Objective: To infer the prevalence and variables predictive of isolated nocturnal hypoxemia and obstructive sleep apnea (OSA) in patients with COPD and mild hypoxemia. Methods: This was a cross-sectional study involving clinically stable COPD outpatients with mild hypoxemia (oxygen saturation = 90-94%) at a clinical center specializing in respiratory diseases, located in the city of Goiânia, Brazil. The patients underwent clinical evaluation, spirometry, polysomnography, echocardiography, arterial blood gas analysis, six-minute walk test assessment, and chest X-ray. Results: The sample included 64 patients with COPD and mild hypoxemia; 39 (61%) were diagnosed with sleep-disordered breathing (OSA, in 14; and isolated nocturnal hypoxemia, in 25). Correlation analysis showed that PaO2 correlated moderately with mean sleep oxygen saturation (r = 0.45; p = 0.0002), mean rapid eye movement (REM) sleep oxygen saturation (r = 0.43; p = 0.001), and mean non-REM sleep oxygen saturation (r = 0.42; p = 0.001). A cut-off point of PaO2 ≤ 70 mmHg in the arterial blood gas analysis was significantly associated with sleep-disordered breathing (OR = 4.59; 95% CI: 1.54-13.67; p = 0.01). The model showed that, for identifying sleep-disordered breathing, the cut-off point had a specificity of 73.9% (95% CI: 51.6-89.8%), a sensitivity of 63.4% (95% CI: 46.9-77.9%), a positive predictive value of 81.3% (95% CI: 67.7-90.0%), and a negative predictive value of 53.1% (95% CI: 41.4-64.4%), with an area under the ROC curve of 0.69 (95% CI: 0.57-0.80), correctly classifying the observations in 67.2% of the cases. Conclusions: In our sample of patients with COPD and mild hypoxemia, the prevalence of sleep-disordered breathing was high (61%), suggesting that such patients would benefit from sleep studies.

Keywords: Pulmonary disease, chronic obstructive/complications; Sleep wake disorders/epidemiology; Anoxia/etiology.

Objective: To evaluate clinical predictors of poor sleep quality in COPD patients with and without obstructive sleep apnea (OSA). Methods: Consecutive stable patients with COPD were evaluated for OSA by means of overnight polysomnography; for sleep quality by means of the Pittsburgh Sleep Quality Index (PSQI); and for disease impact by means of the COPD Assessment Test. COPD severity was graded in accordance with the 2020 GOLD guidelines. Predictors of poor sleep quality were evaluated by multivariate logistic regression analysis. Results: We studied 51 patients with COPD alone and 51 patients with COPD and OSA. Both groups had similar age (66.2 ± 9.2 years vs. 69.6 ± 10.7, p = 0.09) and airflow limitation (p = 0.37). Poor sleep quality was present in 74.8% of the study participants, with no significant difference between COPD patients with and without OSA regarding PSQI scores (p = 0.73). Polysomnography showed increased stage 1 non-rapid eye movement sleep and arousal index, as well as reduced sleep efficiency and stage 3 non-rapid eye movement sleep, in the group of patients with COPD and OSA (p < 0.05). Independent predictors of poor sleep quality were GOLD grade C/D COPD (OR = 6.4; 95% CI, 1.79-23.3; p < 0.01), a COPD Assessment Test score = 10 (OR = 12.3; 95% CI, 4.1-36.5; p < 0.01), and lowest SaO2 < 80% (p < 0.0001). Conclusions: Poor sleep quality is quite common in patients with COPD and is associated with severe COPD and poor health status, having a negative impact on overall quality of life. Despite changes in polysomnography, OSA appears to have no impact on subjective sleep quality in COPD patients.

Keywords: Pulmonary disease, chronic obstructive; Sleep Quality; Sleep apnea, obstructive; Health status.

