Related Experiment Video
Updated: Jun 13, 2026
06:47
Measurement and Analysis of Extracellular Acid Production to Determine Glycolytic Rate
Published on: December 12, 2015
Hunting down a double gap metabolic acidosis
Ming-Tso Yan1, Tom Chau, Chih-Jen Cheng
1Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Annals of Clinical Biochemistry
|April 22, 2010
Summary
Propylene glycol (PG) caused a high osmolal gap metabolic acidosis in a ventilated patient. Unexpectedly, PG’s metabolites, lactate, were not elevated, highlighting PG as a key differential diagnosis.
Area of Science:
- Toxicology
- Nephrology
- Critical Care Medicine
Background:
- Metabolic acidosis with a high anion gap (AG) and osmolal gap (OG) suggests unmeasured osmoles.
- Acute respiratory failure and anuric renal failure complicated a patient requiring mechanical ventilation and hemodialysis.
Observation:
- A 67-year-old woman developed progressive metabolic acidosis with a high AG and OG.
- Serum analysis revealed elevated propylene glycol (PG) but normal lactate levels.
- Despite hemodialysis removing PG and normalizing the OG, the high AG acidosis persisted.
Findings:
- Propylene glycol (PG) was identified as the cause of the high osmolal gap.
- Metabolic acidosis persisted despite PG removal, suggesting other contributing factors like hypercatabolism and renal failure.
- L- and D-lactate levels were not elevated, despite PG metabolism.
Implications:
- Propylene glycol (PG) should be considered in the differential diagnosis of high osmolal gap metabolic acidosis.
- Elevated lactate is not a mandatory finding in propylene glycol (PG) toxicity.
- Understanding the etiology of persistent high AG metabolic acidosis in critically ill patients is crucial.
Related Concept Videos
01:24Diagnosing Acidosis and Alkalosis
Diagnosing acid-base imbalances involves systematically analyzing arterial blood samples, focusing on three key measurements: pH, bicarbonate (HCO3−) concentration, and carbon dioxide partial pressure (PCO2). This analysis follows a four-step process that helps identify the imbalance's underlying cause and nature.
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...
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...
01:22Diabetic Ketoacidosis ll: Pathophysiology
Diabetic ketoacidosis (DKA) is a metabolic emergency characterized by hyperglycemia, ketonemia, and metabolic acidosis. It results from severe insulin deficiency and an excess of counterregulatory hormones, leading to uncontrolled lipolysis, ketogenesis, and widespread electrolyte and fluid disturbances.Pathophysiology The central event in DKA is a profound loss of insulin action. Without insulin, glucose uptake in insulin-dependent tissues is impaired, while hepatic glucose production...
01:25Diabetic Ketoacidosis l: Introduction
DefinitionDiabetic ketoacidosis (DKA) is an acute, life-threatening complication of diabetes mellitus, characterized by a triad of hyperglycemia (blood glucose >250 mg/dL), ketonemia or ketonuria, and metabolic acidosis (arterial pH <7.30 and serum bicarbonate <18 mEq/L). It results from insulin deficiency combined with elevated levels of counterregulatory hormones—glucagon, catecholamines, cortisol, and growth hormone—leading to increased lipolysis, hepatic ketone production, and...
01:29Disorders of Acid-Base Balance
The human body maintains a precise pH range of arterial blood between 7.35 and 7.45. Deviations result in either acidosis (pH < 7.35) or alkalosis (pH > 7.45). These conditions are further classified as respiratory or metabolic disorders based on their underlying cause.
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...
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...
01:30Acute Respiratory Failure-III
Hypercapnic respiratory failure, also known as Type 2 or ventilatory respiratory failure, is a severe condition characterized by the body's inability to effectively remove carbon dioxide (CO2) from the bloodstream. It leads to an arterial CO2 pressure (PaCO2) exceeding 45 mmHg and a blood pH above 7.35. This situation indicates that the body's ventilatory demand, or the ventilation needed to maintain normal PaCO2 levels, surpasses its supply or the maximum gas flow achievable without causing...
01:25Acid-Base Balance
The human body maintains a narrow pH range regulated through acid-base balance. This balance is crucial as changes in the hydrogen ion concentration can disrupt cell membrane stability, alter protein structures, and change enzyme activities. The normal pH of arterial blood is 7.4, venous blood and interstitial fluid is 7.35, and intracellular fluid averages 7.0.
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...
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...