Acid-base balance in acute gastrointestinal bleeding

Area of Science:

• Gastroenterology
• Critical Care Medicine
• Biochemistry

Background:

• Acid-base balance is crucial in critically ill patients.
• Acute upper gastrointestinal bleeding can lead to significant physiological disturbances.
• Metabolic acidosis is a potential complication requiring careful management.

Purpose of the Study:

• To investigate the characteristics of acid-base balance in patients with acute upper gastrointestinal bleeding.
• To identify the causes and contributing factors of metabolic acidosis in this patient group.
• To evaluate the impact of blood transfusion on acid-base status.

Main Methods:

• Studied acid-base balance in 21 patients with acute upper gastrointestinal bleeding.
• Measured plasma bicarbonate, base deficit, blood pH, and lactate levels.
• Analyzed the relationship between clinical shock, hyperlactataemia, and acid-base status before and after blood transfusion.

Main Results:

• Nine patients (43%) presented with metabolic acidosis, characterized by low plasma bicarbonate and base deficit.
• Hyperlactataemia was a primary contributor to acidosis, potentially due to poor tissue perfusion and anaerobic glycolysis in shocked patients.
• Blood transfusion increased lactate levels in non-shocked patients and did not correct severe acidosis in a shocked patient, likely due to anaerobic metabolism in stored red blood cells.

Conclusions:

• Metabolic acidosis, often driven by hyperlactataemia, is a significant issue in acute upper gastrointestinal bleeding, particularly in shocked patients.
• Monitoring acid-base status is essential for guiding treatment in these patients.
• Intravenous sodium bicarbonate can be used to correct metabolic acidosis, and understanding the effects of blood transfusion on lactate is important.