Interference of patent blue dye with pulse oximetry readings, methemoglobin measurements, and blue urine in sentinel lymph node mapping: a case report and review of the literature.

Patent blue (PB) dye has been successfully used worldwide in breast and cervix surgeries with few complications. Interference of oxyhemoglobin saturation reading by pulse oximetry (SpO(2)) and methemoglobinemia, from injection of PB dye, have rarely been reported in breast and cervix surgeries. We report here the first case of interference of SpO(2) reading, advent of methemoglobinemia, and blue urine from the use of PB dye, which occurred concurrently in a female undergoing bilateral modified radical mastectomy. The unexpected events might be a consequence of excessive administration of PB dye. We also reviewed the published discourses in literature on the adverse effects of PB dye.