The American review of respiratory disease
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Am. Rev. Respir. Dis. · Feb 1992
Multicenter Study Clinical TrialThe lung health study: airway responsiveness to inhaled methacholine in smokers with mild to moderate airflow limitation. The Lung Health Study Research Group.
As part of a multicenter clinical trial (Lung Health Study), methacholine inhalation challenge testing was performed in 5,877 current cigarette smokers, ages 35 to 59 yr (mean 48.5 +/- 6.8 yr), with borderline to moderate airflow limitation (FEV1/FVC ratio 63.0 +/- 5.5). The test was successfully completed in 96.4% of subjects, of whom 63% were male and 95.9% were white. Symptomatic reactions to methacholine were rarely severe enough to require evaluation by a trial physician. ⋯ By contrast, among women, AHR was not significantly associated with chronic cough and/or phlegm (p greater than 0.05) or a past history of asthma or hay fever (p greater than 0.1) and was only weakly related to wheeze and current asthma (p = 0.04), as well as to cigarette pack-years (p = 0.044). These results indicate that most continuing smokers with functional evidence of early chronic obstructive pulmonary disease have nonspecific AHR that is strongly related to gender and baseline lung function and, to a lesser extent, to respiratory symptoms. The reason for the striking effect of gender on AHR in early chronic obstructive pulmonary disease is unclear but cannot be attributed to male-female differences in age, cigarette use, presence of asthma, or baseline degree of airflow obstruction.
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Am. Rev. Respir. Dis. · Aug 1989
Multicenter Study Clinical TrialPrognosis with mechanical ventilation: the influence of disease, severity of disease, age, and chronic health status on survival from an acute illness.
This report presents a model for relating readily available clinical and physiologic measurements to prognosis from mechanical ventilation. Using data from 571 acutely ill, ventilated patients admitted to the intensive care units of 12 hospitals, it illustrates the relationship between the disease, the initiating respiratory failure, the acute severity of the disease, and the patient's age and chronic health status and the patient's probability of survival. ⋯ After 3 days of ICU treatment, estimates for hospital mortality increased to 97% (39 patients). We believe that such estimates, when available from a larger number of patients and combined with additional information on the patient's desires, expectations, preillness quality of life, and prognosis for long-term survival, can be helpful in decisions to withhold and withdraw mechanical ventilation.