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.
Figure 1.
This figure shows the zero oxygen saturation reading of pulse oximeter
Our patient was American Society of Anesthesiologists Class I who was breathing spontaneously, undergoing surgery in spinal anesthesia. Hence, several possibilities of oxygen desaturation were easily ruled out by clinical examination. However, the similar incident in a high-risk patient for major cardiovascular and thoracic surgery could possibly lead to few anxious moments for the anesthesiologist. Even though it was transient in our patient, the persisting “zero saturation” would be definitely a cause of concern for any attending anesthesiologist.
The pulse oximeter is widely used in intensive care units, recovery rooms, postanesthesia care units, and also in the wards. The same event could not have been overlooked by a nurse or other health-care worker who is not routinely using the pulse oximeter. This may result in undesirable false alarm among caregivers and even to patients also. This incident is reported to highlight the reasons for zero oxygen saturation and also to emphasize the need to clinically correlate the monitor always.
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Conflicts of interest
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