ACUTE AND LONG-TERM EFFECTS OF POLYVINYLCHLORIDE (PVC) SMOKE ON THE RESPIRATORY SYSTEM OF THE BABOON AND A COMPARISON WITH THE EFFECTS HYDROGEN-CHLORIDE (HCL)

The acute and long-term effects of smoke produced by flaming and nonfl aming combustion of PVC were investigated in the baboon and compared w ith those produced by HCl. Four groups of three anesthetized adult mal e baboons (Papio cynocephalus) were exposed for 15 minutes to air (con trols), flaming or nonflaming PVC smoke containing a targeted 5000 ppm concentration of HCl, or to HCl at a targeted concentration of 5000 p pm. The animals responded to flaming or nonflaming PVC smoke with an i ncrease in frequency and minute volume, accompanied by decreased arter ial pH and PaO2 and increased PaCO2 values. Although pulmonary functio n tests, CO2 challenge tests, or arterial blood gas measurements in PV C smoke-exposed animals showed sporadic differences from controls at 9 0, 180, or 360 days postexposure, the results did not indicate the dev elopment of impaired pulmonary function. These results were consistent with the absence of exposure-related respiratory tract pathology, alt hough an inflammatory cell response was noted in the minor airways of one animal exposed to flaming PVC smoke. The effects of flaming or non flaming PVC smoke were generally similar to those of HCl, indicating t hat HCl is retained in the upper respiratory tract, even in the presen ce of particulates in smoke.