Postulating a dermal pathway for exposure to anti-neoplastic drugs among hospital workers. Applying a conceptual model to the results of three workplace surveys

Dermal exposure to anti-neoplastic drugs has been suggested as a potentially important route of exposure of hospital workers. Three small-scale workplace surveys were carried out in several hospitals focusing on contamination by leakage from IV infusion systems; contamination by spilled urine of patients treated with anti-neoplastic drugs and particulate phase anti-neoplastic drugs in the air of outpatient and nursing clinics. A new visual scoring technique using a fluorescent tracer was developed. The method showed a very low limit of detection (0.02 μl of contamination) and a very high inter-observer agreement (ICC = 0.99). Evaluation of IV systems and connectors showed distinct differences between the systems. It was estimated that 0.5-250 μg of a drug can become available for contamination during each infusion. Differences in average contamination between nurses were negligible in the experimental set-up. Widespread and frequent contamination due to spillage of contaminated urine was revealed and appeared not to be restricted to the patient's room. Airborne particulate concentrations went undetected for 80% of the measurements. However, in a few cases concentrations up to 2 ng/m3 of cyclophosphamide were measured predominantly in a room of a patient treated with this anti-neoplastic drug. Based on these results and a recently proposed conceptual model for dermal exposure a most likely exposure scenario was postulated both for nurses involved in administering drugs and nurses caring for treated patients. Estimation of all relevant mass transport rates will be a challenge for the near future. (C) 2000 British Occupational Hygiene Society