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

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

Placing External Ventricular Drains

What is an EVD?
A temporary system that allows drainage of CSF from the ventricles to an external closed system.

Caring for a patient undergoing EVD placement Great clinical guideline series by the American Association of Neuroscience Nurses

Preventing Infections When Placing EVDs (video)

Potential placement sites:

Paine's Point

Fraizer's Point

Kocher's Point

If you are having trouble uploading the video, here is the link: http://www.youtube.com/watch?v=x49rY0tZpVI

Pic source: http://www.brain-surgery.us/Drain_Placement.html#kocher

Lumbar Punctures

LUMBAR PUNCTURES

(Source: http://students.washington.edu/aomega/procedures.shtml#chestTube)

Indications: Suspected CNS infection, SAH, Guillain-Barre syndrome, MS, SLE
Measure intracranial pressure (pseudotumor cerebri)

Contraindications: Increased intracranial pressure (except to dx pseudotumor cerebri), supratentorial mass lesion, thrombocytopenia, bleeding dyscrasia

Complications: Post-LP headache, brain herniation if mass lesion present or increased intracranial pressure, bloody tap if venous plexus punctured.


Technique
1. Obtain informed consent
2. Position patient with back near edge of bed in lateral recumbent position. Have patient flex hips and draw knees up to chest to increase curvature of spine.
3. Palpate iliac crests and identify L3 and L4 interspaces.
4. Open tray, wear sterile gloves, and set up tubes in order, 1-4.
5. Prep and drape skin in sterile fashion
6. Infiltrate skin with 1% lidocaine
7. Use 20-22 gauge spinal needle. Insert at interspace with needle angled slightly toward umbilicus (cephalad). Keep level of needle in line with horizontal plane.
8. A course resistance can be felt as the needle passes through the paraspinous ligaments and a “pop” may be felt when needle passes through the dura.
9. Withdraw stylus fully to check for fluid.
10. Once fluid is obtained, place stopcock and manometer on hub of needle to obtain opening pressure.
11. Fill tubes in order, 2-3cc per tube
12. Once fluid has been collected, replace stylus and withdraw needle.
13. Cover site with sterile dressing and have patient remain lying down in supine position for 2 hours.
14. Observe tubes for occult blood. Decreasing amounts of blood in tubes 1-4 suggests a bloody tap, while increasing or steady amounts suggests an CNS bleed.
15. Send fluid for analysis:
Tube #1: glucose, protein, protein electrophoresis
Tube #2: Gram stain, culture, bacteria, fungal, TB, viral
Tube #3: cell count, differential
Tube #4: VDRL, India ink, cytology

Nasogastric Tubes

On the general surgery rotation we place a good number of nasogastric tubes (NGTs). Today's educational topic during our pm rounds will be the NG tube so I thought I'd share what I have studied up on...

What do NGTs do? 

Gain access to the stomach and its contents. It will also allow for drainage and/or lavage in drug over-dosage or poisoning. In trauma settings, NG tubes can be used to aid in the prevention of vomiting and aspiration, as well as for assessment of GI bleeding. NG tubes can also be used for enteral feeding initially.

Indications

• To drain gastric contents
• To decompress the stomach
• To obtain a specimen of the gastric contents
• To introduce a passage into the GI tract. 
• Treatment of gastric immobility and bowel obstruction 

Contraindications

Severe facial trauma (cribriform plate disruption) -  because you might insert the tube intracranially.

Precautions/Protection

High potential for contact with pt fluids. Wear gloves and face/eye protection!

Basic Needs

Personal protective equipment
NG/OG tube
Catheter tip irrigation 60ml syringe
Water-soluble lubricant, preferably 2% Xylocaine jelly
Adhesive tape
Low powered suction device OR Drainage bag
Stethoscope
Cup of water (if necessary)/ ice chips
Emesis basin
pH indicator strips

How to do it

*Directly from Univ of Ottawa's Emergency Medicine page 2003

1. Gather equipment
   
   
2. Don non-sterile gloves
   
   
3. Explain the procedure to the patient and show equipment
   
   
4. If possible, sit patient upright for optimal neck/stomach alignment
   
   
5. Examine nostrils for deformity/obstructions to determine best side for insertion
   
   
6. Measure tubing from bridge of nose to earlobe, then to the point halfway between the end of the sternum and the navel
   
   
7. Mark measured length with a marker or note the distance
   
   
8. Lubricate 2-4 inches of tube with lubricant (preferably 2% Xylocaine). This procedure is very uncomfortable for many patients, so a squirt of Xylocaine jelly in the nostril, and a spray of Xylocaine to the back of the throat will help alleviate the discomfort.
   
   
9. Pass tube via either nare posteriorly, past the pharynx into the esophagus and
   then the stomach.
   
   Instruct the patient to swallow (you may offer ice chips/water) and advance the tube as the patient swallows. Swallowing of small sips of water may enhance passage of tube into esophagus.
   
   If resistance is met, rotate tube slowly with downward advancement toward closes ear. Do not force.
   
   
10. Withdraw tube immediately if changes occur in patient's respiratory status, if
    tube coils in mouth, if the patient begins to cough or turns pretty colours
    
    
11. Advance tube until mark is reached
    
    
12. Check for placement by attaching syringe to free end of the tube, aspirate sample of gastric contents. Do not inject an air bolus, as the best practice is to test the pH of the aspirated contents to ensure that the contents are acidic. The pH should be below 6. Obtain an x-ray to verify placement before instilling any feedings/medications or if you have concerns about the placement of the tube.
    
