Objective: To create a mechanical model that could be regulated to simulate the conditioning of inspired and expired air with the same normal values of temperature, pressure, and relative humidity as those of the respiratory system of a healthy young man on mechanical ventilation. Methods: Using several types of materials, a mechanical device was built and regulated using normal values of vital capacity, tidal volume, maximal inspiratory pressure, positive end-expiratory pressure, and gas temperature in the system. The device was submitted to mechanical ventilation for a period of 29.8 min. The changes in the temperature of the air circulating in the system were recorded every two seconds. Results: The statistical analysis of the data collected revealed that the device was approximately as efficient in the conditioning of air as is the respiratory system of a human being. Conclusion: By the study endpoint, we had developed a mechanical device capable of simulating the conditioning of air in the respiratory tract. The device mimics the conditions of temperature, pressure, and relative humidity seen in the respiratory system of healthy individuals.

Keywords: Thermodynamics; Respiration, artificial; Temperature.

Objective: The aim of this study was to detect late sequelae of foreign body aspiration in the respiratory tract of children. Methods: This study included children admitted from 1987 to 1999 to Hospital da Criança Santo Antônio, of Porto Alegre, with clinical symptoms of foreign body aspiration to the respiratory tract confirmed by chest X-ray and bronchoscopy. Thirty days after the extraction of the foreign body a perfusion lung scan with technetium was performed. Results: 77% of the foreign bodies were organic materials. In 65% of children the aspiration event occurred at least 7 days before referral. The main location of foreign body was in the right lower lobe bronchus. Perfusion lung scans were performed in 24 patients. In 67% of them reduction in lung perfusion was detected. A chance of sequelae was 3.8 times greater in those patients who had the foreign body removed after 7 days from the aspiration event. Conclusion: This study showed that children that have had foreign body aspiration may have perfusion sequelae in their lungs even after removal of the foreign body. These sequelae were more frequent if the removal was delayed in 7 days of aspiration. Pediatricians must keep this in mind at the follow-up of children that have had foreign body aspiration.

Keywords: foreign bodies; aspiration; bronchi; prognosis

Objective: To evaluate the incidence of viral infection in patients with acute asthma treated in the emergency room. Methods: We conducted a cohort study of patients aged 12 and older presenting to the emergency room of the Hospital de Clínicas de Porto Alegre with acute asthma. Nasopharyngeal aspirate was collected, and antigens were detected through indirect immunofluorescence staining for respiratory syncytial virus, adenovirus and influenza, as well as for parainfluenza types 1, 2, 3 and 4. Data were collected regarding demographic characteristics, medical history, the attack that led to the current emergency room visit, and clinical outcomes. Results: From March to July of 2004, 49 patients were examined for viral infection of the respiratory tract. Respiratory viruses were identified in 6 patients (3 with adenovirus, 2 with influenza A, 1 with parainfluenza type 1). The mean age of the patients with viral infection of the respiratory tract was 61.7 ± 11.5 years, compared with 41.7 ± 20.9 years for the patients without such infection (p = 0.027). There were no other significant differences in clinical characteristics or outcomes. Conclusion: The incidence of viral infection of the respiratory tract in acute asthma patients 12 years and older treated in an emergency room was 12.2%, which confirms that viral infection is a significant precipitant of acute asthma for patients in this age bracket.

Keywords: Emergency Service, Hospital; Vírus diseases/prevention & control; Asthma; Respiratory tract infections; Influenza A virus, human

Objective: To determine whether the concentrations of inflammatory mediators (CCL5, soluble intercellular adhesion molecule type 1 [sICAM-1], TNF-α, IL-6 and IL-10) in the nasopharyngeal secretion and in the serum of children with lower respiratory tract infection (LRTI) caused by respiratory syncytial virus (RSV) correlate with the clinical markers of disease severity. Methods: Between July of 2004 and December of 2005, 30 children less than three months of age, diagnosed with LRTI caused by RSV and admitted to a neonatal ICU, were included in this study. Results: The severity of disease at hospital admission, as determined with a modified clinical scoring system, presented a significant positive correlation with sICAM-1 and IL-10 concentrations in the nasopharyngeal secretion, as well as with IL-6 concentrations in the serum, of the patients. In addition, serum IL-6 concentrations presented a significant positive correlation with the duration of oxygen therapy and with the length of hospital stay. Conclusions: At hospital admission, the concentrations of sICAM-1 and IL-10 in the nasopharyngeal secretion, as well as the concentration of IL-6 in the serum, could be used as markers of severity in patients with LRTI caused by RSV. The serum levels of IL-6 determined at admission could also be used to predict prolonged oxygen supplementation and hospital stay.

