To provide high-quality anesthesia care, a clinician must account for the patient’s full health history and current medical condition. Oftentimes, patients undergoing surgery have extensive chronic or acute health problems that interfere with their cardiovascular, respiratory, renal, hepatic or circulatory systems.1 These issues make anesthesia administration complex and can lead to life-threatening perioperative anesthesia-related complications.2 In patients with neurologic disorders, anesthesia-related cerebral alterations can be dangerous and have long-term effects on health.3 Thus, the anesthesia provider should be familiar with the types of different neurologic diseases, the implications for anesthesiology and recommendations for care.
Anesthesia providers must understand the pathophysiology of neurologic disorders and the medications used to treat them in order to prevent and evaluate adverse intraoperative events.4 Neurologic diseases include seizure disorders, Parkinson’s disease, Alzheimer’s disease, cerebrovascular disease, delirium, myasthenia gravis, multiple sclerosis, amyotrophic lateral sclerosis, traumatic brain injury, spinal cord injury and Guillain-Barré syndrome.4 Patients with neurologic disorders may be particularly vulnerable to side effects and complications of anesthesia, and anesthesia providers may need to take extra precautions due to disease-related symptoms.5 For example, patients with Parkinson’s disease have decreased respiratory function, swallowing impairment and cognitive impairment.4 If any patient is diagnosed with such a disorder before surgery, the anesthesia provider should have thorough knowledge of the disease and its management.
There are several instances in which anesthesia can interfere with treatment for or exacerbate the symptoms of a neurologic disease. A patient with epilepsy may be susceptible to the seizure-provoking properties of anesthetic drugs such as anticholinergics or sevoflurane.6 Additionally, some anti-epileptic drugs interfere with the efficacy of anesthetics.6 In fact, anesthetic drugs may interact with many medications for neurologic disease,7 including levodopa, the primary treatment for Parkinson’s disease.8 Patients with cerebrovascular disease typically have a history of transient ischemic attacks (TIAs) or strokes, which puts them at higher risk of stroke while under anesthesia.9 Anesthetic agents also cause changes in cerebral blood flow and intracranial pressure that are particularly harmful to patients with intracranial disease.3 The effects of anesthetics on the respiratory and autonomic nervous systems may be detrimental to patients with neurologic disorders, who sometimes need postoperative ventilatory support and hypotension control.7 Anesthetic drugs often do not mix well with the vulnerability of patients with neurologic disorders and the medications they take to treat such disorders.
There are concrete steps anesthesia providers can take to prevent or ameliorate complications due to neurologic disorders. For one, anesthesia providers should conduct a thorough preoperative exam and risk/benefit analysis before administering anesthetic drugs.10 When choosing an anesthetic, clinicians can opt for ones that have lower risk of complication for patients with neurologic disorders. According to Greene, low concentrations of inhalant anesthetics combined with controlled ventilation are effective in preventing the raised intracranial pressure that normally accompanies inhaled anesthetic drugs.3 Other studies have found that regional anesthesia may be useful for multiple sclerosis, spinal cord injuries or parturients with neurologic disorders.10,11 If seizures occur during surgery, they can be treated with anesthetic drugs such as midazolam, thiopental or propofol, but not opioids.6 Neurologic disorders may cause patients to have some unanticipated side effects during surgery, and the anesthesia provider must be prepared to prevent morbidity or mortality.
Patients with neurologic disorders have many symptoms that may affect perioperative care. Anesthetic drugs can interfere with neurologic medications or even exacerbate symptoms. With a thorough preoperative assessment and risk analysis, calculated choice of anesthetic drugs and adequate preparation for complications, anesthesia providers can ensure successful surgeries for patients with neurologic disorders. Future research should investigate the efficacy of regional anesthetics for patients with more types of neurologic disorders.