Isosulfan blue affects pulse oximetry

Background: Certain vital dyes are known to cause pulse oximetry (Spo(2)) d esaturation. The authors studied the effect of isosulfan blue (IB) on Spo(2 ). Methods: Thirty-three women, aged 34-81 yr, who were undergoing surgery for breast cancer were studied. IB, 5 ml (50 mg), was injected intraparenchyma lly around the tumor area by the surgeon. A pulse oximeter was used to cont inuously record Spo(2) values up to 130 min after IB injection. Friedman re peated-measures analysis of ranks was used to analyze the baseline Spo(2) a nd values at 5, 10, 20, 30, 40, 50, and 60 min. Results: Spo(2) values were significantly different from baseline values at 5, 10, 20, 30, 40, 50, and 60 min (P < 0.05). In a typical patient, a maxi mum Spo(2) decrease of 3% fan be anticipated 25 min after injection of IB. Conclusions: After peritumoral administration of IB, 50 mg, a significant i nterference with Spo(2) will occur.