Home Clinical Neurologic fallout in ICU patients

Neurologic fallout in ICU patients

June 2010

Published in the June 2010 issue of Today’s Hospitalist

In hospitals around the country, hospitalists now take a leading role in treating neurologic patients, caring for conditions like stroke. But many patients in the ICU have serious neurological issues that arise from nonneurological diagnoses. That’s significant because so many hospitalists cover the ICU.

At a hospital medicine conference held last fall by the University of California, San Francisco (UCSF), S. Andrew Josephson, MD, director of the neurohospitalist program and assistant professor of neurology at UCSF, led audience members through several of those ICU emergencies. The cases highlighted the major neurological fall-out that hospitalists confront when treating critically ill patients, and the approaches they should take in treatment.

1. Critical illness polyneuropathy or myopathy
One neurologic problem in the ICU is so common, Dr. Josephson said, that “if you are not seeing this in the majority of patients in your unit who are sick, you’re missing it a lot.”

As many as 70% of patients with sepsis and more than half of those with ARDS have critical illness polyneuropathy or myopathy, which presents as muscle weakness, wasting and flaccid paralysis. The condition can lead to difficulty being weaned from ventilation, increased length of stay, impaired long-term recovery and even increased mortality.

At highest risk are ICU patients with sepsis, multi-organ failure and high-acuity conditions, as well as patients exposed to steroids or neuromuscular junction blockers. Those medications “should be avoided if at all possible in ICU patients,” said Dr. Josephson. Patients generally recover on their own with supportive treatment, although intensive insulin therapy may be useful.

While tight glycemic control in the ICU has been associated with hypoglycemia and no improvement in outcomes, tighter glucose control for patients with critical care neuropathy “is probably a good idea,” Dr. Josephson pointed out. “It might allow patients to recover more quickly.”

2. Intracerebral hemorrhage
For hospitalists, a major turf issue that has emerged in the past several years is the management of intracerebral hemorrhage (ICH). (See “Are you OK taking care of this patient?” in the December 2009 Today’s Hospitalist.) According to Dr. Josephson, neurosurgeons are backing away from surgical interventions and leaving the management of these patients to neurologists and hospitalists.

“Intracerebral hemorrhage is not a neurosurgical disease,” he pointed out. The exceptions are ICH locations that are very close to the surface of the brain and cerebellar hemorrhages. “Other than in those rare surgical situations,” said Dr. Josephson, “treatment is blood pressure management and checking the coags and correcting them with occasional management of high ICP.”

Dr. Josephson said that once a CT shows blood, the No. 1 priority should be controlling blood pressure. At UCSF, Dr. Josephson said the neurohospitalists decrease blood pressure “pretty aggressively” using IV labetalol and nicardipine.

Guidelines suggest decreasing pressure below a mean arterial pressure (MAP) of 110, when possible. Blood pressure control is particularly critical, Dr. Josephson said, to prevent the hemorrhage from expanding.

He noted that one-third of hemorrhages expand within the first few hours, which is associated with poorer outcomes. A major focus of current research, he said, is trying to reduce ICH expansion.

Correcting coagulopathy is another key step. Check platelet counts, stop all anticoagulants, and check other medications patients may be taking and their INR to determine their level of coagulopathy.

For warfarin patients, new guidelines recommend giving a rapid reverser agent, such as factor IX complex concentrate, to prevent the hemorrhage from growing. (Because factor IX complex wears off in a few hours, patients should also receive vitamin K and fresh frozen plasma.) While activated factor VII was once viewed as a promising therapy in patients without coagulopathy, its effectiveness with ICH patients has since been debunked in a large randomized trial.

“We use these rapid corrective agents only for people who are coagulopathic,” Dr. Josephson said, “not for patients with normal coags.”

And stay away from steroids for ICH patients, Dr. Josephson advised, because studies show that the drugs “make things worse.” It’s also a good idea to steer clear of prophylactic anticonvulsants unless patients have experienced a clinical seizure.

3. Intracranial pressure

Finally, Dr. Josephson described a patient with metastatic cancer who becomes obtunded in the ICU. “The patient is herniating before your eyes,” he said. “What do you do?”

The first step to reduce intracranial pressure is to simply sit the patient up, which helps increase venous return from the brain and reduces intracranial pressure “by a fair amount,” he pointed out.

The mainstay of treatment is osmotic agents like mannitol, which removes brain water and shrinks the brain to help with swelling. Because the mannitol dose is 1 g/kg, “I give 50 grams to a little person and 100 grams to a big one,” Dr. Josephson said.

An alternative for patients with renal failure in whom mannitol is contraindicated is 23% saline. “Massively hypertonic saline as a 10 cc bolus has the exact same effect as mannitol,” he explained.

When considering emergent ICP management, Dr. Josephson urged hospitalists to keep the concept of treating emergent cerebral perfusion pressure (CPP) in mind.

“The cerebral perfusion pressure is how much blood is getting to the hemispheres,” he said. “That’s what really matters, not the ICP.” Physicians should keep in mind the following equation, which he finds helpful: CPP=MAP-ICP.

That means you can help CPP in two ways, Dr. Josephson pointed out: either decrease ICP or increase MAP. “That’s why if somebody is herniating, the wrong thing to do is to lower the blood pressure,” he explained. “Elevated blood pressure during herniation is partially the body’s natural response of cerebral vasodilation in an attempt to get perfusion to the hemispheres.” Treating this acutely can only drive the CPP down and lead to worsening injury.

Finally, Dr. Josephson said, hospitalists working in the ICU need to remember how “incredibly common” and neurologically devastating delirium can be. To mitigate the condition, he recommended propofol or dexmedetomidine as top choices for sedatives that have decreased incidence of delirium.

“Choose your sedatives carefully,” Dr. Josephson said.

Sara Jackson is a freelance health care writer based near Richmond, Va.