Endotracheal intubation increases the risk for microaspiration of secretions around the tube cuff. Pepsin has been used as a biomarker for gastric aspiration. Amylase is a newer proposed biomarker for aspiration of oral contents.


To assess the presence of pepsin and amylase in paired oral-tracheal secretions of adult patients treated with mechanical ventilation.


In this descriptive study, paired samples of oral and tracheal secretions were obtained from adult patients at baseline and again within 4 hours when a need for endotracheal suctioning was assessed. Assays of pepsin and amylase were processed in a specialty diagnostic laboratory.


The sample consisted of 10 men and 3 women with a median age of 56 years. The majority were intubated with a subglottic suction endotracheal tube (9 patients, 69%), receiving synchronized intermittent mandatory ventilation (10 patients; 77%), and receiving enteral feedings (11 patients; 85%) through a tube distally placed in the stomach (8 patients; 67%). Pepsin was present in oral secretions of 9 patients (69%), and in tracheal specimens of 7 patients (54%) at one or both sampling times. Amylase was detected in all patients’ oral secretions and in tracheal secretions of 5 patients (38%) at one or both sampling times.


Many patients had pepsin, amylase, or both in tracheal aspirates. Pepsin was more commonly detected than was amylase. Although the relationship of this finding to long-term outcomes was not assessed, findings indicate that microaspiration of oral and gastric secretions occurs frequently.

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