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

Nevitt, Benjamin N.; Langan, Jennifer N.; Adkesson, Michael J.; Mitchell, Mark A.; Henzler, Margaret; Drees, Randi

doi:10.2460/ajvr.75.8.739

Cited by 18 publications

(16 citation statements)

References 42 publications

(47 reference statements)

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“…The Humboldt penguin routinely makes dives of <20 m with a maximum reported depth of only 54 m (Culik, 2001;LunaJorquera and Culik, 1999). This 30 ml kg −1 value in the Humboldt penguin is also supported by recent CT determinations of lung volume (Nevitt et al, 2014).…”

Section: Lung Volumesupporting

confidence: 60%

“…Therefore, in order to try to assess maximum inspiratory air sac volume in penguins, we chose to use the CT scan approach and to measure air sac and lung volumes at different inflation pressures while the penguins were anesthetized, apneic and in the supine (dorsal recumbency) position. Although the supine position is associated with a decrease in volume of the abdominal air sacs because of their compression by the abdominal contents (King and Payne, 1964;Malka et al, 2009;Nevitt et al, 2014), this was the position preferred by the clinical veterinary staff. The supine position has also been often recommended in veterinary texts because the prone (sternal recumbency) position has been considered to restrict respiration in anesthetized birds (Jaensch et al, 2002;Malka et al, 2009).…”

Section: Techniquementioning

confidence: 99%

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Penguin lungs and air sacs: implications for baroprotection, oxygen stores and buoyancy

Ponganis

Leger

Scadeng

2015

Journal of Experimental Biology

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The anatomy and volume of the penguin respiratory system contribute significantly to pulmonary baroprotection, the body O 2 store, buoyancy and hence the overall diving physiology of penguins. Therefore, three-dimensional reconstructions from computerized tomographic (CT) scans of live penguins were utilized to measure lung volumes, air sac volumes, tracheobronchial volumes and total body volumes at different inflation pressures in three species with different dive capacities [Adeĺie (Pygoscelis adeliae), king (Aptenodytes patagonicus) and emperor (A. forsteri) penguins]. Lung volumes scaled to body mass according to published avian allometrics. Air sac volumes at 30 cm H 2 O (2.94 kPa) inflation pressure, the assumed maximum volume possible prior to deep dives, were two to three times allometric air sac predictions and also two to three times previously determined end-of-dive total air volumes. Although it is unknown whether penguins inhale to such high volumes prior to dives, these values were supported by (a) body density/buoyancy calculations, (b) prior air volume measurements in free-diving ducks and (c) previous suggestions that penguins may exhale air prior to the final portions of deep dives. Based upon air capillary volumes, parabronchial volumes and tracheobronchial volumes estimated from the measured lung/airway volumes and the only available morphometry study of a penguin lung, the presumed maximum air sac volumes resulted in air sac volume to air capillary/ parabronchial/tracheobronchial volume ratios that were not large enough to prevent barotrauma to the non-collapsing, rigid air capillaries during the deepest dives of all three species, and during many routine dives of king and emperor penguins. We conclude that volume reduction of airways and lung air spaces, via compression, constriction or blood engorgement, must occur to provide pulmonary baroprotection at depth. It is also possible that relative air capillary and parabronchial volumes are smaller in these deeper-diving species than in the spheniscid penguin of the morphometry study. If penguins do inhale to this maximum air sac volume prior to their deepest dives, the magnitude and distribution of the body O 2 store would change considerably. In emperor penguins, total body O 2 would increase by 75%, and the respiratory fraction would increase from 33% to 61%. We emphasize that the maximum pre-dive respiratory air volume is still unknown in penguins. However, even lesser increases in air sac volume prior to a dive would still significantly increase the O 2 store. More refined evaluations of the respiratory O 2 store and baroprotective mechanisms in penguins await further investigation of species-specific lung morphometry, start-of-dive air volumes and body buoyancy, and the possibility of air exhalation during dives.

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Section: Lung Volumesupporting

confidence: 60%

Section: Techniquementioning

confidence: 99%

Penguin lungs and air sacs: implications for baroprotection, oxygen stores and buoyancy

Ponganis

Leger

Scadeng

2015

Journal of Experimental Biology

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“…For endoscopic retrieval, the penguin was anesthetized with 5% isoflurane (Forane sol., Choongwae, Seoul, Korea) in oxygen administered by a face mask. The penguin was then intubated with a 4 mm uninflated cuffed endotracheal tube, and anesthesia was maintained with 2% to 4% isoflurane in oxygen (flow rate, 1 to 1.5 l /min) with spontaneous ventilation [ 8 ]. After the penguin was anesthetized, a scope (EG27-i10; diameter 90 mm/ working length 1,050 mm/ working angle 210 degrees, flexible type, Pentax) was inserted into the esophagus.…”

mentioning

confidence: 99%

A Case of endoscopic retrieval of a long bamboo stick from a Humboldt penguin (<i>Spheniscus humboldti</i>)

Jung

Cho

et al. 2017

The Journal of Veterinary Medical Science

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An eighteen-month-old female Humboldt penguin (Spheniscus humboldti) that was 50 cm in length and 4.5 kg in weight was presented with anorexia and vomiting. The hematological and blood biochemical profiles revealed no remarkable findings, and no Salmonella, Shigella or Vibrio spp. were isolated from the fecal culture. However, radiographic imaging revealed a long linear foreign body presenting from the lower esophagus to the stomach. To retrieve this foreign body, flexible endoscopic extraction was performed using flexible rat tooth grasping forceps. A long bamboo stick (29 × 1 cm) was removed from the stomach, and the penguin fully recovered.

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“…16 In a paper comparing air sac volume, lung volume and lung densities in Humboldt penguins (Spheniscus humboldti), the air sac volume was largest in penguins in ventral (sternal) recumbency and smallest in penguins positioned in dorsal recumbency. 16 This patient was ultimately positioned in ventral recumbency, and mechanically ventilated successfully for the duration of the MRI.…”

Section: Discussionmentioning

confidence: 99%

Anaesthesia of a little blue penguin (Eudyptula minor) for magnetic resonance imaging

Daly,

McFadzean,

Tucker

2023

Vet Record Case Reports

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A 2‐year‐old, male, entire Eudyptula minor, kept in a colony of little penguins, started displaying neurological signs, including stumbling, shaking and ear scratching. Several treatment trials proved unsuccessful, and previous computed tomography failed to yield images of diagnostic quality. Due to the ongoing progression of the disease, the penguin was presented for general anaesthesia for magnetic resonance imaging. On presentation, a full neurological examination was conducted, the abnormalities were localised to vestibular apparatus or cerebellum, with a top differential diagnosis of bilateral otitis interna. The patient was scheduled for general anaesthesia to facilitate magnetic resonance imaging of the brain. There are limited reported data on anaesthesia of little penguins. When anaesthetising this species, there are multiple pre‐anaesthetic considerations: fasting period, availability of suitable monitoring, the presence of a tracheal septum, positioning of the patient, challenging intravenous access and complications such as alterations in normal body temperature and environmental temperature.

show abstract

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

Cited by 18 publications

References 42 publications

Penguin lungs and air sacs: implications for baroprotection, oxygen stores and buoyancy

Penguin lungs and air sacs: implications for baroprotection, oxygen stores and buoyancy

A Case of endoscopic retrieval of a long bamboo stick from a Humboldt penguin (<i>Spheniscus humboldti</i>)

Anaesthesia of a little blue penguin (Eudyptula minor) for magnetic resonance imaging

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