Comparative mechanics of mammalian respiratory system

Bennett, Frederick M.; Tenney, S.M.

doi:10.1016/0034-5687(82)90069-x

Cited by 74 publications

(22 citation statements)

References 9 publications

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“…Whereas penh and FDP have been applied to examination of bronchoconstricting aerosol dose response characteristics 58 and correlate well with more traditional measures of AR, 15,28,30,3 2 both may be influenced by CO 2 -induced elevation of ventilation in a manner that could be confused with an aerosol effect. Changes in ventilation, breathing pattern, and passive mechanics (Te and Tt) 59 and respiratory drive (Ti/Tt) 60 thought to be characteristic of AR can occur in the absence of bronchoconstriction, 8,26,61,62 and it is possible that the same is true of these nondimensional parameters.…”

Section: Discussionmentioning

confidence: 95%

Carbon Dioxide Accumulation during Small Animal, Whole Body Plethysmography: Effects on Ventilation, Indices of Airway Function, and Aerosol Deposition

Kimmel¹,

Whitehead

Reboulet³

et al. 2002

Journal of Aerosol Medicine

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Barometric (whole body) plethysmography is used to examine changes in ventilation and breathing pattern in unrestrained animals during exposure to therapeutic or toxic aerosols. Whole body plethysmographs (WBP) may be operated with a bias flow in order to maintain an adequate supply of oxygen and remove expired CO(2). However, some aerosol generation and delivery methods may require operation of the WBP without bias flow, which would artificially deplete aerosol concentration. Under these conditions, expired CO(2) accumulates in the plethysmograph and stimulates ventilation, increasing total aerosol deposition, shifting regional deposition, and significantly altering some airway function indices. We characterized these effects in guinea pigs using a commercially available 4.5-L WBP, with and without a 1 L/min bias flow. CO(2)-induced changes in breathing frequency (f), tidal volume (Vt), minute ventilation (Ve), and indices of airway function -- including enhanced pause (penh), flow derived parameter (FDP), and respiratory duty cycle -- were measured. Without bias flow, CO(2) in the plethysmograph increased steadily to 5.4% after 30 min compared to a steady state 0.9% with bias flow. This resulted in a moderate suppression of f, and significant increases in Vt and Ve by factors of 1.5 and 1.4, respectively. Changes in regional deposition were stimulated for 300 mg/m(3) polydisperse aerosols with mass median aerodynamic diameters of 0.3, 1, 3, or 7 microm and geometric standard deviations of 1.7. Percent increase in aerosol deposition from CO(2) inhalation ranged from 24% to 90%, by mass, depending on aerosol size distribution and respiratory tract region. In addition, fractional deposition shifted toward the pulmonary region. Empirical indices of airway constriction, penh and FDP, also were increased significantly to 1.7 and 1.3 times their respective baseline values. The study quantifies the effect of inadvertent coexposure to CO(2) on ventilation, aerosol deposition, and airway function in WBP evaluation of aerosol effects in airway function.

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Section: Discussionmentioning

confidence: 95%

Carbon Dioxide Accumulation during Small Animal, Whole Body Plethysmography: Effects on Ventilation, Indices of Airway Function, and Aerosol Deposition

Kimmel¹,

Whitehead

Reboulet³

et al. 2002

Journal of Aerosol Medicine

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“…DP L,dyn does not take into account the pressure needed to expand the chest wall, whereas the EAdi may. Since chest wall compliance in the rabbit is about five times higher than lung compliance [8], this amount of pressure could be considered negligible.…”

Section: Discussionmentioning

confidence: 99%

Assessment of patient–ventilator breath contribution during neurally adjusted ventilatory assist

et al. 2012

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This study shows that Vt(insp) and EAdi can be used to predict the contribution of the inspiratory muscles versus that of the ventilator during NAVA. If clinically applicable, this could serve to quantify and standardize the adjustment of the level of assist, and hence reduce the risks of excessive ventilatory assist. Further studies are required to evaluate if this method is clinically applicable.

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“…Two other significant features of the mouse lung are the thinness of the respiratory epithelium and the relatively large airway lumen [12,14]. This large airway caliber is speculated to reduce the flow-resistive load that would otherwise result from the rapid respiratory rate (250–350 bpm) required by the mouse to maintain body temperature [15]. An important functional difference between mice and rats compared to humans is the paucity, or even complete absence, of submucosal glands and the presence of high numbers of Clara cells [12].…”

Section: Lung Anatomymentioning

confidence: 99%

Measuring the lung function in the mouse: the challenge of size

2003

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Measurement of the effects of drugs, mediators and infectious agents on various models of lung disease, as well as assessment of lung function in the intact mouse has the potential for significantly advancing our knowledge of lung disease. However, the small size of the mouse presents significant challenges for the assessment of lung function. Because of compromises made between precision and noninvasiveness, data obtained may have an uncertain bearing on the mechanical response of the lung. Nevertheless, considerable recent progress has been made in developing valid and useful measures of mouse lung function. These advances, resulting in our current ability to measure sophisticated indices of lung function in laboratory animals, are likely to lead to important insights into the mechanisms of lung disease.

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Comparative mechanics of mammalian respiratory system

Cited by 74 publications

References 9 publications

Carbon Dioxide Accumulation during Small Animal, Whole Body Plethysmography: Effects on Ventilation, Indices of Airway Function, and Aerosol Deposition

Carbon Dioxide Accumulation during Small Animal, Whole Body Plethysmography: Effects on Ventilation, Indices of Airway Function, and Aerosol Deposition

Assessment of patient–ventilator breath contribution during neurally adjusted ventilatory assist

Measuring the lung function in the mouse: the challenge of size

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