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Biomedical subjects

R Pérez-Padilla

Publications and source records attributed to R Pérez-Padilla.

18 recordsLinked to original sources
PubMed2004

The impact of altitude on mortality from tuberculosis and pneumonia.

OBJECTIVE: To examine the association between altitude and mortality from tuberculosis (TB) and pneumonia-influenza in Mexico. DESIGN: We analysed specific causes of death in Mexico according to death certificates for the period 1993-1997, totalling over 2,700,000 deaths and including nearly 23,000 attributed to TB and 115,000 to pneumonia and influenza. Thirty population subgroups were formed based on altitude of residence (six categories) and level of poverty (five categories). The effect of altitude on mortality was estimated through Poisson regression models, with adjustment for age, gender and socioeconomic status. RESULTS: Adjusted death rates for TB decreased with altitude and increased for pneumonia-influenza. Compared to people living below 500 m above sea level, those living between 2000 and 2499 m had a 58% mortality rate for TB and a three-fold increase in mortality due to pneumonia-influenza, despite adjustment for poverty, age and gender. CONCLUSION: The mortality rate for TB based on death certificates decreases with altitude of residence, whereas the opposite is observed for pneumonia and influenza.

Adolescent↗
PubMed2001

Effect of oxygen on sleep and breathing in patients with interstitial lung disease at moderate altitude.

OBJECTIVE: To investigate the impact of oxygen on sleep and breathing in patients with interstitial lung disease (ILD) in Mexico City, at 2,240 m of altitude. PARTICIPANTS: Nineteen ILD patients with a mean FVC of 58 +/- 17% pred. (SD) and a mean PaO(2) of 51 +/- 6 mm Hg were recruited from a pulmonary clinic in a tertiary referral center. In addition, 14 normal control subjects, matched for age and gender, were studied. All patients underwent two consecutive full polysomnographies (PSG), one breathing room air and one breathing supplementary oxygen through nasal prongs, in random order. Controls were studied for one night breathing room air. RESULTS: The mean oxygen saturation (SaO(2)) in ILD patients was 82.3 +/- 9.1% during sleep on air and 94.8 +/- 2.9% on oxygen (p < 0.001). In controls it was 92.9 +/- 1.9% (p < 0.001). Sleep efficiency was similar in patients and controls (75 vs. 82%, p > 0.05) and did not change with oxygen (77%). Arousal index was 12.4 +/- 6.9.h(-1) in ILD patients breathing room air and 12.9 +/- 9.1.h(-1) breathing oxygen while in controls it was 11.4 +/- 5.4.h(-1). Breathing frequency (f) during sleep was 24.7 +/- 4.2 in ILD patients and decreased breathing oxygen to 22.5 +/- 3.6 (p < 0.001) but was still higher than in controls (15.6 +/- 2.7; p < 0.001). Similarly, the heart rate (HR) in ILD and controls was 79 +/- 12 and 68 +/- 8, respectively (p < 0.001), and decreased to 68 +/- 4 when patients breathed oxygen (p < 0.001). CONCLUSIONS: Oxygen substantially decreases HR and f, but does not normalize the f in ILD patients. The impact of hypoxia on sleep efficiency and arousal index was not demonstrable in our patients acclimatized to moderate altitude.

Adult↗
PubMed2001

Cooking with biomass stoves and tuberculosis: a case control study.

OBJECTIVE: To search for an association between tuberculosis and use of biomass stoves found recently in a cross sectional study. DESIGN: In a case-control study based in a chest referral hospital, the cases were 288 patients with active smear-positive or culture-positive tuberculosis, and the controls were 545 patients with ear nose and throat ailments with no evidence of chest disease studied at the same time as the cases. Exposure to present or previous biomass smoke by history of cooking with traditional wood stoves was assessed by positive or negative response. RESULTS: Exposure to biomass smoke was significantly higher in cases than in controls. Crude odds ratios for tuberculosis and biomass smoke exposure were 5.2 (95%CI 3.1-8.9) for current exposure, 3.4 (95%CI 2.4-5.0) for past or present exposure and 1.8 (95%CI 1.1-3.0) for past exposure. The association was observed only for patients living in Metropolitan Mexico City and urban or suburban areas in the center of Mexico providing most cases and controls. For rural areas, the power of the study was low and the origin of the patients heterogeneous. Odds ratio for Mexico City Metropolitan area and the center of Mexico was 2.4 (95%CI 1.04-5.6), adjusted for age, sex, level of education, crowding, smoking, socio-economic level, zone of residence and state of birth. In the same model smoking had an OR of 1.5 (95%CI 1.0-2.3) for tuberculosis. CONCLUSION: Our results support a causal role of current domestic biomass smoke exposure in tuberculosis.

