title: Evaluation of PaO2 /FiO2 and SaO2 /FiO2 ratios in postoperative dogs recovering on room air or nasal oxygen insufflation.
abstract: OBJECTIVE
  To evaluate partial pressure of oxygen in arterial blood/fractional percentage of inspired oxygen (PaO2 /FiO2 ) and SaO2 /FiO2 ratios (where SaO2 is percentage of oxyhemoglobin saturation in arterial blood), and the correlation between PaO2 /FiO2 and SaO2 /FiO2 , in healthy dogs recovering postoperatively on room air versus nasal oxygen insufflation.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  University veterinary teaching hospital.
  
  
  METHODS
  Nineteen dogs.
  
  
  RESULTS
  Medical records were retrospectively evaluated for data from a previous prospective study of dogs undergoing ovariohysterectomy, subsequently randomized to receive 100 mL/kg/min of nasal oxygen insufflation (estimated 37% FiO2 , n = 9) or room air (estimated 21% FiO2 , n = 10) for 2 hours postoperatively. Baseline information was obtained 1 hour intraoperatively, followed by three postoperative time points (10, 60, and 120 min). Data recorded for each time point included FiO2 , PaO2 , SaO2 , PaO2 /FiO2 , SaO2 /FiO2 , partial pressure of carbon dioxide in arterial blood (PaCO2 ), rectal temperature, and arterial blood pH. The PaO2 /FiO2 in dogs recovering on supplemental oxygen was significantly higher compared to dogs recovering on room air (516 ± 28 vs. 359 ± 10, P < 0.0001), whereas the SaO2 /FiO2 ratio in dogs recovering on supplemental oxygen was significantly lower compared to dogs recovering on room air (268 ± 0.5 versus 448 ± 1.4, P < 0.0001). The PaO2 /FiO2 and SaO2 /FiO2 ratios demonstrated excellent correlation for both groups at each postoperative time point. In dogs breathing room air, PaO2 /FiO2 and SaO2 /FiO2 correlation coefficients were 0.90, 0.95, and 0.93 (P < 0.001). In dogs receiving supplemental oxygen, PaO2 /FiO2 and SaO2 /FiO2 correlation coefficients were 0.94, 0.93, and 0.90 (P < 0.001).
  
  
  CONCLUSIONS
  In this population of postoperative dogs breathing either room air or with nasal oxygen insufflation, PaO2 /FiO2 and SaO2 /FiO2 had excellent correlation. Further evaluation into the correlation between SaO2 /FiO2 or pulse oximeter oxygen saturation (SpO2 )/FiO2 with PaO2 /FiO2 in both healthy dogs, and dogs with pulmonary dysfunction is warranted.
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Colorado State University, Fort Collins, CO, 80523.|Dr. Carver's current address: Michigan State University, Veterinary Teaching Hospital, East Lansing, MI, 48824.
authors.forename: Andy
authors.initials: A
authors.lastname: Carver
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Colorado State University, Fort Collins, CO, 80523.|Dr. Bragg's current address: BluePearl Veterinary Partners, Kansas City, MO.
authors.forename: Ryan
authors.initials: R
authors.lastname: Bragg
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Colorado State University, Fort Collins, CO, 80523.
authors.forename: Lauren
authors.initials: L
authors.lastname: Sullivan
mesh_terms: D000818:Animals; D001784:Blood Gas Analysis / Q000662:veterinary; D004283:Dog Diseases / Q000517:prevention & control*; D004285:Dogs; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000517:prevention & control / Q000662:veterinary*; D007044:Hysterectomy / Q000662:veterinary; D007327:Insufflation / Q000662:veterinary; D008991:Monitoring, Physiologic / Q000662:veterinary; D010052:Ovariectomy / Q000662:veterinary; D010092:Oximetry / Q000662:veterinary*; D010100:Oxygen / Q000097:blood*; D010313:Partial Pressure; D011184:Postoperative Period; D011446:Prospective Studies; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D010100:Oxygen
keywords: blood gas analysis; hypoxemia; postoperative period; ratios