Mechanics of the respiratory system in healthy newborn calves using impulse oscillometry

Arterial blood gases, acid-base balance and respiratory function tests usin g impulse oscillometry (IOS) were performed on 40 clinically healthy newbor n calves during the first 24 hours of life to evaluate their respiratory ad aptation to extrauterine life. Gas exchange efficiency of the lung was sign ificantly improved with time and was accompanied by the correction of the m ixed acidosis observed at birth and by significant changes in respiratory m echanics. Major changes were detected within the first 6 hours. The signifi cant decrease in resistance (R) and the increase in reactance (x) with time , demonstrate the improvement in respiratory mechanics of both upper and lo wer airways, and reflect the increase in lung volume, the improved lung tis sue elasticity and/or distribution of the ventilation. Respiratory mechanic al, arterial blood gases and acid-base balance data provided in this study describe a successful respiratory adaptation to extrauterine life in health y newborn calves. (C) 2000 Harcourt Publishers Ltd.