Adult↗
PubMed1998

Utility of a provocation test for diagnosis of chronic pigeon Breeder's disease.

Chronic hypersensitivity pneumonitis (CHP) can be difficult to differentiate from other interstitial lung diseases (ILD). To determine the diagnostic usefulness of a provocation test (PT), 17 patients with CHP induced by avian antigens, 17 with other ILD, and five healthy control subjects were challenged with pigeon serum. After PT, an increase in body temperature (BT) and a decrease in FVC, PaO2 and SaO2% were observed in all patients with CHP and in three with ILD. No reaction was noticed in healthy subjects. ROC curves showed that for FVC the best cut point was a drop of 16% displaying sensitivity (S): 76%, specificity (SP): 81%, positive predictive value (PPV): 81%, and negative predictive value (NPV): 83%. For a drop of 3 mm Hg in PaO2 or 3% SaO2, S was 88% for both, SP was 82 and 86%, PPV was 81 and 82%, and NPV was 82 and 86%, respectively. An increase of BT > 0.5(o) C showed S, 100%; SP, 82%; PPV, 100%; NPV, 86%. A univariate regression analysis confirmed that changes in BT and FVC are predicting values of CHP: RR, 82.5 (CI, 10.43 to 651.76) and 1.21 (CI, 1.06 to 1.36). There were no challenge test complications. These findings suggest that PT is a useful tool for diagnosis of CHP.

Adult↗
PubMed1998

Gas exchange at rest during simulated altitude in patients with chronic lung disease.

BACKGROUND: To characterize the gasometric and oximetric response to simulated altitudes of 3,100 m and sea level of patients with Chronic Obstructive Pulmonary Disease (COPD) and Interstitial Lung Disease (ILD) studied at 2,240 m above sea level. METHODS: Consecutive stable patients with COPD and ILD were studied at the National Institute of Respiratory Diseases, a referral center for pulmonary diseases in Mexico City, and a healthy control group. The patients breathed room air (FIO2 = 0.21), for at least 15 min, then, a hypoxic mixture (FIO2 = 0.18, simulating 3,100 m), and finally, a hyperoxic mixture (FIO2 = 0.28, simulating sea level). Arterial blood gases and oxygen saturation were measured by a pulse oximeter at the end of each stage. RESULTS: Twelve patients with COPD, 13 patients with ILD and 11 healthy controls were studied. The PaCO2 and pH were constant in the three study stages in both groups of patients and controls. A slope of PaO2 vs. altitude of 9 Torr per Km was found for each of the study's patients, either by simple linear regression or multiple regression, which is identical to that previously obtained at sea level with COPD patients (Gong et al.). Oxygen desaturation per Km of altitude change was alinear, higher for the hypoxic than for the hyperoxic challenge and more severe for the most hypoxic patients. CONCLUSIONS: Exposure tests to simulated altitudes are safe, and orient the physician concerning the patient's condition at altitudes different from the place where the measurement is done. Alveolar ventilation remains constant despite hypoxia or hyperoxia during the challenges. A computer model of the lung reproduces many of the findings in the challenges of this study.

Adult↗
PubMed1996

Correlation between pulmonary fibrosis and the lung pressure-volume curve.