Objective: To determine the nocturnal oximetry pattern in chronic obstructive pulmonary disease patients having no sleep apnea and presenting mild daytime hypoxemia, to identify probable daytime parameters capable of predicting nocturnal desaturation, and to evaluate the influence of nocturnal desaturation on the sleep pattern of these patients. Methods: Twenty-five patients were divided into two groups: those with nocturnal desaturation and those without. Results: Comparing the first group (52%) with the second, we found the following: age, 63 + 5 years versus 63 + 6 years; forced expiratory volume in the first second = 53 + 31% versus 56 + 19% predicted; ratio of forced expiratory volume in the first second to forced vital capacity, 49 + 14% versus 52 + 10%; arterial oxygen tension, 68 + 8 mmHg versus 72 + 68 mmHg; and arterial oxygen saturation, 93 + 2% versus 94 + 1%. Patients in the nocturnal desaturation group presented lower daytime arterial oxygen saturation and nocturnal arterial oxygen saturation by pulse oximetry. There was no difference between the two groups in terms of the sleep patterns observed. The ratio of forced expiratory volume in the first second to forced vital capacity was found to correlate with forced vital capacity, daytime arterial oxygen tension and daytime arterial oxygen saturation. In addition, arterial oxygen saturation by pulse oximetry during exercise was found to correlate with nocturnal arterial oxygen saturation by pulse oximetry. However, only daytime arterial oxygen saturation was predictive of nocturnal desaturation. Conclusion: The only variable capable of predicting nocturnal desaturation was daytime arterial oxygen saturation. Nocturnal desaturation did not influence the sleep patterns of patients with chronic obstructive pulmonary disease accompanied by mild daytime hypoxemia.

Keywords: Sleep, REM; Pulmonary disease, chronic obstructive; Anoxemia; Spirometry; Wakefulness

Objective: To verify association between left ventricular (LV) mass and thickness and the presence of significant nocturnal hypoxemia in patients with COPD with mild diurnal hypoxemia. Methods: A cross-sectional study carried out in clinically stable outpatients with COPD and mild hypoxemia (oxygen saturation ≥90 to ≤94%, identified by noninvasive oximetry) in a clinic specialized in the treatment of respiratory diseases in Goiânia-GO. All patients were submitted to clinical evaluation, spirometry, polysomnography, echocardiography, arterial blood gas analysis, 6-minute walk test and chest X-ray. Results: Patients with significant nocturnal hypoxemia had echocardiographic parameters associated with increase of LV musculature when compared to patients with mild nocturnal hypoxemia. The LV volume/mass ratio was significantly lower in the group with significant nocturnal hypoxemia (ratio 0.64 ± 0.13 versus 0.72 ± 0.12, p = 0.04), the thickness diastolic diameter of the interventricular septum and the diastolic thickness of the LV posterior wall were significantly higher in this group (9.7 ± 0.92 versus 9.1 ± 0.90 p = 0.03), (9.7 ± 1.0 versus 8.9 ± 1.0, p = 0.01. The time in REM sleep with saturation below 85% significantly predicted septum thickness (adjustment for BMI, age and mean blood pressure, r2 = 0.20; p = 0.046). Conclusion: We observed association between severe REM sleep hypoxemia and echocardiographic parameters indicating increased LV mass in individuals with COPD and significant nocturnal hypoxemia. This suggests that this subgroup of individuals may benefit from an echocardiographic evaluation of the left ventricle.

Keywords: Chronic Obstructive Pulmonary Disease; Left ventricular hypertrophy; Echocardiography.

Objective: There are many ways of assessing sleepiness, which has many dimensions. In patients presenting a borderline apnea-hypopnea index (AHI, expressed as events/hour of sleep), the mechanisms of excessive daytime sleepiness (EDS) remain only partially understood. In the initial stages of sleep-disordered breathing, the AHI might be related to as-yet-unexplored EDS dimensions. Methods: We reviewed the polysomnography results of 331 patients (52% males). The mean age was 40 ± 13 years, and the mean AHI was 4 ± 2 (range, 0-9). We assessed ten potential dimensions of sleepiness based on polysomnography results and medical histories. Results: The AHI in non-rapid eye movement (NREM) stage 1 sleep (AHI-N1), in NREM stage 2 sleep (AHI-N2), and in REM sleep (AHI-REM) were, respectively, 6 ± 7, 3 ± 3 and 10 ± 4. The AHI-N2 correlated significantly with the greatest number of EDS dimensions (5/10), including the Epworth sleepiness scale score (r = 0.216, p < 0.001). Factor analysis, using Cronbach's alpha, reduced the variables to three relevant factors: QUESTIONNAIRE (α = 0.7); POLYSOMNOGRAPHY (α = 0.68); and COMPLAINTS (α = 0.55). We used these factors as dependent variables in a stepwise multiple regression analysis, adjusting for age, gender, and body mass index. The AHI-N1 correlated significantly with POLYSOMNOGRAPHY (β = −0.173, p = 0.003), and the AHI-N2 correlated significantly with COMPLAINTS (β = −0.152, p = 0.017). The AHI-REM did not correlate with any factor. Conclusions: Our results underscore the multidimensionality of EDS in mild sleep apnea.

