Traffic-related exposures, airway function, inflammation, and respiratory symptoms in children.

RATIONALE: Traffic-related emissions have been associated with respiratory symptoms in some studies. However, there is limited information on how traffic-related emissions relate to lung function and airway inflammation. OBJECTIVES: To determine the differential association of traffic-related exposures with exhaled nitric oxide (NO) and lung volumes and symptoms in children with and without asthma. METHODS: We performed a longitudinal study of 200 children from ages 6 to 12 years of whom half had physician-diagnosed asthma. Two-week NO(2) and 48-hour average levels of elemental carbon and particulate matter of less than 2.5 microm (PM(2.5)) were measured at participating schools. Road and traffic densities were determined at schools and at each participant's house. MEASUREMENTS AND MAIN RESULTS: In children with asthma, an interquartile increase in road density within the 50-, 100-, and 200-m home buffer areas was associated with increased exhaled NO (50 m: 28%; P = 0.03; 95% confidence interval [CI], 3-60; 100 m: 27%; P = 0.005; 95% CI, 8-49; 200 m: 17%, P = 0.09, 95% CI, -2 to 40), and reduced FEV(1) (50 m: -0.091 L; P = 0.038; 95% CI, -0.174 to -0.007; 100 m: -0.072 L, P = -0.028, 95% CI, -0.134 to -0.009; 200 m: -0.106 L, P = 0.002, 95% CI, -0.171 to -0.041]). Exposure to NO(2) at schools was marginally associated with reduced FEV(1) (-0.020; P = 0.060; 95% CI, -0.042 to 0.001). We did not observe significant associations with PM(2.5) or elemental carbon on exhaled NO. We did not observe significant reductions in lung volumes or changes in exhaled NO among healthy children. CONCLUSIONS: Vehicular traffic exposures are associated with increased levels of exhaled NO and reduced lung volumes in children with asthma.

Air pollution and heart rate variability among the elderly in Mexico City.

BACKGROUND: Suspended particles and ozone have been associated with varying degrees of cardiac autonomic dysfunction. METHODS: In Mexico City, residents from a nursing home underwent heart rate variability analysis every other day for 3 months. Indoor and outdoor PM2.5 (particulate matter less than 2.5 mm in diameter) were measured daily at the nursing home. Levels of ozone and other atmospheric pollutants were obtained from a nearby automated monitoring station. RESULTS: Of the initial 42 screened participants, 34 (81%) were followed during the study period. The 24-hour average levels of indoor PM2.5 ranged from 15 to 67 micro g/m3, and outdoor PM2.5 ranged from 9 to 87 micro g/m3. Daily 1-hour maximum ozone levels ranged from 47 to 228 ppb. After adjusting for age and heart rate, we observed a strong decrease in the high frequency component of heart rate variability and the average 24-hour concentrations of PM2.5. Participants with hypertension had considerably larger reductions in their HF-HRV (high frequency-heart rate variability) component in relation to both ozone and PM2.5 exposure. CONCLUSIONS: Our results suggest that ambient levels of PM2.5 and ozone can reduce the high-frequency component of heart rate variability in elderly subjects living in Mexico City and that subjects with underlying hypertension are particularly susceptible to this effect.

Uso de la transfusion autologa en receptores de sangre de Cirugia programada, Hospital San Juan de Dios. Santa Cruz, Bolivia. 1996-1997 / Use antologous transfusion in recipients of blood at programmed surgery, Hospital San Juan de Dios, Santa Cruz-Bolivia 1996-1997

La transfusion de sangre autologa es un procedemiento recomendado en cirugia programada. En el Hospital San Juan de Dios, en 120 cirugias menos del 1 por ciento de los receptores. El 59 (48 por ciento de los receptores con indicacion de transfusion de sangre tenian un nivel de hemoglobina de 12,5 por ciento o mas, en los cuales puedo haberse indicado esta modalidad de transfusion, lo que nos permite recomendar el uso mas frecuentes de ella. Se transfundio a 44 pacientes durante la cirugia. Solo 7 de ellos (16 por ciento) perdieron 500 ml de sangre o mas, lo que significa que se esta indicando en formas injustificada una proporcion significativa de transfusiones de sangre lo que nos permite recomendar la reactualizacion de la clase medica en la indicacion de la transfusion