The severity of pulmonary fibrosis is the main prognostic factor for survival of patients with interstitial lung diseases (ILD). Unfortunately, lung biopsy, which is the best method to assess fibrosis quantitatively, is done only once during the evolution of the disease. In this study we analyzed the relationship between the degree of fibrosis and the exponential constant k, derived from the lung pressure-volume curve (LPVC) in 33 patients with chronic ILD, 19 with pigeon breeder's disease (PBD), and 14 with idiopathic pulmonary fibrosis (IPF). Pulmonary function tests, including the LPVC, were obtained before biopsy. A semiquantitative histologic assessment of the severity of fibrosis was performed on lung tissues. All patients showed a decrease of total lung capacity, residual volume, compliance, and Pao2. The mean value of the constant k was 0.08 +/- 0.06. When expressed as a percent of normal values, 25 patients exhibited values of k lower than 70% of predicted; of the remaining 8 patients whose values were above 70% of predicted, 7 had PBD and only one IPF. On morphologic analysis, 19 patients displayed more than 50% fibrosis. No significant correlations were found between the extent of the lesion or severity of lung fibrosis and the conventional pulmonary function tests. By contrast, a moderate but significant correlation was found between k and the severity of lung fibrosis (r = -0.38, p < 0.05). These findings show that the shape of the LPVC, represented by the constant k, predicts the degree of lung fibrosis and could be useful in the clinical assessment and follow-up of patients with ILD.

Adolescent↗
PubMed1996

Exposure to biomass smoke and chronic airway disease in Mexican women. A case-control study.

A case-control study was performed in women older than 40 yr of age to evaluate the risk of cooking with traditional wood stoves for chronic bronchitis and chronic airway obstruction (CAO). The subjects were recruited from patients attending a referral chest hospital in Mexico City. We selected 127 patients with chronic bronchitis or CAO, of which 63 had chronic bronchitis alone, 23 had CAO alone (FEV1 less than 75% of predicted), and 41 had both chronic bronchitis and CAO (cases). Four control groups were selected: 83 patients with pulmonary tuberculosis, 100 patients with interstitial lung diseases, 97 patients with ear, nose and throat ailments, and 95 healthy visitors to the hospital (controls). Exposure to wood smoke, assessed as any or none, and as hour-years (years of exposure multiplied by average hours of exposure per day) was significantly higher in cases than in controls. Crude odds ratios for wood smoke exposure were 3.9 (95% CI, 2.0 to 7.6) for chronic bronchitis only, 9.7 (95% CI, 3.7 to 27) for CAO plus chronic bronchitis, and 1.8 (95% CI, 0.7 to 4.7) for CAO only. Differences in exposure to wood smoke persisted after adjusting by stratification and logistic regression for age, income, education, smoking, place of residence, and place of birth. Risk of chronic bronchitis alone and chronic bronchitis with CAO increased linearly with hour-years of cooking with a wood stove; odds ratios for exposure to more than 200 hour-years compared with nonexposed were 15.0 (95% CI, 5.6 to 40) for chronic bronchitis only and 75 (95% CI, 18 to 306) for chronic bronchitis with CAO. The findings support a causal role of domestic wood smoke exposure in chronic bronchitis and chronic airflow obstruction.

Adult↗
PubMed1996

Bronchiolitis in chronic pigeon breeder's disease. Morphologic evidence of a spectrum of small airway lesions in hypersensitivity pneumonitis induced by avian antigens.

We analyzed 36 open lung biopsy specimens from patients with chronic pigeon breeder's disease (PBD) to assess bronchiolar involvement and its relationship to the parenchymal pathologic abnormalities. Likewise, 21 biopsy specimens obtained from patients with usual interstitial pneumonia (UIP) were also examined. The bronchiolar abnormalities were scored by the method of Wright et al using a panel of photographs. In addition, the severity of lung fibrosis was evaluated in all samples and expressed as percentage in multiples of ten. A variable degree of epithelial cell metaplasia, bronchiolar inflammation and fibrosis, smooth muscle hypertrophy, extrinsic small airways narrowing, and intraluminal macrophages was observed in both diseases. Occasionally, hyperplasia of lymphoid follicles was also present. Bronchiolar changes were proportional in type and severity to the parenchymal damage. Spearman's nonparametric correlation between fibrosis in parenchyma and fibrosis in membranous bronchiole for the complete group (including patients with UIP and with PBD) showed a moderate but significant association (R = 0.51; p < 0.01). A significant association was also demonstrated when the score for bronchiolar fibrosis and inflammation was evaluated in relation to lung fibrosis divided in high degree (> 50%) and low degree (< 50%), respectively. In the case of patients with PBD, the correlation between bronchiolar and parenchymatous fibrosis was of 0.33 (p < 0.05). In general, bronchiolar fibrosis was less severe and inflammation more severe in PBD lungs compared with patients with UIP. Fibrosis in membranous bronchioles correlated with increased mortality in the complete group of patients, but the impact on mortality disappeared after correcting for overall fibrosis in the biopsy sample. Our findings demonstrate that a spectrum of bronchiolar lesions is usually observed in chronic PBD lungs, although the predominant pattern is similar to that found in the surrounding parenchyma, suggesting that the damage occurs in parallel.

