Objective: To evaluate the pleurodesis and the lung damage caused by intrapleural silver nitrate or talc in an experimental model in rabbits to consider the use in human beings. Design: 112 rabbits were randomized to receive intrapleural 0.5% silver nitrate or 400 mg/kg talc slurry in 2 ml saline. Eight rabbits in each group were sacrificed 1, 2, 4, 6, 8, 10, or 12 months post injection. The degree of pleurodesis (gross pleural fibrosis and inflammation), lung damage (collapse and edema), and cellular infiltrates were graded on a 0 to 4 scale. Results: The intrapleural injection of silver nitrate produced a better pleurodesis than did the intrapleural injection of talc slurry. The lung damage was moderate 1 month after silver nitrate and greater than after talc. They were similar as from the second month. Conclusions: The better pleurodesis induced by silver nitrate persists for at least one year. The more evident lung damage after silver nitrate was mild with reversible changes which show a clear tendency to normalize with time. For these reasons, the efficacy of silver nitrate as a sclerosing agent in humans should be evaluated.

Keywords: Pleurodesis. Talc. Silver nitrate. Pleural effusion.

Objective: To evaluate the role of intrapleural positioning of a pleural catheter in early lung expansion and pleurodesis success in patients with recurrent malignant pleural effusion (RMPE). Methods: This was a retrospective study nested into a larger prospective cohort study including patients with RMPE recruited from a tertiary university teaching hospital between June of 2009 and September of 2014. The patients underwent pleural catheter insertion followed by bedside pleurodesis. Chest CT scans were performed twice: immediately before pleurodesis (iCT) and 30 days after pleurodesis (CT30). Catheter positioning was categorized based on iCT scans as posterolateral, anterior, fissural, and subpulmonary. We used the pleural volume on iCT scans to estimate early lung expansion and the difference between the pleural volumes on CT30 and iCT scans to evaluate radiological success of pleurodesis. Clinical pleurodesis success was defined as no need for any other pleural procedure. Results: Of the 131 eligible patients from the original study, 85 were included in this nested study (64 women; mean age: 60.74 years). Catheter tip positioning was subpulmonary in 35 patients (41%), anterior in 23 (27%), posterolateral in 17 (20%), and fissural in 10 (12%). No significant differences were found among the groups regarding early lung expansion (median residual pleural cavity = 377 mL; interquartile range: 171-722 mL; p = 0.645), radiological success of pleurodesis (median volume = 33 mL; interquartile range: −225 to 257 mL; p = 0.923), and clinical success of pleurodesis (85.8%; p = 0.676). Conclusions: Our results suggest that the position of the tip of the pleural catheter influences neither early lung expansion nor bedside pleurodesis success in patients with RMPE.

Keywords: Pleurodesis; Pleural effusion, malignant; Tomography; Catheters.

Because it has direct and indirect action on lung tissue, oleic acid (OA) has been used experimentally as a model of fat embolism and acute respiratory distress syndrome (ARDS). The aim of this study was to describe acute and chronic pulmonary lesions induced in rats by intravenous injection of OA. Male Wistar rats were injected a 0.05 ml dose of OA. Groups of 5 animals were sacrificed 2, 24, 48 hours, and 5, 10, 30, and 90 days after injection. Diffuse alveolar edema, foci of intra-alveolar hemorrhage, and foci of ischemic necrosis were observed by light microscopic from 2 to 48 hours. At this period of time, severe endothelial injuries and type II alveolar cell lesions were observed on electron microscopy. After the fifth day, no injury was observed and discrete morphological sequelae were found. The lungs of the animals sacrificed at the thirtieth and ninetieth days were identical to those of the control groups. The present model allows animal to survive, being suitable for studies on fat embolism and on ARDS.

Keywords: Oleic acid. Fat embolism. Acute respiratory distress syndrome, ARDS. Experimental model.

Every year, a large number of individuals become dependent on mechanical ventilation because of a loss of diaphragm function. The most common causes are cervical spinal trauma and neuromuscular diseases. We have developed an experimental model to evaluate the performance of electrical stimulation of the diaphragm in rabbits using single-channel electrodes implanted directly into the muscle. Various current intensities (10, 16, 20, and 26 mA) produced tidal volumes above the baseline value, showing that this model is effective for the study of diaphragm performance at different levels of electrical stimulation.

Keywords: Rabbits; Diaphragm; Electric stimulation; Models, animal.

