Anesthesia Techniques and Monitors
Local Is Better Than General Anesthesia During Endovascular Acute Stroke Interventions
Gupta R (Grady Memorial Hosp, Atlanta, GA) Stroke 41:2718-2719, 2010§
Patients suffering acute ischemic stroke often undergo endovascular reperfusion techniques to improve clinical outcome. Acute stroke protocols are usually designed for emergency departments and stroke units, but procedures done in the endovascular suite may not adhere to standard protocols such as close monitoring of all medical parameters. General anesthesia (GA) is typically used in endovascular suites, but the safety of GA compared to conscious sedation (CS) has not been closely analyzed.
The criteria used to assess the safety of GA versus CS focus on the rate of intracranial hemorrhages that occur, which is a surrogate for wire perforations, and the number of patients who require emergency intubation who were initially given CS. Recent publications demonstrate no difference in hemorrhage statistics between the two approaches, so procedures can be safely performed under CS. The conversion rate from CS to GA is only 2.7%. In addition, patients treated under GA have had higher rates of pneumonia, longer stays in the intensive care unit (ICU), and larger infarct volumes.
GA is favored for endovascular reperfusion because it provides patient immobility, allows tight control of hemodynamics, may protect the brain, and addresses compromised airway concerns, a common problem in acute stroke. However, evidence does not support a need for patient immobility. Awake patients can participate in neurological assessments that help the operator to determine their neurological status. This real-time determination can impact neurological outcome, especially with aggressive attempts to achieve an angiographic result.
Patients with acute stroke often have other problems such as coronary artery disease, pulmonary disease, cardiac dysrhythmias, renal disease, and valve disease. These increase the possibility that semielective or planned surgical procedures will be done under GA. Comorbidities may be incompletely characterized in the acute stroke situation. Emergency intubation may also increase the risk of airway injury and pulmonary aspiration, especially when rapid sequence intubation is not done.
Protection for cerebral structures from inhaled gases is based on an as-yet-unproved hypothesis. Maintaining cerebral autoregulation with arterial occlusion is needed so cerebral perfusion pressure remains sufficient to the target penumbra where therapy is being delivered. Anesthetic induction often causes hypotension, which is managed with vasopressors that can breach the upper limits of autoregulation. Clinical outcomes of acute stroke are worse with wide fluctuations in blood pressure.
When patients are intubated for acute stroke interventions, they are often brought to the ICU before being extubated. Although there is understandable reluctance to extubate patients with moderate to severe strokes, each day the tube remains in place raises the risk of nosocomial infections, delays rehabilitation, and complicates discharge planning. Care withdrawal is more likely when the family sees loved ones on “life support” and having a profound neurological deficit.