RESUMEN
BACKGROUND: Gastroesophageal reflux (GER) and pulmonary aspiration are frequent in patients in the ICU. The presence of pepsin in airways seems to be the link between them. However, pepsin isoforms A (gastric specific) and C (pneumocyte potentially derived) need to be distinguished. This study aimed to evaluate GER patterns and to determine the presence of pepsin A and C in tracheal secretions of critically ill children receiving mechanical ventilation. METHODS: All patients underwent combined multichannel intraluminal impedance-pH (MII-pH) monitoring. Tracheal secretion samples were collected to determine the presence of pepsin. Pepsin A and C were evaluated by Western blot. MII-pH parameters analyzed were number of total GER episodes (NGER); acid, weakly acidic, and weakly alkaline GER episodes; and proximal and distal GER episodes. RESULTS: Thirty-four patients (median age, 4 months; range, 1-174 months) were included. MII-pH monitoring detected 2,172 GER episodes (77.0% were weakly acidic; 71.7% were proximal). The median NGER episodes per patient was 59.5 (25th-75th percentile, 20.3-85.3). Weakly acidic GER episodes per patient were significantly more frequent than acid GER episodes per patient (median [25th-75th percentile], 43.5 [20.3-68.3] vs 1.0 [0-13.8], respectively; P < .001). Only three patients had an altered acid reflux index (44.9%, 12.7%, and 13.6%) while not taking antacid drugs. Pepsin A was found in 100% of samples and pepsin C in 76.5%. CONCLUSIONS: The majority of GER episodes of children in the ICU were proximal and weakly acidic. All patients had aspiration of gastric contents as detected by pepsin A in tracheal fluid. A specific pepsin assay should be performed to establish gastropulmonary aspiration because pepsin C was found in > 70% of samples.