Objectives-To describe the frequency of pepsin-positive tracheal secretions (a proxy for the aspiration of gastric contents), outcomes associated with aspiration (including a positive Clinical Pulmonary Infection Score [a proxy for pneumonia] and use of hospital resources), and risk factors associated with aspiration and pneumonia in a population of critically ill tube-fed patients.Design-Prospective descriptive study conducted over a 2-yr period. Setting-Five intensive care units in a university-affiliated medical center with level I trauma status.Patients-Each of the 360 adult patients participated for 4 days. Among the inclusion criteria were mechanical ventilation and tube feedings. An exclusion criterion was physician-diagnosed pneumonia at the time of enrollment. Intervention-None.Measurements and Major Results-Almost 6,000 tracheal secretions collected during routine suctioning were assayed for pepsin; of these, 31.3% were positive. At least one aspiration event was identified in 88.9% (n = 320) of the participants. The incidence of pneumonia (as determined by the Clinical Pulmonary Infection Score) increased from 24% on day 1 to 48% on day 4. Patients with pneumonia on day 4 had a significantly higher percentage of pepsin-positive tracheal secretions than did those without pneumonia (42.2% vs. 21.1%, respectively; p < .001). Length of stay in the intensive care unit and need for ventilator support were significantly greater for patients with pneumonia (p < .01). A low backrest elevation was a risk factor for aspiration (p = .024) and pneumonia (p = .018). Other risk factors for aspiration included vomiting (p = .007), gastric feedings (p = .009), a Glasgow Coma Scale score <9 (p = .021), and gastroesophageal reflux disease (p = .033). The most significant independent risk factors for pneumonia were aspiration (p < .001), use of paralytic agents (p = .002), and a high sedation level (p = .039).Conclusions-Aspiration of gastric contents is common in critically ill tube-fed patients and is a major risk factor for pneumonia. Furthermore, it leads to greater use of hospital resources. Modifiable risk factors for aspiration need to be addressed. Keywords critical illness; enteral nutrition; aspiration pneumonia; risk factors; gastroesophageal reflux; gastric emptyingThe authors have no financial interests to disclose.The study was performed at Saint Louis University Hospital, in St. Louis, MO. NIH Public Access Author ManuscriptCrit Care Med. Author manuscript; available in PMC 2008 May 23. Published in final edited form as:Crit Care Med. 2006 April ; 34(4): 1007-1015. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptTracheobronchial aspiration can be defined as the inhalation of oropharyngeal or gastric contents into the respiratory tract (1). Although aspiration from either source is important, the type of greatest concern in critically ill tube-fed patients is tracheobronchial aspiration of gastric contents. The extent to which aspiration of gastric contents occurs is difficu...