Current clinical guidelines recommend capnography as one of the best non-invasive methods to assess adequacy of ventilation in the non-intubated patient. Alveolar hypoventilation or respiratory depression is a serious event that occurs in a variety of clinical settings where patients receive sedatives and opioids. With the large number of procedures performed outside the operating room under the effects of sedatives and the increased use of patient-controlled analgesia, the need for capnography for monitoring has dramatically increased. Despite the succesful use of capnography to monitor ventilation in the operating room over several decades, other clinical areas have been very slow adapters of the technology and still rely heavily upon pulse oximetry to detect hypoventilation. This article reviews the most current evidence for using capnography in the non-intubated patient and summarizes the results of outcome measures reported in recent clinical trials. Capnography should be routinely used for non-intubated patients at risk for respiratory depression, in particular those receiving supplemental oxygen.
Keywords: capnography; carbon dioxide; hypoventilation; patient-controlled analgesia; procedural sedation; respiratory depression; volumetric CO2.