Encyclopedia of capnograms
Bhavani Shankar Kodali MD
Equipment malfunction
Sampling leaks Sampling tube leaks, Sampling via oxygen face mask, nasal cannula |
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Sampling leaks Break in the sampling tube system or loose connections at sampling tube end of the monitor |
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Sampling leaks -Breakage in the sampling filter Dual plateau capnogram |
Details |
Slit Sampling tube (tail-up capnogram) |
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Partial disconnection of main stream sensor (like curare cleft) |
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Inspiratory valve defects
Inspiratory valve not closing properly resulting in a flip in the plateau at the beginning of inspiration- Note inspiration shown as red.
Details
Inspiratory valve malfunction - valve displaced or totally incompetent- note rebreathing during inspiration as red

Details
Expiratory valve stuck open
Base line is elevated, phase II is prolonged and descending limb of inspiration is prolonged or slanting
Details
Exhausted Soda lime
Gradual rise of base line and height of the waveform
Base line is elevated, but height can remain the same due to hyperventilation

Base line is elevated, there is an inspiratory wave due to rebreathing of Inspiration, the height of the capnogram is gradually increasing.
Inspiration

Details
Contamination of Inspiration sensor
Sudden rise of base line and height of the waveform


Apnea
Ventilator failure, disconnections, accidental extubation

Slow response or side-stream analyzer capnograms in children

zeroing Monitor Some monitors may show flat line during zeroing

Monitor warming up

Dilution of PETInspiration by fresh gas flow
