Opioids are frequently given to patients in the pre-hospital and acute care setting to relieve pain. A known adverse effect of opioid administration is respiratory depression. This is particularly worrisome for patients with head injuries as hypercarbia is detrimental to these patients. This study attempts to determine if clinically significant respiratory depression occurs in the acute care setting from opioid administration.
Conscious, nonintubated patients presenting to Boston Medflight and the Massachusetts General Hospital Emergency Department were enrolled. A nasal cannula was applied to patients prior to opioid administration and end-tidal carbon dioxide monitoring via the Necllor Puritan Bennett NPB-75 (Pleasanton, California) occurred continuously. Opioids included morphine, fentanyl, meperidine and hydromorphone. The opioid was administered intravenously and post administration end-tidal carbon dioxide levels were obtained for up to ten minutes. Multiple doses were often recorded.
The mean age of patients in the study was 38.5 years old with a standard deviation of 14.0. The average end-tidal carbon dioxide level before an opioid was administered was 34.2 millimeters of mercury with a standard deviation of 4.3. After opioid administration, the average end-tidal carbon dioxide level was 34.9 millimeters of mercury with a standard deviation of 4.6. The mean change was 0.78 millimeters of mercury. There was no difference between the pre and post end-tidal carbon dioxide levels based on the Wilcoxon signed-rank test which had a p-value of 0.15.
The administration of intravenous opioids to nonintubated patients in the pre-hospital and emergency department has no effect on ventilatory status as evident by lack of a significant change to end-tidal carbon dioxide levels.
Based on these results, it is safe to administer opioids to nonintubated injured or ill patients due to the lack of significant respiratory depression or hypercarbia caused by analgesia. Monitoring acute care patients end-tidal carbon dioxide levels can aid in early detection of an opioid toxicity.
A.A. Aronson, None.