ETCO2....the 11 uses

ETCO2  aids the evaluation of the exhaled [CO₂], especially end-tidal CO₂, which is the maximum partial pressure of CO₂exhaled during a tidal breath (just prior to the beginning of inspiration) and is designated PetCO_2.
it is highy used in the OR...less in ICU...lesser in other units...
below are the main uses

1. Use as an adjunct to determine that tracheal rather than esophageal intubation has taken place (Low or absent cardiac output may negate its use for this indication.);colorimetric CO₂ detectors are adequate devices for this purpose.

2. Monitoring severity of pulmonary disease and evaluating response to therapy, especially therapy intended to improve the ratio of dead
space to tidal volume (V_D/V_T) and the matching of ventilation to perfusion (V/Q) ,and, possibly, to increase coronary blood flow

3. Continued monitoring of the integrity of the ventilatory circuit, including the artificial airway

4. Evaluation of the efficiency of mechanical ventilatory support by determination of the difference between the arterial partial pressure for CO₂ (PaCO₂) and the PetCO₂
5. Monitoring adequacy of pulmonary, systemic, and coronary blood flow

6. Estimation of effective (nonshunted) pulmonary capillary blood flow by a partial rebreathing method.

7. Use as an adjunctive tool to screen for pulmonary embolism (Evidence for the utility of dead space determinations as a screening tool for pulmonary embolism is at present not conclusive.)

8. Monitoring the matching of ventilation to perfusion during independent lung ventilation for unilateral pulmonary contusion

9. Monitoring inspired CO₂ when CO₂ gas is being therapeutically administered
10. Graphic evaluation of the ventilator-patient interface; evaluation of the shape of the capnogram may be useful in detecting rebreathing of
CO₂, obstructive pulmonary disease, waning neuromuscular blockade (‘curare cleft’), cardiogenic oscillations, esophageal intubation, cardiac arrest, and contamination of the monitor or sampling line with secretions or mucus.
11- Measurement of the volume of CO₂ elimination to assess metabolic rate as what happens in malignant hyperthermia,thyroid storm....et