Henna dye: A cause of erroneous pulse oximetry readings
A 65-year-old female presented in hospital for a herniated disc surgery. A preoperative clinical exam showed a darkened skin coloration of the hands and toes.\nA week prior to admission, she had applied henna on her hands and feet. On the day of the surgery, she was shifted to the operating room for the procedure under general anesthesia. Preinduction monitors using pulse oximeter failed to produce a waveform on reading from any of the fingers or toes. Equipment failure was excluded by trying the probe on members of the staff. A change of oximeter also failed to produce a signal. The alternative of using others sites like the earlobe for monitoring was not viable because of the prone position required the surgery. The procedure was then delayed to a later date. Repeated attempts to clean fingers with a diluted bleach solvent did help in mitigating the dark coloration of the skin of the fingers []. The patient could be monitored successfully by applying the probe to the fingers four days later.