What are the ideal blood pressure parameters for an elderly patient with a subdural hematoma after a fall, who is on anticoagulant medications like warfarin (Coumadin) or aspirin (acetylsalicylic acid)?

Blood Pressure Management in Subdural Hematoma After Fall

Maintain cerebral perfusion pressure (CPP) between 60-70 mmHg, which translates to a mean arterial pressure (MAP) of approximately 80-90 mmHg when intracranial pressure monitoring is available, or target systolic blood pressure >100 mmHg when ICP monitoring is not available. 1, 2

Primary Blood Pressure Targets

When ICP Monitoring is Available

• Target CPP of 60-70 mmHg is the evidence-based goal for adults with traumatic subdural hematoma 1, 2
• Calculate CPP using the formula: CPP = MAP - ICP, with the reference point for MAP measurement placed at the external ear tragus 1, 2
• CPP <60 mmHg is associated with poor neurological outcomes due to inadequate cerebral blood flow 1, 2
• CPP >70 mmHg increases the risk of acute respiratory distress syndrome by 5-fold without improving neurological outcomes 1
• CPP >90 mmHg may worsen vasogenic cerebral edema and should be avoided 1, 2

When ICP Monitoring is NOT Available

• Target MAP ≥80 mmHg or systolic blood pressure (SBP) >100 mmHg to ensure adequate cerebral perfusion 1, 3
• Avoid permissive hypotension strategies used in other trauma patients, as these are contraindicated in traumatic brain injury and subdural hematoma 1
• A recent study comparing SBP 100-150 mmHg versus SBP <180 mmHg showed no difference in 30-day mortality, suggesting that maintaining SBP <180 mmHg is acceptable if tighter control cannot be achieved 4

Special Considerations for Anticoagulated Patients

Reversal of Anticoagulation

• Patients on warfarin or antiplatelet agents who receive appropriate reversal agents early have outcomes comparable to non-anticoagulated patients 5
• The initial hematoma volume and Glasgow Coma Scale score are better predictors of surgical need than anticoagulant use alone 5

Risk of Rebleeding

• Anticoagulants (warfarin) are associated with increased rebleeding risk (OR 2.7,95% CI 1.42-6.96) in chronic subdural hematoma 6
• Antiplatelet agents (aspirin) are NOT associated with increased rebleeding risk in chronic subdural hematoma 6
• The proportion of subdural hematomas related to anticoagulants/antiplatelets has increased significantly in recent years (4.2% in 1996-2000 vs 15.7% in 2006-2010) 7

Fluid Resuscitation Strategy

• Avoid aggressive fluid resuscitation that targets normotension, as this is contraindicated in traumatic brain injury 1
• Use restricted volume replacement with crystalloids initially, but ensure adequate MAP to maintain cerebral perfusion 1
• If restricted volume replacement does not achieve target blood pressure, add noradrenaline to maintain target arterial pressure 1

Critical Pitfalls to Avoid

• Do not use permissive hypotension protocols (targeting SBP 80-90 mmHg) that are appropriate for hemorrhagic shock without brain injury—these are harmful in subdural hematoma 1
• Do not target CPP >70 mmHg routinely, as this increases respiratory complications without neurological benefit 1
• Do not allow CPP to fall below 60 mmHg, as this causes cerebral ischemia and worsens secondary brain injury 1, 2
• Do not measure MAP at the wrong anatomical reference point—always use the external ear tragus for accurate CPP calculations 1, 2
• Be aware of EDTA-dependent pseudothrombocytopenia in elderly patients on anticoagulants, which can falsely suggest severe thrombocytopenia and lead to unnecessary interventions 8

Indications for ICP Monitoring

Consider ICP monitoring after subdural hematoma if any of the following criteria are present: 1

• Glasgow Coma Scale motor response ≤5
• Anisocoria or bilateral mydriasis
• Hemodynamic instability
• Compressed basal cisterns, midline shift >5 mm, or other intracranial lesions on imaging
• Intraoperative cerebral edema
• Postoperative appearance of new intracranial lesions

Autoregulation Considerations

• Patients with preserved cerebral autoregulation may benefit from CPP-based protocols targeting the higher end of the range (closer to 70 mmHg) 1, 2
• Patients with impaired cerebral autoregulation have better outcomes with ICP-based protocols targeting lower CPP (around 60 mmHg) 1, 2
• When autoregulation status is unknown, target the middle of the recommended range (CPP 60-70 mmHg) 1, 2