Critical Care Medicine

Critical Care of the Neurosurgical Patient; Care and management of neurosurgical patients

Strategies of care for the neurosurgical patient

Synonyms

Care and management of neurosurgical patients

Related Conditions

Aneurysm repair, arteriovenous malformation, brain tumor, spinal cord, intracranial hemorrhage, post-operative care

1. Description of the problem

The goal of post-operative neurosurgical care is to prevent or minimize complications related to anesthesia and the surgical procedure. Careful, frequent neurological assessments by neurology-trained staff are the cornerstone of post-operative neurosurgical care. However, management of systemic complications is an essential task that can help minimize serious neurological consequences.

In most cases, post-operative extubation and subsequent examination can take place soon after surgery. Periodically, peri-operative circumstances prevent immediate extubation and an assessment can be obtained only from a temporary sedation "holiday." Patients who are expected to require post-operative neurological intensive care (NICU) after elective or emergent surgery include:

- Supra- and infratentorial craniotomy for tumor or aneurysm

- Craniofacial and transsphenoidal surgery

- Major spine surgery

- Carotid artery surgery

- Endovascular procedures including embolization of arteriovenous malformations (AVM) and aneurysms

- Patients with significant medical comorbidities, elderly, or with difficult intra-operative course

For the patient undergoing a craniotomy for tumor or aneurysm repair, post-operative care should focus on smooth and timely emergence from anesthesia while optimizing hemodynamic, respiratory and electrolyte parameters. The postoperative patient is under a significant amount of physiologic stress that is manifest with fluctuations in blood pressure, blood glucose, heart rate and variations in systemic oxygen consumption (VO2). This stressful state is modulated by changes in sympathetic tone that control body temperature and vascular tone, and are responsive to pain and nausea with or without vomiting.

Several elements are key to manage:

- Vigilance and early detection of surgical complications (stroke, seizures and bleeding)

- Emergence and recovery from anesthesia

- Assessment of impaired consciousness

- Restoring and maintaining normal body temperature

- Pain management

- Post-operative nausea and vomiting

- Prophylaxis for DVT and GI bleeding

The maintenance or attainment of euthermia and prevention of post-operative shivering is an important goal as hypo- or hyperthermia can significantly affect comfort, hemodynamics, and ultimately VO2. Shivering due to hypothermia occurs in 40% of the post-operative population and is associated with a 200-400% increase in systemic oxygen consumption.

Control of post-operative neurosurgical pain is important target that is often missed. Pain is often inadequately controlled because of the potential to cloud neurologic assessments. However, pain is associated with a significant increase in sympathetic tone, hypertension, and systemic oxygen consumption. Pain control can be attained with the administration of short-acting, potent narcotics, NSAIDs and acetaminophen, and sometimes with adjunctive analgesics like ketamine.

Post-operative nausea and vomiting (PONV) is a frequent complication that is particularly prominent in posterior fossa surgery. PONV should be monitored closely and treated aggressively.Projectile vomiting can be an indicator of hydrocephalus or intracranial hemorrhage. PONV is associated with an increased risk of aspiration, hypertension, and elevated intracranial pressure.

Neurologic assessments by neurology-trained, intensive care physicians and staff in a NICU have proven benefit for minimizing in-hospital mortality and length of stay. Neurologic complications after surgery include focal deficits from cerebral edema, intracranial hemorrhage, seizures, stroke, pneumocephalus, and cerebrospinal fluid leaks. Some post-operative focal deficits are a direct result of surgery and are expected in some cases. Brain tissue manipulation and retraction can produce temporary focal symptoms. For example, cranial nerve palsies may occur during posterior fossa operations and transient motor weakness when tumors are adjacent to the motor cortex. Expected neurologic deficits as well as the pre-operative neurologic status of the patient are an important part of the post-operative hand-off and should be communicated clearly by the neurosurgeon upon transporting the patient to the NICU. Cerebral edema is often responsible for transient deficits and occurs as a result of tissue manipulation. Cerebral edema should be expected in patients with glioblastomas, repeat procedures, and those with a prolonged operative time. Treatment includes corticosteroids or osmotherapy but the effectiveness of either therapy is often limited.

