title: Comparison of air sac volume, lung volume, and lung densities determined by use of computed tomography in conscious and anesthetized Humboldt penguins (Spheniscus humboldti) positioned in ventral, dorsal, and right lateral recumbency.
abstract: OBJECTIVE
  To determine the effects of recumbency on air sac volume, lung volume, and lung densities in CT images of healthy, conscious and anesthetized spontaneously breathing Humboldt penguins (Spheniscus humboldti).
  
  
  METHODS
  25 adult (13 male and 12 female) Humboldt penguins.
  
  
  METHODS
  CT images of conscious penguins in ventral recumbency and anesthetized penguins in dorsal, ventral, and right lateral recumbency were obtained. Air sac volume, lung volume, and lung densities in CT images were calculated. A paired samples t test was used to determine whether right and left lung densities differed among recumbencies. Repeated-measures ANOVA (controlled for sex and order of recumbencies during CT) was used to determine whether air sac or lung volumes differed among recumbencies.
  
  
  RESULTS
  Recumbency had a significant effect on air sac volume but not lung volume. Air sac volume was largest in conscious penguins in ventral recumbency (mean ± SD, 347.2 ± 103.1 cm(3)) and lowest in anesthetized penguins in dorsal recumbency (median, 202.0 cm(3); 10th to 90th percentile, 129.2 to 280.3 cm(3)). Lung densities were highest in anesthetized penguins in dorsal recumbency (right lung median, 0.522 g/cm(3); left lung median, 0.511 g/cm(3)) and lowest in anesthetized penguins in ventral recumbency (right lung median, 0.488 g/cm(3); left lung median, 0.482 g/cm(3)).
  
  
  CONCLUSIONS
  Results indicated that anesthetized Humboldt penguins had the lowest air sac volume and highest lung densities in dorsal recumbency. Therefore, this recumbency may not be recommended. Minimal changes in lung volume were detected among recumbencies or between conscious and anesthetized penguins.
authors: Illinois Zoological and Aquatic Animal Residency Program, College of Veterinary Medicine, University of Illinois, Urbana, IL 61802.
authors: Benjamin N
authors: BN
authors: Nevitt
authors: Jennifer N
authors: JN
authors: Langan
authors: Michael J
authors: MJ
authors: Adkesson
authors: Mark A
authors: MA
authors: Mitchell
authors: Margaret
authors: M
authors: Henzler
authors: Randi
authors: R
authors: Drees
mesh_terms: D000400:Air Sacs / Q000033:anatomy & histology*; D000704:Analysis of Variance; D000758:Anesthesia / Q000662:veterinary; D000818:Animals; D000836:Animals, Zoo / Q000033:anatomy & histology* / Q000502:physiology; D001715:Bird Diseases / Q000175:diagnosis; D005260:Female; D008168:Lung / Q000033:anatomy & histology* / Q000502:physiology; D008297:Male; D009929:Organ Size; D056888:Patient Positioning / Q000379:methods / Q000662:veterinary*; D011446:Prospective Studies; D012140:Respiratory Tract Diseases / Q000175:diagnosis / Q000662:veterinary; D012737:Sex Factors; D046429:Spheniscidae / Q000033:anatomy & histology* / Q000502:physiology; D014057:Tomography, X-Ray Computed / Q000662:veterinary