American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · Mar 1996
Randomized Controlled Trial Comparative Study Clinical TrialInhaled bronchodilators reduce dynamic hyperinflation during exercise in patients with chronic obstructive pulmonary disease.
Dynamic hyperinflation (DH) is a major pathophysiologic consequence of airflow limitation during exercise in patients with chronic obstructive pulmonary disease (COPD) and an important contributing factor to breathlessness. In this study we aimed to examine the effect of inhaled beta agonist therapy on DH during exercise in these patients and the relationship between changes in DH and breathlessness. In 13 COPD patients (mean age 65.1 +/- 2.0, FEV1 1.20 +/- 0.17, FEV1/FVC 40 +/- 3) we measured pulmonary function tests, exercise breathlessness by Borg score, and exercise flow volume and pressure volume loops on two separate days. ⋯ The relationships between delta Borg, delta resting volumes, and flow rates were not significant. We conclude that in patients with COPD, inhaled bronchodilator reduces exercise DH and improves inspiratory pressure reserve and neuroventilatory coupling. Changes in DH and neuroventilatory coupling were the main determinants of reduced breathlessness.
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Am. J. Respir. Crit. Care Med. · Mar 1996
Bronchial responsiveness to distilled water and methacholine and its relationship to inflammation and remodeling of the airways in asthma.
Although bronchial hyperresponsiveness in asthma is associated with inflammation within the airways, it is not known whether the degree and type of inflammation influence the response to different stimuli and whether pathologic changes of airway structure influence the bronchoconstrictive responses. Therefore, number of inflammatory cells in the epithelium and the lamina propria and the basement membrane thickness were estimated from bronchial biopsies taken in 27 asthmatic subjects (range percent predicted FEV1: 75.6 to 132.1, range of daily PEF variability: 1.9% to 20%) and related to the degree of bronchial responsiveness to ultrasonically nebulized distilled water (UNDW) and methacholine (M). PD20UNDW (provocative dose) was measurable in 15 of 27 patients and ranged between 1.01 and 20.4 ml. ⋯ A weak but significant correlation was also found between subepithelial layer thickness and PC20M (rs = -0.42; p<0.04). The results of this study demonstrate that eosinophilic inflammation of bronchial epithelium plays a role in determining UNDW and M responsiveness in asthma. Moreover, they suggest that remodeling of the airways such as thickening of subepithelial layer correlates with indices of asthma severity and could contribute to the degree of M but not to UNDW responsiveness.
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Am. J. Respir. Crit. Care Med. · Mar 1996
Noninvasive positive-pressure ventilation in acute respiratory distress without prior chronic respiratory failure.
We evaluated the efficacy of noninvasive mechanical ventilation (NIMV) in alleviating distress and avoiding intubation in patients with de novo acute respiratory failure complicating primary medical disorders. Eleven consecutive patients with severe respiratory distress were entered. In all patients a decision to intubate on an urgent basis had been made, but NIMV could be initiated within minutes. ⋯ The remaining eight patients demonstrated progressive improvement, and none required intubation. The duration of NIMV was 3 h to 2 d. We conclude that when NIMV is made available on a "few minutes" basis, selected patients with severe de novo respiratory distress/failure caused by reversible medical disorders, who would otherwise have been intubated, can be given substantial relief and be spared intubation.
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Am. J. Respir. Crit. Care Med. · Mar 1996
Randomized Controlled Trial Comparative Study Clinical TrialDirect comparison of inhaled nitric oxide and aerosolized prostacyclin in acute respiratory distress syndrome.
Inhalation of NO and aerosolization of PGI2 have been suggested to achieve selective pulmonary vasodilation and improvement of arterial oxygenation in patients with ARDS. We directly compared these two modes of transbronchial vasodilator therapy in 16 ARDS patients mechanically ventilated (mean lung injury score [1] 2.75 +/- 0.05). Patients were randomized to receive either first NO and then PGI2, or vice versa. ⋯ Two further patients displayed an improvement of arterial oxygenation in response to either NO or PGI2. NO decreased mean pulmonary artery pressure from 34.8 +/- 2.2 to 33.0 +/- 1.8 mm Hg, and PGI2 from 35.0 +/- 2.2 to 31.9 +/- 1.7 mm Hg (p<0.05). We conclude that individually titrated doses of inhaled NO and aerosolized PGI2 effect selective pulmonary vasodilation and redistribute blood-flow from shunt-areas to well-ventilated regions with nearly identical efficacy profiles.
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Am. J. Respir. Crit. Care Med. · Mar 1996
Randomized Controlled Trial Comparative Study Clinical TrialSedation of critically ill patients during mechanical ventilation. A comparison of propofol and midazolam.
Propofol (P) and midazolam (M) are frequently given by continuous infusion for sedation in critically ill, mechanically ventilated patients. We compared these drugs with regard to: (1) time-to-awaken; (2) reproducibility of bedside assessments of level of sedation; (3) time-to-sedation; and (4) change in oxygen consumption (V O2) from awake to sedated state. Seventy-three patients were prospectively randomized to receive either P (n=37) or M (n=36). ⋯ Blinded versus unblinded observations had excellent correlation. Average time to sedate and decrease in V O2 were not different. We conclude that in this patient population: (1) both P and M achieved optimal sedation in a large fraction of patients when administered by specified dosing protocols; (2) P had a faster, more reliable, wake-up time; (3) assessments of time-to-awaken were objective and reproducible; (4) time to sedation was not significantly different; (5) V O2 decreased similarly with both.