Raynaud's syndrome in workers who use vibrating pneumatic air knives

Purpose: The use of vibrating tools has been shown to cause Raynaud's syndr ome (RS) in a variety of workers, including those who use chain saws, chipp ers, and grinders. The diagnosis of RS in workers who use vibrating tools i s difficult to document objectively. We studied a patient cohort with RS ca used by the use of a vibrating pneumatic air knife (PAR) for removal of aut omobile windshields and determined our ability to document RS in these work ers by means of digital hypothermic challenge testing (DHCT), a vascular la boratory study that evaluates digital blood pressure response to cooling. Methods: Sixteen male autoglass workers (mean age, 36 years) with RS were e xamined by means of history, physical examination, arm blood pressures, dig ital photoplethysmography, screening serologic studies for underlying conne ctive tissue disorder, and DHCT. Results: No patient had RS before they used a PAR. The mean onset of RS (co lor changes, 100%; pain, 93%; parathesias, 75%) with cold exposure was 3 ye ars (range, 1.5 to 5 years) after initial PAK use (mean estimated PAK use, 2450 hours). Fifty-six percent of workers smoked cigarettes. The findings o f the physical examination, arm blood pressures, digital photoplethysmograp hy, and serologic testing were normal in all patients. At 10 degrees C cool ing with digital cuff and patient cooling blanket, a significant decrease i n digital blood pressure was shown by means of DHCT in 100% of test fingers versus normothermic control fingers (mean decrease, 75%; range, 25% to 100 %; normal response, less than 17%; P <.001). The mean follow-up period was 18 months (range, 1 to 47 months). No patient continued to use the PAR, but symptoms of RS were unchanged in 69% and worse in 31%. Conclusion: PAR use is a possible cause of vibration-induced RS. The presen ce of RS in workers who use the PAR was objectively confirmed by means of D HCT. Cessation of PAK use in the short term did not result in symptomatic i mprovement.