Objective: To study the effects that pneumoperitoneum achieved through carbon dioxide insufflation has on diaphragmatic excursion in pigs. Methods: A total of 14 male Landrace pigs, 30 to 45 days of age and weighing five to seven kilograms each, were used. The sample was randomly and equally divided into two groups: one (n = 7) in which pneumoperitoneum was maintained at 10 mmHg for 60 minutes; and another (n = 7) in which pneumoperitoneum was maintained at 15 mmHg (also for 60 minutes). After anesthetic induction, the animals were intubated. Flow volume was monitored, and the amplitude of diaphragmatic excursion was analyzed using noninvasive ultrasound imaging of the right hemidiaphragm. Results: In both groups, restricted diaphragmatic excursion was observed only during the procedure. There was no statistical difference between the two pressure levels studied. Conclusion: The amplitude of diaphragmatic excursion was restricted during abdominal insufflation, independent of the pressure level (within the 10-15 mmHg range), during the study period.

Keywords: Pneumoperitoneum/chemically induced; Carbon dioxide; Diaphragm; Video-assisted surgery; Swine

Objective: To evaluate the effects of passive inhalation of cigarette smoke on the respiratory system of guinea pigs. Methods: Male guinea pigs were divided into two groups: control and passive smoking, the latter being exposed to the smoke of ten cigarettes for 20 min in the morning, afternoon and evening (30 cigarettes/day) for five days. After that period, inflammatory parameters were studied by quantifying mesenteric mast cell degranulation, as well as oxidative stress, in BAL fluid. In addition, we determined MIP, MEP, and mucociliary transport (in vivo), as well as tracheal contractility response (in vitro). Results: In comparison with the control group, the passive smoking group showed a significant increase in mast cell degranulation (19.75 ± 3.77% vs. 42.53 ± 0.42%; p < 0.001) and in the levels of reduced glutathione (293.9 ± 19.21 vs. 723.7 ± 67.43 nM/g of tissue; p < 0.05); as well as a significant reduction in mucociliary clearance (p < 0.05), which caused significant changes in pulmonary function (in MIP and MEP; p < 0.05 for both) and airway hyperreactivity. Conclusions: Passive inhalation of cigarette smoke caused significant increases in mast cell degranulation and oxidative stress. This inflammatory process seems to influence the decrease in mucociliary transport and to cause changes in pulmonary function, leading to tracheal hyperreactivity.

Keywords: Inflammation; Inhalation exposure; Tobacco smoke pollution.

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 evaluate the effects that early and late systemic administration of methylprednisolone have on lungs in a rat model of brain death. Methods: Twenty-four male Wistar rats were anesthetized and randomly divided into four groups (n = 6 per group): sham-operated (sham); brain death only (BD); brain death plus methylprednisolone (30 mg/kg i.v.) after 5 min (MP5); and brain death plus methylprednisolone (30 mg/kg i.v.) after 60 min (MP60). In the BD, MP5, and MP60 group rats, we induced brain death by inflating a balloon catheter in the extradural space. All of the animals were observed and ventilated for 120 min. We determined hemodynamic and arterial blood gas variables; wet/dry weight ratio; histological score; levels of thiobarbituric acid reactive substances (TBARS); superoxide dismutase (SOD) activity; and catalase activity. In BAL fluid, we determined differential white cell counts, total protein, and lactate dehydrogenase levels. Myeloperoxidase activity, lipid peroxidation, and TNF-α levels were assessed in lung tissue. Results: No significant differences were found among the groups in terms of hemodynamics, arterial blood gases, wet/dry weight ratio, BAL fluid analysis, or histological score-nor in terms of SOD, myeloperoxidase, and catalase activity. The levels of TBARS were significantly higher in the MP5 and MP60 groups than in the sham and BD groups (p < 0.001). The levels of TNF-α were significantly lower in the MP5 and MP60 groups than in the BD group (p < 0.001). Conclusions:áIn this model of brain death, the early and late administration of methylprednisolone had similar effects on inflammatory activity and lipid peroxidation in lung tissue.

