoring and drug administration.
- Measurement of heart rate, arterial blood pressure, and blood gases before and after IV medetomidine-ketamine and atipamezole administration.
Main Results:
- Medetomidine-ketamine caused moderate increases in blood pressure and moderate hypercapnia and hypoxemia.
- No significant changes in heart rate or body temperature were observed.
- Intravenous atipamezole administration resulted in severe hypotension.
Conclusions:
- Intravenous medetomidine-ketamine provides effective short-term immobilization for gopher tortoises.
- The combination induces moderate hypoventilation, necessitating oxygen supplementation or assisted ventilation.
- Intravenous atipamezole is not recommended for reversal due to severe hypotension in these animals.
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