Lumbar Drains | Ottawa ICU Survival Guide for Rotating Residents

Lumbar Drains

Lumbar Drain Parameters

Lumbar Drain Parameters

A lumbar drain is like an EVD for the spinal cord

They are placed for monitoring and treatment in patients who undergo thoracic endovascular aortic repair because of the vulnerability of the perfusion to the anterior spinal cord

We use the identical monitoring system only the laser level is set to the insertion sight instead of the Tragus

Lumbar Drain Parameters

Lumbar Drain Parameters

Lumbar Drain Parameters

The manometer is set at +10 to drain to a maximum of 20cc/hr after which the drain will be clamped

We make 20cc of CSF hourly. We can safely drain up to 20cc of CSF/hour

Their Activity level order should be bed rest. Patients must remain on their backs and in bed until the drain is clamped.

Why Bed Rest?

Lumbar Drain Parameters

Why Bed Rest?

if they are permitted to ambulate there is a risk the lumbar drain will become dislodged with movement.

If they are permitted to sit or stand there is risk that it will over drain with gravity if

Over drainage can put traction on the meninges and meningeal arteries, cause the brain to sag, and results in a subdural hematoma(s)

Spinal Cord Ischemia

Principles of Management of Spinal Cord Ischemia

Principles of Management of Spinal Cord Ischemia

Like the brain, when the spinal cord suffers an ischemic insult it becomes edematous

Like the skull, the vertebrae are extremely unforgiving and poor at creating space for edema

This will manifest as weakness or paralysis with preserved sensation

Principles of Management of Spinal Cord Ischemia

Principles of Management of Spinal Cord Ischemia

Principles of Management of Spinal Cord Ischemia

Management of Spinal Cord Ischemia and raised intrathecal pressure is very similar to Management of raised intracranial pressure

Instead of ICP we measure ITP (intrathecal pressure).

Instead of CPP we target SPP (spinal perfusion pressure)

Instead of CPP = MAP - ICP the equation is SPP = MAP - ITP

We get paid to worry and so we assume some degree of spinal cord edema (as we do in all spinal cord injuries) and set their MAP > 85 as soon as they arrive post op

SPP should be maintained >65

Management of Spinal Cord Ischemia

Principles of Management of Spinal Cord Ischemia

Management of Spinal Cord Ischemia

You are called because the patient has developed lower extremity weakness with preserved sensation

This is spinal cord ischemia until proven otherwise

There is no role for imaging. The lumbar drain is below the conus medullaris and cannot cause weakness. We know the pathophysiology and simply have to act

Confirm the patient is weak
Page (or have someone page) your attending/fellow and Vascular Surgery
Drive up the MAP to >100
Drop the level of the Lumbar Drain and drain 10cc of CSF
Reassess the patient
If still weak give 3% saline 250cc IV

When a patient has a breach in the the calvarium or skull base, CSF leaks can occur

The most common scenario for this is in association with skull base tumor resections (transphenoidal approach to pituitary surgery)

Additionally any post operative craniotomy has a potential tract for CSF to flow if the intracranial pressures are elevated, causing subdural and subgaleal collections of CSF

Lumbar drains are inserted in these scenarios to divert CSF and allow these defects to heal if possible

We are not targeting any specific numbers in this scenario, we are simply trying to offload CSF

Subgaleal and skull base leaks are at risk for infections due to the persistent breach in the blood brain barrier and exposure of CSF to an overlying incision or drainage through the ethmoid sinuses and nasal passage

If they do not heal, these patients will require internalized shunts