In performing DLCO we ask the patient to inhale an air mixture containing Carbon monoxide and Helium. Helium is to obtain the alveolar surface area for that breath (single breath TLC). Patient is expected to hold the breath for 10 seconds and exhale. Technician collects the terminal portion of exhalation (alceolar air) and measures the carbon monoxideconcentration. A complex formula is then used tio calculate DLCO and VA BTPS. You find out the current Hemoglobin to make the necessary correction.

In evaluating the graph note the depth of inhalation, duartion of breath holding and the timing of collection of alveolar air.

Our patient has performed the test satsfactorily.