week 7 Flashcards
Vascular System:
Comprised of:
Depends upon:
Comprised of: Arteries and arterioles Capillaries Veins and venules Lymphatic vessels
Depends upon: Cardiovascular system Systemic blood vessels Circulating blood (volume/viscosity) Nervous & endocrine system activity Metabolic tissues needs … lymphatic system
Vascular System:
Function
How?
Function:
To meet the circulatory needs of the tissues
Constantly changing according to metabolic requirements
When supply doesn’t meet demand = ischaemia
How?
Blood flow (from high pressure to low pressure)
(from arterial [~100mmHg] venous [~4mmHg])
Flow rate = ΔP/R (pressure difference ÷ resistance)
Capillary Fluid exchange
Hydrostatic (blood pressure)/osmotic pressures (proteins)
Any extra between arterial supply & venous reabsorption lymph
Imbalance = oedema
Peripheral Blood Flow
Flow rate = ΔP/R! Affected by:-
Hemodynamic resistance
Blood viscosity
Vessel diameter
Regulation of peripheral vascular resistance
CNS (sympathetic = vasoconstriction)
Hormonal (noradrenaline/adrenaline/angiotensin)
Chemicals/proteins/hypoxia/pH
Movement of fluid across the capillary wall:
To meet metabolic needs
Hydrostatic & osmotic force
Pathophysiology of Vascular Disorder:
Characterised by reduced blood flow
Effect depends on imbalance of demand/supply
Inadequate supply = ischemia
- Heart failure
Left
Pulmonary congestion & reduced cardiac output
Poor arterial blood supply
Right
Venous congestion & ? reduced cardiac output
2. Alteration in vessel supply Lymph/arterial/venous Intact Rupture – aneurysm/trauma Patent Atherosclerosis/thrombus/valve issues Responsive Vasospasm/arteriosclerosis/aging changes
The ability to develop collateral supply can greatly decrease the ischaemic damage
Peripheral Arterial Disorders
PAD
- Intermittent claudication
- Pulses diminished or absent
- Oedema – None/minimal
- Skin changes: Trophic – cold/dry/shiny/hairless/thick opaque toe nails
- Pallor when elevated
- Red when dangling (dependent rubor)
- Ulcers – tips of extremities/ painful/deep/circular/pale to black base or dry gangrene
Peripheral Venous Disorders
PVD
- Pain: aching to cramp like, relieved by activity/elevation
- Pulses usually present
- Oedema – present/increases at the end of day
- Skin changes: warm/thick/ tough/darkened/? dermatitis
- Ulcers – medial malleolus/ pain variable/ superficial/irregular border/granulation base
Intermittent Claudication
Muscular/cramping (ischaemic) type pain Precipitated by exercise Resolves within 10 mins of rest Reproducible Area depend on which vessel affected
Lack of blood supply of oxygen/nutrients when increase in demand
Caused by arterial supply failure
Anaerobic cellular metabolism
Assessing peripheral pulses
Diagnostic:
Doppler studies
Exercise testing ( with ankle systolic blood pressure)
Duplex ultrasound/CT or MRI (with/without angiogram)
Angiogram
Venous studies
Lymphatic studies
Ankle Brachial Index FYI (with hand-held doppler)
Measures degree of PAD
Quantifies stenosis
Systolic BP both arms
Use highest reading
Systolic BP both ankles
Divide ankle systolic/
brachial systolic pressure
Normal ~ 0.90 – 1.30
Mild-mod. – 0.50 – 0.95
Mod-severe – 0 – 0.50
Common Sites of Atherosclerotic Obstruction
Coronary arteries Carotid arteries Aortic bifurcation Iliac and common femoral arteries Distal popliteal artery
Risk Factors for PAD: Modifiable
Smoking
Diet
Hypertension
Hyperlipidaemia
Diabetes
Obesity
Stress
Sedentary lifestyle
C-reactive protein
(inflammation)
Hyperhomocysteinemia
(clotting factor)Risk Factors for PAD: Non Modifiable
Age
Gender
Familial predisposition/genetics
Nursing Process: The care of the patient with PAD — assessment
Health history
Medications
Risk factors
Clinical manifestations of arterial insufficiency
Claudication and rest pain
Colour changes
Weak or absent pulses
Skin changes and skin breakdown
Arterial/venous/lymphatic (medical) diagnosis made
Nursing process: The care of the patient with PAD — diagnoses
Altered peripheral tissue perfusion
Chronic pain
Risk for impaired skin integrity
Knowledge deficient
Nursing process: Altered peripheral tissue perfusion — planning
Major goals include: Increased arterial blood supply Promotion of vasodilatation Prevention of vascular compression Relief of pain Attainment or maintenance of tissue integrity Adherence to self-care programme
Nursing process: Altered peripheral tissue perfusion — implementation
Exercises and activities:
Walking (stop with pain – gradually increase tolerance)
Graded isometric exercises.
