Two internists discuss how to treat common medical conditions in neurosurgery patients by Deborah Gesensway
Published in the October 2010 issue of Today's Hospitalist
It may be the one area of comanagement that makes hospitalists the most nervous: neurosurgery. For many hospitalists, comanaging neurosurgery patients veers too far from their medical training and comfort zone.
But two internists who head up the neurosurgery comanagement service at Seattle's Harborview Medical Center claim that hospitalists have a great deal to offer these patients, once their primary neurosurgical injury is addressed. During a presentation at this spring's Society of Hospital Medicine conference in Maryland, the physicians offered tips on treating medical conditions that are of particular concern in
"Hospitalists are nonchalant about low sodium, but neurosurgeons worry about cerebral edema."
–Rachel Thompson, MD Harborview Medical Center
neurosurgical patients: fever, delirium, sodium imbalance, and—what they called "everyone's favorite controversial topic"—anticoagulation.
At the same time, they acknowledged that some of their hospitalist colleagues were wary when the Harborview comanagement service was first proposed five years ago. They also admitted that most of the comanagement is provided by a few hospitalists who have a particular interest—and expertise—in neurosurgery.
"The brain is a scary thing, and if something goes wrong, it can go wrong quickly," noted Christina M. Gilmore, MD. "That is where establishing a great relationship with your surgical colleagues and having open lines of communication become really important."
Managing nosocomial fever
According to Dr. Gilmore, fever is "extraordinarily common" in neurosurgery patients and frequently caused by an infection, most often respiratory. The second most common infection in these patients is a urinary tract infection.
Fever is particularly alarming in neurosurgery patients, she added, because it can damage the brain by increasing either intracranial hypertension or the permeability of the blood-brain barrier. Fever, Dr. Gilmore noted, "correlates to poor clinical outcomes" and to as many as five additional days for patients with fever in the ICU.
Fever can also be associated with drugs, often carbamazepine and dilantin, but also phenobarbitol and other anticonvulsants; heparin; thyroid hormone; anticholinergics; antihistamines; phenothiazines; and hydralazine. Treatment, Dr. Gilmore said, is to stop the drug. It can take up to two weeks for a drug fever in a neurosurgery patient to clear after the drug is discontinued. Before deciding a neurosurgery patient has central fever—which, she said, is a "diagnosis of exclusion"— hospitalists should consider other possible causes. These may include deep venous thrombosis, sinusitis linked to a feeding tube, hepatitis or HIV.
Dr. Gilmore also pointed out that treating central fever with acetaminophen alone "is rarely successful," and that NSAIDs can be more helpful. At Harborview, the hospitalists sometimes use propranolol.
When it comes to delirium, neurosurgical patients are much more susceptible to the condition than hospitalized medical patients. According to Rachel
Thompson, MD, director of Harborview's medical consult service, one of the biggest problems hospitalists face with this population is determining whether a patient truly has delirium or a neurologic change.
While both Drs. Thompson and Gilmore conduct their own daily neurologic exams, they often—when they suspect delirium—call on the neurosurgical team to compare results of recent neurologic exams. They also review what they called "a trail of imaging" to try to assess possible neurologic changes.
Autonomic storm in this population may look like delirium. Then there are more common etiologies: infections, deranged sleep/wake cycles or medications. "People here love to use atypical antipsychotics for any sort of delirium," Dr. Gilmore said, "and I sometimes just stop them."
Neurosurgeons favor atypicals, she explained, because animal studies have found that they don't delay motor recovery. Unfortunately, that's not the case for typical antipsychotics like Haldol. Still, she recommended judicious use of typicals for managing delirium or agitation, or to consider prescribing a nonselective beta-blocker like propranolol in the case of autonomic storm.
Hyponatremia and the brain
Hyponatremia is another common condition among neurosurgery patients. But low plasma sodium levels tend to elicit very different reactions from internists than from neurosurgeons.
"We hospitalists are nonchalant about low sodium," Dr. Thompson said, "but neurosurgeons are more worried because of the risk of cerebral edema." While surgeons are concerned about brain swelling, which can cause brain damage and death, internists worry mainly about increased seizure risk when sodium levels fall near 110 mM.
