title: Novel method for conscious airway resistance and ventilation estimation in neonatal rodents using plethysmography and a mechanical lung.
abstract: In unrestrained whole body plethysmography, tidal volume is commonly determined using the barometric method, which assumes that temperature and humidity changes (the 'barometric component') are solely responsible for breathing-related chamber pressure fluctuations. However, in small animals chamber pressure is also influenced by a 'mechanical component' dependent on airway resistance and airflow. We devised a novel 'mechanical lung' capable of simulating neonatal mouse breathing in the absence of temperature or humidity changes. Using this device, we confirm that the chamber pressure fluctuations produced by breathing of neonatal mice are dominated by the mechanical component, precluding direct quantitative assessment of tidal volume. Recognizing the importance of airway resistance to the chamber pressure signal and the ability of our device to simulate neonatal breathing at different frequencies and tidal volumes, we invented a novel in vivo, non-invasive method for conscious airway resistance and ventilation estimation (CARVE) in neonatal rodents. This technique will allow evaluation of developmental, pathological and pharmaceutical effects on airway resistance.
authors.affiliation: Department of Physiology and Pharmacology, Hotchkiss Brain Institute & Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Boyang
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Physiology and Pharmacology, Hotchkiss Brain Institute & Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Fiona B
authors.initials: FB
authors.lastname: McDonald
authors.affiliation: Department of Biomedical Sciences, University of Missouri-Columbia, Columbia, MO 65211, USA.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Cummings
authors.affiliation: University of Tasmania, Hobart, Tasmania 7001, Australia.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Frappell
authors.affiliation: Department of Physiology and Pharmacology, Hotchkiss Brain Institute & Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada. Electronic address: wilsonr@ucalgary.ca.
authors.forename: Richard J A
authors.initials: RJ
authors.lastname: Wilson
mesh_terms: D000403:Airway Resistance / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D001831:Body Temperature; D003198:Computer Simulation; D003243:Consciousness / Q000502:physiology*; D008176:Lung Volume Measurements / Q000379:methods*; D051379:Mice; D008954:Models, Biological; D010812:Physical Stimulation; D010991:Plethysmography; D015656:Respiratory Mechanics; D013990:Tidal Volume; D012122:Ventilators, Mechanical
keywords: Airway resistance; Barometric method; Mechanical lung; Neonatal mouse; Plethysmography; Tidal volume