Intracellular and extracellular acid-base changes in hemorrhagic shock

Area of Science:

• Physiology
• Pathophysiology
• Biochemistry

Background:

• Hemorrhagic shock leads to significant physiological derangements.
• Understanding acid-base balance during shock is crucial for treatment.

Purpose of the Study:

• To investigate the acid-base status and lactate levels in arterial and venous blood during hemorrhagic shock.
• To examine the intracellular acid-base balance in skeletal muscle during shock.

Main Methods:

• Inducing hemorrhagic shock in 21 dogs by reducing mean arterial blood pressure to 50 torr for two hours.
• Measuring blood lactate, PCO2, and pH in arterial and mixed venous blood.
• Analyzing intracellular lactate, pH, and bicarbonate in hind limb skeletal muscle.

Main Results:

• Blood lactate concentration increased sixfold during shock.
• Arterial blood showed metabolic acidosis partially compensated by respiratory alkalosis, while venous blood exhibited combined metabolic and respiratory acidosis.
• Skeletal muscle showed increased intracellular lactate and PCO2 but maintained intracellular pH and bicarbonate concentration.

Conclusions:

• Skeletal muscle demonstrates a significant capacity to maintain intracellular acid-base balance during hemorrhagic shock.
• This suggests an enhanced bicarbonate buffering system in muscle cells during severe acidosis.