What is the recommended emergency management for an acute or subacute subdural hematoma, including imaging, surgical indications, and reversal of anticoagulation?

Emergency Management of Subdural Hematoma

Immediate Surgical Indications

Perform immediate surgical evacuation for any subdural hematoma with thickness >5mm, midline shift >5mm, or any patient with neurological deterioration or decreased level of consciousness. 1, 2

Absolute Indications for Emergency Surgery:

• Symptomatic subdural hematoma with significant mass effect 2
• Thickness >5mm with midline shift >5mm 1
• Neurological deterioration or decreased consciousness 2
• Abnormal pupils indicating herniation risk 2
• GCS decline of 2 or more points 1

Imaging Protocol

Initial Imaging:

• Non-contrast CT is mandatory and remains the gold standard for acute hemorrhage detection 1
• Perform CT within 3 hours of symptom onset when possible, as 28-38% of patients show hematoma expansion on follow-up imaging 1
• CT angiography may identify patients at high risk for expansion based on contrast extravasation 1

Follow-up Imaging:

• Repeat CT at 20-24 hours for patients on anticoagulation with initially negative scans 2
• Serial imaging is required for all conservatively managed patients to monitor progression 2

Anticoagulation Reversal

Rapidly reverse anticoagulation using prothrombin complex concentrate plus vitamin K for warfarin patients. 2

Target Coagulation Parameters:

• PT/aPTT <1.5 times normal control before any neurosurgical intervention including ICP probe insertion 1
• Platelet count >50,000/mm³ minimum for systemic hemorrhage control 1
• Higher platelet threshold advisable for neurosurgical procedures 1
• Use point-of-care tests (TEG/ROTEM) when available to optimize coagulation function 1

Anticoagulation Interruption:

• Hold anticoagulation for 7-15 days after subdural hematoma diagnosis 2
• Restart approximately 4 weeks after surgical removal if no ongoing fall risk or alcohol abuse 2

Surgical Approach Selection

Acute Subdural Hematoma:

• Craniotomy is standard for acute subdural hematoma with solid clot components 3, 4
• Emergency decompressive craniotomy in the emergency room if operating room unavailable, particularly for GCS 3-4 patients 5
• Decompressive craniectomy should be considered for refractory intracranial hypertension in multidisciplinary discussion 1

Chronic Subdural Hematoma:

• Burr hole drainage is the preferred first-line approach for chronic subdural hematomas 2, 3
• Place subdural drain during surgery to reduce recurrence rates 2, 3
• Small craniotomy or craniotomy should be considered if subacute subdural hematoma diagnosed on diffusion-weighted MRI 4

Conservative Management Criteria

Conservative management with close monitoring is appropriate only for stable patients without significant neurological deficits and small asymptomatic hematomas. 2

Requirements for Conservative Management:

• No neurological deficits present 2
• Hematoma ≤3mm never required surgery in recent studies, though 11% enlarged 6
• Regular neurological assessments mandatory 2
• Maintain euvolemia (avoid both hypovolemia and hypervolemia) 2, 3

Risk Factors for Expansion Requiring Closer Monitoring:

• Initial SDH size >8.5mm (best threshold predicting need for surgery, AUC 0.81) 6
• Concurrent subarachnoid hemorrhage 6
• Hypertension 6
• Convexity location 6
• Initial midline shift 6

Hemodynamic Management

Blood Pressure Targets:

• Maintain SBP >100mmHg or MAP >80mmHg during emergency interventions 1
• Cerebral perfusion pressure ≥60mmHg when ICP monitoring available 1

Oxygenation and Ventilation:

• PaO₂ between 60-100mmHg during all interventions 1
• PaCO₂ between 35-40mmHg during all interventions 1
• Monitor end-tidal CO₂ continuously in intubated patients 1

Transfusion Thresholds:

• Transfuse RBCs for hemoglobin <7g/dL during emergency interventions 1
• Higher threshold may be used in elderly or patients with cardiovascular disease 1

Intracranial Pressure Management

For Cerebral Herniation:

• Use osmotherapy and/or temporary hypocapnia while awaiting emergency neurosurgery 1
• External ventricular drainage for persisting intracranial hypertension despite sedation 1

ICP Monitoring Indications:

• All patients at risk for intracranial hypertension regardless of need for extra-cranial surgery 1
• Stepwise escalation of therapy, reserving aggressive interventions for non-responders 1

Critical Pitfalls to Avoid

• Never delay surgical intervention when neurological deterioration occurs—this directly worsens outcomes 2
• Do not use hypervolemia—it provides no benefit and causes complications 2, 3
• Avoid prophylactic antiepileptic drugs—they show no benefit for primary prevention and may worsen neurological outcomes 2
• Do not perform burr hole drainage alone for acute-on-chronic subdural hematomas with solid components—craniotomy is required 3, 4