A female client admitted to an acute care facility after a car accident develops signs and symptoms of increased intracranial pressure (ICP). The client is intubated and placed on mechanical ventilation to help reduce ICP. To prevent a further rise in ICP caused by suctioning, the nurse anticipates administering which drug endotracheally before suctioning?
A. phenytoin (Dilantin)
B. mannitol (Osmitrol)
C. lidocaine (Xylocaine)
D. furosemide (Lasix)
Correct Answer: C. lidocaine (Xylocaine)
Administering lidocaine via an endotracheal tube may minimize elevations in ICP caused by suctioning. Lidocaine use, both intravenous (IV) and laryngotracheal (LT), has been reported to blunt the ICP elevations during intubation. Though one would assume that the ICP mediated effects of lidocaine stem from its local anesthetic effect, there are other proposed mechanisms of ICP reduction via the IV route. Lidocaine injected IV has been shown in models to induce cerebral vasoconstriction leading to a decrease in cerebral blood volume and thus ICP. Furthermore, IV lidocaine leads to sodium channel inhibition and thus a reduction in cerebral activity and metabolic demands, as well as excitotoxicity, leading to a potential ICP reduction effect.
Option A: Phenytoin doesn’t reduce ICP directly but may be used to abolish seizures, which can increase ICP. However, phenytoin isn’t administered endotracheally. Phenytoin is a hydantoin derivative, a first-generation anticonvulsant drug that is effective in the treatment of generalized tonic-clonic seizures, complex partial seizures, and status epilepticus without significantly impairing neurological function.
Option B: Mannitol may be used for the reduction of intracranial pressure. In this indication, mannitol administration is intravenous. Mannitol then constitutes a new solute in the plasma, which increases the tonicity of the plasma. Since mannitol cannot cross the intact blood-brain barrier, the increased tonicity from the mannitol draws water out of the brain parenchyma and into the intravascular space. The water then travels with the mannitol to the kidneys, where it gets excreted in the urine.
Option D: Although furosemide may be given to reduce ICP, they’re administered parenterally, not endotracheally. Furosemide inhibits tubular reabsorption of sodium and chloride in the proximal and distal tubules, as well as in the thick ascending loop of Henle by inhibiting sodium-chloride cotransport system resulting in excessive excretion of water along with sodium, chloride, magnesium, and calcium.
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