A home care patient will be receiving nasal O2 at 0.5 L/min using a large compressed gas cylin-der. Which of the following additional equipment would you specify for this patient?

1. Bubble humidifier
2. Pressure-reducing valve
3. Calibrated low-flow flowmeter
a. 1 and 2 only
b. 1, 2, and 3
c. 2 and 3 only
d. 1 and 3 only

ANS: C
In addition to the cylinder gas, a pressure-reducing valve with flowmeter is needed to deliver O2 at the prescribed flow. Standard clinical flowmeters deliver flows up to 15 L/min; flows used in alternative settings are typically in the 0.25 to 5.0 L/min range. For this reason, the respiratory therapist should select a calibrated low-flow flowmeter whenever possible. Alternatively, a preset flow restrictor can be used.