Objective: To evaluate the usefulness of determining the inflammatory component of airway diseases (inflammometry) by induced sputum cell counts, as well as its influence on treatment decisions in a tertiary facility for the treatment of respiratory diseases. Methods: We analyzed 151 sputum samples from 132 consecutive patients referred for clinical sputum induction by five pulmonologists between July of 2006 and February of 2007. A structured questionnaire related to the reasons for requesting the test and to the therapeutic decision making based on test results was completed by each attending physician upon receiving the test results. Induced sputum was obtained and processed according to a technique previously described. Results: The principal motives for ordering the test were inhaled corticosteroid dose titration in patients with moderate-to-severe asthma (in 54.3%), investigation of chronic cough (in 30.5%), and monitoring airway inflammation in patients with bronchiectasis (in 7.3%) or chronic obstructive pulmonary disease (in 6%). Of the 82 patients with asthma, 47 (57%) presented eosinophilic bronchitis (>3% eosinophils). Nonasthmatic eosinophilic bronchitis was diagnosed in 9 (19%) of the 46 patients with chronic cough. Neutrophilic bronchitis (>65% neutrophils) was found in 13 patients, of which 5 had asthma, 2 had chronic cough, and 6 had chronic obstructive pulmonary disease/bronchiectasis. Based on the induced sputum results, the corticosteroid dose was modified in 48 asthma patients (64.7%). Conclusions: The systematic application of inflammometry using induced sputum cell counts can be beneficial for patients with airway diseases, particularly those with asthma or chronic cough.

Keywords: Sputum; Asthma; Bronchitis.

We aimed to test a new model of self-expanding tracheal stent so that it might be made available for clinical use. Using direct laryngoscopy, we placed polyurethane-coated, nitinol stents into the middle third of the trachea in 25 New Zealand rabbits. After a mean observation period of 26 days, we evaluated stent migration, degree of expansion, attachment, adherence, formation of granulation tissue, presence of inflammatory infiltrate, parietal involvement, and epithelial lining. The results showed complete radial expansion, little adherence to the tracheal mucosa, and low tissue attachment, as well as high rates of granuloma formation and stent migration. This new model proved to be biocompatible and showed a behavior similar to that of other stents on the market.

Keywords: Prosthesis implantation; Tracheal stenosis; Rabbits; Stents.

Objective: To compare the effects that prone and supine positioning during high-frequency oscillatory ventilation (HFOV) have on oxygenation and lung inflammation, histological injury, and oxidative stress in a rabbit model of acute lung injury (ALI). Methods: Thirty male Norfolk white rabbits were induced to ALI by tracheal saline lavage (30 mL/kg, 38°C). The injury was induced during conventional mechanical ventilation, and ALI was considered confirmed when a PaO2/FiO2 ratio < 100 mmHg was reached. Rabbits were randomly divided into two groups: HFOV in the supine position (SP group, n = 15); and HFOV with prone positioning (PP group, n = 15). For HFOV, the mean airway pressure was initially set at 16 cmH2O. At 30, 60, and 90 min after the start of the HFOV protocol, the mean airway pressure was reduced to 14, 12, and 10 cmH2O, respectively. At 120 min, the animals were returned to or remained in the supine position for an extra 30 min. We evaluated oxygenation indices and histological lung injury scores, as well as TNF-α levels in BAL fluid and lung tissue. Results: After ALI induction, all of the animals showed significant hypoxemia, decreased respiratory system compliance, decreased oxygenation, and increased mean airway pressure in comparison with the baseline values. There were no statistically significant differences between the two groups, at any of the time points evaluated, in terms of the PaO2 or oxygenation index. However, TNF-α levels in BAL fluid were significantly lower in the PP group than in the SP group, as were histological lung injury scores. Conclusions: Prone positioning appears to attenuate inflammatory and histological lung injury during HFOV in rabbits with ALI.

Keywords: Respiration, artificial/adverse effects; Prone position; Lung/physiopathology; Pneumonia; Respiratory distress syndrome, adult; Acute lung injury; Disease models, animal; Rabbits.

Objective: To analyze psychological morbidity as a moderator of the relationship between smoking representations and quality of life in smokers and former smokers, as well as to determine which psychological variables discriminate between smokers with and without the intention to quit smoking. Methods: This was a quantitative, correlational cross-sectional study involving a convenience sample of 224 smokers and 169 former smokers. Results: In smokers and former smokers, psychological morbidity had a moderating effect on the relationship between mental/physical quality of life and smoking representations (cognitive representations, emotional representations, and comprehensibility). Smokers with the intention to quit smoking more often presented with low comprehensibility, threatening emotional representations, behavioral beliefs, and perceived behavioral control, as well as with normative/control beliefs, than did those without the intention to quit. Conclusions: The results of this study underscore the importance of the moderating effect exerted by psychological morbidity, as well as that of sociocognitive variables, among smokers who have the intention to quit smoking.

We compared the nitrate reductase assay with the proportion method, which is considered the gold standard, in 57 Mycobacterium tuberculosis strains isolated from patients treated at the Federal University of Minas Gerais Hospital das Clínicas, located in the city of Belo Horizonte, Brazil. For rifampin and isoniazid, the sensitivity, specificity, and accuracy of the nitrate reductase assay were all 100%, whereas they were 100%, 88.9%, and 66.7%, respectively, for streptomycin and 98.0%, 100%, and 98.2%, respectively, for ethambutol. The mean time to results was ten days. In the study sample, the nitrate reductase assay proved highly accurate and showed excellent concordance with the gold standard.

