Checking or test capnograph before clinical use

One should ascertain that the capnograph is functioning properly before making any interpretations of PETCO_² readings and waveforms. Secretions and mucus may contaminate the unit, and distort CO_²  waveforms. Similarly, water may partially obstruct sampling lines resulting in distorted waveforms. A leak in the sampling tube may result in low PETCO_² measurements. Therefore, check the monitor to see if it is functioning properly.

The Biomedical Engineering Department should calibrate the capnograph periodically to ensure that it maintains “with-in range” calibrations.

A simple but less accurate method is to record a normal CO_² tracing (e.g. one’s own). The proper functioning of the capnograph is confirmed by a typical CO_² waveform with PETCO_² readings between 38 and 42 mm Hg.