The effects of halothane and isoflurane on cardiovascular function in laterally recumbent horses.
Abstract: Experimental studies in adult horses have shown that general anaesthesia maintained with isoflurane is associated with less depression of cardiovascular function compared with halothane anaesthesia. Adverse effects of intermittent positive-pressure ventilation (IPPV) have also been demonstrated. Nevertheless, the haemodynamic effects of these agents and the effects of differing modes of ventilation have not been assessed during clinical anaesthesia in horses undergoing surgery. Methods: The haemodynamic effects of isoflurane or halothane anaesthesia during spontaneous or IPPV were studied non-invasively in 32 laterally recumbent horses undergoing elective surgery. Indices of cardiac function and measurements of femoral arterial blood flow and resistance were recorded using transoesophageal and transcutaneous Doppler echocardiography, respectively. Arterial pressure was measured directly using a facial artery catheter. Results: Cardiac index (CI) was significantly higher during isoflurane anaesthesia than during halothane anaesthesia and was also higher during spontaneous ventilation with isoflurane. CI decreased significantly over time and an inverse relationship was observed between CI and mean arterial pressure (MAP). Horses with higher MAP had a significantly lower CI. During isoflurane anaesthesia, femoral arterial blood flow was significantly higher in both pelvic limbs compared with halothane anaesthesia, and flow in the lower limb was significantly higher during spontaneous ventilation than during IPPV. No significant change in femoral blood flow was observed over time. Conclusions: The effects of anaesthetics and mode of ventilation on cardiovascular function recorded under surgical conditions in horses are similar to those reported under experimental conditions. However, in contrast with previous experimental studies, CI progressively decreased over time regardless of agent used or mode of ventilation employed.
Publication Date: 2005-06-24 PubMed ID: 15980042DOI: 10.1093/bja/aei180Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article investigates the impacts of two types of general anaesthesia – isoflurane and halothane – on the cardiovascular function in horses during surgery. It found that isoflurane was less harmful to the heart’s function and, interestingly, the method of ventilation did not have a significant effect.
Research Methodology and Data Collection
- Research was conducted in a controlled setting on 32 adult horses in lateral recumbency, meaning lying on their side – a common position for equine surgeries.
- Two types of general anaesthesia, halothane and isoflurane, were administered and their effects on the horses’ cardiovascular function were observed. The modes of ventilation varied between spontaneous and Intermittent positive-pressure ventilation (IPPV) during anaesthesia.
- A series of non-invasive procedures such as transoesophageal and transcutaneous Doppler echocardiography were used to measure the cardiac activity and femoral arterial blood flow over time.
- Arterial pressure was directly measured with facial artery catheterization for utmost precision.
Findings
- The results showed that the cardiac index (CI) which measures cardiac function, was significantly higher during isoflurane anaesthesia as compared to halothane anaesthesia, and also elevated during spontaneous ventilation with isoflurane.
- The CI decreased over time showing an inverse relationship with mean arterial pressure (MAP). Thus, horses with higher MAP had significantly lower CI, meaning higher blood pressure was associated with lower heart function.
- During isoflurane anaesthesia, the femoral arterial blood flow (the flow of blood in the main artery of a horse’s rear limb) was significantly higher in both pelvic limbs in comparison to halothane anaesthesia. The lower limb saw a higher flow during spontaneous ventilation.
- Notably, the researchers did not observe a significant change in femoral blood flow over time.
Conclusions
- The research concluded that the impacts of anaesthetics and mode of ventilation on the cardiovascular function recorded during horse surgeries were similar to the impacts noted in earlier experimental studies.
- Interestingly, they also found, in contrast to the previous studies, that the horses’ CI decreased over time, no matter what anaesthetic was used or the mode of ventilation.
Cite This Article
APA
Raisis AL, Blissitt KJ, Henley W, Rogers K, Adams V, Young LE.
(2005).
The effects of halothane and isoflurane on cardiovascular function in laterally recumbent horses.
Br J Anaesth, 95(3), 317-325.
https://doi.org/10.1093/bja/aei180 Publication
Researcher Affiliations
- Department of Equine Clinical Studies, Animal Health Trust, Lanwades Park, Newmarket, Suffolk, UK.
MeSH Terms
- Anesthesia, Inhalation / methods
- Anesthesia, Inhalation / veterinary
- Anesthetics, Inhalation / pharmacology
- Animals
- Cardiac Output / drug effects
- Echocardiography, Transesophageal / veterinary
- Female
- Femoral Artery / diagnostic imaging
- Femoral Artery / physiopathology
- Halothane / pharmacology
- Hemodynamics / drug effects
- Horses / physiology
- Intermittent Positive-Pressure Ventilation / veterinary
- Isoflurane / pharmacology
- Male
- Posture
- Regional Blood Flow / drug effects
- Vascular Resistance / drug effects
Citations
This article has been cited 6 times.- Tantry TP, Karanth H, Shenoy SP, Shetty PK, Bhandary S, Adappa KK. Sevoflurane versus isoflurane in shoulder arthroscopy in beach chair position in patients with prior interscalene brachial plexus block: A prospective randomised equivalency-based haemodynamic evaluation trial. Indian J Anaesth 2018 Oct;62(10):793-801.
- Tantry TP, Karanth H, Shenoy SP, Ayya SV, Shetty PK, Adappa KK. Isoflurane versus sevoflurane with interscalene block for shoulder arthroscopic procedures: Value of process capability indices as an additional tool for data analysis. Indian J Anaesth 2016 Dec;60(12):939-947.
- Valverde A, Gianotti G, Rioja-Garcia E, Hathway A. Effects of high-volume, rapid-fluid therapy on cardiovascular function and hematological values during isoflurane-induced hypotension in healthy dogs. Can J Vet Res 2012 Apr;76(2):99-108.
- MacFarlane PD, Mosing M. Early experience with continuous positive airway pressure (CPAP) in 5 horses -- a case series. Can Vet J 2012 Apr;53(4):426-9.
- Wessler B, Madias C, Pandian N, Link MS. Short-term effects of ketamine and isoflurane on left ventricular ejection fraction in an experimental Swine model. ISRN Cardiol 2011;2011:582658.
- Sousa MG, Carareto R, De-Nardi AB, Brito FL, Nunes N, Camacho AA. Effects of isoflurane on Tei-index of myocardial performance in healthy dogs. Can Vet J 2007 Mar;48(3):277-82.
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