Incidence and patient characteristics associated with silent aspiration inthe acute care setting

Coughing is a physiologic response to aspiration in normal healthy individu als. However, there are published records that report no cough in response to aspiration (i.e., silent aspiration) in dysphagic patients. In this retr ospective study, for more than 2 years in two acute care hospitals we exami ned frequency of the cough response in patients identified as aspirators by using videofluoroscopy. One thousand one hundred one patients underwent vi deofluorographic evaluation of their swallowing during this 2-year period; 469 aspirated; 276 were silently aspirating. Two hundred twenty-four of the se silent aspirators aspirated once during a swallow and 52 silently aspira ted more than once during a swallow. These two groups of patients were anal yzed separately. Univariate (chi-square and Fisher's exact tests) and multi variate (logistic regression) analyses were conducted to assess the relatio nship of silent aspiration to age, gender, medical diagnosis, timing of asp iration, and etiology of aspiration. In univariate analysis, age (p < 0.001 ), gender (p < 0.004), and medical diagnosis (p = 0.05) were significantly associated with silent aspiration in the group who aspirated once during a swallow. No significant associations were seen in the group of patients who aspirated more than once during a swallow.