Keywords: Respiratory syncytial virus, human; Chemokine CCL5; Intercellular adhesion molecule-1; Interleukin-6; Interleukin-10; Tumor necrosis factor-alpha.

Background: Antimicrobial treatment of community-acquired respiratory tract infections (CARTI) is usually empiric and antibiotics are chosen on the basis of surveillance studies. The SENTRY Program was designed to monitor antimicrobial resistance via a worldwide surveillance network of sentinel laboratories. Three sites in Brazil participated in the 1997 and 1998 SENTRY Program. Methods: A total of 344 bacterial isolates, collected from patients with CARTI in 1997 and 1998, were tested against more than 20 antimicrobial agents by the broth microdilution method. Results: Among S. pneumoniae (176 isolates), 71.6% were susceptible to penicillin. High level resistance to penicillin and resistance to cefotaxime was found in 2.3 and 4.0%, respectively. The newer quinolones, levofloxacin, (MIC90 of 2 mg/mL) and gatifloxacin (MIC90 of 0.5 mg/mL) were active against 100% of the isolates tested. Among the other non-b-lactam drugs tested, the rank order of pneumococci activity was (% susceptible): chloramphenicol (97.5%) > clindamycin (94.0%) > azithromycin (90.3%) > clarithromycin (89.4%) > tetracycline (76.4%) > trimethoprim/sulfamethoxazole (60.2%). The percentage of Haemophilus influenzae (101 isolates) susceptible to amoxicillin was 90.1%, whereas among Moraxella catarrhalis (67 isolates) only 9.0% were susceptible. Clavulanic acid restored the activity of amoxicillin against both H. influenzae and M. catarrhalis. However, H. influenzae showed increased levels of resistance to trimethoprim/sulfametoxazole (55.1% susceptibility), clarithromycin (80.4% susceptibility), and cefaclor (88.2%) susceptibility). All H. influenzae and M. catarrhalis isolates were susceptible to levofloxacin (MIC90, < 0.5 mg/mL for both) and gatifloxacin (MIC90, < 0.06 mg/mL for both) with very low MICs. Conclusion: Results indicate that the rate of S. pneumoniae showing high-level penicillin resistance is still low in Brazil. However, intermediate resistance to penicillin associated with resistance to other classes of antimicrobial agents was relatively high. On the other hand, the new quinolones were highly active against 100% of the respiratory pathogens tested.

Keywords: Respiratory tract infections. Bacterial pneumonia. Microbial drug resistance. Program evaluation. Microbial sensibility tests.

Over the past 250 years-since the Industrial Revolution accelerated the process of pollutant emission, which, until then, had been limited to the domestic use of fuels (mineral and vegetal) and intermittent volcanic emissions-air pollution has been present in various scenarios. Today, approximately 50% of the people in the world live in cities and urban areas and are exposed to progressively higher levels of air pollutants. This is a non-systematic review on the different types and sources of air pollutants, as well as on the respiratory effects attributed to exposure to such contaminants. Aggravation of the symptoms of disease, together with increases in the demand for emergency treatment, the number of hospitalizations, and the number of deaths, can be attributed to particulate and gaseous pollutants, emitted by various sources. Chronic exposure to air pollutants not only causes decompensation of pre-existing diseases but also increases the number of new cases of asthma, COPD, and lung cancer, even in rural areas. Air pollutants now rival tobacco smoke as the leading risk factor for these diseases. We hope that we can impress upon pulmonologists and clinicians the relevance of investigating exposure to air pollutants and of recognizing this as a risk factor that should be taken into account in the adoption of best practices for the control of the acute decompensation of respiratory diseases and for maintenance treatment between exacerbations.

Keywords: Respiratory System; Air pollution; Pregnancy; Pulmonary disease, chronic obstructive; Asthma; Respiratory tract Infections.

Objective: To test the applicability of a geometric model, adapted to the supine position, for the analysis of respiratory mechanics regarding changes in lateral thoracoabdominal areas in children with asthma. Methods: Nineteen children (mean age, 11.26 ± 1.28 years) performed isovolume maneuvers (IVMs) after maximal inspiration, followed by glottal closure and alternation of airflow between the abdominal and thoracic compartments. The maneuvers were recorded in a digital video camera placed perpendicularly to the movement plane, and the images of interest were selected. The geometric model was traced on each image based on surface landmarks of anatomical references. The traced areas were calculated using a computer program, and the results were converted into metric units (cm2) using a surface landmark of a known area. Relative contributions (RCs) of the subcompartments in relation to their original compartments and to the chest wall (CW) were calculated. Results: The model was based on 55 thoracic IVM images and 55 abdominal IVM images. Areas and subareas were compared between the maneuvers. There were significant differences in all subcompartments (p < 0.001). All of the RCs were significantly different for the CW (p < 0.001) but not for the ratios between the subcompartments and their original compartments. Conclusions: This geometric model, applied in children and adapted to the supine position, was effective in profiling changes in the thoracoabdominal silhouette during the IVMs, and the selected subdivisions were useful for the identification of areas contributing the most and the least to CW composition.

