American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · Aug 1995
Racial differences in the association between maternal smoking during pregnancy and lung function in children.
We recently reported that suburban white schoolchildren whose mothers smoked during pregnancy have significantly reduced lung function. Because inner-city and minority children may be at greater risk for respiratory morbidity, we evaluated the relationship between maternal smoking during pregnancy and lung function in 493 white and 383 black schoolchildren 9 to 11 yr of age in three areas of Philadelphia. The child's passive smoking history was determined from reports by the mother. ⋯ After adjusting for height, weight, age, sex, area of city, race, socioeconomic status, and current exposure to environmental tobacco smoke at home, maternal smoking during pregnancy was associated with significant deficits in FEF25-75 (-8.1%) and FEV1/FVC (-2.0%). The observed deficits were larger for black children than for white children, and they were larger for boys than for girls. These results provide additional evidence of an association between maternal smoking during pregnancy and reduced pulmonary function in children, and they suggest that the association may be modified by race and/or sex.
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Am. J. Respir. Crit. Care Med. · Aug 1995
Comparative StudyAcute and chronic effects of cigarette smoking on exhaled nitric oxide.
Cigarette smoking is associated with an increased risk of respiratory tract infections, chronic airway disease, and cardiovascular diseases, all of which may be modulated by endogenous nitric oxide (NO). We have investigated whether cigarette smoking reduces the production of endogenous NO. We compared exhalations of 41 current cigarette smokers with normal lung function and 73 age-matched non-smoking controls. ⋯ Inhalation of carbon monoxide and NO had no effect on exhaled NO in normal subjects. Cigarette smoking decreased exhaled NO, suggesting that it may inhibit the enzyme NO synthase. Since endogenous NO is important in defending the respiratory tract against infection, in counteracting bronchoconstriction and vasoconstriction, and in inhibiting platelet aggregation, this effect may contribute to the increased risks of chronic respiratory and cardiovascular disease in cigarette smokers.
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Am. J. Respir. Crit. Care Med. · Aug 1995
Randomized Controlled Trial Comparative Study Clinical TrialA randomized, double-blind comparison of methoxamine and epinephrine in human cardiopulmonary arrest.
The beneficial effect of epinephrine has been attributed to its alpha-adrenergic properties. The present study was designed to compare the effects of epinephrine and methoxamine in witnessed cardiac arrests. Consecutive, witnessed cardiac-arrest victims presenting to the emergency room or from the inpatient population of our institution were enrolled in this study. ⋯ Of the 145 patients remaining, 77 received methoxamine (M) and 68 epinephrine (E). There was no difference in rate of successful resuscitation (42% versus 53%, M versus E, respectively), or in neurologic outcome as measured by the Glasgow-Pittsburgh Coma Score (GPCS). This study failed to demonstrate any difference in the rate of initial resuscitation, survival to discharge from the hospital, or neurologic status with methoxamine as opposed to epinephrine in the setting of cardiac arrest.
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Am. J. Respir. Crit. Care Med. · Aug 1995
Randomized Controlled Trial Comparative Study Clinical TrialNasal pressure support ventilation plus oxygen compared with oxygen therapy alone in hypercapnic COPD.
Non-invasive ventilation has been used in chronic respiratory failure due to chronic obstructive pulmonary disease (COPD), but the effect of the addition of nasal positive-pressure ventilation to long-term oxygen therapy (LTOT) has not been determined. We report a randomized crossover study of the effect of the combination of nasal pressure support ventilation (NPSV) and domiciliary LTOT as compared with LTOT alone in stable hypercapnic COPD. Fourteen patients were studied, with values (mean +/- SD) of Pao2 of 45.3 +/- 5.7 mm Hg, PaCO2 of 55.8 +/- 3.6 mm Hg, and FEV1 of 0.86 +/- 0.32 L. ⋯ Quality of life with oxygen plus NPSV was significantly better than with oxygen alone. The degree of improvement in daytime PaCO2 was correlated with the improvement in mean overnight PaCO2. Nasal positive-pressure ventilation may be a useful addition to LTOT in stable hypercapnic COPD.
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Am. J. Respir. Crit. Care Med. · Aug 1995
Comparative StudyAlterations of lung and chest wall mechanics in patients with acute lung injury: effects of positive end-expiratory pressure.
In 16 mechanically ventilated patients with acute lung injury (ALI) (eight patients with moderate ALI [moderate group], eight patients with severe ALI [adult respiratory distress syndrome, ARDS group]) and in eight normal anesthetized-paralyzed subjects (control group), we partitioned the total respiratory system mechanics into the lung (L) and chest wall (w) mechanics using the esophageal balloon technique together with the airway occlusion technique during constant flow inflation. We measured lung elastance (Est,L), chest wall elastance (Est,w), and total lung (Rmax, L) and chest wall (Rmax,w) resistance. Rmax,L includes airway (Rmin,L) and "additional" lung resistance (DR,L). ⋯ The end-expiratory lung volume (EELV) was measured at each level of PEEP. Specific total lung (sRmax,L), airway (sRmin,L), and "additional" lung (sDR,L) resistances were obtained as Rmax,L x EELV, Rmin,L x EELV, and DR,L x EELV, respectively. At PEEP 0 cm H2O, we found that both Est,L (23.7 +/- 5.5 and 13.8 +/- 3.3 versus 9.3 +/- 1.7 cm H2O/L; p < 0.01) and Est,w (13.2 +/- 5.4 and 9.9 +/- 2.1 versus 5.6 +/- 2.3 cm H2O/L; p < 0.01) were markedly increased in patients with ARDS and moderate ALI compared with control subjects, with a significant (p < 0.01) effect of the severity of the disease on Est,L (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)