Adult↗
PubMed1993

Mortality in Mexican patients with chronic pigeon breeder's lung compared with those with usual interstitial pneumonia.

The clinical course of chronic pigeon breeder's lung (CPBL) is unknown, especially in comparison with usual interstitial pneumonia (UIP). We studied a cohort of 125 consecutive patients with interstitial lung diseases, including 78 patients with CPBL (74 biopsied) and 47 patients with UIP in the lung biopsy. Patients with UIP were divided into 17 without bird exposure (UIP) and 30 with bird exposure (UIP + BE). All patients were treated with corticosteroids and followed for 33 +/- 23 months. The best predictors of mortality (Cox proportional hazards model) were age > 44 yr, with a relative risk (RR) of 2.5 and 95% confidence interval (CI) of 1.4 to 4.7, masculine gender (RR 4.0, CI 2.1 to 7.6), x-ray honeycombing (RR 7.0, CI 3.8 to 12.7), and severity of fibrosis in the lung biopsy (RR 4.8, CI 2.3 to 9.7). Survival in CPBL 5 yr after diagnosis was 0.71 (SEM 0.08) and in UIP was 0.23 (SEM 0.08), with no statistical difference between UIP + BE and UIP. After adjusting for severity of fibrosis and honeycombing, however, the correlation of diagnosis with survival disappeared. In conclusion, mortality in CPBL is considerable, but lower than in UIP. Lung fibrosis and honeycombing seem to be a final common pathway for the ILD. Adjusting for them, the effect of diagnosis in survival is not significant.

Adult↗
PubMed1993

Airflow obstruction and airway lesions in hypersensitivity pneumonitis.

Peripheral airways of lung biopsies from patients with HP commonly show several morphologic changes, including inflammation, fibrosis, or both. In most cases, damage of the airways is parallel to damage of surrounding parenchyma and the functional result is lung restriction, perhaps with alterations in the so-called "small airway tests." Chronic cough and phlegm also are more common in subjects exposed to organic antigens. Overt airflow obstruction is present in a number of patients with HP, and they usually have other risk factors, such as asthma, cigarette smoking, or dust inhalation. There are limited studies of patients who have HP and CAO but not concomitant risk factors for CAO, making it difficult to reach any firm conclusion about their association. In most cases, the lesion that could explain severe airflow obstruction seems to be located in bronchioles but, based on several clinical reports, there is the possibility that HP occasionally ends in emphysema.

Adrenal Cortex Hormones↗
PubMedDate not supplied

[The surgical risk in sleep apnea: the implications for tonsillectomies].

Hypertrophy of tonsils or adenoids is the commonest cause of obstructive sleep apnea (OSA) in children. Adenotonsillectomy (AT) is frequently curative in children with OSA but riskier than the same procedure without OSA. It is crucial to identify OSA among the patients programmed for AT because they require a detailed evaluation, frequently including total or limited polysomnogram. Patients with OSA need a continuous surveillance before, during, and after surgery, ideally in a referral hospital.

Adult↗
PubMedDate not supplied

[Hypersensitivity pneumonitis in Mexico City].

