How does hypovolaemia contribute to cardiac arrest?

Hypovolaemia, which refers to a decreased volume of blood in the circulatory system, directly impacts oxygen delivery to vital organs. When the blood volume is low, there is insufficient blood to transport adequate oxygen to tissues and organs, including the heart. This lack of oxygen can lead to cellular dysfunction and eventual organ failure.

As the heart, which relies on a sufficient volume of oxygen-rich blood to function effectively, becomes compromised, this can eventually lead to cardiac arrest. The heart may not be able to generate enough pressure to effectively perfuse the body's tissues, which can lead to the cessation of normal cardiac activity.

In scenarios of hypovolaemia, the heart struggles with inadequate preload (the initial stretching of the cardiac muscle prior to contraction), which is essential for maintaining cardiac output. Thus, reduced oxygen delivery plays a critical role in the process that can culminate in cardiac arrest, underscoring the importance of maintaining blood volume for sustaining life.