Pneumocephalus is a frequent and often benign post-operative complication. Small amounts of intracranial air are well tolerated and typically only manifest with headache. In more severe circumstances, intracranial air can produce altered mental status, obtundation and coma, and seizures. Tension pneumocephalus is an infrequent complication of neurosurgery and head trauma that may develop as a result of a ball-valve opening in the dura mater or from an open skull fracture. Tension pneumocephalus is a neurosurgical emergency that requires immediate treatment with needle or burr hole decompression.

Intracerebral hemorrhage (ICH) is an important and dangerous post-operative event. Most cases of ICH occur within 6 hours of surgery and are associated with post-operative hypertension, coagulopathy, and emergent surgery. More than half of post-operative hematomas are intraparenchymal or epidural. A much smaller percentage of ICHs occur remote from the site of surgery, sometimes as a result of venous infarction and hemorrhage.

Seizures occur as a result of cortical irritation from supratentorial operations. They are often associated with high-grade astrocytomas, AVMs, metastatic tumors, abscess, and midline meninigiomas. Seizure prophylaxis with anti-epileptic drugs is frequently prescribed as AEDs may prevent early post-operative seizures. However, anticonvulsants should be discontinued after 1-2 weeks as there is no benefit for preventing late post-operative seizures. In the NICU, any seizure activity should be considered evidence of a post-operative complication such as stroke or hemorrhage until proven otherwise by brain imaging.

Stroke is a complication of neurosurgery, especially when considering carotid artery surgery and endovascular intervention. Endarterectomy, surgical aneurysm clipping, and endovascular embolization of AVMs and aneurysms are associated with more frequent post-operative strokes than other neurosurgical procedures. Venous infarction may occur during craniotomy and can sometimes be associated with ICH that results from disruption of cortical draining veins or dural sinuses.

Cerebrospinal fluid (CSF) leaks are a common complication after transsphenoidal surgery. CSF rhinorrhea predisposes the patient to meningitis and intracranial hypotension. Post-operative care and surgery for repair of the leak can often be complicated and result in a prolonged hospital stay.

An essential component to the care of the post-operative neurosurgical patient is gastrointestinal bleeding and venous thromboembolism prophylaxis. Neurosurgical patients are at increased risk for deep vein thrombosis (DVT) and subsequent pulmonary embolism (PE). Mechanical DVT prophylaxis coupled with chemoprophylaxis with low-molecular-weight heparin (LMWH) or unfractionated heparin is effective for reducing the risk of DVT. Neurosurgical patients are also at increased risk for gastrointestinal bleeding from mucosal ischemia-related bleeding. There is a paucity of data for stress ulcer prophylaxis in elective post-operative neurosurgical patients, but critically ill neurosurgical patients should be started on an anti-histamine-2 receptor blocker or proton pump inhibitor.

2. Emergency Management

Elevations in intracranial pressure and evolving herniation are critical to detect early and act on and represent the most life-threatening complication of neurosurgical procedures. Signs of elevated intracranial hypertension can be seen as a result of evolving cerebral edema from the procedure or peri-operative ischemic stroke and from intracranial hemorrhage. Signs can include headache, nausea and vomiting, anisocoria, and loss of spontaneous venous pulsations on funduscopy. Serial examination is the best method to detect and diagnose post-operative complications and should be performed every 15-30 minutes immediately upon recovery from anesthesia for the first 1-2 hours and then every hour for the next 6 hours. Detection of a new neurological deficit or progressive worsening of a known focal deficit should prompt a more detailed exam and imaging. Once the potential for life-threatening elevations in intracranial pressure have been excluded, alternative explanations for the change in exam findings can be entertained.

Alternative complications that can produce reduced levels of consciousness and focal exam changes include seizures, ischemia, tension pneumocephalus and CSF leak. Evaluations for these complications are provided in greater detail elsewhere, but once imaging has been performed, electroencephalography and core laboratory evaluations should be strongly considered.

