Cardiopulmonary effects of two constant rate infusions of dexmedetomidine in isoflurane anaesthetized ponies.
Abstract: To evaluate the cardiopulmonary effects of two different constant rate infusions (CRI) of dexmedetomidine (1 and 1.75 microg kg(-1 )hour(-1)) in experimental ponies. Methods: Six healthy ponies (mean 306 +/- SD 71 kg, 7.0 +/- 1.6 years). Methods: Prospective, randomized, experimental study. Methods: After premedication with intravenous (IV) dexmedetomidine (3.5 microg kg(-1)), anaesthesia was induced (T0) with ketamine (2.2 mg kg(-1) IV) and midazolam (0.06 mg kg(-1) IV) and maintained with isoflurane (Fe'ISO 1.50%) in 55% oxygen for 150 minutes. Normocapnia was maintained using artificial ventilation. Three ponies received dexmedetomidine CRIs of 1 and 1.75 microg kg(-1 )hour(-1) from T30 to T60 and T90 to T120 respectively. In the other three ponies, the order of the doses was reversed. Continuous monitoring included pulse oximetry, electrocardiography, anaesthetic gas monitoring, arterial and central venous pressures. Cardiac output (LiDCO technique) was measured and arterial and venous bloods taken every 15 minutes. Cardiac index (CI), systemic vascular resistance (SVR), arterial and venous oxygen content (CaO(2), CvO(2)) and oxygen delivery (DO(2)) were calculated. Analysis of variance with separate models for each CRI rate was used to detect differences between values obtained at the end of the CRI and their respective baseline values. A mixed model with these differences as response variable, pony as random effect and treatment and period as fixed effects was applied to find differences between the two CRIs (alpha = 0.05 for all analyses). Results: Heart rate (HR), CI, CaO(2), CvO(2) and DO(2) decreased significantly, while significant increases were found in SVR, systolic arterial pressure and right atrial pressure with both infusion rates. No differences were found between the two dexmedetomidine CRI rates. Conclusions: Although significant, cardiopulmonary effects of the dexmedetomidine CRIs in isoflurane anaesthetized ponies were small, without differences between the two dose rates.
Publication Date: 2010-07-20 PubMed ID: 20636563DOI: 10.1111/j.1467-2995.2010.00537.xGoogle Scholar: Lookup
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Summary
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The research study investigates the cardiopulmonary effects of two different rates of constant dexmedetomidine infusion on isoflurane anaesthetized ponies, revealing noteworthy yet minor effects with no significant difference between the two infusion rates.
Study Methodology
- The study was conducted on six healthy ponies. The weight and age of the ponies were taken into account to ensure uniformity in the experiment.
- A prospective, randomized, experimental study format was adopted.
- The ponies were first premedicated with intravenous dexmedetomidine. Anaesthesia was then induced using ketamine and midazolam, and maintained with isoflurane in 55% oxygen for 150 minutes.
- Normocapnia was maintained through artificial ventilation, ensuring a normal level of carbon dioxide in the ponies’ blood.
- Half of the ponies received dexmedetomidine continuous rate infusions (CRI) at 1 and 1.75 micrograms per kilogram per hour, while for the other half, the order of doses was reversed.
- Continuous monitoring was implemented to record the pulse, electrocardiography data, anesthetic gas concentration, arterial and central venous pressures as well as cardiac output. Blood samples were collected every 15 minutes to measure the oxygen content.
- The Cardiac Index (CI), Systemic Vascular Resistance (SVR), arterial and venous oxygen content, and oxygen delivery were calculated and analysed using variance analysis.
Study Results
- The results indicated that both dexmedetomidine infusion rates resulted in significant decreases in Heart Rate (HR), Cardiac Index (CI), arterial and venous oxygen content, and oxygen delivery.
- At the same time, there were significant increases in Systemic Vascular Resistance (SVR), systolic arterial pressure and the right atrial pressure.
- Despite these effects, no significant difference was found between the two doses of dexmedetomidine CRI.
Conclusions
- The study concludes that while significant, the cardiopulmonary effects of dexmedetomidine CRIs on isoflurane-anaesthetized ponies are minimal and do not vary between the two infusion rates.
- This insight can be useful in veterinary anesthesia practice, particularly for maintaining stable conditions during surgical procedures or other interventions on ponies.
Cite This Article
APA
Marcilla MG, Schauvliege S, Duchateau L, Gasthuys F.
(2010).
Cardiopulmonary effects of two constant rate infusions of dexmedetomidine in isoflurane anaesthetized ponies.
Vet Anaesth Analg, 37(4), 311-321.
https://doi.org/10.1111/j.1467-2995.2010.00537.x Publication
Researcher Affiliations
- Department of Surgery and Anaesthesia of Domestic Animals, Faculty of Veterinary Medicine, University of Ghent, Merelbeke, Belgium. miguel.gozalomarcilla@ugent.be
MeSH Terms
- Anesthesia, Inhalation / veterinary
- Anesthesia, Intravenous / veterinary
- Animals
- Blood Pressure / drug effects
- Cardiac Output / drug effects
- Dexmedetomidine / pharmacology
- Dose-Response Relationship, Drug
- Female
- Heart / drug effects
- Heart / physiology
- Horses
- Hypnotics and Sedatives / pharmacology
- Isoflurane
- Ketamine
- Lung / drug effects
- Lung / physiology
- Male
- Midazolam
- Monitoring, Physiologic / veterinary
- Oxygen / blood
- Oxygen Consumption / drug effects
- Preanesthetic Medication / veterinary
- Stroke Volume / drug effects
- Vascular Resistance / drug effects
Citations
This article has been cited 3 times.- Rabbogliatti V, Amari M, Brioschi FA, Di Cesare F, Zani DD, De Zani D, Di Giancamillo M, Cagnardi P, Ravasio G. Use of dexmedetomidine repeated subcutaneous administration for balanced anaesthesia in horses.. BMC Vet Res 2022 Jul 11;18(1):269.
- Esmailinejad MR, Masoudifard M, Azari O, Sakhaee E, Ghalekhani N. Echocardiographic assessment of intravenous administration of medetomidine and xylazine hydrochloride at different sedative doses in one-humped camel calves (Camelus dromedarious).. Vet Res Forum 2022 Mar;13(1):39-46.
- Duval JD, Pang JM, Boysen SR, Caulkett NA. Cardiopulmonary Effects of a Partial Intravenous Anesthesia Technique for Laboratory Swine.. J Am Assoc Lab Anim Sci 2018 Jul 1;57(4):376-381.
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