What is the recommended blood pressure (BP) target for patients with Subarachnoid Hemorrhage (SAH)?

Blood Pressure Targets in Subarachnoid Hemorrhage (SAH)

For patients with subarachnoid hemorrhage, the recommended blood pressure target is systolic blood pressure <160 mmHg before aneurysm securing, with a minimum mean arterial pressure of 65 mmHg to avoid hypotension. 1

BP Management Based on Disease Stage

Before Aneurysm Securing

• Maintain systolic BP <160 mmHg to reduce rebleeding risk 1
• Ensure MAP remains ≥65 mmHg to maintain cerebral perfusion 1
• Use short-acting, titratable medications (nicardipine, labetalol, clevidipine) for precise BP control 1
• Avoid rapid BP reductions >70 mmHg in 1 hour as this is associated with poor outcomes 1
• Continuous BP monitoring (preferably arterial line) is crucial in the acute phase 1

Higher systolic BP (>160 mmHg) is associated with increased risk of rebleeding, as demonstrated in multiple studies 2, 3. A retrospective analysis showed that MAP below 100 mmHg in the hours before rebleeding was associated with decreased rebleeding risk (at MAP=80 mmHg: aHR 0.30,95% CI 0.11-0.80) 2.

After Aneurysm Securing

• BP targets can be liberalized to balance prevention of delayed cerebral ischemia (DCI)
• Systolic BP can be increased up to 180 mmHg based on neurological response 1
• Avoid hypotension (MAP <60 mmHg) as it increases DCI risk 2

Management of Delayed Cerebral Ischemia (DCI)

• For patients who develop DCI, induced hypertension is recommended unless cardiac status precludes it 1
• Systolic BP targets can be increased up to 180-200 mmHg based on neurological response 1
• A MAP below 60 mmHg in the 24 hours before each time point was associated with increased DCI risk (at MAP=50 mmHg: aHR 2.59,95% CI 1.12-5.96) 2

Important Considerations

Blood Pressure Variability

• Minimize BP variability as it is a risk factor for rebleeding 3
• A study demonstrated that standard deviation of systolic BP (OR 1.254; 95% CI 1.131-1.391) and successive variation of systolic BP (OR 1.131; 95% CI 1.039-1.231) were associated with rebleeding 3

Fluid Management

• Maintain euvolemia rather than hypervolemia 1
• Evidence does not support routine use of hemodilution and hypervolemia components of triple-H therapy 1

Medication Management

• Administer nimodipine to all patients with aneurysmal SAH to improve neurological outcomes 1
• Be aware that nimodipine has BP-lowering effects, which may require adjustment of other antihypertensive medications 1

Monitoring

• Perform frequent neurological assessments (every 1-2 hours initially) to monitor for signs of cerebral ischemia or rebleeding 1
• Consider cerebral perfusion pressure (CPP) monitoring in ICU patients, with a target CPP >70 mmHg 4
  • A retrospective study showed that CPP-guided treatment aimed at maintaining CPP >70 mmHg reduced DCI incidence (14% vs. 64%, p<0.01) and improved functional outcomes 4

Common Pitfalls to Avoid

• Excessive hypotension (systolic BP <110 mmHg) which may compromise cerebral perfusion 1
• Overly aggressive BP lowering, especially rapid reductions 1
• Routine use of antifibrinolytic therapy is not recommended for improving functional outcomes 1
• Neglecting to adjust BP targets based on neurological response 1
• Failing to reverse anticoagulation promptly in SAH patients on anticoagulants 1

Despite these recommendations, there remains significant practice variability in BP management following SAH, with systolic BP limits ranging from 140-180 mmHg before aneurysm treatment and 160-240 mmHg after treatment 5. This variability highlights the need for standardized protocols based on the best available evidence.