Objective: To evaluate the pulmonary alterations of animals with Hepatopulmonary Syndrome (HPS) submitted to Biliary Duct Ligature (BDL), as well as the antioxidant effect of Melatonin (MEL). Methods: Sixteen male Wistar rats, divided into four Sham groups: BDL group, Sham + MEL group and BDL + MEL. The pulmonary and hepatic histology, lipoperoxidation and antioxidant activity of lung tissue, alveolar-arterial O2 difference and lung / body weight ratio (%) were evaluated. Results: When comparing the groups, could be observed an increase of vasodilation and pulmonary fibrosis in the BDL group and the reduction of this in relation to the BDL + MEL group. It was also observed significant changes in the activity of catalase, ApCO2, ApO2 in the LBD group when compared to the other groups. Conclusion: The use of MEL has been shown to be effective in reducing vasodilation, fibrosis levels and oxidative stress as well as gas exchange in an experimental HPS model.

Keywords: Bile duct; Hepatopulmonary Syndrome; Melatonin; Lung.

Objective: To investigate the effects of maternal protein malnutrition during lactation on the elastic fibers in the tracheas of Wistar rat pups. Methods: At delivery, 12 male pups of two Wistar rat dams were equally divided into two groups: control, in which the dam received water and standard rat chow ad libitum during lactation; and protein-restricted (PR), in which the dam received water ad libitum and an isoenergetic PR diet (8% protein). At 21 days of age, the pups were killed and their tracheas were excised. The elastic fibers were stained with Weigert's resorcin-fuchsin (after oxidation) and evaluated under light microscopy. Morphometric determinations were performed by stereology, with the point-counting method, and expressed as volumetric densities. Results: Elastic fibers, most having a longitudinal distribution, were identified beneath the tracheal mucosa. In addition, well-defined circular layers of elastic fibers were found around the inner and outer surfaces of the cartilaginous ring. There were no differences between the groups regarding the organization and distribution of the elastic fibers. The volumetric density of the elastic fibers of the pups in the control and PR groups was 2.46 ± 0.99% and 3.25 ± 1.13%, respectively (p < 0.01). Conclusions: The volumetric density of elastic fibers appears to be greater in rat pups breastfed by dams receiving a PR diet than in those breastfed by dams receiving a normal diet.

Keywords: Trachea/growth and development; Trachea/anatomy and histology; Extracellular matrix; Airway remodeling; Malnutrition.

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 evaluate the electromyographic activity (EA) of sternocleidomastoid (SCM) and scalene muscles during and after the use of expiratory positive airway pressure (EPAP) in patients with COPD. Methods: This was a clinical single-blind trial involving 13 healthy subjects as controls and 12 patients with stable COPD. At baseline, we determined EA during spontaneous respiration, lung function parameters, and respiratory muscle strength. Subsequently, EPAP at 15 cmH2O was applied by means of a face mask for 25 min, during which the EA of the SCM and scalene muscles was recorded every 5 min. A final record was obtained 10 min after the mask removal. Results: We found that the behavior of the EA of SCM and scalene muscles was comparable between the controls and the COPD patients (p = 0.716 and p = 0.789, respectively). However, during the use of EPAP, both muscles showed a trend toward an increase in the EA. In addition, there was a significant decrease in the EA of the SCM between the baseline and final measurements (p = 0.034). Conclusions: The use of EPAP promoted a significant reduction in the EA of the SCM in the controls and in the patients with stable COPD. However, this did not occur regarding the EA of the scalene muscle.

Keywords: Electromyography; Respiratory muscles; Pulmonary disease, chronic obstructive; Positive-pressure respiration.

