Wafula Em

Hypoxaemia in young Kenyan children with acute lower respiratory infection

OBJECTIVES--To determine the prevalence, clinical correlates, and outcome of hypoxaemia in acutely ill children with respiratory symptoms. DESIGN--Prospective observational study. SETTING--Paediatric casualty ward of a referral hospital at 1670 m altitude in Nairobi, Kenya. SUBJECTS--256 Infants and children under 3 years of age with symptoms of respiratory infection. MAIN OUTCOME MEASURES--Prevalence of hypoxaemia, defined as arterial oxygen saturation < 90% determined by pulse oximetry, and condition of patient on the fifth day after admission. RESULTS--Over half (151) of the children were hypoxaemic, and short term mortality was 4.3 times greater in these children. In contrast, the relative risk of a fatal outcome in children with radiographic pneumonia was only 1.03 times that of children without radiographic pneumonia. A logistic regression model showed that in 3-11 month old infants a respiratory rate > or = 70/min, grunting, and retractions were the best independent clinical signs for the prediction of hypoxaemia. In the older children a respiratory rate of > or = 60/min was the single best clinical predictor of hypoxaemia. The presence of hypoxaemia predicted radiographic pneumonia with a sensitivity of 71% and specificity of 55%. CONCLUSIONS--Over half the children presenting to this referral hospital with respiratory symptoms were hypoxaemic. A group of specific clinical signs seem useful in predicting hypoxaemia. The clear association of hypoxaemia with mortality suggests that the detection and effective treatment of hypoxaemia are important aspects of the clinical management of acute infections of the lower respiratory tract in children in hospital in developing regions.

INDOOR AIR POLLUTION IN DEVELOPING COUNTRIES AND ACUTE RESPIRATORY INFECTION IN CHILDREN

Indoor air pollution emerges as an important risk factor for acute respiratory infections (ARI) in developing countries. In many developing countries, in addition to an increasing amount of tobacco smoke, many homes contain high levels of smoke from the combustion of biofuels such as wood, crop residues, and animal dung for cooking or heating. In about half the worlds households, such fuels are used for cooking daily, usually without a flue or chimney and with poor ventilation. Results of investigations in 6 developing nations have shown the range of indoor pollution in such circumstances. The best single indicator for comparison of toxic noncarcinogenic effects is most likely respirable particulates, similar to tar reported for cigarette emissions. Results of studies in animals suggest any difference in respiratory-system toxicity according to mass is not likely to be large. On the basis of the small amount of evidence available, peak and daily exposures to indoor particulate levels in villages in developing countries seem to be about 20 times greater than in developed nations. The results of a semi-quantitative epidemiological study conducted in Nepal showed a direct relation between reported hours/day spent near the stove by infants and children aged under 2 years and episodes of life threatening acute respiratory infections. If one discounts the many possible confounding factors, extrapolation shows that by moving all children into the lowest smoke exposure groups as much as 25% of moderate and severe infections would be eliminated. Extrapolation from studies of both ARI and environmental tobacco smoke also indicates indirectly the potential effect of indoor smoke from biofuels. Some environmental tobacco smoke studies have reported a dose-response relation between the number of cigarettes smoked in the home and respiratory symptoms in children. In sum, biofuel smoke is likely to be a factor in ARI, but its importance in relation to other risk factors is difficult to establish. It may be that prevention of acute respiratory infections could be best realized by initially addressing other risk factors or by addressing smoke solely in the context of broad based programs for several risk factors.