“Moderate probability of PE”: (1) Normal chest roentgenogram, normal ventilation study, and several subsegmental perfusion defects the sum of which is equivalent to two segments. (2) Severe chronic obstructive airways disease, no opacification on the chest roentgenogram, and matched or partially unmatched perfusion defects. (3) Opacification of the chest roentgenogram and nonsegmental perfusion defect that is approximately equal in size to the area of the roentgenogram opacification. proventil inhaler
“High probability cf PE”: (1) Normal chest roentgenogram, normal ventilation, and single or multiple segmental defects. (2) Normal chest roentgenogram, normal ventilation, and single lobar perfusion defect with accompanying single or multiple subsegmental or segmental defects. (3) Opacification of the chest roentgenogram and nonsegmental perfusion defect that is significantly larger than opacification of the chest roentgenogram.
Selective PA was performed in a standard manner.
The uFPA Assay
Urine samples were assayed for FPA by a competitive enzyme-linked immunoassay (Asserachrom FPA, Diagnostica Stago, As-nieres, France). The assay used in this study has been described in detail previously for measuring pFPA. We modified the assay, as described below, for measuring uFPA.