Assessing pulmonary consequences of dysphagia in children with neurological disabilities: when to intervene?

Abstract

Feeding problems are common in children with neuromotor impairments. For example, a community-based survey by Reilly et al. 1 demonstrated oral motor dysfunction in more than 90% of a sample of 49 children with cerebral palsy (CP). The sample contained 21 children with diplegia, 20 with quadriplegia, and six with hemiplegia. Most had either predominantly spastic (n=20) or mixed (n=22) signs. Thirty-three children were classified as having severe to profound functional impairment according to the Standard Recording of Central Motor Deficit. 2 Over one-third of the sample had severe oromotor impairment and was at risk of chronic undernourishment. Although oral motor impairment was observed in all types of CP, moderate to severe oromotor dysfunction was more common in children with four limbs involved. In clinical populations, 60% of children with CP were found to have swallowing problems, with evidence of chronic aspiration in 41%. 3 In assessing children with dysphagia, two issues are, therefore, paramount: is feeding safe, and is it adequate? Where adequacy is in question, measures of weight for height, a change in growth trajectory, skin-fold thickness, and blood indices of poor nutrition are all quantifiable means of setting thresholds for action. By contrast, it is much more difficult to be definitive about safety. What is the definition of 'unsafe to feed' and how do we evaluate the 'harm' accruing from oral feeding? We know that individuals with CP are subject to higher mortality (e.g. a standardized mortality ratio of 8.4) 4 than the general population. Lack of mobility and feeding problems are key mortality predictors but respiratory disease, although common, does not account for the most deaths. 5,6 Therefore, although several factors, including mobility, respiratory disease, and dysphagia, predict mortality, 7 this kind of epidemiological information is not particularly helpful in determining appropriate management in individual clinical situations. Determining when intervention might be required for a specific child logically requires a three-component sequence: first, establishing whether aspiration is occurring; second, quantifying that aspiration; and third, predicting the long-term impact on lung function. On the basis of a review of the literature and four illustrative cases, this paper argues that although we do have techniques, while imperfect, to assess the first step in this sequence, the remaining two steps lack the kind of methodologies and evidence base necessary to direct better informed clinical decision making. Demonstrating the presence of aspiration CLINICAL ASSESSMENT OF ASPIRATION Identification of children who aspirate is not straightforward for several reasons. First, it may not be clinically obvious that aspiration is taking place. Estimates of silent aspiration in children with severe CP and dysphagia undergoing videofluo-roscopy range from 31% to 97%. 8-10 One study, comparing bedside evaluation of aspiration and videofluoroscopy in adult rehabilitation patients, established that the former identified only 42% of patients with aspiration, having a positive predic-tive value of 0.75 and a negative predictive value of 0.70. 11