Week 5 Part 2 Flashcards
Acute thrombus
faintly echogenic, almost invisible
attached to a vein wall over a short area, so it may be a snakelike clot swaying back and forth
at risk for emboli
lumen will expand in cases of occlusive DVT
some compression of walls is possible
Chronic thrombus
complete dissolution of clot over time lumen contracts incompressible walls may become more solid, firmer and more echogenic becomes better attached over time less threat of embolization large collaterals will develop
With an acute thrombus, collaterals will not really have formed. What happens until the collaterals are formed?
an increase in velocity and flow in the saphenous veins or profunda femoris
What are complications of DVT? (5)
PE recurrent DVT incompetent valves varicose veins chronic venous insufficiency
Pulmonary Embolism symptoms
symptoms- difficulty breathing, chest pain on inspirations and palpitations
Clinically- low blood O/cyanosis, rapid breathing and HR
How are PE’s diagnosed?
D-dimer test, CT, pumonary angiography, pulse oximetry (first test)
How are PE’s treated?
anticoagulent therapy-heparin and warfarin
surgical intervention- pulmonary thrombectomy
Pulse oximetry:
simplest, noninvasive way to monitor the percentage of hemoglobin that is saturated with oxygen
places on finger and infrared light is transmitted into tissue
In pulse oximetry, a saturation level of what is abnormal?
<95%
can be caused by other lung/heart problems, or PE
Post thrombotic syndrome (PT’s)
vein walls are permanently damaged in 60% of cases
valve leaflets are immobile and fixed to wall
venous reflux
venous stasis is worse in standing position
Chronic venous obstruction manifests as:
chronic leg swelling, ankle pigmentation and ulcer formations (these can form spontaneously or a trauma inflammatory reaction in tissue)
What causes brown skin pigmentation?
metabolic breakdown of hemoglobin
A complication of PTS is the persistent chronic _______ in venous pressure
elevations
Primary vs. secondary varicose veins:
Primary- hx of DVT is rare and it’s a result of valvular incompetence at SFJ
Secondary- associated with obstruction (DVT) or incompetence of the deep venous system valves
When thrombus is visualized, what images need to be taken:
compression images doppler with augmentation CD presence or absence of flow routine images
What are pitfalls for diagnosing DVT?
swollen, oedematous legs obesity dual femoral and popliteal veins non-occlusive can be missed if vein isn't adequately seen multiple calf veins and variable anatomy iliacs may not be seen due to gas and obesity calcified arterial system pregnancy
Why does pregnancy increase the risk of a DVT?
changes to coagulation system
hormonal effects and pressure from enlarging uterus
c-sections
physiological changes to venous flow in legs
DVT’s only occur in the upper extremitiies 10% of the time. What’s the most common cause of this?
placement of VAD
injury to vein wall
What’s the usual cause for DVT in the lower extremities?
stasis
upper extremities don’t have soleal sinuses which is why it’s not common to have a DVT
Signs/symptoms if the SCV is obstructed:
arm and facial edema
head fullness
blurred vision
vertigo/dyspnea
When a normal person “sniffs”, the IJV or SCV will decrease in diameter and will show an increase in flow velocity. True or false
True– patients with central BCV or SVC obstruction won’t have this response
What are causes of upper extremity DVT?
presence of a central venous catheter or pacemaker lead*
radiation therapy, malignant obstruction and effort induced thrombosis are more frequently with UEDVT
Is upper or lower DVT more severe?
lower– less risk for PE in upper
In Paget-Schroetter syndrome, patients develop a spontaneous UEDVT in what arm? (dominant or non)
dominant
heavy exertion causes microtrauma to the vessel intima and leads to coagulation issues
What gets compressed with TOS?
brachial nerves, subclavian artery, subclavian vein
TOS patients have pain that radiates into the thumb. True or false
False– 4th and 5th digits
What bony structures are sometimes found in TOS patients?
cervical ribs, long trv processes of C-spine
What can be associated with idiopathic TOS?
occult cancers– ie. lymphoma, lung cancer or compression by lymph nodes
Primary UEDVT is
effort induced or idiopathic
Secondary UEDVT:
develops in patients with central venous catheters, pacemakers or cancer
catheter related thrombosis
Why can catheters cause DVT?
vessel wall is damaged, catheter may impede blood flow causing stasis
(incorrect placement of catheters likely cause this issue)
Where should catheters be placed to avoid secondary UEDVT?
lower third of SVC by junction of RA as blood is the most rapid in SVC
Where’s the most common access site for central venous access?
SCV and IJV – they feed it in through here to the SCV
Out of SCV and IJV for a VAD, which one is preferred?
rt. IJV because of it’s straight course to the heart
EJV is the preferred insertion site for a VAD. True or false
False–only if the IJV is obstructed. it’s often tortuous
What are some complications of VAD?
vein damage AVF non target puncture bleeding air embolism cardiac arrhythmia infection
