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Updated: Apr 17, 2026
Simultaneous Laryngopharyngeal and Conventional Esophageal pH Monitoring
Published on: December 14, 2020
Gastric reflux: association with aspiration and oral secretion pH as marker of reflux: a descriptive correlational
Marilyn Schallom1, James A Orr, Norma Metheny
1Marilyn Schallom, PhD, RN, CCNS, is a research scientist in the Department of Research at Barnes-Jewish Hospital at Washington University with a research focus of prevention of complications in critical care patients. James A. Orr, PhD, is a professor in the Department of Molecular Bioscience at the University of Kansas with a research focus on neural reflexes of the heart and lungs. Norma Metheny, PhD, RN, FAAN, is the associate dean of research at St Louis University. Dr Metheny has researched extensively in the field of pulmonary aspiration associated with gastric feedings. John Kirby, MD, FACS, is an associate professor of surgery specializing in acute and critical care surgery and burn/trauma/surgical critical care. Dr Kirby is also the medical director of the wound healing program. Janet Pierce, PhD, APRN, CCRN, FAAN, is a professor of nursing and an adjunct professor in the department of Molecular and Integrative Physiology at the University of Kansas. Dr Pierce is a nurse scientist conducting bench critical care research of shock and oxidative stress models.
Background:
Gastric reflux leading to pulmonary aspiration is a frequent event in mechanically ventilated, gastric-fed patients, which can lead to ventilator-associated complications and pneumonia.
Objectives:
The objectives of this study were to determine the association between gastric reflux and aspiration using the presence of pepsin in oral or tracheal secretions as a marker of reflux or aspiration and to determine the association between the pH (range, 0-14) and the presence of pepsin in oral secretions.
Methods:
A descriptive correlational study was conducted in mechanically ventilated surgical or medical patients receiving gastric tube feedings. Oral secretions were suctioned hourly and tracheal secretions every 2 to 3 hours for 12-hour periods over 1 to 2 days in 15 patients.
Results:
There were 142 paired samples of oral tracheal secretions. A majority of samples (60%) had the same results, with 32% both pepsin-positive and 27% both pepsin-negative. The range of pH measurements was 4 to 8, with a mean of 6.3 ± 0.05. Ninety oral specimens had a pH of 4 to 6. Forty-seven of the oral specimens with pH measures between 4 and 6 (52%) were pepsin-positive. The correlation of pH percent pepsin-positive oral secretions was not significant.
Conclusion:
Aspiration events were more frequent than reflux events. Measurement of actual pepsin concentration to detect new reflux and aspiration events is recommended in future studies. Bedside pH measures of oral secretions are not a valid marker of gastric reflux.
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