気管支喘息発作における過換気と呼吸困難

Is Panic Responsible for Dyspnea in Acute Exacerbation of Asthma ?

　喘息発作における呼吸困難とパニック障害の関係を検討するために，救命救急センター（ER）を受診した喘息390名と過換気症候群（HVS）患者100名の病像を比較検討した．両ともに女性が多く，20歳代と50歳代にピークを持つ2峰性の年齢分布を認めた．喘息（136名）の血液ガス（平均±SD）はpH7.42±0.09,PaCO₂37.0±12.2mmHg,HVS（93名）はpH7.56±0.09,PaCO₂23.4±7.2mmHgであった．喘息患者の呼吸困難はPaCO₂とは明らかな相関がなく，血液ガス1次回帰直線（PCO₂＝1.10×［H^＋］−5.57,R＝0.78,p＜0.0001）はHVSとほぼ重複していた．喘息患者中12名のPaCO₂^—［H^＋］点は喘息の平均±SD枠を逸脱し，HVS枠内に存在していた．以上の結果は，喘息発作の呼吸困難のメカニズムにHVS（パニック障害）の要素も関与している可能性を示唆している．

Mild or moderate exacerbation of bronchial asthma is usually associated with respiratory alkalosis which is one of the major signs of panic disorders. In the present study. we analyzed role of panic on dyspneic sensation in asthma attack. We reviewed records of the patients with bronchial asthma or hyperventilation syndrome (HVS) who visited emergency room of Tokai Univer-sity Hospital for past 19 months. Age distributions of both bronchial asthma (n=390) and HVS (n=100) had two peaks at 20 th and 50 th of age. In both groups female patients were predominant. The mean (SD) pH and PaCO₂ of asthma patients (n=136) were 7.42 (0.09) unit and 37.0 (12.2) mmHg, and those of HVS (n=93) were 7.56 (0.09) unit and 23.4 (7.2) mmHg. PaCO₂ and [H⁺] of asthma had a strong linear relationship as seen in HVS patients. The regression line (PCO₂=0.55× [H⁺] +17.9, R=0.79, p＜0.0001) passed through the point of normal blood gases. The points representing PaCO₂H^- [H⁺] of 26 asthmatic patients located outside of mean ± 1SD frame of asthma and in the frame of HVS patients. These results suggested that panic played any role on dyspneic sensation in acute exacerbation of asthma.