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Designed, Produced, and maintained (Edition 10, March 2019) by 

Bhavani Shankar Kodali MD

Analysis of CO2 waveforms: 4

Clinical Aspects

Bhavani Shankar Kodali MD
  

Analysis of CO2 waveforms:  


Height of the plateau:
Increases in metabolism raise the height of the plateau whereas decreases in metabolism, cardiac output and effective circulating blood volume reduce the height.1-8 The height of the plateau is also dependent on ventilation. Hyperventilation decreases it whereas hypoventilation can result in a gradual increase in the height of the plateau.

 Hypermetabolic states increase the height of the capnograms
 
/Clinicalapplication/Images/MH.gif

 

 Decreases in cardiac output decreases the height of capnograms
 
/Clinicalapplication/Images/COETCO2fall.gif

 

 Effective circulating blood volume can reduce the height of capnograms
 
/Clinicalapplication/Images/Hemorrhage.gif

 

 Hypoventilation  (Gradual elevation of the height of the capnogram, base line remaining at zero)
 
/Clinicalapplication/Images/hypoventilation.gif

 

 Hyperventilation (Gradual decrease in the height of the capnogram, base line remaining at zero)
 
/Clinicalapplication/Images/hyperventilation.gif


References

1.    Leigh MD, Jones JC, Motley HL. The expired carbon dioxide as a continuous guide of the pulmonary and circulatory systems during anesthesia and surgery.  J Thoracic cardiovasc surg 1961;41:597-610.

2.    Askrog V.  Changes in  (a-A)CO2 difference and pulmonary artery pressure in anesthetized man. J Appl Physiol 1966;;21:1299-1305.

3    Shibutani K, Muraoka M, Shirasaki S, Kabul K, Sanchala VT, Gupte P.  Do changes in end-tidal PCO2 quantitatively reflect changes in cardiac output? Anesth Analg 1994;79:829-33.

4.    Maslow A, Stearns G, Bert A, Feng W, Price D, Schwartz C, Mackinnon S, Rotenberg F, Hopkins R, Cooper G, Singh A, Loring SH. Monitoring end-tidal carbon dioxide during weaning from cardiopulmonary bypass in patients without significant lung disease. Anesth Analg 2001;92:306-13.

5.    Weil MH, Bisera J, Trevino RP, Rackow EC.  Cardiac output and end-tidal carbon dioxide. Crit Care Med 1985;13:907-9.

6.    Ornato JP, Garnett AR, Glauser FL.  Relationship between cardiac output and the end-tidal carbon dioxide tension.  Ann Emerg Med 1990;19:1104-6.

7.    Jin X, Weil MH, Povoas H, Pernat A, Xie J, Bisera J.  End-tidal carbon dioxide as a noninvasive indicator of cardiac index during circulatory shock. Crit care Med 2000;28:2415-9.

8.    Isserles SA, Breen PH.  Can changes in end-tidal PCO2 measure changes in cardiac output? Anesth Analg 1991;73:808-14.

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