Acute Ischaemia Flashcards
5 ‘P’s of ischaemic limb:
Painful
Pale
Pulseless (or diminished)
Paraesthesia -late
Paralysis- late
Time before irreversible ischaemia in extremity?
4-6 hours is when necrosis starts to occur and salvage rates drop
High risk of total limb death at 12 hours.
Management of the acutely ischaemic limb:
Limb in dependent position
Keep warm
Optimise O2 and hydration
Analgesia (eg. Ketamine)
Vasc referral
If thrombus/ embolus suspected:
Heparin 80units/kg IV
Then 18units/kg/hr infusion
AIM: APTT 60-100 or 1.5 normal
Assess for cause/ other embolic Cx- incl ECG
Causes of acute ischaemic limb:
LUMEN:
Thrombus
—> instrumentation, atheroma
Embolus
—> AF, vegetations, air/fat
—> ‘Trash hand’
Plaque
Venous: Phlegmasia cerulea/alba dolens
WALL
Vasculitis
Dissection
Vasospasm
EXTERNAL
Compression
Compartment syndrome
NONVASC
Systemic Hypoperfusion
Phlegmasia cerulea dolens.
Congestion of a limb secondary to massive DVT and SVT.
—> Iliofemoral system AND collaterals
—> NO venous drainage occurring
Secondary arterial insufficiency
Complications:
- Gangrene/ ischaemia
- PE
- Reperfusion syndrome
- Postphlebitic venous insufficiency
Phlegmasia alba dolens
AKA Milk Leg
Precursor of cerulea
Affects deep ileofemoral system but collaterals spared
—> some venous drainage ongoing
White and oedematous
Embolus vs Thrombus:
Embolus are sudden, profound and often demarcated (along vessel territory). May be in AF.
Thrombi symptoms develop over hours/ days. Less severe (collaterals). May had history of disease/ trauma at vessels, incl. claudication, ulcers etc.
‘Trash Hand’
Intraarterial injection
—> Vascular irritation/ spasm/ substrate emboli
Pain
Discolouration
May be demarcated to one arterial distribution
Management:
- Same as other arterial ishaemic limb.
—> *Dependent, warm, O2, hydrate, heparin.
- Assess for other IVDU complications (infection, endocarditis etc.)
Address withdrawal potential
Ankle-brachial Index:
If arterial insufficiency suspected
Supine for 10mins
- Take BP of both upper limbs using Doppler at cubi foss
- Take BP of both lower limbs using Doppler at dorsalis pedis and at posterior tibial
ABI=
Highest pressure at ankle in question / Highest upper limb pressure
1- 1.4 normal
Low = arterial disease
High = stiff vessels
Types of ‘ischaemic gut’
Acute mesenteric ischaemia
—> Embolus (50%)
——> usually SMA -45deg angle
—> Thrombosis (25%)
—> Non-occlusive eg. Spasm, compression, IA compartment (15%)
—> Venous (10%)
Chronic mesenteric ischaemia
Usually normal atheroscleroma disease. Vasculopaths.
Post prandial pain and weight loss
Ischaemic colitis
Self-limiting ischaemic episode to vulnerable part of gut
—> splenic flexure, desc, sigmoid
Often type 2 nature: CCF, hypovolaemia, sepsis etc.
Sudden onset low abdo pain and PR bleed
Mx is supportive
CT findings in mesenteric ischaemia:
Triple phase best
NONSPECIFIC:
Bowel wall thickening
Mesenteric oedema
Ascites
DIAGNOSTIC:
Thrombus/ embolus/ flow limitation
PNEUMATOSIS INTESTINALIS
Portal vein gas
—> pneumoBILIA doesn’t reach liver periphery
‘Thumb printing’
Thickened haustra, indicating bowel wall oedema
*Mesenteric ischaemia
Infectious colitis
Inflamm bowel disease
Diverticulitis
… just means a colitis of some kind!
Differential for pneumotosis intestinalis:
Ischaemic gut
Toxic mega colon
NEC
Severe obstruction
Severe enteritis/colitis
Caustic ingestion
COPD- benign
Results from either gas-forming flora, or liminal gas, entering.
Lactate in diagnosis of mesenteric ischaemia
Usually high, but
Normal does NOT rule out!
Management of Acute Mesenteric Ischaemia:
Usual symptomatic and supportive
NBM
NGT
Surgeons
Aggressive fluids
–> 3rd space ++
Triple antibiotics
- Eg. Amoxicillin 1g TDS + Gentamicin 5mg/kg + Metronidazole 500mg BD
If pressors required, avoid adrenaline- sphlanchnic constriction
–> Use eg. dobutamine
Heparin +/-
–> Yes if venous. At surgeons discretion otherwise.
