Tantalum inhalation and airway responses

We studied the effects of tantalum inhalation bronchography on pulmonary function in 14 normal volunteers. Based on the radiographic type of deposition, the subjects were divided into three groups: (1) subjects who deposited tantalum mainly in the trachea, (2) subjects who deposited tantalum in segmental bronchi without radiographic evidence of bronchospasm, and (3) subjects who deposited tantalum in segmental bronchi with radiographic evidence of bronchospasm. Unlike the first two groups, the third group developed a significant but small decrease in the FEV₁. Airway reactivity as assessed by methacholine challenge did not explain the difference in response to tantalum in the third group. There were no consistent changes in total lung capacity, residual volume, or closing volume in any of the groups. Even though there were falls in FEV₁ and specific conductance in individuals in groups 2 and 3, these changes did not pose any significant clinical risk.