Objective: Silicosis is a pneumoconiosis characterized by fibrosis of the lung parenchyma caused by inhalation of silica particles. Genetic factors might play a role in the severity silicosis. We sought to evaluate the influence of polymorphisms in the ACE, FAS, FASLG, NOS2, IL1RN, FAM13A, TGFB1, and TNF genes on the severity of silicosis. Methods: Nine polymorphisms were genotyped by PCR in a sample of 143 patients with silicosis in the state of Rio de Janeiro, Brazil. Results: Fifty-seven patients (40%) were classified as having simple silicosis and 86 (60%) were classified as having complicated silicosis. The TT genotype of rs1800469 in the TGFB1 gene showed a protective effect for complicated silicosis (OR = 0.35; 95% CI, 0.14-0.92; p = 0.028) when compared with the other two genotypes (CC+CT). The polymorphic T allele of rs763110 in the FASLG gene (OR = 0.56; 95% CI, 0.31-0.99; p = 0.047), as well as a dominant model for the T allele (TT+CT: OR = 0.37; 95% CI, 0.15-0.96; p = 0.037), also showed a protective effect. When patients with simple silicosis despite having been exposed to silica for a longer time (> 44,229 hours) were compared with patients with complicated silicosis despite having been exposed to silica for a shorter time, the T allele of rs763110 in the FASLG gene (OR = 0.20; 95% CI, 0.08-0.48; p < 0.0001), as well as dominant and recessive models (OR = 0.06; 95% CI, 0.00-0.49; p = 0.01 and OR = 0.22; 95% CI, 0.06-0.77; p = 0.014, respectively), showed a protective effect against the severity of silicosis. Conclusions: It appears that rs1800469 polymorphisms in the TGFB1 gene and rs763110 polymorphisms in the FASLG gene are involved in the severity of silicosis. Given the lack of studies relating genetic polymorphisms to the severity of silicosis, these results should be replicated in other populations.

Keywords: Silicosis; Polymorphism, genetic; Genetic association studies; Cytokines.

Objective: To investigate the applicability of ultrasound imaging of the diaphragm in interstitial lung disease (ILD). Methods: Using ultrasound, we compared ILD patients and healthy volunteers (controls) in terms of diaphragmatic mobility during quiet and deep breathing; diaphragm thickness at functional residual capacity (FRC) and at total lung capacity (TLC); and the thickening fraction (TF, proportional diaphragm thickening from FRC to TLC). We also evaluated correlations between diaphragmatic dysfunction and lung function variables. Results: Between the ILD patients (n = 40) and the controls (n = 16), mean diaphragmatic mobility was comparable during quiet breathing, although it was significantly lower in the patients during deep breathing (4.5 ± 1.7 cm vs. 7.6 ± 1.4 cm; p < 0.01). The patients showed greater diaphragm thickness at FRC (p = 0.05), although, due to lower diaphragm thickness at TLC, they also showed a lower TF (p < 0.01). The FVC as a percentage of the predicted value (FVC%) correlated with diaphragmatic mobility (r = 0.73; p < 0.01), and an FVC% cut-off value of < 60% presented high sensitivity (92%) and specificity (81%) for indentifying decreased diaphragmatic mobility. Conclusions: Using ultrasound, we were able to show that diaphragmatic mobility and the TF were lower in ILD patients than in healthy controls, despite the greater diaphragm thickness at FRC in the former. Diaphragmatic mobility correlated with ILD functional severity, and an FVC% cut-off value of < 60% was found to be highly accurate for indentifying diaphragmatic dysfunction on ultrasound.

Keywords: Diaphragm/ultrasonography; Lung diseases, interstitial; Respiratory muscles; Respiratory function tests.

Objective: To study the effects of short-term exposure to high oxygen concentrations (hyperoxia) on Wistar rat lungs. Methods: Animals were divided into three groups exposed to hyperoxia for 10', 30' and 90' (O10', O30', O90', respectively), together with a control group (exposed to room air). The animals were sacrificed 24 h after exposure. Bronchoalveolar lavage was performed, and the lungs were removed for histological and stereological analysis. Results: In the O10', O30', and O90' groups, respectively and in comparison with the controls, we observed an increase in the numbers of macrophages (2169.9 ± 118.0, 1560.5 ± 107.0, and 1467.6 ± 39.0 vs. 781.3 ± 78.3) and neutrophils (396.3 ± 35.4, 338.4 ± 17.3, and 388.7 ± 11.7 vs. 61.6 ± 4.2), concomitant with an increase in oxidative damage (143.0 ± 7.8%, 180.4 ± 5.6%, and 235.0 ± 13.7% vs. 100.6 ± 1.7%). The histological and stereological analyses revealed normal alveoli and alveolar septa in the controls (83.51 ± 1.20% and 15 ± 1.21%), in the O10' group (81.32 ± 0.51% and 16.64 ± 0.70%), and in the O30' group (78.75 ± 0.54% and 17.73 ± 0.26%). However, in the O90' group, inflammatory cell infiltration was observed in the alveoli and alveolar septa. Red blood cells extravasated from capillaries to the alveoli (59.06 ± 1.22%), with evidence of congestion, hemorrhage, and septal edema (35.15 ± 0.69%). Conclusion: Hyperoxia for 90' caused injury of the lung parenchyma, resulting in oxidative damage and inflammatory cell infiltration.

