[Reproducibility of spirometry in Mexican workers and international reference values]. / Reproducibilidad de espirometrías en trabajadores mexicanos y valores de referencia internacionales.

OBJECTIVE: To describe spirometric function and adjustment to foreign prediction equations in Mexican workers claiming work related disability. MATERIAL AND METHODS: We reviewed 5771 spirometries done at the Mexican National Institute of Respiratory Diseases performed with equipment and methods proposed by the American Thoracic Society. With the spirometries we generated multiple regression equations separated for men and women based on age and height, compared to other in common use reported by Knudson and Hankinson in North America and by Quanjer in europeans. RESULTS: 80% of the tests were reproducible for FVC and FEV1 according to ATS, whereas 10% were reproducible for neither. Mean FVC in men was 12% above values reported by Quanjer, 22% above Knudson, 3% above Hankinson and 6% above Rodriguez-Reynaga, whereas similar values for women were 18%, 10%, 0% and 1%. Excluding obese and those who had less than 2 acceptable maneuvers, the numbers increase by 1-2%. FEV1 was also above predicted. CONCLUSIONS: Most workers requesting disability are able to generate a reproducible spirometry. However for the same gender, age and height, workers had a FEV1 and a FVC above normal values reported by Knudson and Quanjer and are more similar to those reported by Hankinson in Mexican-Americans. While a set of appropriate reference values are obtained, regression equations obtained from the studied group will generate less error in the evaluation of disability in mexican workers. The English version of this paper is available at: http://www.insp.mx/salud/index.html.

[The domestic inhalation of the smoke from firewood and of other biological materials. A risk for the development of respiratory diseases]. / La inhalación doméstica del humo de leña y otros materiales biológicos. Un riesgo para el desarrollo de enfermedades respiratorias.

A high proportion of the world population, especially in developing countries, is exposed to indoor pollutants produced by inefficient biomass stoves. The levels of pollutants, including toxins and carcinogens in the kitchen are usually very high. This potential pathogenic exposure has been scarcely studied. The exposure to biomass smoke has been associated to chronic bronchitis and chronic airflow obstruction in adults and to acute respiratory infections in children. At the National Institute of Pulmonary Diseases in Mexico, we have observed the entire spectrum of diseases associated with tobacco in people who never smoked and who were exposed to wood smoke. Women exposed to wood smoke had a five-fold risk of chronic bronchitis and chronic airflow obstruction, as compared to the non-exposed, according to a recent case-control study done at our Institute. The indoor levels of suspended particles smaller than 10 microns were frequently above 1,000 micrograms/m3 in a rural community in the state of Mexico. This information supports a causal role for biomass smoke for the genesis of several respiratory diseases, representing a potentially public health problem.

[Normal ventilatory response to hypoxia and hypercapnia at an altitude of 2240 meters]. / Respuesta ventilatoria normal a hipoxia e hipercapnia a una altitud de 2240 metros.

OBJECTIVE: To evaluate the ventilatory response to hypoxia and hypercapnia in healthy residents of Mexico City at 2240 m above sea level. METHODS: 15 healthy subjects, 10 women and 5 men, were studied (mean age 38; range 26-76). All completed one or two tests of ventilatory response to hypoxia and hypercapnia as described by Rebuck-Campbell and Read, respectively. The results were analyzed by linear regression using the minute ventilation as the dependent variable and SaO2 (hypoxia) or PCO2 (hypercapnia) as the independent variables. RESULTS: Seven subjects had very low or no response to hypoxia. The mean hypoxia slope was 0.7 +/- 0.6 L/min/% (+/- SD) and the hypercapnia slope was 3.0 +/- 1.4 L/min/mmHg. The intercepts were 176 +/- 278 for SaO2 and 3.0 +/- 7 for PCO2. CONCLUSIONS: A low respiratory response to hypoxia was found in Mexico City Healthy residents. The response to hypercapnia was similar in slope to other studies but had an intercept shifted to lower values. The Mexico City residents showed a behavior typical of patients with chronic hypoxemia or of dwellers at high altitudes.