Unexplained decrease in measured oxygen saturation by pulse oximetry following injection of Lymphazurin 1% (isosulfan blue) during a lymphatic mapping procedure.

A rare case of alteration in measured pulse oximetry during a lymphatic mapping procedure for cervical carcinoma is reported. Over a 5-min period following injection of perilesional Lymphazurin 1% dye (3 ml total), a profound pulse oximetry desaturation was observed. Concomitant arterial blood gas determinations confirmed patient's well-being. Interaction of this agent's absorptive spectroscopy and wavelengths used to measure oxygen saturation by commercial pulse oximetry devices is suspected.