Keywords: Hyperoxia; Lung/injuries; Oxidative stress.

Objective: To investigate the effects of airway obstruction on albuterol-mediated variations in the resistive and elastic properties of the respiratory system of adult patients with asthma. Methods: This study comprised 24 healthy controls and 69 patients with asthma, all of whom were nonsmokers. The patients were divided into three groups according to the severity of airway obstruction (mild, moderate or severe). Each of the three groups was divided into two subgroups according to the bronchodilator response (BR): positive (BR+) or negative (BR−). These measurements were conducted before and after albuterol use (300 µg). Airway obstruction was determined by means of spirometry, and the resistive and elastic properties were determined by means of the forced oscillation technique. Results: The resistance at the intercept (R0) presented greater reductions in the groups with higher obstruction. This reduction was more evident in the BR+ subgroups than in the BR− subgroups (p < 0.02 and p < 0.03, respectively). There was a significant difference between the control group and the BR+ subgroup with severe obstruction (p < 0.002). The reductions in dynamic elastance (Edyn) were significantly greater in proportion to the degree of obstruction, in the BR− subgroups (p < 0.03), and in the BR+ subgroups (p < 0.003). The reductions in Edyn were significantly greater in the BR− subgroup with moderate obstruction (p < 0.008) and in the BR+ subgroup with severe obstruction (p < 0.0005) than in the control group. Conclusions: In patients with asthma, increased airway obstruction results in greater reductions in R0 and Edyn after albuterol use. These reductions are greater among BR+ patients than among BR− patients.

Keywords: Asthma; Bronchodilator agents; Respiratory mechanics; Spirometry; Albuterol.

Objective: To investigate the effects of manual chest compression (MCC) on the expiratory flow bias during the positive end-expiratory pressure-zero end-expiratory pressure (PEEP-ZEEP) airway clearance maneuver applied in patients on mechanical ventilation. The flow bias, which influences pulmonary secretion removal, is evaluated by the ratio and difference between the peak expiratory flow (PEF) and the peak inspiratory flow (PIF). Methods: This was a crossover randomized study involving 10 patients. The PEEP-ZEEP maneuver was applied at four time points, one without MCC and the other three with MCC, which were performed by three different respiratory therapists. Respiratory mechanics data were obtained with a specific monitor. Results: The PEEP-ZEEP maneuver without MCC was enough to exceed the threshold that is considered necessary to move secretion toward the glottis (PEF − PIF difference > 33 L/min): a mean PEF − PIF difference of 49.1 ± 9.4 L/min was achieved. The mean PEF/PIF ratio achieved was 3.3 ± 0.7. Using MCC with PEEP-ZEEP increased the mean PEF − PIF difference by 6.7 ± 3.4 L/min. We found a moderate correlation between respiratory therapist hand grip strength and the flow bias generated with MCC. No adverse hemodynamic or respiratory effects were found. Conclusions: The PEEP-ZEEP maneuver, without MCC, resulted in an expiratory flow bias superior to that necessary to facilitate pulmonary secretion removal. Combining MCC with the PEEP-ZEEP maneuver increased the expiratory flow bias, which increases the potential of the maneuver to remove secretions.

Keywords: Physical therapy modalities; Critical care; Respiration, artificial; Bodily secretions.

