The effect of the inspired oxygen fraction on arterial blood oxygenation in spontaneously breathing, isoflurane anaesthetized horses: a retrospective study.
Abstract: To investigate the influence of two inspired oxygen fractions (FiO(2)) on the arterial oxygenation in horses anaesthetized with isoflurane. Methods: Retrospective, case-control clinical study. Methods: Two hundred equine patients undergoing non-abdominal surgery (ASA class 1-2), using a standardized anaesthetic protocol and selected from anaesthetic records of a period of three years, based on pre-defined inclusion criteria. Methods: In group O (n = 100), medical oxygen acted as carrier gas, while in group M (n = 100), a medical mixture of oxygen and air (FiO(2) 0.60) was used. Demographic data, FiO(2), arterial oxygen tension (PaO(2)) and routinely monitored physiologic data were recorded. The alveolar-arterial oxygen tension difference [P(A-a)O(2)] and PaO(2)/FiO(2) ratio were calculated. The area under the curve, standardized to the anaesthetic duration, was calculated and statistically compared between groups using t-tests or Mann-Whitney tests as appropriate. Categorical data were compared using Chi-square tests. Results: No significant differences in age, body weight, sex, breed, surgical procedure, position, anaesthetic duration or arterial carbon dioxide tension were found. Mean FiO(2) was 0.78 in group O and 0.60 in group M. Compared to group O, significantly lower values for PaO(2) and for P(A-a)O(2) were found in group M. In contrast, the PaO(2)/FiO(2) ratio and the percentage of horses with a PaO(2) <100 mmHg (13.33 kPa) were comparable in both groups. Conclusions: Although a reduction of the inspired oxygen fraction resulted in a lower PaO(2), the P(A-a)O(2) was also lower and the number of horses with PaO(2) values <100 mmHg was comparable. Conclusions: In healthy isoflurane anaesthetized horses, the use of a mixture of oxygen and air as carrier gas seems acceptable, but further, prospective studies are needed to confirm whether it results in a lower degree of ventilation/perfusion mismatching.
© 2014 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.
Publication Date: 2014-07-21 PubMed ID: 25039320DOI: 10.1111/vaa.12208Google Scholar: Lookup
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- Journal Article
Summary
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The study investigates the effect of using varying fractions of oxygen on blood oxygenation in horses anaesthetized using isoflurane. The researchers found that using a lower fraction of inspired oxygen led to less oxygen in arterial blood, although the amount of horses with critically low arterial blood oxygen levels remained the same.
Methodology
- The study retrospectively analyzed the records of 200 horses that had undergone non-abdominal surgery under isoflurane anesthesia.
- The horses were divided into two groups. In group O (100 horses), pure medical oxygen was used as a carrier gas. In group M (also 100 horses), a mixture of oxygen and air (60% oxygen) was used.
- The researchers collected demographic data, oxygen tension in arterial blood (PaO(2)), inspired oxygen fraction (FiO(2)), and physiological data routinely monitored during surgery.
- The alveolar-arterial oxygen tension difference (P(A-a)O(2)) and the PaO(2)/FiO(2) ratio were calculated for each horse.
- The researchers then compared the data between the two groups using statistical tests.
Results
- There were no significant differences between the two groups in terms of age, body weight, sex, breed, surgical procedure, animal position during surgery, duration of anesthesia, or arterial carbon dioxide tension.
- Group O had a mean FiO(2) of 0.78, while group M had 0.60.
- Group M had significantly lower average PaO(2) and P(A-a)O(2) values compared to group O. The PaO(2)/FiO(2) ratio and the percentage of horses with PaO(2) below 100 mmHg were comparable in both groups.
Conclusions
- The researchers concluded that the use of a lower fraction of oxygen resulted in lower arterial oxygen tension, but didn’t increase the proportion of horses with dangerously low oxygen levels.
- In healthy horses anesthetized with isoflurane, using a mixture of air and oxygen as carrier gas appears to be acceptable based on this study.
- Future studies are suggested to confirm the implications of these findings on the potential lower degree of mismatching between ventilation and blood supply (ventilation/perfusion mismatch).
Cite This Article
APA
Schauvliege S, Savvas I, Gasthuys F.
(2014).
The effect of the inspired oxygen fraction on arterial blood oxygenation in spontaneously breathing, isoflurane anaesthetized horses: a retrospective study.
Vet Anaesth Analg, 42(3), 280-285.
https://doi.org/10.1111/vaa.12208 Publication
Researcher Affiliations
- Department of Surgery and Anaesthesia of Domestic Animals, Faculty of Veterinary Medicine, University of Gent, Merelbeke, Belgium.
MeSH Terms
- Anesthesia, Inhalation / veterinary
- Anesthetics, Inhalation / administration & dosage
- Anesthetics, Inhalation / pharmacology
- Animals
- Blood Gas Analysis / veterinary
- Case-Control Studies
- Horses / physiology
- Isoflurane / pharmacology
- Oxygen / blood
- Oxygen / pharmacology
- Partial Pressure
- Pulmonary Gas Exchange / drug effects
- Respiration / drug effects
- Retrospective Studies
Citations
This article has been cited 4 times.- Savvas I, Pavlidou K, Braun C, Schauvliege S, Staffieri F, Moens Y. Evaluation of the Effect of the Inspired Oxygen Fraction on Blood Oxygenation during Inhalant Anaesthesia in Horses: A Systematic Review with Meta-Analysis. Animals (Basel) 2021 Jul 30;11(8).
- Dupont J, Serteyn D, Sandersen C. Prolonged Recovery From General Anesthesia Possibly Related to Persistent Hypoxemia in a Draft Horse. Front Vet Sci 2018;5:235.
- Bukoski A, Downs J, Hodgson DS, Le-Bert CR, Thomen R, Flors L, Thombs L, Bailey J. Cardiopulmonary effects of apneustic anesthesia ventilation in anesthetized pigs: a new mode of ventilation for anesthetized veterinary species. Front Vet Sci 2024;11:1378617.
- Le-Bert CR, Bukoski A, Downs J, Hodgson DS, Thombs L, Ridgway SH, Bailey J. Apneustic anesthesia ventilation improves pulmonary function in anesthetized bottlenose dolphins (Tursiops truncatus). Front Vet Sci 2024;11:1287478.
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