Keywords: Disorders of excessive somnolence; Sleep apnea syndromes; Sleep, REM; Polysomnography.

Objective: To analyze adolescents clinically diagnosed with asthma, in terms of the physiological changes occurring during acute hypoxia and during a maximal stress test. Methods: This was a descriptive, cross-sectional study involving 48 adolescents (12-14 years of age) who were divided into three groups: mild intermittent asthma (MIA, n = 12); mild persistent asthma (MPA, n = 12); and control (n = 24). All subjects were induced to acute hypoxia and were submitted to maximal stress testing. Anthropometric data were collected, and functional variables were assessed before and after the maximal stress test. During acute hypoxia, the time to a decrease in SpO2 and the time to recovery of SpO2 (at rest) were determined. Results: No significant differences were found among the groups regarding the anthropometric variables or regarding the ventilatory variables during the stress test. Significant differences were found in oxygen half-saturation pressure of hemoglobin prior to the test and in PaO2 prior to the test between the MPA and control groups (p = 0.0279 and p = 0.0116, respectively), as was in the oxygen extraction tension prior to the test between the MIA and MPA groups (p = 0.0419). There were no significant differences in terms of the SpO2 times under any of the conditions studied. Oxygen consumption and respiratory efficiency were similar among the groups. The use of a bronchodilator provided no significant benefit during the hypoxia test. No correlations were found between the hypoxia test results and the physiological variables. Conclusions: Our findings suggest that adolescents with mild persistent asthma have a greater capacity to adapt to hypoxia than do those with other types of asthma.

Keywords: Asthma; Adolescent; Cell hypoxia; Exercise test.

Objective: To translate the Breathing Problems Questionnaire (BPQ) into Portuguese and adapt it to the Brazilian culture, as well as to evaluate its reproducibility in patients with COPD. Methods: After the BPQ had been translated and adapted to the Brazilian culture, it was administered to a subgroup of 8 patients in order to identify their uncertainties and difficulties. The questionnaire was reviewed by an expert committee, and its final version was arrived at. A second translator back-translated the final version into English, which was sent to the original author in order to verify that the original meaning of the questionnaire had been maintained. After the approval of the original author, the final Portuguese-language version of the questionnaire was administered to 50 patients with COPD, in order to evaluate its reproducibility. Results: The mean response time was 9.5 min. Of the 50 patients, 21 were female and 29 were male. The mean age was 65.8 ± 7.5 years. Most of the patients were classified as having moderate COPD (29.16%) or severe COPD (52%). The intraclass correlation coefficient (ICC) for the total score was 0.94. The ICCs for the eleven BPQ domains and its two subscales were also above 0.70. Moderate correlations were found between the BPQ domains and subscales. Conclusions: The translation and cultural adaptation of the BPQ for use in Brazil was deemed appropriate, because the patients could easily understand and answer the questions. In addition, the Brazilian version of the BPQ questionnaire was found to be reliable, showing good reproducibility.

Keywords: Pulmonary disease; chronic obstructive; Quality of life; Reproducibility of results.

Objective: To determine the prevalence of alpha 1-antitrypsin (AAT) deficiency (AATD), as well as allele frequency, in COPD patients in Brazil. Methods: This was a cross-sectional study involving 926 COPD patients 40 years of age or older, from five Brazilian states. All patients underwent determination of AAT levels in dried blood spot (DBS) samples by nephelometry. Those with DBS AAT levels ≤ 2.64 mg/dL underwent determination of serum AAT levels. Those with serum AAT levels of < 113 mg/dL underwent genotyping. In case of conflicting results, SERPINA1 gene sequencing was performed. Results: Of the 926 COPD patients studied, 85 had DBS AAT levels ≤ 2.64 mg/dL, and 24 (2.6% of the study sample) had serum AAT levels of < 113 mg/dL. Genotype distribution in this subset of 24 patients was as follows: PI*MS, in 3 (12.5%); PI*MZ, in 13 (54.2%); PI*SZ, in 1 (4.2%); PI*SS, in 1 (4.2%); and PI*ZZ, in 6 (25.0%). In the sample as a whole, the overall prevalence of AATD was 2.8% and the prevalence of the PI*ZZ genotype (severe AATD) was 0.8% Conclusions: The prevalence of AATD in COPD patients in Brazil is similar to that found in most countries and reinforces the recommendation that AAT levels be measured in all COPD patients.