Promote circulation & development of collateral circulation
Specialist advice before commencement
-Contraindications include leg ulcers/cellulitis/thrombotic occlusions
Positioning strategies
Temperature
Effects of heat (vasodilation) & cold (avoid)
Stop smoking
Stress reduction (counselling)
Peripheral Arterial Disease (PAD)
Complications
Atrophy of skin/nerves /muscles
Delayed healing/wound necrosis/infection/gangrene
PAD – Medical treatment
Medical (relieve symptoms/improve arterial supply)
Risk factor modification (smoking/diet/exercise)
Drugs (aspirin …/prostaglandin)
Management of diabetes/hypertension/obesity
Refer to podiatrist/physio/rehab. speciallist
Surgical (relieve symptoms/improve arterial supply)
PTBA (balloon angioplasty/stent)
Peripheral arterial bypass graft (femoral-popliteal)
Endarterectomy/patch graft
Amputation (last resort)
Nursing Management – Peripheral arterial bypass graft
Vital signs/neurovascular observations (pulses) Graft patency obs (doppler) Ankle brachial index (8hrly) IDC 1hrly measures Complex invasive line care Wound care (bleeding/haematoma) Elevate extremity/gently exercise Graduated compression stockings(?) Analgesia Discharge advice/patient education Care of co-morbidities
Arterial Aneurysms
An aneurysm is a localised sac or dilation formed at a weak point in the wall of the aorta
Aortic Aneurysm: Classified
Classified:- Type True – wall of artery forms the aneurysm False – disruption of all artery layers (trauma/infection) Shape Position (thoracic 85%)
Aortic Aneurysm: Risk factors: (exact pathophysiology unknown)
Atherosclerosis in most cases Genetic link/congenital vessel wall weakness Trauma/disease/inflammation After formation tends to enlarge Smoking/hypertension
Aortic Aneurysm: Clinical manifestations
Clinical manifestations (often asymptomatic/varied)
Pain/throbbing/”beating”
Ascending – voice hoarseness/dysphagia/venous return interruption (distended neck vessels/oedema)
Thoracic – deep spreading chest pain
Abdominal –back pain/bowel pressure/bruit/palpable
From thrombosis of smaller vessels
Aortic Aneurysm: Diagnosis
Routine examination
Pulsatile mass in 80% cases/bruit
Chest x-ray – calcification/widening of aorta
ECG to rule out MI
Echocardiology – aortic insufficiency
Ultrasound/ CT scan/MRI scan
Angiography – useful to assess other vessel involvement
Medical Management - Aortic Aneurysm
Depends on symptoms/prognosis/position/ patient co-morbidities
High rate of surgical death/complications
Prevent rupture/early detection essential
Conservative (small aneurysm/poor surgical risk)
Risk factor/behaviour modification (hypertension/smoking/sedentary lifestyle)
Manage co-morbidities & other atherosclerosis
Operative
Surgical - graft or primary closure
Endovascular – femoral/iliac artery catheter accessed
minimally invasive/strict criteria
Open Repair of an Ascending Aortic Aneurysm- Postop Nursing Care
Complex major surgery/surgical ICU/HDU area
Patient may have complex co-morbidities
Vital signs/neurovascular – frequent/regular
Monitoring for signs of occlusion/thrombosis/emboli
Monitor all systems (respiratory/renal – IDC 1 hrly)
Monitor T° 4 hrly (graft rejection)
Assess site/wound – haematoma/ooze/inflammation
Often first or second day post op walking
Surgeon/facility dependent
Thromboembolism(VTE) Prevention & Care
“Deep vein thrombosis (DVT) is one of the most common, preventable complications of surgery
DVT - Prevention/prophylaxis
often medically prescribed - though not always
nothing stopping us from initiating interventions (Dr have you considered …)
Prevention is better than cure!
Early mobility/ambulation/SOOB
Bed exercises/deep breathing & coughing/alter position
Compression stockings/(good for distal DVT but what about proximal)? –
Fit correctly!!!!
(some contra-indications – see the readings)
Pneumatic compression devices - SCDs/ICDs
(some contra-indications – see the readings)
Drugs
Anticoagulants - Heparin(LMWH)/enoxaparin/warfarin (phasing out)/others
DVT treatment
Treatment (of diagnosed DVT)
Prevent further growth & fragmentation (into PE)
Bed rest with limb elevation
Anticoagulants (prevent further thrombi)
Thrombi resolves naturally (not through anticoags)
Then mobilise with quality stockings (not the cheapies)
Drug Therapy
Heparin – IV infusion/SCI/Warfarin/more modern types
Thrombolytics
Previously (with DVTs) only for limb threatening situations
Now being trialled to ascertain treatment as more routine
Surgery (uncommon)
Vena cava filter
Open thrombolectomy
