Pulseless Pulse Oximetry

We read with great interest the article by Aldrich et al 1 in this issue of CHEST (see page 1484 ). In 2003, we reported our trial of measuring noninvasive arterial saturation during a pulseless situation (cardiopulmonary bypass [CPB]) by inducing a simulated pulse. 2 We were interested in fi nding a way to obtain pulse oximeter function during CPB at the time because we had experienced a mortally instructive cardiac case in which the routine anesthesia practice of turning off the pulse oximeter during CPB resulted in severe hypoxic brain damage.