Maneuvers that increase intra-abdominal pressure such as bending
over or exercise may increase episodes of reflux.
There is an initial increase in bicarbonate-containing saliva following
placement of a nasogastric tube, which can underestimate GER.
Mahajan, et al. Reproducibility of 24-hour intraesophageal
pH monitoring in pediatric patients. Pediatrics, 1998;101:260-263.
Sondheimer J. Continuous monitoring of distal esophageal pH:
A diagnostic test for gastroesophageal reflux in infants.
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Friesen, et al. Accuracy and reproducibility of 12-hour esophageal
pH monitoring. Journal of Pediatric Gastroenterology and
Nutrition, 1991; 12:166-168.