Cerebral edema and Intracerebral hemorrhage

Post-operative cerebral edema can be severe in infrequent cases. Cerebral edema or intracranial hemorrhage should be suspected with the development of new neurologic deficits, cranial nerve abnormalities, decreased level of consciousness, and seizures. In cases of suspected cerebral edema or intracranial hemorrhage, emergent CT imaging and notification of the neurosurgeon is warranted. Surgical intervention and treatment (external ventricular drain placement, hematoma evacuation, and decompressive hemicraniectomy) is often necessary for monitoring and prevention of secondary neurologic injury as a result of intracranial hypertension, herniation syndromes and brainstem compression. Rapid expansion of the hematoma frequently requires evacuation. Emergency medical treatment of intracranial hypertension and cerebral edema can include patient positioning, intubation and brief hyperventilation, osmotherapy, sedation, and induced coma for suppression of cortical electrical activity (burst suppression.)

As first-line medical therapy, the patient’s head should be straight and the head of the bed should elevated to at least 30 degrees to facilitate venous outflow from the brain. Any external compression of the neck, including devices (cervical collar), should be removed if it is safe to do so. If the patient has a natural airway at the time of intracranial crisis, the patient should undergo tracheal intubation and sedation. Cerebral edema is often worsened by elevations of carbon dioxide, which can be managed with invasive mechanical ventilation. Brief periods (< 2-3 hours) of hyperventilation below a normal partial pressure of carbon dioxide can be induced to alleviate intracranial hypertension. Prolonged periods of hyperventilation result in the development of cerebral ischemia due to arterial vasoconstriction. Sedation with various sedative-hypnotics can reduce the metabolic requirements of the brain and thereby reduce cerebral blood volume.

Osmotherapy, in the form of intravenous mannitol or hypertonic saline, is often necessary. Osmotherapy is typically administered in periodic bolus dosing (see Specific Treatment). In cases of cerebral edema, corticosteroids (dexamethasone or methylprednisolone) may also be given. However, the effect of corticosteroids is often minimal and they should not be administered alone in cases of severe cerebral edema.

Seizures

If the patient does not have known epilepsy, seizures in the post-operative period should be considered the result of intracranial hemorrhage until proven otherwise by urgent imaging of the brain. If intracranial hemorrhage is detected, the neurosurgeon should be notified immediately as surgical evacuation may be necessary. Seizures should be treated promptly with anticonvulsant agents as seizure activity is a major physiologic stressor that can result in elevated intracranial pressure and significant increases in systemic oxygen consumption. In most circumstances, intravenous medications are preferred, including fosphenytoin/phenytoin, valproic acid, phenobarbital, and newer anticonvulsants such as levetiracetam and lacosamide. For persistent or prolonged seizures, IV benzodiazepines should be administered concurrently with anticonvulsant agents. Status epilepticus may require additional benzodiazepines, anticonvulsants and sedation with high-dose sedatives or barbiturates.

Stroke

Stroke in the post-operative period may be the result of cardiogenic thromboembolism, distal embolism of foreign material (glue or embolizing material from endovascular procedures), systemic hypotension in the setting of vascular stenosis or occlusion, and artery-to-artery embolism as a result of catheter manipulation. Vascular occlusion may also result from cerebral edema, if brain herniation develops. In the post-operative patient, ischemic stroke is often treated conservatively with permissive or, less often, induced hypertension and low-dose aspirin without anticoagulants or fibrinolytics. Induced hypertension is not a first-line therapy and is not routinely recommended. In rare circumstances, intra-arterial thrombolysis or clot extraction may be possible if the the risk of post-operative bleeding is minimal.

Tension Pneumocephalus

Tension pneumocephalus should be suspected in a patient with known or suspected skull fracture and in post-operative neurosurgical patients. It is a rare complication of neurological surgery but the diagnosis, if missed, can be fatal. Emergent CT imaging of the head will show extensive bifrontal air collection. When air is trapped in the bilateral frontal lobes with air trapped along the falx meninges, the appearance on head CT is called the Mount Fuji radiologic sign.

Infection from CSF Leak

If meningitis or ventriculitis is suspected as a result of a CSF leak, early treatment and hemodynamic support with broad-spectrum antibiotics and fluids are indicated at the first signs of a systemic inflammatory response. CSF should be sent to the laboratory for fluid culture if possible. Antibiotic regimens vary greatly by institution; however, early treatment for nosocomial bacteria such as methicillin-resistant Staphylococcus aureus and Pseudomonas is likely indicated in most cases until an organism and susceptibilities are isolated. Early indicators of meningitis as a result of CSF leak may be subtle and include only fever and an elevated white blood cell count without evidence of meningismus.

