School of Medicine Publications and Presentations

Document Type


Publication Date

Fall 2019


Background: Carbon dioxide levels can be monitored throughout the respiratory cycle via capnography. In this way, capnography allows healthcare professionals to follow several respiratory factors in real-time, including respiratory depression, apnea, and hypercapnia. Postoperative patients are subjected to significant harm while receiving sedating medications without appropriate monitoring and intervention. Earlier detection of alterations to ventilation status will better enable providers to more accurately dose medications during procedures, especially in high-risk patient populations.

Methods: Patient selection included post-operative patients in the intensive care unit that were receiving sedation/analgesia, high dose or high frequency opioids, epidural or intrathecal pain management, patients that are difficult to arouse, patients with a history of respiratory disease, and patients undergoing resuscitative efforts and/or endotracheal intubation. Patients were monitored with capnography to assess respiratory distress indicators and capnography waveforms.

Results: The high-risk target populations above should receive continuous pulse oximetry by telemetry. If supplemental oxygen is used, add continuous EtCO2 monitoring. Pulse oximetry may suggest adequate oxygenation in patients who are actively experiencing respiratory depression when supplemental oxygen is used. Capnography indicators of respiratory depression include no waveform for any period, change in EtCO2 of 20% above baseline, hypoventilation, shallow breathing hypoventilation, airway obstruction, apnea, or rebreathing EtCO2. Definitions and descriptions of waveforms for each capnography indicator is described in Table 2.

Conclusions: Capnography is an essential monitoring device for post-operative patients in the intensive care unit. Monitoring carbon dioxide levels will help decrease the morbidity and mortality in high-risk surgical patients who experience postoperative pulmonary complications.

Academic Level

medical student



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