[Changes in respiratory function before and after laryngectomy].
Many patients with head and neck cancer have a smoking history, and pulmonary complications frequently lead to post-operative death. Due to technical problems, spirometric pulmonary function tests are rarely performed in patients with laryngectomy. The purpose of this study is to evaluate respiratory function in patients with laryngectomy. We made a tracheal mask with a heat and moisture exchanging baseholder, and used it for spirometry. Eight patients with laryngectomy, including 5 with laryngeal cancer and 3 with hypopharyngeal cancer, were studied. Arterial blood gas analysis and pulmonary function measurements, such as VC, % VC, FEV1.0% and V25/height (V25/HT), were evaluated before and after laryngectomy. Statistical analysis of the data was performed with the Wilcoxon rank-sum test. The following results were obtained: 1) No statistically significant changes in arterial blood gases and FEV1.0% were found. 2) A statistically significant decrease in VC was found after total laryngectomy (p < 0.05). 3) A statistically significant decrease in V25/HT, which reflects small air way closure of the lung, was observed after total laryngectomy (p < 0.05). In all cases, the V25/HT value was below normal limits. We concluded that the decrease in VC was caused by a decrease in dead space in the upper airway, and that V25/HT may be a good parameter for evaluation of pulmonary function after laryngectomy.