    
13. Secure tube with tape or commercially prepared tube holder
    
    
14. If for suction, remove syringe from free end of tube; connect to suction; set machine on type of suction and pressure as prescribed.
    
    
15. Document the reason for the tube insertion, type & size of tube, the nature and amount of aspirate, the type of suction and pressure setting if for suction, the nature and amount of drainage, and the effectiveness of the intervention.

 Source: Univ of Ottawa's Emergency Medicine page 2003

CT Surgery Starter Resource

This is an excellent starting resource for PAs starting out in CT surgery or PA students rotating in CT surgery. It is designed for CT surg residents starting out - but I have found it very helpful.

CTSWOT

Chest Tubes

Today we put in a chest tube on a patient with about a 20-25% pneumo. Thought I'd share what I found in my research leading up to placing the tube:

CHEST TUBE PLACEMENT

Indications: Pneumothorax, hemothorax, empyema, recurrent pleural effusion
Contraindic.: Bleeding dyscrasia, anticoagulation, empyema caused by AFB
Technique
1. Obtain informed consent
2. Check coags / platelets
3. Consider sedating patient (painful)
4. Use 18-20 French tube for pneumothorax, 32-36 French tube for fluid or hemothorax
5. Assemble suction/drainage equipment and connect to suction
6. Position patient in supine position, elevate head of bed 30-60 degrees. Usual insertion site is at anterior axillary line at 4th or 5th intercostals space. Mark site.
7. Prep and drape in sterile fashion. Wear gown and mask.
8. Anesthesia at pleural insertion site: anesthetize skin over rib using 2 gauge needle, 10 cc syringe, 1% lidocaine. Anesthesia at incision site (rib below rib of pleural insertion). Using 22 gauge needle and 1% lidocaine, infiltrate subQ, muscle, periosteum, and parietal pleura.
9. Make 2-4 cm incision through skin and tissues over rib. Extend incision with blunt dissection using Kelly clamp, working towards superior aspect of rib above tunneling the course of the chest tube before entering the chest cavity.
10. Push Kelly clamp through parietal pleura. Inside pleural cavity, open clamp, then withdraw. Air or fluid should rush out.
11. Check to see that pleural space has been entered with finger.
12. Grasp chest tube with curved clamp. Clamp free end of chest tube with another clamp.
13. Place tube in pleural space. Direct tube superior, medial, posterior for fluid drainage. Direct tube superior and anterior for pneumothorax. All ventilation holes need to be in pleural space.
14. Attach end of tube to suction/drainage.
15. Use 1-0 or 2-0 silk or nylon to suture chest tube in place.
16. Cover site with 4x4 gauze (with Y cuts to fit around tube)
17. Tape gauze and tube in place
18. Obtain CXR to confirm placement
19. Remove chest tube when there is less than 150cc of fluid in 24hrs and no air leak.



Source: http://students.washington.edu/aomega/procedures.shtml#chestTube

Cardiothoracic Imaging Resource

Yale's Introduction to Cardiothoracic Imaging. It includes cardiothoracic anatomy, imagining, case, and reference resource. Very high quality.

Wound Closure Series

This site provides 12 great videos on wound closure. Check it out:

• Chapter 1: Equipment (1:54 min)
• Chapter 2: Anesthesia (3:09 min)
• Chapter 3: Irrigation (1:11 min)
• Chapter 4: Starting the Procedure (2:30 min)
• Chapter 5: Simple Interrupted (3:45 min)
• Chapter 6: Horizontal Mattress (3:11 min)
• Chapter 7: Vertical Mattress (1:10 min)
• Chapter 8: Corner Suture (1:30 min)
• Chapter 9: Buried Suture (1:51 min)
• Chapter 10: Dermabond (1:56 min)
• Chapter 11: Steristrips (0:39 min)
• Chapter 12: Staples (0:47 min)

Wound Closure Series: Academic Life in the Emergency Room

Awake During Brain Surgery

Tomorrow I will be participating in a Deep Brain Stimulation case - awake brain surgery! So interesting.

AANS YouTube Channel

The American Association of Neurosurgeons have put a great YouTube Channel that has educational videos including power points, surgical videos, and lectures. I've learned a lot from it. It is definitely worth checking out if you are interested in neurosurgery!

Cranioplasty

My first couple days in Neurosurgery have been awesome. I have spent 90% of the time scrubbing into cases so I have had the chance to participate is some cool surgeries. Next week I will spend some time on the floors as well as in the OR which I am looking forward to.

Some of the procedures that I've been in on this week:
1. C1-C3 Fusion for an occipital fx
2. Carpal Tunnel release
3. Lateral Approach L3-L5 fusion for scoliosis
4. Burr Hole and EVD placement
5. Cranioplasty

The Cranioplasty was one of my favorite so far, so that is what I'll write about today.

Indications:
1. Cosmetic restoration of external skull symmetry
2. Sx relief secondary to craniotomy
3. Protection from trauma in an area void of skull bone

Material Options (some):
1. Methylmethacrylate
2. Titanium mesh
3. Split thickness calvaria
*It is recommended that foreign materials be perforated to prevent fluid collections underneath

Basic Suturing Technique

There are a ton of suturing tutorial videos online, but I often find that it is tough to see exactly what they are doing in the videos. SIM SUTURE is a company that makes an at-home practice kit so they came up with a 7 part suturing tutorial that has great lighting, instructions, and visuals. Happy sewing!

SIM SUTURE TUTORIALS

Paracentesis Video

NEJM Paracentesis Procedure Video

I am in my Ambulatory clinical rotation and I was able to do 2 paracentesis procedures in one day. One was therapeutic (drained 13L) and one was diagnostic. It was awesome! I love doing procedures.