What intervention should be taken first upon noticing signs of hemolysis?

Stopping the blood pump is the critical first intervention upon noticing signs of hemolysis during hemodialysis. Hemolysis, which is the destruction of red blood cells, can lead to significant complications such as a sudden drop in hemoglobin levels, hemoglobinuria, and potential acute kidney injury. By stopping the blood pump immediately, healthcare providers prevent further blood flow through the dialysis system where hemolysis is occurring, thereby minimizing additional damage to the patient's erythrocytes and preventing more serious systemic effects.

This action allows for the immediate assessment and stabilization of the patient before taking further steps, such as monitoring vital signs, notifying the physician, or administering supplemental oxygen, which are essential but may follow after ensuring that blood flow is halted to address the hemolysis. This prioritization is crucial in an acute setting to safeguard the patient's health and prevent worsening of the condition.