Objective: To evaluate the effects of exposure to emissions from sugar cane burning on inflammatory mechanisms in tissues of the trachea and lung parenchyma in Wistar rats after different periods of exposure. Methods: This was an experimental open randomized study. The animals were divided into four groups: a control group (CG) underwent standard laboratory conditions, and three experimental groups were exposed to emissions from sugar cane burning over different periods of time, in days-1 (EG1), 7 (EG7), and 21 (EG21). After euthanasia with 200 mg/kg of ketamine/xylazine, fragments of trachea and lung were collected and fixed in 10% formalin. Histological analyses were performed with H&E and picrosirius red staining. Results: No inflammatory infiltrates were found in the tissues of CG rats. The histological examination of tissues of the trachea and lung parenchyma revealed that the inflammatory process was significantly more intense in EG7 than in the CG (p < 0.05 and p < 0.01, respectively). In comparison with the CG and EG1, angiogenesis in the lung parenchyma and collagen deposition in tracheal tissues were significantly greater only in EG21 (p < 0.001 and p < 0.01, respectively). Conclusions: In this sample, emissions from sugar cane burning induced acute focal and diffuse inflammation in the lamina propria of tracheal tissues, with no loss of ciliated epithelial tissue. In the lung parenchyma of the animals in the experimental groups, there was interstitial and alveolar edema, together with polymorphonuclear cell infiltrates.

Keywords: Saccharum; Smoke; Inflammation; Respiratory system.

Objective: To determine the effects of acute and chronic administration of methylprednisolone on oxidative stress, as quantified by measuring lipid peroxidation (LPO) and total reactive antioxidant potential (TRAP), in rat lungs. Methods: Forty Wistar rats were divided into four groups: acute treatment, comprising rats receiving a single injection of methylprednisolone (50 mg/kg i.p.); acute control, comprising rats i.p. injected with saline; chronic treatment, comprising rats receiving methylprednisolone in drinking water (6 mg/kg per day for 30 days); and chronic control, comprising rats receiving normal drinking water. Results: The levels of TRAP were significantly higher in the acute treatment group rats than in the acute control rats, suggesting an improvement in the pulmonary defenses of the former. The levels of lung LPO were significantly higher in the chronic treatment group rats than in the chronic control rats, indicating oxidative damage in the lung tissue of the former. Conclusions: Our results suggest that the acute use of corticosteroids is beneficial to lung tissue, whereas their chronic use is not. The chronic use of methylprednisolone appears to increase lung LPO levels.

Keywords: Lung; Methylprednisolone; Glucocorticoids; Lipid peroxidation; Antioxidant response elements.

Objective: To evaluate the effects of positive expiratory pressure (PEP) on pulmonary epithelial membrane permeability in healthy subjects. Methods: We evaluated a cohort of 30 healthy subjects (15 males and 15 females) with a mean age of 28.3 ± 5.4 years, a mean FEV1/FVC ratio of 0.89 ± 0.14, and a mean FEV1 of 98.5 ± 13.1% of predicted. Subjects underwent technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA) radioaerosol inhalation lung scintigraphy in two stages: during spontaneous breathing; and while breathing through a PEP mask at one of three PEP levels-10 cmH2O (n = 10), 15 cmH2O (n = 10), and 20 cmH2O (n = 10). The 99mTc-DTPA was nebulized for 3 min, and its clearance was recorded by scintigraphy over a 30-min period during spontaneous breathing and over a 30-min period during breathing through a PEP mask. Results: The pulmonary clearance of 99mTc-DTPA was significantly shorter when PEP was applied-at 10 cmH2O (p = 0.044), 15 cmH2O (p = 0.044), and 20 cmH2O (p = 0.004)-in comparison with that observed during spontaneous breathing. Conclusions: Our findings indicate that PEP, at the levels tested, is able to induce an increase in pulmonary epithelial membrane permeability and lung volume in healthy subjects.

Keywords: Lung/metabolism; Technetium Tc 99m pentetate/pharmacokinetics; Radiopharmaceuticals; Positive-pressure respiration.

Objective: To compare the effects of voluntary breath stacking (VBS) and involuntary breath stacking (IBS) techniques on respiratory mechanics, lung function patterns, and inspiratory capacity in tracheostomized patients. Methods: This was a randomized crossover clinical trial involving 20 tracheostomized patients admitted to the ICU and submitted to the VBS and IBS techniques, in random order, with an interval of 5 h between each. Ten cycles of each technique were performed with an interval of 30 s between each cycle. In VBS, patients performed successive inspirations for up to 30 s through a one-way valve, whereas in IBS, successive slow insufflations were performed with a resuscitator bag until the pressure reached 40 cmH2O. Respiratory mechanics, inspiratory capacity, and the lung function pattern were evaluated before and after the interventions. Results: After IBS, there was an increase in static compliance (p = 0.007), which was also higher after IBS than after VBS (p = 0.03). There was no significant difference between the pre-VBS and post-VBS evaluations in terms of static compliance (p = 0.42). Inspiratory capacity was also greater after IBS than after VBS (2,420.7 ± 480.9 mL vs. 1,211.3 ± 562.8 mL; p < 0.001), as was airway pressure (38.3 ± 2.6 cmH2O vs. 25.8 ± 5.5 cmH2O; p < 0.001). There were no changes in resistance or lung function pattern after the application of either technique. Conclusions: In comparison with VBS, IBS promoted greater inspiratory capacity and higher airway pressure, resulting in an increase in static compliance.

