Improvement in arterial oxygen tension with change in posture in anaesthetised horses.
Abstract: Observations were made on horses spontaneously breathing oxygen, with halothane at a constant end tidal concentration. The horses were positioned in dorsal recumbency for the first 45 minutes of each anaesthetic episode during which the arterial oxygen tension (PaO2) was found to peak and then decline. The remaining 60 minutes of each anaesthesia was used to test the effect of various manoeuvres on PaO2. The PaO2 of horses decreased further both when remaining in dorsal recumbency and when repositioned in right or left recumbency. In contrast, placing the horses in sternal recumbency for these remaining 60 minutes caused the PaO2 to rise rapidly providing evidence for redistribution of ventilation. Replacing some inspired oxygen with less absorbable nitrogen did not improve PaO2 in dorsal recumbency. Thus there was no evidence that the low PaO2 of dorsal recumbency was associated with alveoli that had collapsed because of gas absorption.
Publication Date: 1988-03-01 PubMed ID: 3133731
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- Journal Article
- Research Support
- U.S. Gov't
- Non-P.H.S.
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research in this article focuses on analyzing how the posture of anesthetized horses affects their arterial oxygen tension (PaO2) levels.
Study Design and Setting
- The study observed horses that were spontaneously breathing oxygen, with halothane at a constant end tidal concentration. Anesthetic conditions were maintained constant throughout the research to ensure reliability of the results.
- All the horses were placed in dorsal recumbency (lying on their back) for the first 45mins of each anaesthetic episode. This was followed by checking their arterial oxygen tension (PaO2), which was found to peak and then started to decline.
Research Findings
- For the remaining 60 minutes of each anaesthesia episode, the horses were repositioned in several ways to test the effects on their PaO2.
- The study found that the PaO2 levels of horses significantly dropped when they remained in dorsal recumbency or were repositioned to lie on either their right or left sides.
- On the other hand, positioning the horses in sternal recumbency (lying on their chest), caused a rapid rise in their PaO2 levels. This suggests that a redistribution of ventilation occurs when horses are positioned in sternal recumbency.
Further Testing
- To verify whether the decline in PaO2 during dorsal recumbency was primarily due to alveolar gas absorption (which can cause alveoli to collapse), the research also experimented by replacing some of the inspired oxygen with nitrogen, a gas that is less absorbable.
- However, this did not improve PaO2 in horses lying dorsally proving that there was no evidence to suggest that the low levels of PaO2 associated with dorsal recumbency were due to the collapse of alveoli from gas absorption.
Conclusion
- In conclusion, the research showed that the posture of anesthetized horses significantly impacts their arterial oxygen tension levels.
- This will be critical information to veterinarians and animal health professionals involved in any surgical or invasive procedures involving anesthetized horses, as it will help them understand how to best position horses to maintain healthy PaO2 levels.
Cite This Article
APA
Gleed RD, Dobson A.
(1988).
Improvement in arterial oxygen tension with change in posture in anaesthetised horses.
Res Vet Sci, 44(2), 255-259.
Publication
Researcher Affiliations
- Department of Clinical Sciences, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853.
MeSH Terms
- Anesthesia / veterinary
- Animals
- Carbon Dioxide / blood
- Halothane
- Horses / blood
- Horses / physiology
- Oxygen / blood
- Posture
- Respiration
Citations
This article has been cited 5 times.- Niyom S, Mama KR, King M, Contino E, Ferris D, Valdes-Martinez A, Frisbie DD, McIlwraith W, Zumbrunnen J. Influence of changing lateral recumbency and mode of ventilation on the alveolar-arterial oxygen tension gradient and selected laboratory analytes in adult isoflurane anesthetized horses. J Vet Med Sci 2018 Nov 1;80(10):1584-1589.
- Fahlman Å, Edner A, Wenger S, Foggin C, Nyman G. Pulmonary gas exchange and acid-base status during immobilisation of black rhinoceroses (Diceros bicornis) in Zimbabwe. J S Afr Vet Assoc 2016 Dec 2;87(1):e1-e9.
- Chesnel MA, Aprea F, Clutton RE. Anesthetic management of a horse with traumatic pneumothorax. Can Vet J 2012 Jun;53(6):648-52.
- Byrne DP, Keeshan B, Hosgood G, Adler A, Mosing M. Comparison of electrical impedance tomography and spirometry-based measures of airflow in healthy adult horses. Front Physiol 2023;14:1164646.
- Gardoni N, Björck S, Morelli J, Evans AL, Barros DSB, Wiklund R, Græsli AR, Thiel A, Arnemo JM, Lian M. Arterial oxygenation and acid-base status before and during oxygen supplementation in captive European bison (Bison bonasus) immobilized with etorphine-acepromazine-xylazine. Front Vet Sci 2023;10:1125919.
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