Keywords: Photogrammetry; Respiratory mechanics; Image processing, computer-assisted.

Objective: To identify factors associated with the minimal clinically important difference (MCID) for health-related quality of life (HRQoL) after physical conditioning in patients with COPD. Methods: Thirty-five patients were submitted to a 12-week program of physical conditioning (strength training plus low-intensity aerobic exercise). Body composition, incremental treadmill test results, endurance treadmill test results, six-minute walk test results, peripheral muscle strength, MIP, baseline dyspnea index (BDI) and Saint George's Respiratory Questionnaire (SGRQ) scores were assessed at baseline and after the program, thus allowing the variations (Δ) to be calculated. The MCID for HRQoL was defined as a reduction of ≥ 4% in the SGRQ total score. Subjects who responded to the program, achieving the MCID for HRQoL, were allocated to the responders (R) group (n = 24), and the remainder were allocated to the non-responders (NR) group (n = 11). Results: The values obtained for the following variables were significantly higher in group R than in group NR (p < 0.05): FEV1 (1.48 ± 0.54 L vs. 1.04 ± 0.34 L); VEF1/FVC (47.9 ± 11.7% vs. 35.5 ± 10.7%); PaO2 (74.1 ± 9.7 mmHg vs. 65.0 ± 8.9 mmHg); and ΔBDI, expressed as median and interquartile range (2.0 [0.0-3.5] vs. 0.0 [0.0-1.0]). The ΔBDI correlated significantly with the ΔSGRQ symptoms domain score, activity domain score and total score (r = 0.44, 0.60 and 0.62, respectively, p < 0.01 for all). After logistic regression, only ΔBDI remained as a predictor of MCID for HRQoL. Conclusions: Achieving the MCID for HRQoL after physical conditioning is associated with dyspnea reduction in COPD patients. Therefore, there is a need to develop treatment strategies designed to interrupt the dyspnea-inactivity-dyspnea cycle in such patients.

Keywords: Pulmonary disease, chronic obstructive; Quality of life; Dyspnea; Exercise; Rehabilitation.

Objective: This study aimed to investigate acute and chronic effects of varenicline on lung tissue in an experimental study. Methods: A total of 34 rats were randomly allocated into study (varenicline) and control groups. The rats were divided into two groups (i) control group, (ii) varenicline group. Then, the rats in the each group were sub‑divided equally in turn as acute (C1; V1) and chronic (C2; V2) ; all rats of acute and chronic groups were sacrificed under the anesthesia on the 45th day for acute group [C1 (n=5) and V1 (n=12)] and the 90th day for chronic group [C2 (n=5) and V2 (n=12)], respectively. Thus, biochemical and histopathological analysis were carried out. Results: Thirty four rats completed the study, 24 were in varenicline group and 10 were in control group. In chronic exposure to varenicline, oxidant levels comprising of malondialdehyde (MDA), and myeloperoxidase (MPO) increased and superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and glutathione peroxidase (GPx) levels, named as antioxidants, decreased significantly when compared to the control group. MDA and MPO levels were also significantly higher and SOD, CAT, GPx, GSH levels were also significantly lower in chronic varenicline group when compared to acute varenicline group. These findings were also supported by histopathological observations. Conclusion: This is the first study, which evaluated pulmonary effects of varenicline experimentally on an animal model. It was observed that chronic varenicline treatments cause inflammation and lung cell injury.

Keywords: Varenicline; Lung tissue; Oxidative stress; Pulmonary toxicity.

