Because most therapies for elevated ICP dehydrate the patient or reduce cardiac filling pressures, thereby leading to hypotension, a middle course of avoiding both severe hypertension and any degree of hypotension seems the best compromise. In lowering high levels of blood pressure, diuretics, beta-adrenergic blocking agents, or angiotensin-converting enzyme inhibitors are generally used, rather than agents that potentially dilate the cerebral vasculature (nitroglycerin and nitroprusside, hydralazine, and some of the calcium channel blockers may present this risk). Hypotension should be corrected by vasopressor agents such as phenylephrine or norepinephrine. The precise level of blood pressure that requires treatment must be judged in the context of the ICP and the presence of plateau waves, the goal being to maintain normal cerebral perfusion pressure of 60 to 80 mm Hg, as well as the patient’s previous blood pressure level; evidence of organ failure from either hyperor hypotension, such as cardiac or renal ischemia, must also be considered.
If coma persists for more than 48 h, a nasogastric tube should be passed and fluids and nutrition should be given by this route. A basilar skull fracture, especially if there is a CSF leak, may preclude this route and compel a directly situated gastric tube. Agents that reduce gastric acid production—or the equivalent, antacids by stomach tube to keep gastric acidity at a pH above 3.5—are of value in preventing gastric hemorrhage. The prophylactic use of antiepileptic drugs, as discussed earlier, under “Posttraumatic Epilepsy,” recently has been favored, but there is no evidence that delayed epileptic seizures are reduced (see Chang and Lowenstein). Only if there has been a seizure are antiepileptics given.
Restlessness is controlled by diazepam, propofol, or a similar drug, but only if careful nursing fails to quiet the patient and provide sleep for a few hours at a time. Etomidate and dexmedetomidine may be preferable for reducing agitation because they are minimally sedating. Fever is counteracted by antipyretics such as acetaminophen and, if necessary, by a cooling blanket. The use of morphine or bromocriptine to quiet episodes of vigorous extensor posturing and accompanying adrenergic activity already has been mentioned.
The need for surgical intervention during the acute posttraumatic period is decided by two factors: the clinical status of the patient and the findings on imaging. The presence of a subdural or epidural clot that is causing a shift of central brain structures calls for evacuation of the collection. The approach to these lesions has been discussed earlier. Should the elevated ICP not respond to this procedure or to the standard osmotic agents and other medical measures outlined earlier, or should the condition of the patient and vital signs then begin to deteriorate (heart rate rising, temperature rising or falling below normal, state of consciousness worsening, hemiplegia, plantar reflexes more clearly extensor), a renewed search must be undertaken for a late-occurring cerebral hemorrhage. Usually in these clinical circumstances, CT scanning will disclose a new or enlarged epidural, subdural, or intracerebral hematoma, or worsened cerebral edema. If death or severe disability is to be avoided, operation in these cases must be undertaken before the advanced signs of brainstem compression—decerebrate or decorticate posturing, hypertension, bradycardia—have appeared.