While hyponatremia is potentially more damaging in neurosurgical populations, severe hyponatremia may have different causes in these patients. Most are due to syndrome of inappropriate antidiuretic hormone hypersecretion (SIADH), although a subset may be due to cerebral salt wasting (CSW). (CSW is usually not seen in the medical population, Dr. Thompson said.) SIADH is characterized by excessive antidiuretic hormone, extracellular fluid volume expansion through renal water reabsorption, and balanced sodium. CSW, by contrast, is marked by a negative sodium balance and contracted volume.
With neurosurgery patients, it's important to determine which is causing a patient's hyponatremia, Dr. Thompson added, "because the way we treat them is different." CSW is treated with normal saline and salt replacement; SIADH is treated with fluid restriction. And fluid restriction has to be done "with caution" in brain-injured patients for fear of cerebral hypoperfusion, she said.
Between 1% and 10% of neurosurgery patients have DVTs, said Dr. Gilmore, so hospitalists need to decide which type of prophylaxis—and what timing of delivery— is most effective and safe.
Compression stockings are one common option. Low-dose unfractionated heparin also appears to decrease the incidence of venous thromboembolism by at least 40% without increasing risks of intracranial hemorrhage. That's according to a meta-analysis of DVT prophylaxis in neurosurgery published in the July 18, 2008, issue of Chest. Use of heparin "48 hours after craniotomy," Dr. Gilmore said, is "acceptable at our institution"
There are fewer data on whether to use low molecular weight heparin, which may have an overall trend toward increased bleeding. But evidence suggests that for patients with multiple trauma or spinal cord injury, "enoxaparin is superior to unfractionated heparin," she explained.
Harborview's protocol calls for using compression devices and heparin for most neurosurgery patients after they are clinically stable and bleeding risks are low. "Unfractionated heparin is probably safer," Dr. Gilmore pointed out, "but more studies are needed."
Deborah Gesensway is a freelance writer based in Toronto who covers U.S. health care.
How one comanagement service evolved
ASK RACHEL THOMPSON, MD, director of the medical consult service at Harborview Medical Center in Seattle, about neurosurgical comanagement, and she'll quickly list the benefits of working closely with neurosurgery. The pros include less need for multiple subspecialty consults; better patient flow and satisfaction; improved care transitions for patients with medical comorbidities; and possibly, decreased length of stay and morbidity.
But she'll also tell you that the definition of comanagement varies greatly depending on the institution, and her hospital is a case in point. At Harborview, the hospitalists' comanagement of neurosurgery patients has gone through three iterations over the past five years, evolving from a consult to a primary service before settling into a more typical comanagement arrangement.
At the Society of Hospital Medicine meeting in April, Dr. Thompson said that in the program's first iteration, the hospitalists at Harborview began serving as medical consultants to the neurosurgeons. They were called in on a case-by-case basis to manage medical problems.
But a year or two later, the hospital took another tack and created a hospital medicine team that focused only on neurosurgical patients. Under that model, hospitalists acted as those patients' primary attendings once surgery was completed.
Why the switch? Dr. Thompson said that one factor was the success that hospitalists had acting as consultants. "The neurosurgeons found us really useful," she noted. At that time, neurosurgery was struggling with volume and with patients who had complicated medical comorbidities. The hospitalists, everyone felt, could improve patient flow and outcomes.
During that time, hospitalists took part in the neurosurgeons' 7a.m. rounds, and a hospitalist with a background in neurobiology was hired specifically to staff the service. That physician, Christina M. Gilmore, MD, pointed out that only a few of the hospitalists rotated through that primary service. As part of their training, those physicians attended weekly neurosurgical conferences and were schooled in how to read CTs and MRIs.
"We had lectures from the neurosurgeons, the way they might teach their own residents to watch out for things on the floor," Dr. Gilmore said. "That was a huge benefit."
Now, however, what had been a primary neurosurgical service has been converted to a robust comanagement model. What changed, said Dr. Thompson, was partly "the economics," including a nationwide decrease in trauma cases. That, along with improved patient flow, resulted in a lower patient census.
Today, the neurosurgery service might have between 60 and 100 patients in-house at any one time, with one-third to one-half of those patients comanaged by an intensivist in the ICU. Non-ICU patients are managed with assistance from midlevels on the neurosurgery service, with the hospitalists typically comanaging only 10 or fewer every day
As part of their comanagement arrangement, one of the hospitalists sits down every day with an attending neurosurgeon to review the patient list and decide which patients a hospitalist should follow. To help that selection process, Dr. Thompson pointed out, the hospitalists are developing a computerized screening tool to identify patients with medical conditions based on vital signs, lab values and medications.