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.
PIP: In 1989, pediatricians followed 256 children 7 days to 36 months old with symptoms of respiratory infection at Kenyatta National Hospital (1670 m altitude) in Nairobi, Kenya. The symptoms were serious enough to warrant hospital admission for 209 of these children. The most common clinical diagnoses were pneumonia (53%) and bronchiolitis (33%). 59% of the children admitted to the hospital were hypoxemic (arterial oxygen saturation or + to 90%). 10% of all admitted children died. 90.4% of them were hypoxemic with arterial oxygen saturations ranging from 40-88%. Children with hypoxemia were 4.3 times more apt to die within 5 days than those with no hypoxemia (p = .02). On the other hand, children with radiographic pneumonia had a relative risk of short-term mortality of only 1.03. Hypoxemia on admission predicted short-term mortality with 90% sensitivity and 34% specificity. It predicted pneumonia with 71% sensitivity and 55% specificity (p .0001). Children who lived for at least 5 days had arterial oxygen saturations ranging from 41-98. Even though all of the children with clinically evident cyanosis were less than a year old, 89% of the hypoxemic infants less than 1 year old did not exhibit cyanosis. Mothers' reports of blueness in newborns and infants less than 2 months was the best predictor of hypoxemia (62% accuracy; p .05). For children 3-11 months old, the best predictors of hypoxemia, with an accuracy of 70%, were a respiratory rate of at least 70/minute (odds ratio [OR] 2.6; p .001). For children at least 12 months old, the sole best predictor was a respiratory rate of at least 60/minute (70% accuracy; OR 5.1; p .01). This study should be followed by well-designed studies of the clinical effectiveness of proper treatment with oxygen in preventing mortality in hypoxemic infants and children.