Oxygen consumption monitor for infants

A computer controlled, continuous oxygen consumption analyzer was designed, constructed, and tested for determining the cardiac output of infants using Fick´s method. The analyzer continuously pulled air at a rate between 10 and 60 L/min from a hood placed over the infant´s head and shoulders. A sample flow of 200 mL/min was drawn from this main air flow and passed through a paramagnetic oxygen sensor and an infra-red carbon dioxide sensor. The analyzer used the data from these sensors to calculate oxygen consumption. The analyzer´s performance was tested and verified by infusing a constant flow of nitrogen into the hood at different air flow rates through the hood and different nitrogen flow rates, thus simulating various levels of oxygen consumption. A simulated oxygen consumption of 100 mL/min resulted in a measured oxygen consumption of 100.73±1.25 mL/min (mean and standard deviation) at various hood flow rates of 15 to 55 L/min. Finally, the analyzer was tested on several infants with cardiovascular defects