Preoperative Evaluation of Patients With Neurological Disease

Kathrin Lieb, MD; Magdy H. Selim, MD, PhD

Disclosures

Semin Neurol. 2008;28(5):603-610. 

In This Article

Cerebrovascular Diseases: Stroke and TIA

Patients with a history of stroke or TIA are at increased risk for perioperative stroke after major cardiac and vascular surgical procedures.[6] In contrast, a previous stroke or TIA appears to be a minor clinical predictor for the risk of perioperative cardiac complications.[37] In most cases, patients with few risk factors for perioperative stroke undergoing low-risk noncardiac surgery do not need further testing. However, in patients with stroke history and planned cardiac procedure, including aortic manipulation, performing a transesophageal echocardiography to identify aortic atherosclerotic plaques should be considered. Perioperative strokes are predominantly embolic, and are related in large part to perioperative atrial fibrillation, especially after cardiac procedures.[38,39] Preoperative initiation of amiodarone or ß-blockers may decrease the incidence of postoperative atrial fibrillation and stroke.[40]

Antithrombotics are widely used for secondary stroke prevention. Abrupt discontinuation of antiplatelet agents before surgery may be associated with increased risk for stroke recurrence due to rebound hypercoagulability.[41] Aspirin should be stopped only 2 to 3 days before major neurosurgical procedures. Continuation of aspirin therapy is acceptable during regional spinal anesthesia, nerve blocks, dermatological cutaneous surgeries, dental procedures, ophthalmological procedures, peripheral vascular procedures, cardiac surgeries, and endoscopies.[11] Clopidogrel, on the other hand, appears unsafe and should be discontinued 5 to 7 days before surgical procedures.[42] There are no studies regarding the safety of dipyridamole, alone or in combination with aspirin, during surgery. It is therefore prudent to withhold it 5 to 7 days preoperatively. We recommend substituting clopidogrel and dipyridamole with aspirin in patients at high risk for stroke during the preoperative period. For many patients taking warfarin for stroke prevention, the risk of perioperative discontinuation of anticoagulation exceeds the risk of bleeding complications. Preoperative bridging therapy with heparin is advised and warfarin is discontinued. Heparin can be stopped hours prior to the procedure and warfarin restarted 24 hours after surgery.

Preoperative assessment of stroke patients undergoing carotid revascularization should ensure that blood pressure is adequately controlled throughout the perioperative period, particularly in hypertensive patients, to minimize the risk for postoperative hyperperfusion syndrome.

Subarachnoid Hemorrhage

Cardiac ischemia resulting from increased sympathetic outflow, increased cardiac afterload, or impaired contractility is common after subarachnoid hemorrhage (SAH). Preoperative evaluation of these patients should include electrocardiography, echocardiography, and measurement of serum markers of myocardial damage. These patients are also more susceptible to develop electrolyte abnormalities, in particular hyponatremia secondary to cerebral salt wasting or SIADH, which could predispose them to seizures or cardiac arrhythmias. The patient's cardiac function and electrolytes should be optimized before undergoing surgery. Inotropic agents, such as dopamine, may be required preoperatively in patients with reduced cardiac output because this could impair the ability to tolerate barbiturates administered during surgery due to their myocardial suppressant effects. Maintaining adequate hydration and euvolemia is important to minimize the risk of vasospasm during the perioperative period. In addition, the mean arterial blood pressure must be maintained within the autoregulatory range while avoiding high mean pressure to prevent rebleeding in patients with SAH due to ruptured aneurysm.

Multiple Sclerosis

Some reports indicate that anesthesia, especially regional anesthesia, may worsen multiple sclerosis.[43,44] Therefore, the patient should be advised preoperatively that surgery and anesthesia could produce a relapse despite careful perioperative management.[36] Bladder dysfunction is not uncommon in multiple sclerosis. Therefore, testing urinalysis for urinary infection should be performed prior to surgery. Intermittent catheterization or use of anticholinergic agents may be necessary,[28] requiring cautious use of other anticholinergics such as atropine. Patients treated with corticosteroids may need steroid supplementation during the perioperative period. For patients treated with baclofen in whom oral intake is interrupted perioperatively, a gradual change may be made to diazepam. Baclofen is not available for injection, and abrupt withdrawal may precipitate seizures or hallucinations.[28] Interferons and glatiramer acetate can be continued throughout the perioperative period.

Epilepsy

Perioperative seizures can lead to significant complications. The preoperative evaluation affords an opportunity to identify patients at high risk for seizure, such as patients with brain tumors, cerebrovascular disease, head injury, and metabolic disturbances,[45] and to prepare patients with known epilepsy for the surgery. It is important to ensure that the serum levels of antiepileptic drug(s) are therapeutic during the perioperative period. The prescribed medication should be continued until the morning of surgery and, if necessary, administered parenterally until oral intake can be resumed.[36] Furthermore, possible interactions between the anticonvulsant agent and the anesthetic drug have to be considered. For example, phenobarbital may accelerate and increase the magnitude of biotransformation of the anesthetic agent.[36] Conversely, the anesthetic agent may increase the likelihood of seizure activity. Anticonvulsant anesthetic drugs like barbiturates, benzodiazepines, propofol, halothane, or isoflurane should be considered.[35]

Parkinson Disease

The established medication regimen should be continued until the morning of surgery ( Table 1 ). Dependent on the length of the surgery, the short half-life of levodopa has to be considered. An interruption of more than 6 to 12 hours may result in severe muscle rigidity interfering with the ventilation management. This syndrome mimics neuroleptic malignant syndrome, including autonomic instability, fever, delirium, and muscle rigidity. Postoperatively, levodopa should be resumed via nasogastric feeding if the patient is not capable of swallowing. Alternatives routes include parenteral or topical administration or parenteral administration of dopamine agonists such as bromocriptine if gastric administration is not possible. Phenothiazines and butyrophenones should be avoided because of their antidopaminergic properties.[36] Excessive salivation, dysphagia, and esophageal dysfunction in patients with Parkinson disease may result in aspiration pneumonia. Parkinson disease is also associated with a reduction in respiratory reserve capacity, which increases the risk of postoperative atelectasis and pneumonia.[28,46] Preoperative pulmonary function testing and postoperative breathing exercises should be considered.

Alzheimer Disease (Dementia)

Currently used cholinesterase inhibitors may impair hepatic function requiring careful use of halogenated, volatile anesthetics. In patients treated with anticholinergic agents, measurement of liver enzyme levels should be considered. Glycopyrrolate should be used instead of atropine or scopolamine if anticholinergic drugs are necessary. Using anesthetic agents like propofol or sevoflurane may hasten postanesthetic recovery of mental status.[36]

Spinal Cord Injury

Preoperative assessment of patients with spinal injuries should attempt to detect and treat secondary complications, such as sympathetic dysfunction, spinal shock, impaired respiratory muscle strength, and bradycardia or hypotension. These patients may require fluid and vasopressors and ventilatory support preoperatively.

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