TEVAR

What we need to know about them to look after them

Preoperative Condition

Functional status

Were there limitations to their activities due to claudication
This matters because coronary ischemia may not manifest at baseline if there is no demand and it heightens our awareness in the perioperative period

Coronary Artery Disease

Do they have pre-existing CAD/stents/bypass

Were they seen by a cardiologist?

Did their pre-op ECG have changes?

Did they have any stress testing?

COPD

Did they have important findings on PFTs?

Are they on Home O2

Kidney Disease

Did they have pre-existing kidney disease

What is their baseline creatinine

List of all other comorbidities

Intraoperative Course

What was done?

TEVAR

TEVAR AND EVAR

TEVAR with open repair of abdominal aorta portion of aneurysm

Were any bypasses created

These are planned surgeries

Unlike most other postoperative patients in the ICU, these are usually elective surgeries. The Vascular surgeons know their patients well and often times their families very well as they have been following them for years (or at least months) prior to their surgeries

If a patient is having a complication, call the ICU attending but also let the Vascular Surgical team know. It is not uncommon for families to call the surgeon directly or run into them in the hospital and so they need to know if something untoward has happened

Post operative orders

Admit

Under the Intensivist

Diet

NPO until lon longer nauseated and has passed gas

NG to low intermittent suction (if present. you do not have to put one in if not)

Activity

Bed rest while lumber drain is in situ

Vitals

per unit protocol (hourly). These patients usually have an arterial line

Neurovascular Vitals q 1 h until specifically discontinued (it is essential to check pulses and their ability to move hourly)

call MD immediately if any change in pulses or motor exam

Ins/Outs hourly

Oxygen to maintain O2 sats >95 (this is not a time to be weaning oxygen. There is a spinal cord at risk of ischemia)

Target MAP > 85 AND target spinal cord perfusion pressure (SCPP) > 65

Medications/Infusions:

IV NS at 75cc/hr x 24hrs

IV Norepinephrine but change the cap to 15ug/min. Write a specific order to "call MD if more is required for consideration of a fluid bolus"

Ancef 2g IV q8h x 3 (antibiotics are essential. infected aortic grafts are a disastrous complication)

ASA 81 mg to start in am

Lipitor 40mg to start in am

DVT prophylaxis is to start the next evening (remember that they have been anticoagulated in the OR and you will have to overtride the APS orders)

NO NSAIDS
NO ACE-INHIBITORS
NO ARBS
NO ANTIPLATELET AGENTS (OUTSIDE OF ASA)
NO BOWEL PROTOCOL

Analgesia

This is percutaneous procedure - they do not have much pain

Acetominphone 975mg q6h

Hydromorphone 0.2ug IV as needed

Investigations

Baseline CXR only if a central line was attempted or placed in the OR or if they are intubated (neither is likely)

Baseline ECG and follow up in am

Baseline Troponin and CK and follow up in am x 2 days

Baseline CBC, the q6h x 3 then daily

Baseline PTT, INR, FIbrinogen then q6h x 3

Baseline Lytes, BUN, Creatinine and then daily

Baseline extended lytes and LFTs and then in am

Baseline arterial blood gas and then every 2 hours x 12 (it is important to follow lactate and Hb hourly

The Posterior Spinal Arteries

The Anterior Spinal Arteries and The Artery of Adamkiewicz

The Anterior Spinal Arteries and The Artery of Adamkiewicz

The Posterior Spinal Arteries supply the Dorsal Columns and the Posterior Horns

Dorsal Columns and Posterior Horns convey sensations of fine touch, vibration, two-point discrimination, and proprioception from the skin and joints.

PSAs arise from the vertebral arteries and have a rich rich and redundant blood supply from enumerable radicular arteries.

The PSAs also form anastamoses with one another wihich futher promotes vascular supply to the Dorsal Columns and Posterior Horns

This blood supply is not vulnerable which is why the sine qua non of spinal cord ischemia is a patient who has intact sensation but cannot move

The Anterior Spinal Arteries and The Artery of Adamkiewicz

The Anterior Spinal Arteries and The Artery of Adamkiewicz

The Anterior Spinal Arteries and The Artery of Adamkiewicz

Anterior Spinal Artery arises from the vertebral arteries and is the longest artery in the body (from the foramen magnum to the conus medullaris.

Supplies the anterior 2/3rds of the spinal cord including the Anterior Horns, Spinothalamic Tracts, and Corticospinal Tracts

The Spinothalamic Tracts, and Corticospinal Tracts contain motor neurons

The ASA has much less contribution from the radicular arteries and varies in diameter through its course (smallest diameter in the thoracic region)

Luckily, the Artery of Adamkiewicz contributes to the ASA at T9-T12 in 75% of people (the rest have the artery located above or below)

There is no way to know exactly where the artery is and so there is a chance that the thoracic graft will cover, partially cover, create turbulent flow at the artery and will be extremely vulnerable to hypotension resulting in weakness or paralysis that may respond exceptionally well to early recognition and intervention (see next)

It is our responsibilty in the ICU to be vigilant about monitoring for this and acting immediately when there is a change in motor function

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

Targets and Suggestions for you

Lab Targets

Hb > 90
IINR <1.6
Platelets >70

Fluid Boluses

This is a percutaneous procedure and so these patients do not require a lot of IV fluids

They mainly receive crystalloids in the OR

They are at risk for spinal cord ischemia and so It is ok to avoid crystalloids and use blood, factors, 25% Albumin, and artificial colloids (starches) in this population (see link to "fluids" topic below).

Options

If Hb < 90 give blood

If INR > 1.5 give FFP (also give Vitamin K 10mg IV)

200cc of 25 % albumin

Volulyte 250cc at a time to a maxium of 1L/24 hours

If there is a bona fide concern for spinal cord ischemia a bolus of 3% can even be used

NO hypotonic fluids with risk of spinal cord ischemia