Impact of obesity on the severity and therapeutic responsiveness of acute episodes of asthma.

Background: It has been suggested that obesity adversely influences both the severity and the therapeutic responsiveness of chronic asthma. However, it is unclear if it also impacts acute situations.

Methods: To determine whether adiposity worsens the clinical and physiological manifestations of acute asthma and limits therapeutic effectiveness of standard treatment, we contrasted signs, symptoms, medication use, arterial oxygen saturation, peak expiratory flow rate, and the bronchodilator response to standard doses of albuterol in 90 non-obese and 90 obese asthmatics as they presented for urgent care.

Critical comparisons of the clinical performance of oxygen-conserving devices.

Rationale: Clinical testing of oxygen-conserving devices is not mandated before marketing. Consequently, little is known about individual or comparative therapeutic effectiveness.

Objectives: To relate oxygen delivery from prototypical instruments to physiological performance.

Observations on the physiological interactions between obesity and asthma.

To explore whether asthma and obesity share overlapping pathogenic features, we examined the impact of each alone, and in combination, on multiple aspects of lung function. We reasoned that if they influenced the lungs through similar mechanisms, the individual physiological manifestations in the comorbid state should interact in a complex fashion. If not, then the abnormalities should simply add.

Impact of race on the severity of acute episodes of asthma and adrenergic responsiveness.

Rationale: African Americans acutely ill with asthma come to emergency departments more frequently and are admitted to hospital more often than whites but the reasons are unclear.

Objectives: To determine whether such phenomena represent racial differences in attack severity or limited effectiveness of beta(2)-agonist therapy.

Methods And Main Results: We contrasted clinical features, airflow limitation, and albuterol responsiveness in adults acutely ill with asthma, 155 of whom where African American and 140 white, as they presented to eight emergency departments.

The effects of hyperpnea on exhaled nitric oxide synthesis in normal subjects.

Study Objectives: To determine if the concentration of nitric oxide (NO) in the lungs increases with hyperpnea by contrasting calculated production (ie, the product of the fractional expired NO concentration [FeNO] and minute ventilation [Ve]) [Vno] with the amount of NO in equilibrium with the conducting airways (eNOair) and the amount of NO diffusing from the alveoli (eNOalv).

Design: Observational study.

Setting: University teaching hospital.

Bronchoprotective effects of single doses of salmeterol combined with montelukast in thermally induced bronchospasm.

Study Objectives: Salmeterol (S) and montelukast (M) individually inhibit the obstructive consequences of thermal stimuli such as exercise and hyperventilation (HV), but there is no information on whether these drugs can interact positively.

Design: Randomized trial.

Setting: University teaching hospital.

Morphometric changes after thermal and methacholine bronchoprovocations.

To determine whether there are distinctions in the location and pattern of response between different bronchoprovocations, we performed high-resolution computer-assisted tomography in 10 asthmatic subjects before and after isocapnic hyperventilation of frigid air (HV) and methacholine (Meth). The luminal areas of the trachea, main stem, lobar, and segmental bronchi were computed before and after each provocation and blindly compared. Both stimuli reduced the 1-s forced expiratory volume similarly (percent change in 1-s forced expiratory volume HV = 28.

Desiccation and hypertonicity of the airway surface fluid and thermally induced asthma.

To determine whether drying and hypertonicity of the airway surface fluid (ASF) are involved in thermally induced asthma, nine subjects performed isocapnic hyperventilation (HV) (minute ventilation 62.2 +/- 8.3 l/min) of frigid air (-8.