Background: Isosulfan blue dye is widely used in sentinel node surgery for malignant melanoma. Intravascular dye injection is known to interfere with pulse oximetry (SpO2), but the effects of intradermal dye injection are not well known. Our aim was to determine the effects of intradermal dye injection on SpO2.
Methods: This was a controlled, prospective study of 84 consecutive patients undergoing wide local excision of malignant melanoma and sentinel lymph node biopsy. The control group (n=24) received no dye. The dye group (n=60) received isosulfan blue dye intradermally at the biopsy site. SpO2 declines of > or =2% were considered significant.
Results: Two patients in the control group (8%) and 20 patients in the dye group (33%) had a clinically significant SpO2 decline (P<.02). In those with significant declines in the dye group, the amount ranged from 2% to 4%. The latency of decline from the time of injection was 22.8 +/- 12.7 minutes.
Conclusions: Patients who receive intradermal dye injection for sentinel lymph node surgery have a 4-fold increased rate of developing declines in SpO2. With the increasing trend toward using intradermal dye administration to map lymphatic drainage in melanoma and breast surgery, declines in SpO2 readings can be expected to occur frequently. To our knowledge, this is the first report of the effects of intradermal dye injection on SpO2 readings in a large series of patients.