Recently, a 40-yr-old otherwise healthy man was undergoing a nephroscopy in the prone position under monitored anesthesia care. In the middle of procedure, as the urologist advanced a fiberoptic instrument into the ureter, the patient complained of severe pain. The anesthesiologist proceeded to administer 50 μg of fentanyl and shortly thereafter instructed the patient to take a deep breath. Moments later, the oxygen saturation dropped from 100%to 95%.

The anesthesiologist again asked the patient to take a deep breath to which the suffering man responded “I did” in a soft but strained voice. The oxygen saturation continued to drop and the anesthesiologist once again instructed the patient to take a deep breath. By this time the saturation had decreased to 89% and the concerned anesthesiologist told the patient in a loud and commanding tone “take a deep breath.” An angry and exasperated patient then exhaled and responded, “I did … and I was still holding it!”

Boston University Medical Center, Boston, Massachusetts. rortega@bu.edu.