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20 Cards in this Set
- Front
- Back
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Thresholds for EVD insertion in SAH |
GCS <12 HH3 or greater
At K Lee's institution, all SAH not following commands are candidates for EVD insertion. |
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Normal ICP ranges (adults and young children) |
10-15 and 3-7 |
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These post-op patients are at high risk for CSF leak and may benefit from EVD insertion |
Posterior fossa surgery via SOC or far lateral approach |
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Target location of EVD catheter tip? |
At the foramen of Monro |
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Burr hole entry point should avoid these structures |
Lateral to midline to avoid SSS and tributaries
Anterior to coronal suture to avoid motor strip |
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Location of the motor strip? By anatomic landmarks |
Typically 4-5 cm behind coronal suture |
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Where is Kocher point? |
12-13 cm posterior to nasion in AP direction
3 cm lateral to midline |
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Trajectory of EVD pass |
Aim at the medial canthus in a medial lateral direction and the tragus in AP direction |
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How deep are the ventricles typically? |
Surgeon usually passes cath 4-5cm into parenchyma before feeling a pop indicating entry into lateral ventricle |
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How deep should the EVD be inserted? |
6.5 to 7.0 cm from outer table of skull |
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How deep should the EVD be inserted? |
6.5 to 7.0 cm from outer table of skull |
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EVD should be at this level after insertion in SAH |
20 cm H20 |
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Convert mm Hg to cm H20 |
1mm Hg = 1.35 cm H20 1cm H20 = 0.735 mm Hg |
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Describe Lundberg A (plateau) waves |
Always pathological
Mean >50mm Hg, lasts 5-20min, returns to slightly elevated baseline |
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What does Lundberg A waves indicate? |
Reflects ischemia |
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What are Lundberg B waves? (Pressure pulses) |
>20-50mm Hg, lasts up to 3 mins
Due to respiratory changes, can be seen in sleep, suggests A waves may form |
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What are Lundberg C waves? (Preterminal wave) |
<20mm Hg
Represents cyclic variation of systemic BP transmitted to ICP, high amplitude may be preterminal |
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What is tidaling / bouncing? |
Free movement of CSF within the tubing |
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Good tidaling without CSF drainage - what is the implication? |
Collapsed ventricles with no CSF to drain |
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What is the inhibitory quotient? |
Dividing trough CSF antibiotic concentration by MIC of drug for the isolate
Should not exceed 10-20 |
