Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2008 Jun;1(5):28-35.

Capnography monitoring enhances safety of postoperative patient-controlled analgesia

Thomas McCarter  1 , Zakir Shaik  2 , Keith Scarfo  2 , Laura J Thompson  3
Affiliations

Capnography monitoring enhances safety of postoperative patient-controlled analgesia

Thomas McCarter et al. Am Health Drug Benefits. 2008 Jun.

Abstract

Background: Patient-controlled analgesia is associated with potentially fatal opioid-related respiratory depression. Opioids are a well-recognized cause of respiratory depression. However, in the postoperative patient, unrecognized pulmonary disease may lead to retention of carbon dioxide, which is further antagonized by opioids and may lead to life-threatening respiratory depression. Therefore, using a method that would provide earlier warnings for respiratory problems could improve patient outcomes.

Objective: To assess the efficacy of monitoring postoperative patients who were receiving patient-controlled opioid therapy with capnography modules in addition to the routine use of pulse oximetry to monitor ventilatory status and generate alerts when respiratory parameters exceed hospital-established limits.

Method: Postoperative patients receiving patient-controlled analgesia were compared in relation to the use of pulse oximetry and capnography modules and their ability to generate alerts about abnormal respiratory parameters. A total of 634 patients receiving patient-controlled analgesia therapy were studied, of whom 239 (38%) received hydromorphone, 297 (47%) received morphine, and 98 (15%) received fentanyl. All 9 patients experiencing respiratory depression received supplemental oxygen.

Results: Of the 634 patients studied, 9 (1.4%) experienced respiratory depression by bradypnea (<6 breaths per minute). Six (67%) events were related to hydromorphone and 3 (33%) were related to morphine. In 7 (78%) events, there was no basal infusion rate and the saturation of peripheral oxygen was >92%. All respiratory depression events occurred within the first 24 hours of patient-controlled analgesia therapy. In all cases, capnography, but not pulse oximetry, alerted the nurse to impending respiratory depression.

Conclusions: Capnography was more effective than pulse oximetry in providing early warning of respiratory depression in patients receiving supplemental oxygen. Capnographic monitoring and automatic pausing of patient-controlled analgesia improved postoperative outcomes in situations that could have otherwise been fatal. Use of capnography improved clinician confidence that opioid dosing could be safely continued in postoperative patients for more effective pain management.

PubMed Disclaimer

Figures

Figure
Figure. Modified Sampling Cannula: CO2 Sampling/O2 Delivery for Nonintubated Patients
None
Thomas McCarter, MD, FACP
See this image and copyright information in PMC

References

    1. Maddox RR, Williams CK, Fields M. Respiratory monitoring in patient-controlled analgesia. Am J Health Syst Pharm. 2004; 61: 2628–2635 - PubMed
    1. McPhee SJ, Papadakis MA, Tierney LM, Jr, eds. Gonzales R, Zeiger R, online eds. Current Medical Diagnosis and Treatment 2007. San Francisco, CA: McGraw-Hill Medical; 2007
    1. ISMP Medication Safety Alert. Safety issues with patient-controlled analgesia Part I—How errors occur. July 10, 2003. http://www.ismp.org/newsletters/acutecare/articles/20030710.asp Accessed May 13, 2008.
    1. ISMP Medication Safety Alert. Frequent problems with medication systems noted during ISMP hospital evaluations Part 2. June 17, 1998. http://www.ismp.org/newsletters/acutecare/articles/19980617.asp Accessed May 13, 2008.
    1. ISMP Medication Safety Alert. More on avoiding opiate toxicity with PCA by proxy. May 29, 2002. http://www.ismp.org/newsletters/acutecare/articles/20020529.asp Accessed May 13, 2008.

LinkOut - more resources