Objective: To determine the prevalence, outcomes, and predictors of multidrug-resistant nosocomial lower respiratory tract infections (LRTI) in patients in an ICU. Methods: This was an observational cohort study involving patients with nosocomial LRTI (health care-associated pneumonia, hospital-acquired pneumonia, or ventilator-associated pneumonia). Data were prospectively collected between 2015 and 2019. The multidrug-resistant pathogens (MDRPs) identified in the isolates studied included resistant to extended-spectrum cephalosporin-resistant and carbapenem-resistant Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa, carbapenem-resistant Enterobacteriaceae, and methicillin-resistant Staphylococcus aureus at microbiological diagnosis. Results: During the study period, 267 patients in the ICU were diagnosed with LRTI, microbiological confirmation of LRTI having been obtained in 237. Of these, 146 (62%) had at least one MDRP isolate. Patients infected with MDRP were found to have poorer outcomes than patients infected with susceptible strains, such as prolonged mechanical ventilation (18.0 days vs. 12.0 days; p < 0.001), prolonged ICU length of stay (23.0 days vs.16.0 days; p < 0.001), and higher mortality (73% vs. 53%; p < 0.001) when compared with patients infected with susceptible strains. Hospital length of stay = 5 days (OR = 3.20; 95% CI: 1.39-7.39; p = 0.005) and prolonged use vasoactive drugs (OR = 3.15; 95% CI: 1.42-7.01; p = 0.004) were independent predictors of LRTI caused by MDRPs (LRTI-MDRP). The presence of LRTI-MDRP was found to be an independent predictor of death (OR = 2.311; 95% CI: 1.091-4.894; p = 0.028). Conclusions: Prolonged use of vasoactive drugs and prolonged hospital length of stay were independent predictors of LRTI-MDRP in this population of critically ill patients with very poor outcomes.

Keywords: Drug resistance, multiple; Healthcare-associated pneumonia; Pneumonia, ventilator-associated; Cross infection; Intensive care units.

Objective: To evaluate the association between the risk of death from COPD and air temperature events in ten major Brazilian microregions. Methods: This was a time series analysis of daily COPD deaths and daily mean air temperatures between 1996 and 2017. Using distributed nonlinear lag models, we estimated the cumulative relative risks of COPD mortality for four temperature percentiles (representing moderate and extreme cold and heat events) in relation to a minimum mortality temperature, with a lag of 21 days, in each microregion. Results: Significant associations were found between extreme air temperature events and the risk of death from COPD in the southern and southeastern microregions in Brazil. There was an association of extreme cold and an increased mortality risk in the following microregions: 36% (95% CI, 1.12-1.65), in Porto Alegre; 27% (95% CI, 1.03-1.58), in Curitiba; and 34% (95% CI, 1.19-1.52), in São Paulo; whereas moderate cold was associated with an increased risk of 20% (95% CI, 1.01-1.41), 33% (95% CI, 1.09-1.62), and 24% (95% CI, 1.12-1.38) in the same microregions, respectively. There was an increased COPD mortality risk in the São Paulo and Rio de Janeiro microregions: 17% (95% CI, 1.05-1.31) and 12% (95% CI, 1,02-1,23), respectively, due to moderate heat, and 23% (95% CI, 1,09-1,38) and 32% (95% CI, 1,15-1,50) due to extreme heat. Conclusions: Non-optimal air temperature events were associated with an increased risk of death from COPD in tropical and subtropical areas of Brazil.

Keywords: Pulmonary disease, chronic obstructive/mortality; Temperature; Climate.

Objective: To determine whether a short-term protocol using subcutaneous sensitization with ovalbumin, without the use of adjuvants, would induce an eosinophilic response in the lungs of mice similar to that observed in previous, well-established protocols. Methods: Adult female BALB/c mice were randomized and divided into groups according to the number of sensitizations with ovalbumin and the number/dosage of intranasal ovalbumin challenges. The short-term protocol (10 days) consisted of one sensitization with ovalbumin and three ovalbumin challenges (100 µg). Total and differential cell counts in BAL fluid, levels of eosinophil peroxidase in lung tissue, and histopathological examination of the lungs were performed 24 h after the last ovalbumin challenge. Results: No significant differences were found among the groups regarding the variables studied. The short-term protocol, as well as the other protocols studied, induced an eosinophilic response similar to that obtained in the positive control. Conclusions: Subcutaneous sensitization with ovalbumin and without the use of adjuvants resulted in a significant allergic response in the lungs of mice, even in the short-term protocol group. Our findings suggest that this short-term protocol can be used as a first-line pre-clinical test for the study of new medications, reducing the costs and observation periods.

Keywords: Ovalbumin; Mice; Asthma.

