What are the anesthetic considerations for stroke patients undergoing surgery?

Anesthetic Considerations for Stroke Patients Undergoing Surgery

Critical Blood Pressure Management

Meticulous blood pressure control is the single most important anesthetic consideration for stroke patients, as even small decreases (≥10% from baseline) significantly worsen neurological outcomes and mortality. 1, 2, 3

Blood Pressure Targets by Stroke Type

• Acute ischemic stroke: Maintain systolic BP >110 mmHg and <185 mmHg if patient received or is candidate for thrombolysis; <220 mmHg if thrombectomy only 1
• Hemorrhagic stroke/intracerebral hemorrhage: Target systolic BP >140 mmHg and <150 mmHg (if within 6 hours of symptom onset) 1, 2
• Subarachnoid hemorrhage: Keep systolic BP <160 mmHg 1
• Traumatic brain injury: Maintain systolic BP >110 mmHg (and MAP >90 mmHg) and <150 mmHg 1

Hemodynamic Management Strategy

• Place arterial line before induction of anesthesia whenever possible to enable real-time blood pressure monitoring 1
• Position transducer at level of tragus (external auditory meatus) to accurately reflect cerebral perfusion pressure 1
• Have vasopressors immediately available (ephedrine or metaraminol) to treat hypotension during induction 1
• Avoid hypotension at all costs—persistent hypotension adversely affects neurological outcome and should delay transfer until stabilized 1
• Use vasopressor infusions (e.g., metaraminol, noradrenaline) if hypotension persists after correcting hypovolemia or excess sedation 2

Ventilation and Oxygenation Parameters

Maintain strict normocapnia (PaCO₂ 4.5-5.0 kPa or end-tidal CO₂ 35-45 mmHg) as both hypocapnia and hypercapnia worsen cerebral ischemia. 1, 4

• Avoid hyperventilation: Hypocapnia causes vasoconstriction and reduces cerebral blood flow, potentially worsening ischemia 1, 4
• Target PaO₂ ≥13 kPa for most stroke patients 1
• For acute ischemic stroke specifically: Oxygen saturation ≥95% is acceptable; avoid routine supplemental oxygen if saturation adequate 1
• Validate end-tidal CO₂ with arterial blood gas to ensure accuracy of A-a gradient 1

Induction and Maintenance Anesthesia

Pre-induction Preparation

• Administer intravenous fluids overnight before surgery to maintain hydration and reduce hypotension risk 1
• Ensure patient is euvolemic to mildly hypervolemic before induction 1
• Attach neuromuscular monitoring before induction 1

Induction Drug Regimen

• Opioids: High-dose fentanyl (3-5 µg/kg), alfentanil (10-20 µg/kg), or remifentanil TCI (target ≥3 ng/mL); reduce doses in hemodynamically unstable patients 1
• Induction agent: Choose agent and dose to maintain adequate MAP; ketamine (1-2 mg/kg) useful in unstable patients 1
• Neuromuscular blockade: Suxamethonium 1.5 mg/kg or rocuronium 1 mg/kg 1
• Use rapid sequence induction with cricoid pressure if aspiration risk present 1

Maintenance Anesthesia Choice

Consider propofol-based total intravenous anesthesia over volatile agents, as emerging evidence suggests propofol may improve functional independence at 3 months in stroke thrombectomy patients. 5

• Propofol anesthesia associated with improved functional independence (OR 2.65) compared to volatile agents in one retrospective analysis 5
• Volatile anesthetics (sevoflurane, desflurane) remain acceptable alternatives but may have differential cerebral hemodynamic effects 5, 6
• Both general anesthesia and conscious sedation can achieve good outcomes when hemodynamics carefully managed 7, 8

Fluid Management

• Use isotonic fluids only (0.9% normal saline preferred) to maintain euvolemia 2, 4
• Avoid hypotonic fluids (5% dextrose, Ringer's lactate, Ringer's acetate, gelatins) as they worsen cerebral edema 2
• Do not use albumin or synthetic colloids in early stroke management 2
• Avoid mannitol during moyamoya or revascularization procedures as it can decrease cerebral perfusion pressure 1

Temperature Management

• Maintain normothermia (36-37°C) throughout perioperative period 1
• Use core temperature monitoring (bladder or esophageal probe) 1
• Avoid aggressive rewarming until emergence timing planned 4

Special Considerations for Moyamoya Disease/Syndrome

Patients with moyamoya require exceptionally strict hemodynamic and ventilatory control due to compromised cerebrovascular reserve. 1

• Maintain systolic BP at or above preoperative baseline at which patient asymptomatic; avoid systolic BP >180 mmHg 1
• Strict normocapnia (end-tidal CO₂ 35-45 mmHg) mandatory—even mild hypocapnia causes vasoconstriction and ischemia 1
• Keep euvolemic to mildly hypervolemic intraoperatively 1
• Monitor for cerebral hyperperfusion syndrome (CHS) postoperatively—occurs in 19.9% of adults 1
• If CHS develops: Strict BP control (systolic <130 mmHg), consider minocycline or edaravone 1

Airway Management

Indications for Intubation

• GCS ≤8 1
• Deteriorating consciousness (fall in GCS ≥2 points or motor score ≥1 point) 1
• Loss of protective airway reflexes 1
• Inability to maintain adequate oxygenation or ventilation 1
• Seizures 1

Intubation Technique

• Secure endotracheal tube with tape rather than ties to avoid venous drainage obstruction 1
• Maintain head-up tilt during intubation 1

Monitoring Requirements

• Continuous invasive arterial blood pressure monitoring 1
• End-tidal CO₂ monitoring with periodic arterial blood gas validation 1
• Core temperature monitoring 1
• Blood glucose monitoring (target 6-10 mmol/L) 1
• Neuromuscular monitoring if paralysis used 1

Critical Pitfalls to Avoid

• Never allow blood pressure to drop ≥10% from baseline—this single factor dramatically increases poor outcomes even under conscious sedation 3
• Never hyperventilate except briefly for impending uncal herniation—hypocapnia worsens ischemia 1, 4
• Never use hypotonic fluids—they exacerbate cerebral edema 2
• Never delay arterial line placement—blind blood pressure management during induction risks catastrophic hypotension 1
• Avoid aggressive blood pressure control in hemorrhagic stroke—excessive reduction can worsen ischemia in penumbral regions 2
• Do not transfer unstable, hypotensive patients—stabilize first 1