A pilot study of pepsin in tracheal and oral secretions.

BACKGROUND: Because reflux of gastric juice into the oropharynx must precede its aspiration into the lungs, it is reasonable to hypothesize that the detection of pepsin (the major gastric enzyme in gastric juice) in oral secretions may provide a relatively noninvasive method of predicting risk for aspiration. OBJECTIVE: To describe the incidence of pepsin in oral and tracheal secretions collected concurrently from a sample of 50 gastric-fed patients undergoing mechanical ventilation. METHODS: An exploratory descriptive design with a convenience sample from 4 medical and surgical intensive care units. An oral secretion and a tracheal secretion were collected concurrently from each patient (yielding a sample of 50 oral and 50 tracheal secretions). The tracheal secretions were obtained via the inline suction system with an attached sputum trap; oral secretions were obtained via a Yankauer suction tip with an attached sputum trap. All specimens were assayed for pepsin by the Western blot method. RESULTS: Oral secretions from 10 patients (20%) and tracheal secretions from 2 patients (4%) were pepsin-positive. Both patients with pepsin-positive tracheal secretions also had pepsin-positive oral secretions. Pepsin was not found in the tracheal secretions from the remaining 8 patients with pepsin-positive oral secretions. CONCLUSIONS: Although reflux of gastric juice into the oropharynx must precede its aspiration into the lungs, individual reflux events do not necessarily lead to aspiration. Thus, it is reasonable that we found pepsin 5 times more often in oral secretions than in tracheal secretions.

Early biochemical markers of inflammation in a swine model of endotracheal intubation.

BACKGROUND: A common complaint after endotracheal tube use is sore throat, which may be due to abrasion, ischemia-reperfusion injury, or an inflammatory reaction. Few studies have evaluated localized tracheal inflammation as part of the response to intubation. METHODS: Inflammation of the trachea due to intubation was assessed in a swine model by following indicators of inflammation over time in the tracheal lumen. Repeated tracheal lavages proximal to the endotracheal tube cuff were performed, and recovered lavage was analyzed for cells, protein, lactate dehydrogenase, and cytokines. RESULTS: The baseline tracheal lavage samples contained 18% polymorphonuclear cells. These cells increased rapidly to 43% by 1 h. The polymorphonuclear cell increase from baseline was significant at 1, 2, and 4 h (P < 0.01) after intubation. Tumor necrosis factor alpha, interleukin 1beta, interleukin 6, and interleukin 8 increased over time, but only interleukin 6 increased significantly (P < 0.01). Interleukin 6 was not detected at baseline or 1 h, but was detected at 2 h and increased significantly by 4 h. Neither lavage protein concentration nor lactate dehydrogenase activity increased over time. CONCLUSIONS: These results demonstrate that inflammation does occur during tracheal intubation, even when markers suggest minimal tracheal damage. The dramatic elevation in polymorphonuclear cells, along with the increase in interleukin 6, suggests an inflammatory response to the endotracheal tube itself or to some aspect of the intubation process. A more complete understanding of the response of the tracheal tissues is important in improving the treatment of intubated patients.