3. Diagnosis

Post-operative stroke and cerebral edema present with focal deficits referable to the operative site in most cases. Supratentorial operations may manifest with a variety of clinical symptoms, including pyramidal weakness, sensory loss, visual deficits, and aphasia. An unusual and uncommon complication of midline tumor or epilepsy surgery is supplementary motor area (SMA) syndrome. This occurs when a tumor or epileptic focus is close to the SMA and manifests with unilateral weakness, neglect, and significant difficulty initiating activity.

SMA syndrome is almost universally transient and symptoms improve over a period of days to weeks. Posterior fossa surgery may present with new cranial nerve deficits, nausea and projectile vomiting, and “crossed-signs” referable to the brainstem, where cranial nerve deficits such as a facial droop occur on the side contralateral to the motor weakness. Intracranial hemorrhage may manifest with focal signs and alteration in level of consciousness if a herniation syndrome or intracranial hypertension develops. Seizures may also occur as a result of intracranial hemorrhage.

Serial exam is the best method to detect and diagnose post-operative complications. Elevations in intracranial pressure and evolving herniation are critical to detect early and act on. Signs of elevated intracranial hypertension as a result of cerebral edema or intracranial hemorrhage can include headache, nausea and vomiting, anisocoria, and loss of spontaneous venous pulsations on funduscopy.

Brain imaging with CT or MRI is often necessary to differentiate stroke from cerebral edema and hemorrhage. Often these complications are associated with a reduction in level of consciousness. It is preferable to secure the airway prior to imaging in a rapidly declining patient and treat empirically based on clinical exam findings until imaging can be obtained. The most common mimicker of impending herniation and acute exam change is non-convulsive or subclinical seizures. Thus, when imaging is obtained and no obvious cause for the decline is found, electroencephalography should be performed to evaluate for seizures.

4. Specific Treatment

Hypertension

Post-operative hypertension is frequently treated with sympatholytic agents, especially beta-blockers. As hypertension is often transient, short-acting intravenous agents dosed intermittently or continuous infusions are preferred as first-line therapy.

Drugs and dosages

1. Labetalol 10-20 mg IV Q30minutes-1 hour as needed or infusion

2. Nicardipine infusion

3. Hydralazine 10 mg IV Q30minutes-1 hour PRN

4. Enalaprilat 2.5 mg IV q6hr PRN

PONV (post-operative nausea and vomiting)

1. Ondanestron 4-8 mg q6h PRN

2. Promethazine 6.25-25 mg q6-8h PRN

Note: Sedation is a prominent side effect of treatment with promethazine in a dose-dependent manner.

3. Droperidol 0.625-2.5mg q6h PRN

Note: Monitoring of the QTc interval is often required with repeated administration of droperidol.

4. Corticosteroids

Note: Dexamethasone can also be used to control PONV in addition to use for post-operative edema.

Pain

The mainstay of post-operative pain therapy can include oral and intravenous analgesics alone or in combination. Repeated dosing of narcotics may result in sedation or respiratory depression. Patient-controlled administration (PCA) with dose-limiting pumps is highly effective for awake patients. Though codeine or codeine/acetaminophen combinations are often administered to post-operative patients, codeine frequently causes nausea and vomiting and its effectiveness is hampered by genetic variability in cytochrome P450 conversion to its active component, morphine. Suggested medications can include:

Drugs and dosages

1. Acetaminophen 500-1000 mg q4-6h as needed

2. Fentanyl 12.5-50 mcg q1-2h as needed or a continuous infusion or PCA

3. Morphine 1-2 mg q2-4h as needed

4. Hydromorphone 0.5-1 mg q1-4h as needed or as a continuous infusion or PCA

5. Oral agents including oxycodone or hydrocodone q4-6h as needed

Shivering

Therapy for shivering should focus on warming the patient to a normal body temperature. Warm blankets and forced-air warming devices are effective in most cases. If shivering persists, medications can be considered.