Keywords: alpha 1-antitrypsin deficiency/epidemiology; pulmonary disease, chronic obstructive/epidemiology; Alleles; alpha 1-antitrypsin.

Objective: To determine the impact of adherence to long-term oxygen therapy (LTOT) on quality of life, dyspnea, and exercise capacity in patients with COPD and exertional hypoxemia followed for one year. Methods: Patients experiencing severe hypoxemia during a six-minute walk test (6MWT) performed while breathing room air but not at rest were included in the study. At baseline and after one year of follow-up, all patients were assessed for comorbidities, body composition, SpO2, and dyspnea, as well as for anxiety and depression, having also undergone spirometry, arterial blood gas analysis, and the 6MWT with supplemental oxygen. The Saint George's Respiratory Questionnaire (SGRQ) was used in order to assess quality of life, and the Body mass index, airflow Obstruction, Dyspnea, and Exercise capacity (BODE) index was calculated. The frequency of exacerbations and the mortality rate were noted. Treatment nonadherence was defined as LTOT use for < 12 h per day or no LTOT use during exercise. Results: A total of 60 patients with COPD and exertional hypoxemia were included in the study. Of those, 10 died and 11 experienced severe hypoxemia during follow-up, 39 patients therefore being included in the final analysis. Of those, only 18 (46.1%) were adherent to LTOT, showing better SGRQ scores, higher SpO2 values, and lower PaCO2 values than did nonadherent patients. In all patients, SaO2, the six-minute walk distance, and the BODE index worsened after one year. There were no differences between the proportions of adherence to LTOT at 3 and 12 months of follow-up. Conclusions: Quality of life appears to be lower in patients with COPD and exertional hypoxemia who do not adhere to LTOT than in those who do. In addition, LTOT appears to have a beneficial effect on COPD symptoms (as assessed by SGRQ scores). (Brazilian Registry of Clinical Trials - ReBEC; identification number RBR‑9b4v63 [http://www.ensaiosclinicos.gov.br])

Keywords: Respiratory insufficiency; Pulmonary disease, chronic obstructive; Patient compliance; Hypoxia; Oxygen inhalation therapy.

Objective: To assess and compare the prevalence of comorbidities and risk factors for cardiovascular disease (CVD) in COPD patients according to disease severity. Methods: The study included 25 patients with mild-to-moderate COPD (68% male; mean age, 65 ± 8 years; mean FEV1, 73 ± 15% of predicted) and 25 with severe-to-very severe COPD (males, 56%; mean age, 69 ± 9 years; mean FEV1, 40 ± 18% of predicted). Comorbidities were recorded on the basis of data obtained from medical charts and clinical evaluations. Comorbidities were registered on the basis of data obtained from medical charts and clinical evaluations. The Charlson comorbidity index was calculated, and the Hospital Anxiety and Depression Scale (HADS) score was determined. Results: Of the 50 patients evaluated, 38 (76%) had been diagnosed with at least one comorbidity, 21 (42%) having been diagnosed with at least one CVD. Twenty-four patients (48%) had more than one CVD. Eighteen (36%) of the patients were current smokers, 10 (20%) had depression, 7 (14%) had dyslipidemia, and 7 (14%) had diabetes mellitus. Current smoking, depression, and dyslipidemia were more prevalent among the patients with mild-to-moderate COPD than among those with severe-to-very severe COPD (p < 0.001, p = 0.008, and p = 0.02, respectively). The prevalence of high blood pressure, diabetes mellitus, alcoholism, ischemic heart disease, and chronic heart failure was comparable between the two groups. The Charlson comorbidity index and HADS scores did not differ between the groups. Conclusions: Comorbidities are highly prevalent in COPD, regardless of its severity. Certain risk factors for CVD, themselves classified as diseases (including smoking, dyslipidemia, and depression), appear to be more prevalent in patients with mild-to-moderate COPD.

Keywords: Pulmonary disease, chronic obstructive; Spirometry; Cardiovascular diseases; Risk factors.

