Related Experiment Video
Updated: May 19, 2026
Real-Time, Semi-Automated Fluorescent Measurement of the Airway Surface Liquid pH of Primary Human Airway Epithelial Cells
Published on: June 13, 2019
Salivary Bicarbonate Fails to Mirror Systemic Acid-Base Balance in Pediatric Patients at Risk of Metabolic
Nicola Bertazza Partigiani1, Marco Moi1, Alessandro D'Uva1
1Pediatric Nephrology, Department of Women's and Children's Health, University Hospital of Padua, Padua, Italy.
Insights
Salivary bicarbonate does not indicate systemic acid-base status in children. However, elevated levels in saliva were observed in advanced chronic kidney disease (CKD), suggesting a localized regulatory mechanism.
Area of Science:
- Pediatric Nephrology
- Biochemistry
- Clinical Chemistry
Background:
- The utility of salivary bicarbonate as a non-invasive marker for systemic acid-base status in pediatric patients is not well-established.
- Investigating salivary bicarbonate is crucial for patients at risk of acid-base disturbances, such as those with chronic kidney disease (CKD) or on acetazolamide therapy.
Purpose of the Study:
- To determine the correlation between salivary bicarbonate and systemic acid-base status assessed via blood gas analysis in pediatric patients.
- To explore the relationship between salivary bicarbonate and clinical factors like chronic kidney disease severity and medication use.
Main Methods:
- A single-center cross-sectional study involving 94 pediatric patients (aged 6-18 years) was conducted.
- Simultaneous blood and saliva samples were collected for comprehensive gas analysis.
- Patients were categorized into metabolic acidosis, normal, or metabolic alkalosis groups based on serum bicarbonate levels.
Main Results:
- No significant correlation was found between salivary bicarbonate and serum bicarbonate, pH, or base excess.
- Strong positive correlations were observed between salivary bicarbonate and salivary pH (r=0.682) and salivary base excess (r=0.865).
- Patients with estimated glomerular filtration rate (eGFR) <30 ml/min/1.73m² exhibited significantly higher salivary bicarbonate levels, negatively associated with calcium and lactate.
Conclusions:
- Salivary bicarbonate does not accurately reflect systemic acid-base balance in pediatric patients.
- Elevated salivary bicarbonate in advanced CKD suggests a localized regulatory process that warrants further investigation.
- Salivary analysis may offer insights into specific physiological changes in pediatric kidney disease, independent of systemic acid-base status.
Abstract:
Introduction. The utility of salivary bicarbonate as a non-invasive marker of systemic acid-base status in pediatric patients remains unclear. This study investigated the possible correlation between salivary and blood gas analysis at risk for acid-base disturbances, including those with chronic kidney disease (CKD) or receiving acetazolamide. Methods. In a single-center cross-sectional study (July 2024-March 2025), 94 pediatric patients (6-18 years) underwent simultaneous blood and saliva sampling for gas analysis. Patients were stratified into metabolic acidosis (<22 mmol/L), normal (22-26 mmol/L), or metabolic alkalosis (>26 mmol/L) groups based on serum bicarbonate. Results. No relationship was observed between salivary and serum bicarbonate (r = 0.112, p = 0.281), pH, or base excess. However, strong correlations emerged within salivary parameters: bicarbonate was positively associated with salivary pH (r = 0.682, p < 0.001) and base excess (r = 0.865, p < 0.001). Patients with eGFR <30 ml/min/1.73m² had significantly higher salivary bicarbonate (13.6 mmol/L vs 6.8 mmol/L, p = 0.004), independently of bicarbonate supplementation. This was also negatively associated with calcium (β = -8.67, p = 0.004) and lactate (β = -0.82, p = 0.008). Dialysis status and underlying diagnosis were additional independent predictors. While patients with metabolic acidosis showed higher median salivary bicarbonate than those with normal or alkalotic profiles, this difference was not statistically significant (p = 0.545). Conclusions. Salivary bicarbonate does not reflect systemic acid-base balance but is elevated in advanced CKD, suggesting a local regulatory phenomenon worthy of further exploration.
Related Concept Videos
01:22Bicarbonate-Carbonic Acid Buffer
01:29Disorders of Acid-Base Balance
Respiratory Acidosis and Alkalosis
Respiratory acidosis occurs due to an increase in the partial pressure of carbon dioxide PCO2 in the blood. It often arises from shallow breathing or impaired gas exchange caused by...
01:24Diagnosing Acidosis and Alkalosis
First, the pH level is assessed to determine whether the blood pH is normal (7.35–7.45), low (acidosis), or high (alkalosis).
Next, the PCO2 and HCO3− values are examined to...
01:25Acid-Base Balance
When the pH of arterial blood rises above 7.45, it results in a condition called alkalosis. Conversely, a drop below 7.35 leads to...
01:18Respiratory Regulation of Acid-Base Balance
When carbon dioxide levels increase in the blood, more H+ and HCO3⁻ are produced, leading to a...
01:29Renal Regulation of Acid-Base Balance
In the kidneys, cells within the proximal convoluted tubules (PCT) and the collecting ducts secrete hydrogen ions (H+) into the tubular fluid. Specifically, in the PCT, Na+/H+ antiporters secrete H+ while reabsorbing Na+.
However, the intercalated cells in...