Factitious oxygen desaturation after isosulfan blue injection.

Profound pulse oximetery desaturations are observed following isosulfan blue dye injection during breast sentinel node biopsy. The objective of this study was to examine the effect isosulfan dye has on oxygenation status and the reliability of pulse oximetery in evaluating this parameter. After study design, institutional review board approval was obtained. A prospective 5-month study was performed between January and April 2002. Twenty-one women with invasive breast cancer were monitored during breast sentinel node biopsies. Twenty-two operative cases were analyzed by pulse oximetry and arterial catheterization to record oxygen saturation. Time intervals of analysis were 0, 5, 10, 20, 30, and 40 minutes following injection of isosulfan blue dye. Simultaneous pulse oximetry and arterial blood gas analysis allowed comparison of indirect oximetry oxygen saturation (SpO2) to actual arterial oxygen saturation (SaO2). SpO2 values were decreased from baseline values at 10, 20, and 30 minutes without decrease in SaO2 saturation (P < 0.001). The mean oximetry SpO2 desaturation was 5.6 per cent, with a range to 9 per cent. After injection with isosulfan blue dye, a significant SpO2 desaturation occurs. Clinicians must be aware of the factitious effect isosulfan blue dye has on SpO2 monitoring, to assess accurately the oxygenation status of the anesthetized patient.