Objective: To determine the prevalence of nocturnal hypoxemia and its association with pulmonary function, nutritional status, sleep macrostructure, and obstructive respiratory events during sleep in a population of clinically stable children and adolescents with cystic fibrosis (CF). Methods: This was a cross-sectional study involving 67 children and adolescents with CF between 2 and 14 years of age. All of the participants underwent polysomnography, and SpO2 was measured by pulse oximetry. We also evaluated the Shwachman-Kulczycki (S-K) scores, spirometry findings, and nutritional status of the patients. Results: The study involved 67 patients. The mean age of the patients was 8 years. The S-K scores differed significantly between the patients with and without nocturnal hypoxemia, which was defined as an SpO2 < 90% for more than 5% of the total sleep time (73.75  6.29 vs. 86.38  8.70; p < 0.01). Nocturnal hypoxemia correlated with the severity of lung disease, FEV1 (rs = −0.42; p = 0.01), FVC (rs = −0.46; p = 0.01), microarousal index (rs = 0.32; p = 0.01), and apnea-hypopnea index (rs = 0.56; p = 0.01). Conclusions: In this sample of patients with CF and mild-to-moderate lung disease, nocturnal oxygenation correlated with the S-K score, spirometry variables, sleep macrostructure variables, and the apnea-hypopnea index.

Keywords: Cystic fibrosis; Sleep; Oximetry.

Objective: To assess the prevalence of smoking and associated variables in female sex workers (FSWs). Methods: This was a quantitative cross-sectional study involving FSWs in the city of Botucatu, Brazil, who completed a sociodemographic questionnaire, including data regarding smoking status, motivational stage of change, and degree of nicotine dependence, as well as the Perceived Stress Scale and the Hospital Anxiety and Depression Scale. Results: We included 83 FSWs. The mean age was 26.8 years. Among the participants, 58 (69.8%) had at least a high school education, only 26 (31.3%) resided in the city of Botucatu, 59 (71.1%) were smokers, 5 (6.0%) were former smokers, 74 (89.2%) regularly consumed alcohol, and 43 (51.8%) used illicit drugs. The majority of the women were classified as having an intermediate stress level, and 51 (61.4%) were classified as having possible or probable anxiety, whereas depression was found to be improbable in 57 (68.7%). The level of nicotine dependence was high among the smokers, the majority of whom showed no intention to quit smoking. Smoking was associated with illicit drug use (p = 0.0271) and with alcohol consumption (p = 0.0001), although not with the levels of stress, anxiety, or depression; nor was the age at smoking initiation associated with the length of time as an FSW (p = 0.4651). Conclusions: The prevalence of smoking among the FSWs evaluated here was much higher than the 8.3% reported for the overall female population of Brazil. Our findings show that FSWs are exposed to various risk factors inherent to their profession. Therefore, harm reduction is an important strategy to be adopted.

Keywords: Women, Smoking, Sex workers; Prevalence; Risk factors.

Objective: To evaluate and correlate the quality of life (QoL) of COPD patients on long-term home oxygen therapy (LTOT) with their sociodemographic/clinical characteristics and level of dependence. Methods: This was a cross-sectional analytical study involving COPD patients on LTOT followed at the Oxygen Therapy Outpatient Clinic of the Federal University of São Paulo Hospital São Paulo, in the city of São Paulo, Brazil. Sociodemographic, clinical, and biochemical data were collected. We assessed QoL and level of dependence using the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36) and the Katz index, respectively. Multiple linear regression models were constructed in order to determine the influence of these variables on QoL. Results: We included 80 patients in the study. The mean age was 69.6 ± 9.1 years, and 51.3% were female. The lowest SF-36 scores were for the physical functioning and role-physical domains. All sociodemographic characteristics (except gender) were found to correlate significantly with the SF-36 domains mental health, vitality, role-physical, and social functioning. We also found that body mass index, PaO2, post-bronchodilator FEV1, hemoglobin, and Katz index correlated significantly with the physical functioning, mental health, role-physical, and bodily pain domains. In addition, oxygen flows were found to correlate negatively with the physical functioning, mental health, vitality, and role-emotional domains. Conclusions: Low scores for SF-36 domains, as well as the variables that negatively influence them, should be considered and analyzed during the development and implementation of strategies for improving the QoL of COPD patients on LTOT.

Keywords: Pulmonary disease, chronic obstructive; Quality of life; Oxygen inhalation therapy.

