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Response to nasopharyngeal oxygen administration in horses with lung disease
Author(s) -
Wilson D. V.,
II H. C. Schott,
Robinson N. E.,
Berney C. E.,
Eberhart S. W.
Publication year - 2006
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.2746/042516406776866345
Subject(s) - medicine , horse , anesthesia , oxygenation , oxygen , arterial blood , blood flow , respiratory system , chemistry , biology , paleontology , organic chemistry
Summary Reasons for performing study : Guidelines for administration of oxygen to standing horses are unavailable because previous investigations of the efficacy of oxygen administration to increase arterial oxygenation in standing horses have produced equivocal results. Objective : To determine the eff ect of nasal oxygen supplementation on inspired and arterial blood gas tensions in control horses and those with moderate to severe recurrent airway obstruction (RAO). Methods : Normal horses (n = 6) and horses during an attack of RAO induced by stabling (n = 6) were studied. Oxygen was administered through either one or 2 cannulae, passed via the nares into the nasopharynx to the level of the medial canthus of each eye. Intratracheal inspired oxygen and carbon dioxide concentration and arterial blood gas tensions were measured at baseline and during delivery of 5, 10, 15, 20 and 30 l/min oxygen. Results : Nasal can nulae and all but the highest oxy gen flow rates were well tolerated. Fractional inspired oxygen concentration (F I O 2 ) increased with flow but was significantly lower at all flow rates in horses with RAO compared with controls. Arterial oxygen tension (PaO 2 ) was significantly increased (P<0.001) by all flow rates, but was always lower in RAO‐affected animals. At 30 l/min, PaO 2 increased to 319 ± 31 mmHg in control horses and 264 ± 69 mmHg in horses with RAO. Additionally, a large arterial to end‐tidal gradient for CO 2 in RAO‐affected horses was observed, indicating increased alveolar deadspace ventilation in these animals. Conclusions : The use of nasal cannulae to deliver oxygen effectively increases both F I O 2 and PaO 2 in horses with moderate to severe RAO. Oxygen flow rates up to 20 l/min are well tolerated, but flow rates of 30 l/min produce occasional coughing or gagging. Potential relevance : Oxygen therapy delivered by means of an intranasal cannula is a highly effective means of increasing arterial oxygen tension in horses with respiratory disease. Generally, flows of 10–20 l/min should be effective. If higher flows (20–30 l/min) are necessary, they should be delivered by means of 2 cannulae.