The relation between air pollution and the exacerbation of childhood asthma was studied in a panel of 71 children (aged 5 to 7 yr) with mild asthma who resided in the northern part of mexico City. During the follow-up, ambient measures of particulate matter less than 10 microns (PM10, 24-h average) and ozone (1-h maximum) frequently exceeded the Mexican standards for these contaminants. The peak expiratory flow rate (PEFR) was strongly associated with PM10 levels and marginally with ozone levels. Respiratory symptoms (coughing, phlegm production, wheezing, and difficulty breathing) were associated with both PM10 and ozone levels. An increase of 20 micrograms/m3 of PM10 was related to an 8% increase in lower respiratory illness (LRI) among children on the same day (95% confidence interval [CI] = 1.04-1.15), and an increase of 10 micrograms/m3 in the weekly mean of particulate matter less than 2.5 microns (PM2.5) was related to a 21% increase in LRI (95% CI = 1.08-1.35). A 50 parts per billion (ppb) increase in ozone was associated with a 9% increase in LRI (95% CI = 1.03-1.15) on the same day. We concluded that children with mild asthma are affected by the high ambient levels of particulate matter and ozone observed in the northern part of Mexico City.
This is the fi rst clinical practice guideline from the American Academy of Pediatrics that specifi cally applies to patients who have experienced an apparent life-threatening event (ALTE). This clinical practice guideline has 3 objectives. First, it recommends the replacement of the term ALTE with a new term, brief resolved unexplained event (BRUE). Second, it provides an approach to patient evaluation that is based on the risk that the infant will have a repeat event or has a serious underlying disorder. Finally, it provides management recommendations, or key action statements, for lower-risk infants. The term BRUE is defi ned as an event occurring in an infant younger than 1 year when the observer reports a sudden, brief, and now resolved episode of ≥1 of the following: (1) cyanosis or pallor; (2) absent, decreased, or irregular breathing; (3) marked change in tone (hyper-or hypotonia); and (4) altered level of responsiveness. A BRUE is diagnosed only when there is no explanation for a qualifying event after conducting an appropriate history and physical examination. By using this defi nition and framework, infants younger than 1 year who present with a BRUE are categorized either as (1) a lower-risk patient on the basis of history and physical examination for whom evidence-based recommendations for evaluation and management are offered or (2) a higher-risk patient whose history and physical examination suggest the need for further investigation and treatment but for whom recommendations are not offered. This clinical practice guideline is intended to foster a patient-and family-centered approach to care, reduce unnecessary and costly medical interventions, improve patient outcomes, support implementation, and provide direction for future research. Each key action statement indicates a level of evidence, the benefi t-harm relationship, and the strength of recommendation.
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