Objectives: Pleural tuberculosis (PlTB) diagnosis is a challenge due to its paucibacillary nature and to the need of invasive procedures. This study aimed to identify easily available variables and build a predictive model for PlTB diagnosis which may allow earlier and affordable alternative strategy to be used in basic health care units. Methods: An observational cross-sectional study compared PlTB and non-TB patients followed at a tertiary Brazilian hospital between 2010 and 2018. Unconditional logistic regression analysis was performed and a Decision Tree Classifier (DTC) model was validated and applied in additional PlTB patients with empiric diagnosis. The accuracy (Acc), sensitivity (Se), specificity (Sp), positive and negative predictive values were calculated. Results: From 1,135 TB patients, 160 were considered for analysis (111 confirmed PlTB and 49 unconfirmed PlTB). Indeed, 58 non-TB patients were enrolled as controls. Hyporexia [adjusted odds ratio (aOR) 27.39 (95% CI 6.26 - 119.89)] and cellular/biochemical characteristics on pleural fluid (PF) (polimorphonuclear in two categories: 3-14% aOR 26.22, 95% CI 7.11 - 96.68 and < 3% aOR 28.67, 95% CI 5.51 - 149.25; and protein = 5g/dL aOR 7.24, 95% CI 3.07 - 17.11) were associated with higher risk for TB. The DTC constructed using these variables showed Acc=87.6%, Se=89.2%, Sp=84.5% for PlTB diagnosis and was successfully applied in unconfirmed PlTB patients. Conclusion: The DTC model showed an excellent performance for PlTB diagnosis and can be considered as an alternative diagnostic strategy by using clinical patterns in association with PF cellular/biochemical characteristics, which were affordable and easily performed in basic health care units.

Keywords: Pleural tuberculosis; Diagnosis; Decision tree classifier.

Objective: To determine the prevalence of and factors associated with smoking among medical students, as well as to evaluate the profile of this group. Methods: A total of 316 medical students (98.7% of the total) at the University of Passo Fundo, in the city of Passo Fundo, Brazil, completed a self-report questionnaire with questions on tobacco intake and on attitudes related to smoking. In accordance with the World Health Organization guidelines, the students were classified as daily smokers, occasional smokers, former smokers or nonsmokers, those in the two first categories being considered active smokers. Results: We found that 16.5% of the students were active smokers (daily smokers, 5.4%; occasional smokers, 11.1%) and that 3.5% were former smokers. The mean age was 22.2 ± 2.4 years. Factors significantly associated with the smoking habit (p < 0.05) were male gender, paternal smoking, regular alcohol consumption and use of antidepressants or anxiolytics. For the majority (69.2%) of the smokers, the age at smoking onset was 15-19 years of age, and the main motivations to start smoking were self-initiative and influence of friends. The conceptualization of smoking as an illness was significantly higher among the nonsmokers. In 70.6% of the smokers, tobacco intake was 1-10 cigarettes a day. Among the smokers, 92.3% agreed that smoking is harmful to health, 67.3% had tried to quit smoking, 96.0% believed themselves able to do so, and 87.2% intended to quit smoking. Conclusions: The prevalence of smoking remains significant among medical students. Therefore, it is fundamental that we develop more effective strategies for smoking prevention and cessation in order to reduce the number of smokers among future doctors.

Keywords: Smoking; Prevalence; Students, medical; Behavior.

Objective: To test the hypothesis that disease severity in patients with cystic fibrosis (CF) is correlated with an increased risk of sleep apnea. Methods: A total of 34 CF patients underwent clinical and functional evaluation, as well as portable polysomnography, spirometry, and determination of IL-1β levels. Results: Mean apnea-hypopnea index (AHI), SpO2 on room air, and Epworth Sleepiness Scale score were 4.8 ± 2.6, 95.9 ± 1.9%, and 7.6 ± 3.8 points, respectively. Of the 34 patients, 19 were well-nourished, 6 were at nutritional risk, and 9 were malnourished. In the multivariate model to predict the AHI, the following variables remained significant: nutritional status (β = −0.386; p = 0.014); SpO2 (β = −0.453; p = 0.005), and the Epworth Sleepiness Scale score (β = 0.429; p = 0.006). The model explained 51% of the variation in the AHI. Conclusions: The major determinants of sleep apnea were nutritional status, SpO2, and daytime sleepiness. This knowledge not only provides an opportunity to define the clinical risk of having sleep apnea but also creates an avenue for the treatment and prevention of the disease.

