The nurse is caring for a mechanically ventilated patient with a brain injury.Arterial blood gas values indicate a PaCO₂ of 60 mm Hg.The nurse understands this value to have which effect on cerebral blood flow? A) Altered cerebral spinal fluid production and reabsorption B) Decreased cerebral blood volume due to vessel constriction C) Increased cerebral blood volume due to vessel dilation D) No effect on cerebral blood flow (PaCO₂ of 60 mm Hg is normal)

Question

Quizplus · Accepted Answer

Cerebral vessels dilate when PaCO₂ levels increase,increasing cerebral blood volume. To compensate for increased cerebral blood volume,cerebral spinal fluid may be displaced,but the scenario is asking for the effect of hypercarbia (elevated PaCO₂)on cerebral blood flow.PaCO₂ of 60 mm Hg is elevated,which would cause cerebral vasodilation and increased cerebral blood volume.

The Nurse Is Caring for a Mechanically Ventilated Patient with a Brain