Respiratory mechanics in small newborn mammals.

摘要: Abstract The passive mechanical properties of the lung and respiratory system have been measured in newborn opossums, hamsters mice, which, by ranging size between 0.3 3 g are among smallest mammals. Compared to newborns larger species, resistances not increased as much compliances decreased. This indicates that geometry changes protecting airway resistance limits energetic losses determined breathing at high frequencies. In opossum is disproportionately large, possibly indicating existence a lower limit beyond which design mammalian would be functionally efficient. Finally, time constants were 40–60 msec (without upper resistance). These values shorter than several considerations indicate they could even during spontaneous breathing. However, compatible with extremely brief inspiratory times large tidal volumes required sustain oxygen requirements expected for mammals such small size. therefore supports hypothesis these animals can pose constraint rate resting ventilation and, possibly, consumption.