Circulation 122,210 • Volume 32, No. 1 • June 2017   Issue PDF

The Role of Capnography to Prevent Postoperative Respiratory Events

David Bronheim; Bill Paulsen, PhD

Letter to the Editor:

gap in pediatric mask

Figure 1. Pulse oximetry and capnography waveforms.

To the Editor:

Dr. Geralemou and colleagues make an excellent argument for capnography monitoring in the postoperative
period for evidence of hypoventilation in their October 2016 APSF Newsletter article entitled “The Role of Capnography to Prevent Postoperative Respiratory Adverse Events.” However, that doesn’t necessarily mean capnography should be recommended as a standard outside the operating room. In the postoperative setting, there is little published data on the sensitivity, specificity, and predictive value of capnography, nor its relative merit as compared to other respiratory monitoring techniques such as acoustic monitoring or plethysmography. In my own personal experience, the use of capnography is associated with a very high false alarm rate, which could naturally result in alarm fatigue. An aggressive pursuit of research to assess the value of postoperative respiratory monitoring on patient outcomes should commence. Until then, caution should be used to definitively anoint capnography as a recommended standard based upon our current knowledge.

David Bronheim
Medical Director, Post Anesthesia Care Unit
Department of Anesthesiology and Perioperative Care
Icahn School of Medicine at Mount Sinai
New York, NY

In Reply:

Dear Dr. Bronheim:

I agree that capnography is not perfect and our experience in the operating room cannot be easily translated to non-critical care areas. There is a large body of evidence to suggest that spontaneously ventilating patients can be monitored effectively when using the correct sampling lines. I think that use of capnography in non-critical care areas requires a significant education for those taking care of the patients. I do agree that other methods such as acoustic monitoring of breath sounds, plethysmography, microwave radar, and other techniques have not been compared to capnography in order to establish the techniques with the best sensitivity and specificity.

Bill Paulsen, PhD
Chair, APSF Committee on Technology