OBJECTIVE: To investigate the association between the urban area of origin of patients and the prevalence of hypersensitivity pneumonitis (HP), induced by avian antigens. MATERIAL AND METHODS: A case-control study was conducted in 1999 at the National Institute of Respiratory Diseases (NIRD). Cases were 109 consecutive HP patients and controls were 184 patients: 39 with idiopathic pulmonary fibrosis (IPF), 63 with pulmonary tuberculosis (PTB), and 82 with asthma. Mexico City and surrounding counties (SC) were divided into 5 geographical areas: 1) Downtown; 2) North-East (NE); 3) South-East (SE); 4) North-West (NW) and 5) South-West (SW). Statistical analysis consisted of calculation of disease prevalence by urban area; associations were assessed with odds ratios and 95% confidence intervals. Multivariate analysis with multiple logistic regression was performed to adjust for age, gender and socioeconomic level. RESULTS: Eighty HP cases were located in the NE southernmost and SE northernmost areas of Mexico City (48 and 32, respectively) (OR = 3.86; 95% CI 2.17-6.96). Thirty-six controls with asthma came from the SW area, (where NIRD is located) (p < 0.05), and four from SC. Controls with PTB and IPF were scattered throughout the study area. CONCLUSIONS: The NE southernmost and SE northernmost areas were associated with HP. The cause of HP may not be geographical; a garbage dump used to be located in this area, suggesting that exposure to organic particles might contribute to the development of HP in susceptible individuals.

Adult↗
PubMedDate not supplied

Rating of breathlessness at rest during acute asthma: correlation with spirometry and usefulness of breath-holding time.

We studied 13 patients with acute attacks of asthma to test the hypothesis that magnitude of dyspnea at rest correlates well with spirometry and with breath-holding time. Dyspnea ("falta de aire" in Spanish) was quantitated with a linear numerical scale from 0 to 10. We measured breath-holding time, breathing frequency (f), and FEV1 and FVC both expressed as percent of normal. Measurements were done on the patient's arrival and were repeated 3 to 6 times until dyspnea at rest disappeared or was minimal. Dyspnea magnitude, f, and breath-holding time correlated well with FEV1% and FVC% (r between 0.65 and 0.78), and better with changes in FEV1% and FVC% with respect to initial values (delta FEV1 y delta FVC; r between 0.80 and 0.89). Breath-holding time and f changed in proportion to magnitude of dyspnea (r = -0.85 and 0.87 respectively). Regression equations were: dyspnea = 6.34 -0.16 (delta FEV1) r = 0.80, and dyspnea = 7.82-0.105 (FEV1%) r = 0.62. Using multiple regression we improved prediction of FEV1% with easily obtained variables (R = 0.76). These results suggest that: 1) magnitude of dysnea, f, and breath-holding time correlate with severity of airflow obstruction in acute asthma attacks associated with dyspnea at rest; and 2) breath-holding time varies inversely with dyspnea magnitude when it is present at rest.

Acute Disease↗
PubMedDate not supplied

[Capability of clinical and laboratory findings to predict the grade of fibrosis and the diagnosis in diffuse interstitial lung diseases].

Our objective was to assess the capacity of clinical and laboratory information to predict findings in the lung biopsy in interstitial lung diseases (ILD). We studied 121 patients with ILD as a cohort recruited in our institute from 1983 to 1987 with the diagnosis of hypersensitivity pneumonitis (HP) and usual interstitial pneumonia (UIP). Histologic diagnosis (HP vs UIP) and degree of fibrosis (< 50% of the biopsy surface vs > or = 50%) were used as the gold standard to compare a series of clinical and laboratory variables in the initial assessment. We used a stepwise logistic regression model to predict the biopsy results. The model was calculated in half of the patients selected by random sampling, and the calculated model was tested in the other half of the patients. Variables found to predict degree of fibrosis were (with relative risk RR and 95% confidence interval): a radiographic pattern of honeycombing (RR 5.0 from 0.9-29), digital clubbing (RR 8 from 1.4-48) and gender (RR 2.9 from 0.4-20). This model classified correctly 72% of the biopsies, with a sensitivity of 0.38, a specificity of 0.85 and a kappa of 0.25 +/- 0.19 (p = 0.17 NS). For histologic diagnosis (NIU vs NH), the model included gender (RR 6.6, 1.3-33), honeycombing (RR 1.6, from 0.4-6.0), digital clubbing (RR 4.6, from 1.2-18), and vital capacity expressed as percent of predicted (RR 0.96, from 0.92-1.00).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