Keywords: Mucociliary clearance; Respiratory care units; Respiratory mechanics; Physical therapy modalities.

Objective: To compare the incidence and intensity of acute adverse effects and the variation in the temperature of facial skin by thermography after the use of noninvasive ventilation (NIV). Methods: We included 20 healthy volunteers receiving NIV via oronasal mask for 1 h. The volunteers were randomly divided into two groups according to the ventilatory mode: bilevel positive airway pressure (BiPAP) or continuous positive airway pressure (CPAP). Facial thermography was performed in order to determine the temperature of the face where it was in contact with the mask and of the nasal dorsum at various time points. After removal of the mask, the volunteers completed a questionnaire about adverse effects of NIV. Results: The incidence and intensity of acute adverse effects were higher in the individuals receiving BiPAP than in those receiving CPAP (16.1% vs. 5.6%). Thermographic analysis showed a significant cooling of the facial skin in the two regions of interest immediately after removal of the mask. The more intense acute adverse effects occurred predominantly among the participants in whom the decrease in the mean temperature of the nasal dorsum was lower (14.4% vs. 7.2%). The thermographic visual analysis of the zones of cooling and heating on the face identified areas of hypoperfusion or reactive hyperemia. Conclusions: The use of BiPAP mode was associated with a higher incidence and intensity of NIV-related acute adverse effects. There was an association between acute adverse effects and less cooling of the nasal dorsum immediately after removal of the mask. Cutaneous thermography can be an additional tool to detect adverse effects that the use of NIV has on facial skin.

Keywords: Masks; Noninvasive ventilation; Thermography.

Objective: To investigate the concurrent validity, as well as the intra- and inter-rater reliability, of assessing diaphragmatic mobility by area (DMarea) on chest X-rays of healthy adults. Methods: We evaluated anthropometric parameters, pulmonary function, and diaphragmatic mobility in 43 participants. Two observers (rater A and rater B) determined diaphragmatic mobility at two time points. We used Pearson's correlation coefficient to evaluate the correlation between DMarea and the assessment of diaphragmatic mobility by distance (DMdist). To evaluate intra- and inter-rater reliability, we used the intraclass correlation coefficient (ICC [2,1]), 95% CI, and Bland-Altman analysis. Results: A significant correlation was found between the DMarea and DMdist methods (r = 0.743; p < 0.0001). For DMarea, the intra-rater reliability was found to be quite high for the right hemidiaphragm (RHD)-ICC (2,1) = 0.92 (95% CI: 0.86-0.95) for rater A and ICC (2,1) = 0.90 (95% CI: 0.84-0.94) for rater B-and the left hemidiaphragm (LHD)-ICC (2,1) = 0.96 (95% CI: 0.93-0.97) for rater A and ICC (2,1) = 0.91 (95% CI: 0.81-0.95) for rater B-(p < 0.0001 for all). Also for DMarea, the inter-rater reliability was found to be quite high for the first and second evaluations of the RHD-ICC (2,1) = 0.99 (95% CI: 0.98-0.99) and ICC (2,1) = 0.95 (95% CI: 0.86-0.97), respectively-and the LHD-ICC (2,1) = 0.99 (95% CI: 0.98-0.99) and ICC (2,1) = 0.94 (95% CI: 0.87-0.97)-(p < 0.0001 for both). The Bland-Altman analysis showed good agreement between the mobility of the RHD and that of the LHD. Conclusions: The DMarea method proved to be a valid, reliable measure of diaphragmatic mobility.

Keywords: Diaphragm/physiology; Validation studies; Reproducibility of results; Radiography.