Oximetry and peak expiratory flow in assessment of acute childhood asthma

Two methods of evaluating children with acute asthma are compared: determination of peak expiratory flow (PEF, the maximal rate at which air can be forced out of the lungs) versus the extent to which blood hemoglobin (to which oxygen is bound) is saturated with oxygen (SaO2, measured by a small, noninvasive finger probe). One hundred ten children (average age, nine) served as subjects; all were under regular or episodic treatment for asthma. Their PEF and SaO2 were determined in the emergency department, and then the patients underwent clinical examination. Follow-up telephone calls were placed to the children's parents 10 days later to learn more concerning the course of the acute episode. Seventy-nine children were released from the emergency ward, while 31 remained as inpatients. Children who were admitted had lower PEF and SaO2 values (less peak flow and oxygen saturation, respectively) than those who went home, and children who went home with additional asthma medication had lower values than those who went home without a new prescription. However, PEF did not differ between children who went home and stayed there, and children who had to return to the hospital, while SaO2 values did discriminate between these two groups. A low SaO2 level was a better predictor of outcome than a low PEF. The SaO2 test is easy to perform on young patients who may be uncooperative or too ill to participate in determining PEF. It may also reflect the pathological changes that occur in asthma, which are briefly discussed. (Consumer Summary produced by Reliance Medical Information, Inc.)