Drugs and dosages

1. Meperidine 25 mg q3-4h as needed. Repeated dosing may result in accumulation of its primary metabolite, normeperidine, which can lower seizure threshold.

2. Low doses of propofol if the patient is intubated may reduce shivering.

Venous thromboembolism prophylaxis

1. Sequential compression stockings/boots should be applied to all neurosurgical patients unless anatomic or functional barriers exist.

2. Low-molecular-weight heparin (ie, enoxaparin 40 mg SC once per day or 30 mg twice per day) OR

3. Unfractionated heparin 5000 units 2 or 3 times per day

Gastrointestinal Bleeding Prophylaxis

H-2 receptor blockers or proton-pump inhibitors should be administered to all neurosurgical patients.

Drugs and dosages

1. Famotidine 20 mg IV/PO twice per day OR

2. Pantoprazole 20 mg PO twice per day

5. Disease monitoring, follow-up and disposition

Careful post-operative neurologic monitoring is indicated in all neurosurgical patients for a minimum of 6 hours after surgery. In most cases, the patient will require overnight monitoring in the NICU. Disposition of most post-operative patients is determined by the type of surgery, with the majority of elective cases able to leave the intensive care unit within 24 hours. Less severe complications such as pain and PONV are usually self-limited and will resolve with prompt treatment. If the patient experiences an intracranial hemorrhage or severe cerebral edema, a longer ICU stay is appropriate until the patient is stable.

Pathophysiology

N/A

Epidemiology

It is estimated that up to half of all post-operative patients will experience a complication in their post-operative course. 10% of these complications are serious and incur significant morbidity and mortality. Peri-operative mortality for elective tumor surgery is 1-7%, 4% for unruptured aneurysm clipping, and 2% for posterior fossa surgery. Transsphenoidal surgery has a peri-operative mortality of 1%. However, most complications that neurosurgical patients experience are related to pain, PONV, and shivering. Pain should be expected in up to 80% of patients. while PONV and shivering occur in approximately 50% and 30%, respectively.

Among the most serious complications that can occur is intracranial hemorrhage. ICH is encountered in 1-3% of neurosurgical patients. When it occurs, mortality can be as high as 30%, while peri-operative morbidity decreases post-operative independence by as much as 50%. ICH is independently associated with peri-operative hypertension, coagulopathy, thrombocytopenia (<100,000), high-grade vascular tumors, emergent surgery, and AVMs and after subdural hematoma resection.

Early post-operative seizures occur in 10-20% of patients and are associated with high-grade astrocytomas, midline meningiomas, metastatic tumors, and AVMs. The development of epilepsy in one year following surgery for aneurysms should be expected in 1-2% of patients. Prophylactic anticonvulsant administration is expected to reduce the incidence of early post-operative seizures by 30-50%. Prophylactic administration does not reduce the likelihood of developing late epilepsy.

Stroke occurs in 2-3% of patients undergoing carotid endarterectomy and 4-8% of those undergoing an endovascular procedure, including aneurysm coiling and carotid angioplasty and stent. A recent trial showed that stroke was more likely in those undergoing stent placement in the carotid artery than those undergoing endarterectomy. However, endarterectomy was more frequently associated with myocardial infarct. However, stroke is likely associated with a higher degree of morbidity than MI in many circumstances.

CSF leaks occur in 2-5% of transsphenoidal surgeries. Risk factors for leaks include pre-operative radiation treatment, repeat procedures, large tumor size, and advanced age. Procedures performed in the hands of experienced surgeons may decrease the risk for a CSF leak.

Prognosis

In general, post-operative patients will require only 12-24 hours of ICU-level monitoring and can then be discharged to the general floor. However, when complications occur, the time to detect and intervene on the problem will directly affect the recovery and the level of function the patient achieves in recovery. Also to be considered is the pre-operative level of function and the underlying clinical condition for which the patient is undergoing surgery.

Special considerations for nursing and allied health professionals.

N/A

What's the evidence?

Agnelli, G., Piovella, F., Buoncristiani, P.. "Enoxaparin plus compression stockings compared with compression stockings alone in the prevention of venous thromboembolism after elective neurosurgery.". N Engl J Med. vol. 339. 1998. pp. 80-5.

