title: Evaluation of the effects of dorsal versus lateral recumbency on the cardiopulmonary system during anesthesia with isoflurane in red-tailed hawks (Buteo jamaicensis).
abstract: OBJECTIVE
  To evaluate the effects of dorsal versus lateral recumbency on the cardiopulmonary system during isoflurane anesthesia in red-tailed hawks (Buteo jamaicensis).
  
  
  METHODS
  6 adult 1.1- to 1.6-kg red-tailed hawks.
  
  
  METHODS
  A randomized, crossover study was used to evaluate changes in respiratory rate, tidal volume, minute ventilation, heart rate, mean arterial and indirect blood pressures, and end-tidal Pco(2) measured every 5 minutes plus Paco(2) and Pao(2) and arterial pH measured every 15 minutes throughout a 75-minute study period.
  
  
  RESULTS
  Respiratory rate was higher, tidal volume lower, and minute ventilation not different in lateral versus dorsal recumbency. Position did not affect heart rate, mean arterial blood pressure, or indirect blood pressure, although heart rate decreased during the anesthetic period. Birds hypoventilated in both positions and Paco(2) differed with time and position × time interaction. The Petco(2) position × time interaction was significant and Petco(2) was a mean of 7 Torr higher than Paco(2). The Paco(2) in dorsal recumbency was a mean of 32 Torr higher than in lateral recumbency. Birds in both positions developed respiratory acidosis.
  
  
  CONCLUSIONS
  Differences in tidal volume with similar minute ventilation suggested red-tailed hawks in dorsal recumbency might have lower dead space ventilation. Despite similar minute ventilation in both positions, birds in dorsal recumbency hypoventilated more yet maintained higher Pao(2), suggesting parabronchial ventilatory or pulmonary blood flow distribution changes with position. The results refute the hypothesis that dorsal recumbency compromises ventilation and O(2) transport more than lateral recumbency in red-tailed hawks.
authors.affiliation: Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, CA 95616, USA. mghawkins@ucdavis.edu
authors.forename: Michelle G
authors.initials: MG
authors.lastname: Hawkins
authors.forename: Shachar
authors.initials: S
authors.lastname: Malka
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Pascoe
authors.forename: Adrian M
authors.initials: AM
authors.lastname: Solano
authors.forename: Philip H
authors.initials: PH
authors.lastname: Kass
authors.forename: Hajime
authors.initials: H
authors.lastname: Ohmura
authors.forename: James H
authors.initials: JH
authors.lastname: Jones
mesh_terms: D000769:Anesthesia, Inhalation / Q000379:methods* / Q000662:veterinary; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D018592:Cross-Over Studies; D046428:Hawks / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects*; D007530:Isoflurane / Q000008:administration & dosage; D011187:Posture; D012119:Respiration / Q000187:drug effects*
chemical_list: D018685:Anesthetics, Inhalation; D007530:Isoflurane