We assessed the effects of lodenafil on hemodynamics and inflammation in the rat model of monocrotaline-induced pulmonary hypertension (PH). Thirty male Sprague-Dawley rats were randomly divided into three groups: control; monocrotaline (experimental model); and lodenafil (experimental model followed by lodenafil treatment, p.o., 5 mg/kg daily for 28 days) Mean pulmonary artery pressure (mPAP) was obtained by right heart catheterization. We investigated right ventricular hypertrophy (RVH) and IL-1 levels in lung fragments. The number of cases of RVH was significantly higher in the monocrotaline group than in the lodenafil and control groups, as were mPAP and IL-1 levels. We conclude that lodenafil can prevent monocrotaline-induced PH, RVH, and inflammation.

Keywords: Hypertension, pulmonary; Monocrotaline; Interleukin-1.

Objective: To establish the accuracy of frozen section examination in identifying tumor spread through air spaces (STAS), as well as to propose a reproducible technical methodology for frozen section analysis. We also aim to propose a method to be incorporated into the decision making about the need for conversion to lobectomy during sublobar resection. Methods: This was a nonrandomized prospective study of 38 patients with lung cancer who underwent surgical resection. The findings regarding STAS in the frozen section were compared with the definitive histopathological study of paraffin-embedded sections. We calculated a confusion matrix to obtain the positive predictive value (PPV), negative predictive value (NPV), sensitivity, specificity and accuracy. Results: The intraoperative frozen section analysis identified 7 STAS-positive cases that were also positive in the histopathological examination, as well as 3 STAS-negative cases that were positive in the in the histopathological examination. Therefore, frozen section analysis was determined to have a sensitivity of 70%, specificity of 100%, PPV of 100%, NPV of 90.3%, and accuracy of 92% for identifying STAS. Conclusions: Frozen section analysis is capable of identifying STAS during resection in patients with lung cancer. The PPV, NPV, sensitivity, and specificity showed that the technique proposed could be incorporated at other centers and would allow advances directly linked to prognosis. In addition, given the high accuracy of the technique, it could inform intraoperative decisions regarding sublobar versus lobar resection.

Keywords: Neoplasm invasiveness; Frozen sections; Lung neoplasms/pathology; Lung neoplasms/surgery.

Background: The search for an ideal procedure to accomplish aerostasis, after partial surgical resection of the lung parenchyma, remains a practical challenge for the thoracic surgeon. Objective: The objective of this study was to compare the ability of four types of parenchymal pulmonary sutures in preventing air leaks, using a porcine model with incremental endobronchial pressures. Method: Ex vivo experimental study in porcine lungs (n = 5) at the Laboratory of Experimental Surgery of the Universidade de Caxias do Sul. Four different parenchymal pulmonary types of suture were analyzed: type 1 (absorbable suture), type 2: (stapled suture), type 3 (stapled suture with bovine pericardium) and type 4 (stapled suture with biologic glue). The surgical sutures (n = 40) were exposed to different intrabronchial pressure levels, varying from 10 cmH2O to 60 cmH2O. The presence of air leaks along the suture line was verified through the water seal maneuver. Results: The mean intrabronchial pressure level needed to cause suture line air leaks for each type were: type 1 (n = 10): 29 cmH2O; type 2 (n = 10): 38.5 cmH2O; type 3 (n = 10): 44 cmH2O; and type 4 (n = 10): 51.4 cmH2O. The comparison between the mean intrabronchial pressure level of type 1 and of types 2 and 3 sutures was statistically significant, respectively: p = 0.04 and p = 0.01. However, the comparison between types 2, 3 and 4 did not show statistic significance (p > 0.05). Conclusions: The pulmonary suture covered by biologic glue demonstrated more resistance to incremental levels of intrabronchial pressure. Parenchymal pulmonary sutures using stapled suture exclusively or stapled with bovine pericardium or biologic glue demonstrated an increased ability to avoid air leaks if compared to absorbable sutures in a model of porcine lung with incremental levels of intrabronchial pressure. There were no differences between stapler exclusively or stapler and bovine pericardium or biologic glue.

Keywords: Experimental study. Thoracic surgery. Biologic glue. Staplers.

This article reviews Act 3,523 of the Brazilian Ministry of Health which regulates the indoor air quality of air-conditioned environments, focusing mainly on biological standards for contaminant particles. Additionally, a concise analysis on nosocomial air-borne infections is performed, as well as on nosocomial units where air-borne infectious diseases may be important and a special ventilation system is required. Detailed analysis of the most common biological contaminant particles, differences between countries of both Northern and Southern hemispheres, and the aspects of the methodology used to perform their analysis are considered. The authors conclude that there are no established standards for safe levels of air-borne organisms, and that there is no available data in Brazil to set up standards for biological contaminant particles

Keywords: Air pollutants. Air conditioning. Air quality standards. Indoor air pollution. Brazil.