(This article presents the evidence for the suggested form of venous thromboembolism prophylaxis in most neurosurgical patients.)

Brophy, G. M., Brackbill, M. L., Bidwell, K. L.. "Prospective, randomized comparison of lansoprazole suspension, and intermittent intravenous famotidine on gastric pH and acid production in critically ill neurosurgical patients". Neurocrit Care. vol. 13. pp. 176-81.

(This recent research study describes two strategies of nearly equal efficacy for the reducing the incidence of stress ulcer prophylaxis in critically -ill neurosurgical patients.)

Diringer, M. N., Edwards, D. F. "Admission to a neurologic/neurosurgical intensive care unit is associated with reduced mortality rate after intracerebral hemorrhage". Crit Care Med. vol. 29. 2001. pp. 635-40.

(This article analyzes the impact of specialized NeuroICU care for neurosurgical patients, particularly those with intracranial hemorrhage.)

Glantz, M. J., Cole, B. F., Forsyth, P. A.. "Practice parameter: anticonvulsant prophylaxis in patients with newly diagnosed brain tumors. Report of the Quality Standards Subcommittee of the American Academy of Neurology". Neurology. vol. 54. 2000. pp. 1886-93.

(An explanation of practice recommended by the AAN for the care of patients with newly diagnosed brain tumors, including those who will need prophylactic anticonvulsants for neurosurgery.)

Manninen, P. H., Raman, S. K., Boyle, K.. "Early postoperative complications following neurosurgical procedures". Can J Anaesth. vol. 46. 1999. pp. 7-14.

(A large observational study examining early post-operative complications of neurosurgery.)

Mantese, V. A., Timaran, C. H., Chiu, D.. "The Carotid Revascularization Endarterectomy versus Stenting Trial (CREST): stenting versus carotid endarterectomy for carotid disease". Stroke. vol. 41. pp. S31-4.

(A large, randomized trial of carotid artery stenting versus endarectomy with observed post-operative complications.)

Milligan, T. A., Hurwitz, S., Bromfield, E. B.. "Efficacy and tolerability of levetiracetam versus phenytoin after supratentorial neurosurgery". Neurology. vol. 71. 2008. pp. 665-9.

(A recent study examining prophylactic anticonvulsant choice for patients undergoing neurosurgery.)

Moza, K., McMenomey, S. O., Delashaw, J. B.. "Indications for cerebrospinal fluid drainage and avoidance of complications". Otolaryngol Clin North Am. vol. 38. 2005. pp. 577-82.

(An interesting review article examining CSF physiology, indications for CSF drainage, and the different methods.)

Nishioka, H., Haraoka, J., Ikeda, Y.. "Risk factors of cerebrospinal fluid rhinorrhea following transsphenoidal surgery". Acta Neurochir (Wien). vol. 147. 2005. pp. 1163-6.

(An observational study examining the risk factors for CSF leaks after transsphenoidal neurosurgery.)

Rosenberg, H., Clofine, R., Bialik, O.. "Neurologic changes during awakening from anesthesia". Anesthesiology. vol. 54. 1981. pp. 125-30.

(An interesting historical piece on post-anesthesia neurologic exam findings.)

Seifman, M. A., Lewis, P. M., Rosenfeld, J. V.. "Postoperative intracranial haemorrhage: a review". Neurosurg Rev.

(An excellent review examining various risk factors and preventative strategies for post-operative intracranial hemorrhage.)

Taylor, W. A., Thomas, N. W., Wellings, J. A.. "Timing of postoperative intracranial hematoma development and implications for the best use of neurosurgical intensive care". J Neurosurg. vol. 82. 1995. pp. 48-50.

(An interesting observational study examining the timing of post-operative intracranial hemorrhage and resource utilization in the NeuroICU.)

Wilson, P. V., Ammar, A. D.. "The incidence of ischemic stroke versus intracerebral hemorrhage after carotid endarterectomy: a review of 2452 cases". Ann Vasc Surg. vol. 19. 2005. pp. 1-4.

(A large, retrospective review examining ischemic and hemorrhagic stroke complications after carotid artery endarterectomy.)
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