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Updated: Aug 12, 2026
Simultaneous Laryngopharyngeal and Conventional Esophageal pH Monitoring
Published on: December 14, 2020
Control and variability of gastric pH in critically ill children
R G Gedeit1, C G Weigle, P L Havens
1Department of Pediatrics, Medical College of Wisconsin, Milwaukee.
Insights
Pediatric ICU patients with severe illness or central nervous system injury had poor gastric pH control with ranitidine. Continuous ranitidine infusion reduced gastric pH variability, improving monitoring accuracy.
Area of Science:
- Pediatric critical care medicine
- Gastroenterology
- Pharmacology
Background:
- Gastric acid suppression is crucial in pediatric intensive care units (ICUs).
- Ranitidine is commonly used, but its efficacy varies.
- Illness severity and central nervous system (CNS) injury may impact gastric pH control.
Purpose of the Study:
- To assess the effect of illness severity and acute CNS injury on gastric pH control and variability in pediatric ICU patients receiving ranitidine.
- To compare gastric pH control between patients with severe/CNS injury and others.
- To evaluate the impact of ranitidine administration method (bolus vs. continuous) on gastric pH variability.
Main Methods:
- Prospective, descriptive study in a pediatric ICU.
- Fourteen pediatric ICU patients received ranitidine (4 mg/kg/day).
- Gastric pH was continuously monitored; illness severity assessed by Pediatric Risk of Mortality (PRISM) score; CNS injury was categorized.
Main Results:
- Patients with severe illness or acute CNS injury had lower mean gastric pH (4.6 vs. 6.4) and spent more time with pH < 4.0 (47.5% vs. 12.5%).
- Poor gastric pH control (pH < 4.0 for >20% of time) occurred in 100% of severe/CNS injury patients versus 20% of others.
- Continuous ranitidine infusion resulted in less gastric pH variability compared to bolus administration (p = .045).
Conclusions:
- Children with acute CNS injury or high PRISM scores (> or = 20) exhibit poor gastric pH control despite ranitidine therapy.
- Continuous ranitidine infusion improves gastric pH control by reducing variability.
- Illness type and severity predict ranitidine response, suggesting tailored dosing strategies may be necessary.
Objectives:
To determine the effect of illness severity and acute central nervous system injury on the control and variability of gastric pH in pediatric intensive care unit (ICU) patients receiving ranitidine.
Design:
Prospective, descriptive study.
Setting:
Pediatric ICU of a children's hospital.
Patients:
Fourteen pediatric ICU patients.
Interventions:
Ranitidine (4 mg/kg/day) was administered to all patients.
Measurements And Main Results:
Patients enrolled in the study were divided into two groups based on illness type and severity. Illness severity was measured by the Pediatric Risk of Mortality (PRISM) score, with a PRISM score of > or = 20 defining severe illness. Illness type was designated as central nervous system or noncentral nervous system. Gastric pH was continuously monitored in all patients using an intragastric, pH-sensitive electrode. Poor control of gastric pH was defined as a pH of < 4.0 for > 20% of the time monitored. The statistical significance of the differences between groups was measured using the Wilcoxon two-sample test or Fisher's exact test. Patients with severe illness or acute central nervous system injury had a lower mean gastric pH than all other patients (4.6 vs. 6.4; p = .008) and spent more time with a gastric pH of < 4.0 than other patients (47.5% of time monitored vs. 12.5% of time monitored; p = .003). Poor control of gastric pH occurred in 100% of patients with severe illness or acute central nervous system injury, while only 20% of the remaining patients had poor control of gastric pH (p = .01). Using power-spectrum analysis to evaluate gastric pH variability, gastric pH in patients receiving bolus ranitidine was more variable than gastric pH in patients receiving ranitidine continuously (p = .045). Illness severity or type had no effect on gastric pH variability (p = .78).
Conclusions:
a) Continuous infusion of ranitidine decreases variability of gastric pH in pediatric ICU patients; b) gastric pH variability may make intermittent monitoring of gastric pH inaccurate; c) children with acute central nervous system injury or PRISM scores of > or = 20 have poor control of gastric pH; d) type of injury and PRISM scores predict response to ranitidine therapy.
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