Effects of prostaglandin E2 inhalation on hypercapnic response in normal subjects

Role of ventilatory drive in asthma and chronic obstructive pulmonary disease

The ventilatory drive is affected by several factors such as chemosensitivity, basal arterial oxygen or carbon dioxide tension, mechanical impedance, and respiratory muscle dysfunction. Blunted ventilatory drive or a decrease in the perception of dyspnea in bronchial asthma and chronic obstructive pulmonary disease (COPD) could lead to a decrease in the alarm reaction to dangerous situations such as severe airway obstruction, severe hypoxemia, or severe hypercapnia. This could delay management and treatment, causing an increase in the morbidity and mortality of patients with bronchial asthma and COPD. The ventilatory drive to chemical stimuli can be altered by a beta-2-agonist, oxygen administration; and lung volume reduction, and an increased dyspnea sensation may be improved by corticosteroid, chest wall vibration, or lung volume reduction. The ventilatory drive has been found to play a key role in determining the severity of asthma and COPD.

New strategies of screening and treatment for sleep apnea syndrome

The prevalence of sleep apnea syndrome (SAS) is approximately 7.5% in Japanese adults aged 18-68 years old. SAS is characterized by repeated episodes of apnea, especially obstructive apnea, during sleep. Severe SAS has life-threatening complications such as pulmonary hypertension, arrhythmias, right heart failure or brain damage, which could be caused by hypoxemia and/or hypercapnia. Upper airway relaxation is responsible for the obstruction during apnea, and an increase in the activities of the upper airway muscles dilates and stiffens the upper airway wall. Maintaining the activities of the upper airway muscles may contribute to keeping the airway patent. Submental electrical stimulation of the upper airway muscles would be a novel treatment method for obstructive apnea.