Zero Oxygen Saturation in Pulse Oximeter: Need for Clinical Correlation

Sir, I would like to share an unusual incident, which had happened recently in our operation theater. This event had occurred while conducting spinal anesthesia for a 28-year-male patient with an inguinal hernia for meshplasty. His preoperative anesthetic evaluation and investigations were unremarkable. In the operating room, the blood pressure (BP) cuff and pulse oximeter were applied in the same arm. After spinal anesthesia and during the procedure, we noted the “zero saturation” in pulse oximeter. It was ignored as the patient was clinically normal and the event was transient. The pulse oximeter waveform disappeared and reappeared while the BP cuff was measuring. On careful observation, we noted that “zero saturation” correlated with the reappearance of pulse oximeter waveform after cycling of BP cuff [Figure 1]. It was assumed due to technical malfunction of the pulse oximeter. The incident was discussed with service engineers, and they could not nail down the problem as the issue was transient.