Safety of regadenoson, a selective adenosine A2A agonist, in patients with chronic obstructive pulmonary disease: A randomized, double-blind, placebo-controlled trial (RegCOPD trial).

Background: Patients with reactive airways are at risk for adenosine-induced bronchoconstriction, mediated via A(2B) and/or A(3) adenosine receptors.

Methods And Results: In this randomized, double-blind, placebo-controlled crossover trial, we examined the safety of regadenoson, a selective adenosine A(2A) receptor agonist, in patients with moderate chronic obstructive pulmonary disease (COPD) (n = 38) and patients with severe COPD (n = 11) with a baseline mean forced expiratory volume in 1 second (FEV(1)) of 1.74 +/- 0.

Voluntary hyperventilation into a simple mixing chamber relieves high altitude hypoxia.

Involuntary hyperventilation is a critical factor in acclimatization to a high altitude. Unacclimatized subjects do poorly when acutely exposed to high altitude. This may not be due to hypocapnia itself, but rather an associated symptom which inhibits hypoxic respiratory stimulation.

Flow-volume curves reflect pharyngeal airway abnormalities in sleep apnea syndrome.

Twenty-nine patients with disorders of excessive somnolence were evaluated with standard nocturnal polysomnography, fiberoptic laryngoscopy, and flow-volume curves. Twenty-two had evidence of obstructive sleep apnea (OSA) by polysomnography and most had abnormal flow-volume curves, supporting earlier observations. Three of 7 patients without obstructive sleep apnea also had abnormal curves.