Vascular & Haematology Flashcards
What is difference between thrombus and embolus?
Thrombus is a blood clot in a vein
An embolus is an plug of material e.g. clot, foreign body, bacterial clump, piece of tumour, air
Describe the different Central Venous Catheters (CVC) and their advantages/disadvantages.
Non-Tunneled CVC
Direct Protrusion of Catheter
Placed at Bedside
Tunneled CVC
Passed Under Skin to Separate Site
Placed by IR or in OR
*Lower Infection Risk
Peripherally Inserted Central Catheter (PICC)
Longer Line Placed Peripherally in an Arm Vein
Less Invasive & Lower Infection Risk
Smaller Caliber Lumens
Often Used if Anticipating Long-Term Need (TPN or ABX)
Subcutaneous Port
Completely Tunneled with No Exposed Ports
Placed Under Anesthesia
Lower Infection Risk than Tunneled or Non-Tunneled CVC
Longer Patency – Ideal for Chemotherapy
What is the preferred site for CVC placement?
Right internal jugular vein as has a straight path the the subclavian (less likely to cause intimal damage and technically easier to place than left) and in neck is lower risk of infection and DVT than groin (c.f. femoral). The IJV is also easier to compress to stop bleeding than directly into subclavian vein.
NB: if patient already has a pneumothorax and chest drain then strongly consider placing CVC on ipsilateral side. (already has the Ptx and drain so a ‘free shot’ so to speak at placing the CVC).
Describe the approach for blind placement of IJV, subclavian and femoral CVCs.
Internal Jugular (IJ) Vein
Insertion:
Anterior Approach: Along the Medial Border of the SCM, 2-3 Fingerbreadths Above the Clavicle
Central Approach: The Apex of the Bifurcation of the SCM Heads
Angle: 30-45 Degrees
Aim: Ipsilateral Nipple
*Palpate the Carotid Artery During Placement (Vein Should be Lateral to Pulse)
Subclavian Vein
Insert: 2-3 cm Below Midpoint of Clavicle (1-2 cm Lateral of Bend)
Aim: Just Deep to Suprasternal Notch
If Clavicle is Hit, Withdraw and March Down
Femoral Vein
Insert: 1-2 cm Below Inguinal Ligament & 1 cm Medial to the Femoral Artery Pulse
Angle: 30-45 Degrees
Describe the Seldinger technique for CVC placement.
Puncture Vein with Hollow Introducer Needle
Attach Syringe with Gentle Negative Pressure During Advancement
Dark Non-Pulsatile Blood Confirms Venipuncture (Caution: Arterial Blood in Hypoxic Patients May Also be Dark)
Pass Guidewire Through the Needle
Always Maintain Control of the Guidewire During Placement – Should Never Completely Enter the Vein
Withdraw Needle
Make Small Skin Incision at the Entry Site
Pass Dilator Over the Guidewire & Remove the Dilator
Pass CVC Over the Guidewire
Withdraw Guidewire
Suture CVC to Skin & Place Sterile Dressing
Always Obtain Post-Procedure Chest XR to Confirm Appropriate Positioning & Look for Pneumothorax
(CVC: 1-2 cm Above the Right Atrium-SVC Junction
Seen as Just Above the Carina on CXR)
What are some possible complications of CVC placement and how would you treat them?
