American journal of respiratory and critical care medicine
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Patient-triggered ventilation (PTV) has not been feasible for infants because of large trigger pressures and long delay times with pressure-triggered systems. Recently, four infant ventilators with flow triggering have become available. We questioned if delay times, trigger pressures, and trigger work with these ventilators would be acceptable for PTV in infants. ⋯ Delay time was greatest with the 3-mm endotracheal tube at high ventilatory drive (maximum 138.2 +/- 2.1 ms). Both trigger pressure (minimum 0.23 +/- 0.02 cm H2O) and trigger work (minimum 0.05 +/- 0.01 g.ml) increased with decreasing endotracheal tube size, increasing ventilatory demand, use of PEEP, and site of measurement: alveolus > trachea > airway (maximum: trigger pressure 5.04 +/- 0.02 cm H2O; trigger work 114.48 +/- 0.88 g.ml). PTV may not be appropriate under conditions of increased ventilatory drive and small endotracheal tube size in infants.
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Chronic pulmonary infection with Pseudomonas aeruginosa continues to be the major cause of morbidity and mortality in cystic fibrosis (CF). Several characteristics of CF, including the excessive influx of neutrophils into the airways, cachexia, and hyperglobulinemia, could reflect the effects of cytokines, such as interleukin-1 (IL-1), IL-6, IL-8, and tumor necrosis factor (TNF-alpha). We hypothesized that these pro-inflammatory cytokines, produced by alveolar macrophages in response to pseudomonas and/or other microorganisms, promote the destructive inflammatory process in the lung. ⋯ In contrast, HC BAL contained significantly more IL-10 than CF BAL (p < 0.05), but TNF-sR and IL-1Ra were similar. Immunocytochemistry demonstrated a higher percentage of CF than control BAL macrophages expressing intracellular cytokines (p < 0.05). Thus, enhanced macrophage production of proinflammatory cytokines and decreased production of the regulatory molecule IL-10 may have important roles in the pathogenesis of CF lung disease.
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Am. J. Respir. Crit. Care Med. · Dec 1995
The importance of bronchoscopy with transbronchial biopsy and bronchoalveolar lavage in the management of lung transplant recipients.
Medical and surgical advances have made lung transplantation a feasible therapy for end-stage lung disease. Fiberoptic bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial lung biopsy (TBBx) is an accepted technique for detecting clinically evident rejection and infection in the allograft of symptomatic recipients. The role of TBBx and BAL in managing asymptomatic recipients is less defined. ⋯ We compared the clinical impression recorded by the physician on the day of the procedure with the final diagnosis determined after the results of the TBBx and BAL were known. We found unsuspected rejection and/or infection that required therapy in 25% (90/355) of all surveillance bronchoscopy procedures. Most episodes (61/90, 68%) of unsuspected rejection and/or infection occurred in the first 6 mo after transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)
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Am. J. Respir. Crit. Care Med. · Dec 1995
Randomized Controlled Trial Comparative Study Clinical TrialThe role of intragastric acidity and stress ulcus prophylaxis on colonization and infection in mechanically ventilated ICU patients. A stratified, randomized, double-blind study of sucralfate versus antacids.
This study evaluates the effects of sucralfate and antacids on intragastric acidity, colonization of stomach, oropharynx and trachea, and the incidence of ventilator-associated pneumonia (VAP) in mechanically ventilated patients in intensive care units. We conducted a prospective randomized double-blind trial in which patients were stratified on initial gastric pH. Intragastric acidity was measured with computerized, continuous intragastric monitoring. The diagnosis of VAP was established with protected specimen brush and/or bronchoalveolar lavage. The study included consecutive eligible patients with mechanical ventilation and nasogastric tube. ⋯ After stratification on initial intragastric pH into two groups, patients from both groups were randomly assigned to receive either antacids (a suspension of aluminum hydroxide and magnesium hydroxide), 30 mL every 4 h, or sucralfate, 1 g every 4 h. Continuous intragastric pH monitoring was performed in 112 patients (58 antacids, 54 sucralfate). Using predetermined criteria, colonization of stomach, oropharynx, and trachea, and the incidence of VAP were assessed. Altogether, 141 patients were included (74 receiving antacids, 67 sucralfate) and continuous intragastric pH monitoring was performed in 112 patients, with a mean of 75 h per patient. The median pH and the percentage of time with a pH < 4.0 were calculated from each measurement. No significant differences in median pH values (4.7 +/- 2.2 and 4.5 +/- 2.0 for antacids and sucralfate, respectively) were observed. Median pH values were higher in patients with gastric bacterial colonization than in noncolonized patients (5.5 +/- 2.1 and 3.3 +/- 2.0, p < 0.01), but colonization of oropharynx and trachea was not related to intragastric acidity. Thirty-one patients (22%) developed VAP, with a similar incidence in both treatment groups. In addition, antibiotic use, duration of hospitalization, and mortality rates were similar in both groups. Enteral feeding did not change intragastric acidity significantly but increased gastric colonization with Enterobacteriaceae, without influencing oropharyngeal and tracheal colonization. Antacids and sucralfate had a similar effect on intragastric acidity, colonization rates, and incidence of VAP. Intragastric acidity influenced gastric colonization but not colonization of the upper respiratory tract or the incidence of VAP. Therefore, it is unlikely that the gastropulmonary route is important for the development of VAP.