Keywords: Mycobacterium tuberculosis; Microbial sensitivity tests; Tuberculosis, multidrug-resistant; Nitrate reductase.

Pleural empyema carries high morbidity and mortality rates. Therapy focuses on the control of the infectious process in its initial phase when parenteral antibiotics and chest drainage are likely to be most effective. The ability of dextrans in preventing peritoneal adhesions leads one to test their potential effectiveness in reducing fibrinous proliferation in a rat model of pleural empyema. Twenty-four Wistar rats weighing 250-400 grams were anesthetized, submitted to a right thoracotomy and then randomized into 3 groups (n = 8 each). Animals in group I were given intrapleural dextran 40 (1 ml/kg) + 1 ml/kg of Staphylococcus aureus extract (1010 cells/ml) in heart-brain culture media obtained from oropharyngeal swabs of the animals. Animals in group II received saline solution (1 ml/kg) +1 ml/kg of Staphylococcus aureus extract (1010 cells/ml) in heart-brain culture media. Animals in group III (controls) were given the culture media without bacteria (1 ml/kg) in addition to saline (1 ml/kg). Upon completion, the chest was deaired, the thoracotomy wound was closed, the animals recovered, observed for 4 days, and sacrificed. Only the animals in groups I and II developed pleural effusion and empyema (average volume of 9.7 ml and 8.1 ml respectively, p > 0.05, NS). There was a significant weight loss in groups I and II compared to control animals (p = 0.004). There were no significant differences in blood work-up tests between groups. The pleural fluid of all animals in groups I and II had positive cultures for Staphylococcus aureus. The biochemical analysis of the pleural fluid in animals from groups I and II did not show any significant differences. The authors concluded that in this novel and reliable model of pleural empyema in rats, the intrapleural administration of dextran 40 at time of inoculation of bacteria did not result in any measurable reduction of the pleural reaction after 96 hours of observation.

Keywords: Empyema. Pleura. Rat. Dextrans. Staphylococcus.

Abstract Objective: To evaluate whether respiratory therapy techniques influence the number of cells within and quantity of induced sputum in patients with asthma or chronic obstructive pulmonary disease (COPD). Methods: Randomized clinical trial, in which patients with asthma or COPD under intervention (n = 16 and 10, respectively) were compared with control groups (n = 16 and 10). Patients in the asthma/intervention (A/I) and COPD/intervention (C/I) groups were submitted to oscillating positive expiratory pressure maneuvers for 5 min, followed by 10 forced expiratory technique sequences. These patients were also submitted to an induced sputum protocol with inhaled hypertonic saline (3%, 4% or 5%; A/I group) or inhaled isotonic saline (C/I group). The asthma/control (A/C) and COPD/control (C/C) groups were submitted only to the standard induced sputum protocol. Results: The final mean weight of the sputum samples was significantly greater in the A/I group than in the A/C group (2,767.25 ± 998.08 mg vs. 1,689.17 ± 1,189.96 mg; p = 0.03). The mean/median total cell counts (×106/mL) were higher in the A/I and C/I groups than in the A/C and C/C groups (4.06/0.95 and 0.63/0.39, p = 0.05, vs. 5.08/1.77 and 0.64/0.40, p = 0.02). There were no statistically significant differences among the groups in terms of cell viability. Conclusions: The use of respiratory therapy techniques can increase sputum sample weight in asthma patients, as well as increasing total cell counts in patients with asthma or COPD.

Keywords: Asthma; Pulmonary disease, obstructive chronic; Sputum; Physical therapy modalities.

Objective: To establish reference values for cellularity in induced sputum samples collected from healthy adults. Methods: Induced sputum samples were obtained from 88 healthy adult never-smokers (39 males). The mean age was 36 years (range, 18-68 years). The participants had been residing in the city of Florianópolis, Brazil (a medium-sized non-industrial city) for at least two years. After the samples had been processed, we obtained total and differential cell counts. Results: The mean total cell count was 4.8 ± 4.2 × 106 cells/g. There was a predominance of macrophages (mean, 77.5 ± 14.7%) and neutrophils (mean, 23.4 ± 14.3%). Eosinophils were virtually absent (mean, 0.1 ± 0.3%). Lymphocytes and bronchial epithelial cells were scarce. Neither age nor atopy had any effect on the total or differential cell counts. Conclusions: In the induced sputum of this healthy adult population, macrophages and neutrophils predominated. However, the proportion of neutrophils was lower than that reported in previous studies, which suggests that reference values might vary depending on geographic location.

Keywords: Sputum; Reference values; Brazil.