Mechanisms of life-shrecthening attacks of asthma.

本研究的目的是研究哮喘发作死亡的确切机制。具体来说，我想澄清我的假设，即在哮喘发作期间增加体力活动和/或吸入β - 2兴奋剂可能会引发昏迷，导致死亡。本课题的主要研究结果如下：1。我采访了28名几乎致命的哮喘患者，他们在发作期间有失去意识的经历，或者接受过机械呼吸机的治疗。他们中68%的濒死事件发生在增加体力活动之后，特别是步行，17%发生在通过超声波雾化器吸入β -兴奋剂之后或期间。这些结果表明，在哮喘发作期间，体力活动的增加和β -兴奋剂的吸入可能是无意识的触发因素，从而导致死亡研究还表明，在哮喘发作期间，体力活动的增加和β -兴奋剂的吸入都降低了动脉氧饱和度。以呼气流量峰值表示的气道支气管收缩越严重，吸入β 2-兴奋剂降低的氧饱和度越多。经证实，多巴胺可通过呼吸阻力和低氧通气反应增加呼吸困难的感觉。这表明，doxapram可能改善两个危险因素，即呼吸困难的感觉减弱和低氧通气反应，患者的近致命性哮喘。这种药物可能对治疗几乎致命的哮喘病人有用。

The purpose of the present was to examine the precise mechanisms of death from asthma attacks. Specifically, I intended to clarify my hypothesis that an increase in physical activity and/or an inhalation of beta2-stimulant during an exerbation of asthma maybe a trigger of unconsciousness, leading to death.Main findings in this project were as follows.1. I interviewed to 28 patients with near-fatal asthma, who had in experience of unconsciousness during an attack or had received treatment with a mechanical ventilator. Sixty-eight percent of their near-fatal episodes had occurred just after the increasing physical activity, in particular walking, and 17 percent had occurred after/or during the inhalation of beta2-stimulant through an ultrasonic nebulizer. These results suggest that the increase in physical activity and the inhalation of beta2-stimulant during an exerbation of asthma may be a trigger of unconsciousness, leading to death.2 It was also demonstrated that both the increase physical activity and the inhalation of beta2-stimulant decreased in arterial oxygen saturation during an exacerbation of asthma. The more severe airway bronchoconstriction expressed by peak expiatory flow was, the more oxygen saturation decreased by an inhalation of beta2-stimulant.3. It was demonstrated that doxapram increases the perception of dyspnea during breathing through resistances as well as hypoxic ventilatory response. This suggest that doxapram may improve the two risk factors, i.e. blunted perception of dyspnea and lower edhypoxic ventilatory response, of patients with near-fatal asthma. This drug may be useful for a treatment for patients with near-fatal asthma.