Final answer:
The primary purpose of hyperventilation in a patient with increased intracranial pressure is to decrease cerebral blood flow by inducing hypocapnia, leading to vasoconstriction in cerebral vessels and a subsequent lowering of ICP.
Step-by-step explanation:
The purpose of hyperventilation in a client with increased intracranial pressure (ICP) and placed on mechanical ventilation is to decrease cerebral blood flow. Hyperventilation involves increasing the rate of ventilation which leads to a decrease in blood carbon dioxide levels (hypocapnia). This reduction in CO₂ levels causes vasoconstriction of cerebral vessels, ultimately lowering cerebral blood flow and thus ICP. Hypercapnia, on the other hand, would worsen the ICP by increasing cerebral blood flow.
Therefore, hyperventilation provides a therapeutic benefit by reducing ICP and potentially minimizing further brain injury. The other options such as preventing the development of acute respiratory failure, increasing systemic tissue perfusion, and preventing cerebral anoxia, are not the primary intentions of hyperventilation in this context