What is a WADA exam?

What is a WADA exam?

A WADA exam is also known as an intracarotid amytal test. It is one of the “non-invasive” tests used to determine which hemisphere is language dominant in epileptic patients and also assess the ability of the non-affected side to maintain memory when isolated. For example, if you were to remove the R hippocampus – could the L side support language and memory alone?

No test is perfect... here are a couple of the WADA Shortcomings:

1. If patient has a high flow AVM – reading can be inaccurate
2. A portion of the hippocampus that you are trying to shut down could get its blood supply from posterior circulation making it hard to tell how accurately the patient will respond with full resection.

How is it done?

1. Get angiogram (to assess cross flow – which is a contraindication to shutting down the side of primary supply)
2. Cath ICA (usually start on lesion side)
3. Ask pt to hold opposite arm in the arm as amobarbital is rapidly injected into the ICA
4. What should happen? An almost immediate flaccid exam of the arm that begins to wear off in about 8 minutes. If it wears off faster (around 2 minutes) you may think about a high flow AVM.
5. Assess language by asking pt to name objects and remember them
6. Assess memory by asking pt to recall as many of the objects as possible 15 minutes later
7. Procedure can be repeated on the other side if needed

Photo source: http://www.instantanatomy.net/headneck/vessels/articinskull.html
Source: Handbook of Neurosurgery, Greenberg 6th Ed

Rheumatology/Orthopedic Buzz Terms

Rheumatology. I'm not sure there is a more gray area of medicine... perhaps that's why I don't like it that much. I remember sitting in rheumatology class listening to cases thinking, "it could be any of the rheum diseases that we've talked about!" They all sound the same and there is no ONE test that gives you the answer. I find it immensely frustrating (perhaps why I ended up in a surgical field), but I tip my hats to the providers that work in it. It is so difficult to pin down a diagnosis and successfully treat a patient with rheum issues... so for me, I stick to the basics.

See below for my knowledge extent on these rheum/orthopedic PANCE/PANRE test-able gems:

Osteoarthritis (OA)
Exercise, PT
If knee joints involves - encourage weight loss indicting
Pool activities
NSAIDS

Rheumatoid arthritis (RA)
Aspirin, other NSAIDS
methotrexate for severe cases
benefits take months to see after therapy initiation

Ankylosing Spondylitis
PT
Indomethacin
Bamboo spine on plain films

SLE
NSAIDs for joint symptoms
Benign cases only need supportive care
Systemic corticosteroids for serious complications
Could be a cause of thrombosis in young women (oral contraceptives can also cause this)

Rickets
Vit D deficiency

Osteomyelitis
Aspirate and culture
Immobilize
Generally start with IV antibiotics then follow with PO antibiotics




Source: Medical boards Step 2 Made Ridiculously Simple - A. Carl, MD, PhD
Photo: wiki.cns.org

Postoperative management of temporal lobectomy

Postoperative management of temporal lobectomy:

1.     OR to PACU x 1 day to floor x 1-2 day – aim for D/C on POD3
2. ·      Early rise in body temp post op, think about incentive spirometery
3. ·      Hep lock as soon as patient starts taking PO fluids
4. ·      Encourage sitting and ambulating
5. ·     Patient remains on preop AEDs for 1-2 years post op (managed by Epilepsy folks)

·      Possible complications to look for:

o   Hemiparesis

§  Usually happens after cauterization/tearing of perforating vessels (from posterior communicating vessels or anterior choroidal a.)

§  Paralysis usually occurs immediately – this would be known before post op check

o   Visual field defects

§  Contralateral superior quadrant anopsia from damage of the Meyer loop

§  Always check visual fields

o   Dysphasia

§  Usually transient (1-3 weeks post op)

§  Approx 50% of dominant temp. lobe resections have dysphasia

o   Aseptic meningitis

§  A complication that usually presents 72 hrs – 1 week post op

§  Stiff neck, severe HA, nausea, elevated body temp

§  Diagnosis of exclusion with LP

o   Post operative seizures

§  Sz w/in 1^st 24hrs does not correlate to poor long term outcomes

§  Sz after 48hrs (with adequate AED blood levels) indicate poor long term outcome

Source: Neurosurgical Operative Atlas 2nd Ed- Starr, Barbaro, Larson

Pic source: http://www.neuros.net/en/epilepsy_surgery.php

Preoperative Patients on Coumadin

If you work in surgery or with the elderly - anticoagulation is an every day part of life. INRs, PTs, PTTs, etc... it is important to know what measures what and what reversal agents (if any) are available. Let's talk about Coumadin today.

Scenario: 79 yo patient is coming in for a surgical procedure, but he is on Coumadin. You did your due diligence and had them stop it about 5 days pre-op, but their INR is still 1.6 on preoperative blood work. What are your next steps?

Generally if you are going to bring someone to the OR you'd like their INR to be less than 1.5. If it is higher, you would consider a reversal agent.

Your 1st option for reversal is Vit K. 

• PO is most predictable and is preferred to IV if rapid reversal is not needed. PO Vit K lowers INR in about 24-48 hours. 
• IV works in approximately 12-24 hrs, but you run a greater risk of anaphylaxis and it must be administered over a longer period of time (approx 20 minutes). 

Your 2nd option for reversal is Fresh Frozen Plasma (FFP).

• FFP is more expensive than Vit K, but works within 12 hrs. FFP replaces clotting factors.

So, even though you did your due diligence, why was the INR still high? There are several reasons that can delay the drop of a patient's INR:

1. Age - Elderly pts
2. Malignancy (active)
3. Liver disease
4. CHF, unstable
5. Meds that keep Coumadin around in the blood (check their med list)

Sources:

Ansell, J, Hirsh, J, Poller, L, et al. The pharmacology and management of the vitamin K antagonists: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004; 126:204S. 

Normalization of INR After Stopping Coumadin: http://www.fpnotebook.com/mobile/HemeOnc/Surgery/PrprtvAntcgltn.htm

Surgical Training for Neurosurgical PAs

Laminectomy

Last week I had the privilege of attending a surgical training in San Francisco, California. The event was created by the Association of Neurosurgical Physician Assistants (ANSPA) in conjunction with Ethicon. I must say it was a fantastic experience. I was able to spend a half a day in a live porcine wet lab. The lab was for PAs only so it enabled me to spend more time with the surgical instruments and take the lead on certain aspects of the surgeries that we performed - both opportunities that I don't necessarily get on a day to day basis. It was successful in building my confidence.

We performed a craniotomy and tumor removal as well as a laminectomy with a focus on hemostasis. This is an unusual experience and I learned a great deal from both the PAs that attended and the Ethicon reps regarding hemostasis products. I had the least amount of surgical experience of all the PAs that were there (9 months), however all of the PAs were friendly and helpful and I learned quite a few new techniques. It was also inspirational to see what other PAs around the nation were doing as part of their daily grind. It ranged from PAs that spent the majority of their time in the OR as co-surgeons to those that split their time 50-50 between OR and floor work.

I was able to meet and spend some time with Josh, a neurosurgical PA for over 10 years, who is the current president of ANSPA. The AAPA recently completed a video on him and his contributions to his neurosurgical practice. The surgeons that he works with on a daily basis speak very highly of his surgical and patient skill sets. Mike Nido, PA-C and Dean Barone, PA-C were also instrumental in making this event happen.

All in all, hats off to ANSPA for working hard to make this happen for PAs. They hope to create more of these learning opportunities for neurosurgical PAs in the near future. If you are not a member, I highly encourage you to do so if you're interested in neurosurgery as a physician assistant.





*Disclosure: I am in no way financial tied to Ethicon. Just attended the event.