Encyclopedia of capnograms

Bhavani Shankar Kodali MD

A Normal Capnogram in adult

Capnograms in pregnancy

Normal capnogram Capnogram with increased phase III slope Capnogram with phase IV
Details

Capnograms in pediatrics

Capnograms in infants and children can have the following format under normal circumstances due to faster respiratory rates, smaller tidal volumes, and relatively longer response time of capnographs (dispersion of gases in side-stream capnographs). Baseline can be elevated, with a prolongation of phase II, increase in the slope of phase III and prolongation of descending limb. Occasionally the alveolar plateau may be short- sine wave capnograms).
	Details

Airway obtruction / Bronchospasm

Phase II and phase III are prolonged

 

Ventilation

Normal Most commonly seen capnograms
Spontaneous ventilation Short alveolar plateau
Hyperventilation Baseline at zero, but height is reduced gradually
Hypoventilation Base line at zero, but height is increased gradually
IMV ventilation Note IMV breaths interposed with spontaneous ventilation
Apnea Self explanatory

 

Ripple effect - Cardiogenic Oscillations

Ripples on the alveolar plateau and descending limb due to movement of gas in the airway as a result of cardiogenic oscillations

Curare Cleft

A cleft on the alveolar plateau as result of the patient attempting to breath, suggesting recovery from muscle relaxants. This can also result from surgical manipulation of abdomen.

Curare Cleft as a result of partial disconnection of main stream CO₂ sensor

A cleft on the alveolar plateau as result of a partial disconnection at the main stream CO2 sensor has been reported by Tripathi et al (Anesthesiology 1998;88:1117-19)