In order to determine whether opioid-naive patients at risk for respiratory depression are better monitored with either capnography or pulse oximetry and respiratory-rate assessment, the authors conducted a randomized, prospective trial. In 54 opioid-naive postoperative orthopedic patients at one hospital, capnography resulted in greater detection of respiratory depression, and the authors conclude that capnography may be more appropriate for use with postsurgical high-risk patients taking opioids on the general care nursing unit. Capnography's sensitivity in the detection of pauses in breathing in the sedated patient may have the added advantage of indicating those patients who may be at risk for obstructive sleep apnea. Further research is needed to confirm these results.