NREMT Advanced EMT Practice Test #4

Answer - C - A normal blood PaCO2 level is 40mm Hg. Increasing the PaCO2 causes cerebral vasodilation, while decreasing it results in cerebral vasoconstriction. If the patient is poorly ventilated, the PaCO2 will increase, causing even further vasodilation with a subsequent increase in intracranial pressure. Hyperventilation can decrease the PaCO2 to nearly 25mm Hg, effectively causing vasoconstriction of the cerebral vessels. This will help minimize brain swelling. Hyperventilate patient at 20 ventilations per minute only if there is evidence of brain herniation.