THE TEMPERATURE OF INSPIRED AIR INFLUENCES RESPIRATORY WATER-LOSS IN YOUNG LAMBS

The temperature of inspired air influences respiratory water loss (RWL ) in young lambs. Water loss from the airways, oxygen consumption and carbon dioxide production were measured using an open flow-through sys tem with a mass spectrometer, specially equipped with a water channel, for gas analysis. Measurements were made in 9 newborn lambs at 3 diff erent inspired air temperatures keeping all other environmental factor s stable, including the ambient air temperature. The water content of the inspired air was also kept constant. RWL was found to be 9.9 +/- 3 .9 (SD) mg/kg/min when the temperature of the inspired air was 30 degr ees C and its humidity 30%. At 40 degrees C this loss increased to 11. 5 +/- 3.6 mg/kg/min, and at about 60 degrees C it increased further to 26.0 +/- 8.2 mg/kg/ min. The oxygen consumption was 10.0 +/- 0.8 (SD) ml/kg/min at 30 degrees C and 10.4 +/- 2.0 ml/kg/min at 60 degrees C, a change which is not significant. Thus RWL is influenced by the temp erature of the inspired air, with greater loss at higher temperatures.