Near-fatal asthmaとnon-near-fatal asthmaにおける換気応答の相違  [in Japanese] Difference in Respiratory Responses between Near-fatal Asthma and Non-near-fatal Asthma  [in Japanese]

対象は新潟大学医歯学総合病院・喘息呼吸器外来に通院中の気管支喘息患者10名(near-fatal asthma; NFA5名,non-near-fatal asthma; Non-NFA5名).呼吸抵抗負荷,高炭酸ガス吸入,低酸素ガス吸入に対する換気応答を行った.心理的因子の評価に,Hospital Anxiety and Depression Scaleを使用した.1)呼吸抵抗負荷換気応答:呼吸困難感(visual analog scale; VAS)はNFA患者がNon-NFA患者より高値であった.またNon-NFA患者のVASの最高値と不安,抑うつの間に相関が認められた.分時換気量の変化/VASの変化はNFA患者がNon-NFA患者より低値であった.2)高炭酸ガス換気応答:t_i(吸気時間)/t_<tot>(1回の呼吸時問)について,NFA患者はNon-NFA患者より高値であった.NFA患者でt_i/t_<tot>とVAS値の間に相関が認められた.

Objectives: We carried out a study with an aim to verify if: (1) there is a difference in respiratory responses between near-fatal asthma (NFA) patients and Non-NFA patients; (2) there is a difference in psychological characteristics between NFA patients and Non-NFA patients relating to respiratory responses. Subjects: The study population included 10 patients (5 NFA and 5 Non-NFA) referred from the outpatient clinic of Niigata University Medical and Dental Hospital. Method: We examined whether or not dyspnea and chemosensitivity to hypoxia and hypercapnia and resistive load are different between NFA patients and Non-NFA patients. Patients were administered a self-rated psychological measures, including the Japanese version of the Hospital Anxiety and Depression Scale (HADS). Results: The mean value of visual analog scale (VAS) (perception of dyspnea) during resistive loaded breathing was significantly higher in NFA patients than in Non-NFA patients (p=0.00). There was a relation between maximal values of VAS and both anxiety (r=-0.51) and depression (r=-0.67) during resistive loaded breathing in Non-NFA patients. The mean value of slope of the minute ventilation (V_E) (Change in V_E/Change in VAS) was significantly lower (p=0.03) in NFA patients than in Non-NFA patients during resistive loaded breathing. The mean value of duty ratio in hyperoxic hypercapnic responses was significantly higher in NFA patients than in Non-NFA patients (p=0.00). There was a relation between values of VAS and values of duty ratio in hyperoxic hypercapnic responses in NFA patients (r=0.82). Conclusion: These results have clinical implications for managing asthma. We need to know the characteristics of perception of dyspnea in asthma.