title: Efficacy of a portable oxygen concentrator with pulsed delivery for treatment of hypoxemia during equine field anesthesia.
abstract: OBJECTIVE
  Hypoxemia is common during equine field anesthesia. Our hypothesis was that oxygen therapy from a portable oxygen concentrator would increase PaO2 during field anesthesia compared with the breathing of ambient air.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  Fifteen yearling (250 - 400 kg) horses during field castration.
  
  
  METHODS
  Horses were maintained in dorsal recumbency during anesthesia with an intravenous infusion of 2000 mg ketamine and 500 mg xylazine in 1 L of 5% guaifenesin. Arterial samples for blood gas analysis were collected immediately post-induction (PI), and at 15 and 30 minutes PI. The control group (n = 6) breathed ambient air. The treatment group (n = 9) were administered pulsed-flow oxygen (192 mL per bolus) by nasal insufflation during inspiration for 15 minutes PI, then breathed ambient air. The study was performed at 1300 m above sea level. One-way and two-way repeated-measures anova with post-hoc Bonferroni tests were used for within and between-group comparisons, respectively. Significance was set at p ≤ 0.05.
  
  
  RESULTS
  Mean ± SD PaO2 in controls at 0, 15 and 30 minutes PI were 46 ± 7 mmHg (6.1 ± 0.9 kPa), 42 ± 9 mmHg (5.6 ± 1.1 kPa), and 48 ± 7 mmHg (6.4 ± 0.1 kPa), respectively (p = 0.4). In treatment animals, oxygen administration significantly increased PaO2 at 15 minutes PI to 60 ± 13 mmHg (8.0 ± 1.7 kPa), compared with baseline values of 46 ± 8 mmHg (6.1 ± 1 kPa) (p = 0.007), and 30 minute PI values of 48 ± 7 mmHg (6.5 ± 0.9 kPa) (p = 0.003).
  
  
  CONCLUSIONS
  These data show that a pulsed-flow delivery of oxygen can increase PaO2 in dorsally recumbent horses during field anesthesia with ketamine-xylazine-guaifenesin.
  
  
  CONCLUSIONS
  The portable oxygen concentrator may help combat hypoxemia during field anesthesia in horses.
authors: Veterinary and Clinical Diagnostic Sciences, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.
authors: Paige
authors: P
authors: Coutu
authors: Veterinary and Clinical Diagnostic Sciences, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.
authors: Nigel
authors: N
authors: Caulkett
authors: Veterinary and Clinical Diagnostic Sciences, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.|Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
authors: Daniel
authors: D
authors: Pang
authors: Veterinary and Clinical Diagnostic Sciences, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.
authors: Søren
authors: S
authors: Boysen
mesh_terms: D000771:Anesthesia, Intravenous / Q000662:veterinary*; D000818:Animals; D006734:Horse Diseases / Q000628:therapy*; D006736:Horses / Q000502:physiology* / Q000601:surgery; D000860:Hypoxia / Q000628:therapy / Q000662:veterinary*; D008297:Male; D009919:Orchiectomy / Q000662:veterinary; D010100:Oxygen / Q000008:administration & dosage*; D010102:Oxygen Inhalation Therapy / Q000295:instrumentation / Q000662:veterinary*; D019095:Point-of-Care Systems / Q000592:standards; D011446:Prospective Studies
chemical_list: D010100:Oxygen
keywords: anesthesia; equine; horse; hypoxemia; oxygen concentrator