Which of the following offers the most accurate and reliable method for measuring the tempera-ture and humidity level within a ventilator circuit?

a. Humidity control of hot-wire humidifica-tion system
b. Oxygen analyzer
c. Hygrometer-thermometer
d. Not able to measure humidity level

ANS: C
The most accurate and reliable way to ensure that patients are receiving gas at the expected tem-perature and humidity level is to measure these parameters with the portable battery-operated digital hygrometer-thermometer system. Humidity control on a hot-wire humidification system will not provide a measurement of absolute humidity or relative humidity; instead, it will enable the measurement of only the temperature differential between the humidifier and the airway sensor.