Lessons from normal heart and respiratory rates in children.

Of all the dilemmas in acute paediatrics, that of distinguishing serious life-threatening illness in young children from self-limiting, acute viral infections is probably the problem that causes most anxieties for clinicians and parents. It is not possible, nor desirable, to admit and investigate every child with a high temperature, but of equal importance is prevention of progression of serious illness or infection. The restricted ability of young children to report how they feel, especially when distressed, means that this assessment is largely based on clinical examination. The front-line staff who make judgments about whether a child should be admitted or not are usually not paediatricians, adding further diffi culty. Thus, although more than 25% of all patients seen in emergency departments in the UK are children, huge variation exists between National Health Service Trusts (4–24%) in the proportion of children admitted from these departments. To help address this problem, various guidelines, checklists, and algorithms have been developed, prompting the clinician to assess the presence of a constellation of symptoms and signs that can show whether the child is likely to be at high risk. Measurements of heart rate and respiratory rate are usually fundamental to the assessment of physiological status, and have the advantage of being easy to measure and generally raised during acute illnesses. Rapid breathing is recognised worldwide as an important red fl ag for serious infection in children, and is integral to the diagnosis of acute lower respiratory infection in resource-poor settings—its absence making such a diagnosis very unlikely. However, to add to the challenges, infancy and childhood are periods of enormous physiological and developmental changes, particularly in the early months and years. Although researchers have attempted to establish what constitutes normal heart and respiratory rates at diff erent ages, these investigations have been in various populations, settings, and geographical locations, with use of diff erent measurement techniques, during at least the past six decades. The result is that the *Wagih Shafi k El Masri(y), Naveen Kumar Keele University, The Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Staff ordshire SY10 7AG, UK [email protected]