Thanks to Dr Joanna Middleton for leading the discussion this month

Edited by Dr David Lewis

Top tips from this month’s rounds:

1. Imaging reports can underestimate the clinical impact of an incidental finding

2. Neuro ICU in the Emergency Department?

Imaging reports can underestimate the clinical impact of an incidental finding

Not all benign conditions have a benign outcome. A CT report will occasionally underestimate the clinical impact of an incidental finding. Its always worth reviewing the images yourself.

For example – a report might read – “No acute bleed or infarct, incidental finding of frontal bone fibrous dysplasia” –  may sound innocuous and unrelated to the patient’s headache, until you review the scans yourself:

Fibrous dysplasia is a benign condition which can present with new craniofacial asymmetry. Whilst the condition itself may be benign, the location and speed of growth can result in symptoms, especially headache and even cranial nerve compression.

Clinical Guidelines for managing craniofacial fibrous dysplasia

Neuro ICU in the Emergency Department?

Management of Intracranial Hemorrhage in the Emergency Department can be complex. The diagnosis is usually straightforward with CT (providing it has been considered as a possibility – subarachnoid hemorrhage can present with syncope alone) and the broad category of bleed determined by the history, patient age, CT appearance, etc.

ED Management will depend on the category of bleed (Primary ICH, Subdural, Epidural, Traumatic SAH, Spontaneous SAH).

From ALIEM.com, click here for the full article

Initial management of intracranial hemorrhage can be simplified / summarized as follows:

Airway – ET Intubation if GCS < 9

Breathing – Ventilate if GCS < 9 (SaO2 >94%, ETCO2 35-45 mmHg)

Circulation

1. Stop the bleeding
   1. Neurosurgery (see here for indications)
   2. Reverse anticoagulation
   3. ?Tranexamic acid
2. Maintain an adequate cerebral perfusion pressure (CPP) to ensure adequate tissue oxygenation
   1. CPP = Mean Arterial Pressure (MAP) – Intracranial Pressure (ICP)
      1. Seems simple enough? – ensure the patient’s blood pressure is high enough to overcome the ICP
   2. However, the optimal CPP following acute brain injury is not known (general consensus suggest 50-70 mmHg)
      1. In the normal brain CPP is maintained by autoregualtion
      2. Autoregulation is less effective after brain injury
      3. If the CPP is too low brain hypoxia occurs
      4. If the CPP is too high there may be a risk of hematoma expansion
   3. However, it’s not easy to measure the ICP
      1. Methods of non-invasive ICP estimation:
         1. Level of consciousness
         2. Papilledema
         3. CT appearances
         4. Transcranial doppler
         5. Sonographic Optic Nerve Sheath Diameter
         6. Lots of others
         7. None of these are perfect
      2. Invasive ICP measurement
         1. External Ventricular Drain – Neurosurgical procedure
         2. Setting up the EVD and measuring ICP requires experienced nursing staff (see below)
   4. Even measuring the MAP is not without its own problems in the ED
      1. MAP = (Systolic BP + 2(Diastolic BP))/3
      2. However non invasive measurement of MAP (based on SBP and DBP peripheral sphygmomanometry) is not accurate.
      3. An accurate measurement of MAP requires invasive monitoring via an arterial line.
   5. Assuming that we are able to accurately measure ICP and MAP, there is then the question of how to adjust these values reliably via therapeutic interventions.
      1. ICP Management (Normal = 0-15, Goal < 20)
         1. Patient position, head up
         2. Sedation and paralysis, if patient aggitated
         3. Mannitol – potential risk of acute kidney failure in prolonged use
         4. Hyperventilation – will also reduce cerebral blood flow – so PaCO2 no lower than 35 mmHg
         5. CSF Drainage : 
         6. Hypothermia
      2. MAP Management
         1. IV Fluid (crystalloid vs colloid?)
         2. Diuretics / Antihypertensives vs Inotropes
         3. A very detailed guide to blood pressure management in stroke can be viewed here: BP-Stroke

I suspect that most emergency physicians/nurses are wondering whether this level of care falls within their remit. In most hospitals the answer will be NO, these cases are stabilised and managed in an Intensive Care Unit. However, there are occasions when this level of care is required prior to transfer to another unit/hospital, in which case it is likely that the care will be directed by the local neurosurgeon / neurointensivist and the receiving specialists.

EVD Drainage System and ICP Monitoring

Suggest ICP Protocol from Vancouver General ICU

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