Evaluation of a modification of the Hudson demand valve in ventilated and spontaneously breathing horses.
Abstract: Hypoxaemia commonly develops during general anaesthesia and in the recovery period in horses. The Hudson demand valve has been used to increase arterial PO2, but it has been found to increase airway resistance considerably when used during spontaneous ventilation. This paper evaluates a modification of the valve designed to reduce this resistance. The effects of the valve and its modification on arterial oxygen (PaO2), and carbon dioxide (PaCO2) tensions were evaluated in four ponies anaesthetised by a total intravenous technique. The valve increased PaO2 from 8.3 +/- 1.1 to 32.7 +/- 7.6 kPa during spontaneous ventilation and to 44.2 +/- 7.4 kPa during intermittent positive pressure ventilation. With the modification, the PaCO2 was increased to 9.0 +/- 2.5 kPa during spontaneous ventilation PaO2 was unchanged by the valve (7.2 +/- 0.4 kPa to 7.1 +/- 0.7 kPa) but it was reduced to 6.4 +/- 0.9 kPa with the modification. The valve was also evaluated in 20 clinical cases during their recovery from halothane anaesthesia. It increased PaO2 from 7.4 +/- 2.1 kPa to 17 +/- 18.3 kPa during spontaneous ventilation and from 8.0 +/- 1.8 kPa to 23.4 +/- 22.2 kPa during positive pressure ventilation. With the modification, PaO2 was increased from 7.8 +/- 1.4 kPa to 10.4 +/- 3.8 kPa during spontaneous ventilation and from 7.6 +/- 1.5 kPa to 14.8 +/- 8.4 kPa during positive pressure ventilation. During spontaneous ventilation PaCO2 was increased from 5.9 +/- 0.4 kPa to 6.2 +/- 0.6 kPa with the unmodified valve and from 6.3 +/- 0.5 kPa to 6.6 +/- 0.5 kPa with the modification.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1994-12-10 PubMed ID: 7886896
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- Journal Article
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 evaluates a modification to the Hudson demand valve, a device used in general anaesthesia to increase arterial oxygen. The study observed the effects of this device and its modifications on arterial oxygen and carbon dioxide in horses during anaesthesia and recovery.
Study Context
- This research revolves around the Hudson demand valve, a device frequently used during general anaesthesia in horses. Hypoxaemia, or low blood oxygen, often develops during the anesthesia and recovery periods in horses. The Hudson valve increases arterial oxygen but also increases airway resistance during spontaneous ventilation. This study evaluates a modification to this valve, aiming to reduce such resistance.
Research Methodology
- The researchers tested the valve and its modification on four ponies that were anesthetised using a total intravenous technique. They evaluated the effects on arterial oxygen (PaO2) and carbon dioxide (PaCO2) tensions in the horses’ blood during both spontaneous ventilation and intermittent positive pressure ventilation.
- The device’s effects were also analyzed in 20 additional clinical cases during their recovery from halothane anaesthesia.
Findings
- In the anaesthetised ponies, the Hudson demand valve increased PaO2 significantly, both during spontaneous ventilation and intermittent positive pressure ventilation. With the valve modification, PaCO2 was increased during spontaneous ventilation though PaO2 remained essentially the same.
- In the 20 halothane anaesthesia cases, the device also increased PaO2 during both spontaneous and positive pressure ventilation, while the valve modification increased the PaO2 to a lesser extent.
- During spontaneous ventilation, both the unmodified valve and the modification slightly increased PaCO2.
Implications
- The results suggest that the Hudson demand valve significantly increases arterial oxygen during anaesthesia and recovery, but it can raise airway resistance during spontaneous ventilation. The proposed modification reduces this resistance but does not improve arterial oxygen to the same extent as the original unmodified valve.
Cite This Article
APA
Johnson CB, Adam EN, Taylor PM.
(1994).
Evaluation of a modification of the Hudson demand valve in ventilated and spontaneously breathing horses.
Vet Rec, 135(24), 569-572.
Publication
Researcher Affiliations
- Animal Health Trust, Newmarket, Suffolk.
MeSH Terms
- Anesthesia, General / veterinary
- Animals
- Equipment Design
- Horse Diseases / therapy
- Horses
- Hypoxia / therapy
- Hypoxia / veterinary
- Oxygen Inhalation Therapy / instrumentation
- Oxygen Inhalation Therapy / veterinary
- Ventilators, Mechanical / veterinary
Citations
This article has been cited 1 times.- Gozalo-Marcilla M, Ringer SK. Recovery after General Anaesthesia in Adult Horses: A Structured Summary of the Literature. Animals (Basel) 2021 Jun 14;11(6).
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