What is the function of antidiuretic hormone (ADH) during positive pressure ventilation?

The function of antidiuretic hormone (ADH) during positive pressure ventilation is primarily to regulate fluid balance. When positive pressure ventilation is applied, it can lead to increased intrathoracic pressure, which can affect venous return to the heart and potentially result in a relative decrease in blood volume. In response to this change, the body may release ADH to promote water reabsorption in the kidneys, thus helping to maintain blood volume and osmotic balance.

This fluid retention is crucial because maintaining adequate blood volume can prevent complications such as hypotension and help ensure that organs receive sufficient perfusion. By regulating fluid balance, ADH plays a key role in the body's response to the physiological changes experienced with positive pressure ventilation, ensuring stability in hemodynamics and overall fluid homeostasis.