Physiologic differences between infants, children and adults

Lung volumes – Total lung capacity (90 ml/kg), dead space volume (2 ml/kg), tidal volume (7-9 ml/kg) all similar to adult values on a per kg basis. Oxygen consumption much higher in infants; 6-8 ml/kg/min compared to 3-4 ml/kg/min in adults. Closing volume much higher in infants – may explain lower normal values for PaO2 during infancy. ................
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