The Oxygen Cost of Breathing in the Premature Infant

Work of breathing, oxygen cost of breathing, and calculated mechanical efficiency were studied in normal prematures using the plethysmograph method. The results indicate that the oxygen cost of breathing in these subjects averaged 0.9 ml per 500 ml ventilated. Calculated mechanical efficiency averaged 4.1%. These results were compared with those reported for normal adults, and premature infants were shown to have a higher oxygen cost of breathing and a lower mechanical efficiency. The sources of error of the method are discussed and emphasis is given to the fact that the absolute quantitative results may not be exact.