To the Editor.
—As an anesthesiologist who uses pulse oximeter technology daily, I read with great interest the American Medical Association Council on Scientific Affairs report.1 It is vital to realize that pulse oximetry reveals nothing regarding adequacy of ventilation. Although this important point was addressed briefly in the Council's report, I feel it deserves greater emphasis. Too often, physicians become complacent when arterial oxygen saturation is normal.In pioneering work detailing physiology of apneic oxygenation, Frumin and colleagues2 induced periods of apnea in eight subjects lasting 18 to 55 minutes while simultaneously insufflating oxygen endotracheally at rates of 200 mL/min. The lowest arterial oxygen saturation recorded was 98%, yet profound hypercarbia was documented. In one individual, apnea lasted 53 minutes and the lowest arterial oxygen saturation recorded was 98%, yet at the same time the arterial carbon dioxide tension has increased to 250 mm Hg and the
Chaney MA. Pulse Oximetry During Conscious Sedation. JAMA. 1994;271(6):429. doi:10.1001/jama.1994.03510300029026