Keywords: Cystic fibrosis; Oxygenation; Sleep apnea, obstructive.

Objective: To assess children and adolescents diagnosed with mild intermittent or mild persistent asthma, in terms of their aerobic capacity between attacks. Methods: We included 33 children and adolescents recently diagnosed with asthma (mild intermittent or mild persistent) and 36 healthy children and adolescents. Those with asthma were evaluated between attacks. All participants underwent clinical evaluation; assessment of baseline physical activity level; pre- and post-bronchodilator spirometry; and a maximal exercise test, including determination of maximal voluntary ventilation, maximal oxygen uptake, respiratory quotient, maximal minute ventilation, ventilatory equivalent, ventilatory reserve, maximal HR, SpO2, and serum lactate. Results: No significant differences were found among the groups (intermittent asthma, persistent asthma, and control) regarding anthropometric or spirometric variables. There were no significant differences among the groups regarding the variables studied during the maximal exercise test. Conclusions: A diagnosis of mild intermittent/persistent asthma has no effect on the aerobic capacity of children and adolescents between asthma attacks.

Keywords: : Asthma; Exercise; Respiratory function tests.

Objective: To determine whether COPD patients with diaphragmatic dysfunction present higher risk of mortality than do those without such dysfunction. Methods: We evaluated pulmonary function, diaphragm mobility and quality of life, as well as determining the Body mass index, airway Obstruction, Dyspnea, and Exercise capacity (BODE) index, in 42 COPD patients. The patients were allocated to two groups according to the degree to which diaphragm mobility was impaired: low mobility (LM; mobility ≤ 33.99 mm); and high mobility (HM; mobility ≥ 34.00 mm). The BODE index and the quality of life were quantified in both groups. All patients were followed up prospectively for up to 48 months in order to determine the number of deaths resulting from respiratory complications due to COPD. Results: Of the 42 patients evaluated, 20 were allocated to the LM group, and 22 were allocated to the HM group. There were no significant differences between the groups regarding age, lung hyperinflation or quality of life. However, BODE index values were higher in the LM group than in the HM group (p = 0.01). During the 48-month follow-up period, there were four deaths within the population studied, and all of those deaths occurred in the LM group (15.79%; p = 0.02). Conclusions: These findings suggest that COPD patients with diaphragmatic dysfunction, characterized by low diaphragm mobility, have a higher risk of death than do those without such dysfunction.

Keywords: Pulmonary disease, chronic obstructive/mortality; Diaphragm; Exercise tolerance; Quality of life.

Background: The decision to drain parapneumonic pleural effusion in children is still controversial. An indicative scoring system to assess the need for chest-tube drainage arose from a partnership between pediatricians and surgeons. Objective: To evaluate the utility of the score in indicating whether drainage should be performed in pediatric patients with parapneumonic effusion. Method: A cross-sectional study involving 250 inpatients with parapneumonic effusion, treated in a tertiary-care hospital between 1994 and 1999. The following variables were analyzed: clinical presentation, chest X-rays, pleural fluid culture and biochemical analysis of the pleural fluid, as well as the score and treatment. The score was based on four categories: general appearance of the pleural fluid, chest X-rays, laboratory findings, and the second thoracentesis. Drainage was recommended for patients scoring higher than 5.5. Results: Of 941 children with pneumonia, parapneumonic effusion occurred in 304 (32.2%), 250 of which were included in the study. Of those, 146 (58.4%) were male, with mean of age of 3 years (median, 2 years). The cutoff points (determined through receiver operating characteristic curve analysis) for suggesting pleural drainage were pH < 7.29 (89.2% sensitivity and 76.5% specificity), score > 5.0 (68.7% sensitivity and 81.7% specificity). These values were more strongly correlated with the need for drainage (p = 0.001), as were those reported in the literature (pH = 7.0 and glucose < 40). The lactate dehydrogenase did not prove to be a good parameter for indicating a need for drainage. Conclusion: In addition to the purulent aspect, pH = 7.29 and score were the best indicators of the need for chest-tube drainage in pediatric patients with parapneumonic effusion. However, we suggest that some score variables be readjusted to improve the usefulness of this particular scoring system.

Keywords: Empyema. Pleural effusion. Pneumonia.