Carotid Cannulation (Arterial Injury)
Can Cause Life-Threatening Hemorrhage
Reduce Risk by Using Ultrasound-Guidance for Placement
Diagnosis:
ABG
Pressure Transducer Showing Arterial Waveform
CXR Showing Line to the Left of the Spine
Treatment:
Cannulation with Probe Needle Only: Remove & Hold Pressure for 5-10 Minutes
Cannulation with Dilator or Catheter: Remove in OR
Malposition
Tip Abutting into the Wall of the Superior Vena Cava
Risk for SVC Puncture
Treatment: Retract to the Innominate Vein (Do Not Advance)
Tip in Right Atrium
Risk for Atrial Wall Puncture
Treatment: Retract to the Right-Atrium-SVC Junction
Pneumothorax (PTX)
Risk: 1-6.6% (Higher Risk in Emergency Setting or if Multiple Needle Passes are Required to Find the Vein)
*See Trauma: Pulmonary Trauma
Cardiac Tamponade
From Puncture of the Right Atrium
*See Trauma: Cardiac Trauma
Thrombosis
*See Vascular: Deep Venous Thrombosis (DVT)
Treatment:
If Catheter Not Needed: Remove & Heparin
If Catheter Needed: Systemic Heparin or tPA Down the Line
Air Embolism
*See Vascular: Other Venous Emboli
Central Line-Associated Bloodstream Infection (CLABSI)
Also Known as Catheter-Related Bloodstream Infection (CRBSI)
Risk Increases with Duration of Placement (However there is No Indication for Routine Catheter Changing Based on the Number of Days)
Most Common Source: Skin Colonization
Most Common Organisms:
S. epidermidis (Most Common)
S. aureus (Second Most Common)
Enterococci
Candida
Presentation:
Inflammation & Purulence at the Catheter Insertion Site
Fever
Sepsis (Often Sudden Onset)
Complications:
Septic Thrombophlebitis
Infective Endocarditis
Treatment: Antibiotics & Catheter Removal
If Clinically Unable to Remove the Catheter – Consider Exchange Over a Guidewire
What are indications for anticoagulation in atrial fibrillation.
Anticoagulation Indications:
Postoperatively Persists > 48 Hours
If Requires Cardioversion
CHADS-VASC Score ≥ 1-2
CHF History (+1)
HTN History (+1)
Age ≥ 65 (+1) or ≥ 75 (+2)
DM History (+1)
Stroke/TIA/Thromboembolism History (+2)
Vascular Disease History (MI, PAD or Aortic Plaque) (+1)
Sex Female (+1)
DVT treatment
VTE provoked by a reversible risk factor, or a first unprovoked isolated distal (calf) deep vein thrombosis (DVT), has a low risk of recurrence and is usually treated for 3 months.
VTE associated with active cancer, or a second unprovoked VTE, has a high risk of recurrence and is usually treated indefinitely.
Describe the ligamentous attachments of the spleen.
Gastrosplenic
- hilum to greater curvature of stomach.
- contains short gastrics and left gastroepiploic artery.
Lienorenal (splenorenal)
- hilum to left kidney
- contains splenic artery & vein
- contains tail of pancreas
Splenocolic
- inferior pole to colon
- avascular
Splenophrenic
- superior pole to diaphragm
- avascular
Phrenicocolic - not directly attached to spleen but does cradle/support the spleen to some extent.
What is the normal function of the spleen?
Red pulp and white pulp function differently.
Red pulp filters and removes aged/damaged RBC debris.
- Arteries bring blood to the cords
- cords filter and drain into sinuses
- sinuses drain into venous system.
White pulp immunologic function in IgM antibotides and the malpighian corpuscles contain B cells (lymphoid follicles) and T cells (Periarteriolar lymphoid sheaths (PALS)).
What is an accessory spleen?
An additional segment of splenic tissue at an ectopic site.
What are the most common sites for accessory spleens?
Splenic hilum
Pancreatic tail
Greater omentum
Along splenic artery
Gastrosplenic ligament
Splenocolic ligament
Retroperitoneum
Greater curve of the stomach
Gastrocolic ligament
Small bowel mesentery
How do accessory spleens usually present?
Assymptomatic/incidental finding
Can be prone to torsion
Can be ‘symptomatic’ as a relapse of ITP post splenectomy.
What are these and their relevance?
These are Howell Jolly bodies.
They are left over nuclear remnants that are usually removed when red blood cells are in the spleen.
Presence of Howell Jolly bodies indicates asplenism (anatomically or functionally).
What are these and their relevance?
Schistocytes (red arrow) and helmet cells (blue arrow) are common in any disease where there is shearing or mechanical destruction of the red cells. This includes, disseminated intravascular coagulation, thrombotic thrombocytopenic purpura and aortic stenosis.
What are these and their relevance?
Target cells (AKA codocytes) appear as bullseyes, as seen here. These can be seen in liver disease, alpha/beta thalassemia, hemoglobin C disease and in asplenia.
