Epidural Contraindications
Absolute Contraindications
-- Patient refusal
-- Coagulopathy ‘Blood does not clot normally’
Insertion of an epidural needle or catheter into the epidural space may cause traumatic bleeding into the epidural space with development of a large haematoma leading to spinal cord compression.
-- Therapeutic anticoagulation
As above
-- Skin infection at injection site
Insertion of the epidural needle through an area of infected skin may introduce pathogenic bacteria into the epidural space, leading to serious complications such as meningitis or epidural abscess.
-- Raised intracranial pressure
Accidental dural puncture in a patient with raised ICP may lead to brainstem herniation (coning).
-- Hypovolaemia ‘low blood voume’
The sympathetic blockade produced by epidurals, in combination with low blood volume may cause profound circulatory collapse.
Relative Contrindications
-- UnCooperative patients
It may be impossible to position correctly or unable to remain still enough to safely insert an epidural.
-- Pre-existing neurological disorders
Such as multiple sclerosis, may be a contraindication, because any new neurological symptoms may be ascribed to the epidural.
-- Fixed cardiac output states
Probably relative rather than absolute. This includes aortic stenosis, hypertrophic obstructive cardiomyopathy (HOCM), mitral stenosis and complete heart block. Patients with these cardiovascular abnormalities are unable to increase their cardiac output in response to the peripheral vasodilatation caused by epidural blockade, and may develop profound circulatory collapse which is very difficult to treat.
-- Anatomical abnormalities of vertebral column
‘Spines’may make the placement of an epidural technically impossible.
-- Prophylactic low dose heparin
Epidurals and anticoagulants
Full oral anticoagulation with warfarin or standard heparin (SH) are absolute contraindications to epidural blockade.
Partial anticoagulation with low molecular weight heparin (LMWH) or low dose warfarin (INR <1.5) are relative contraindications.
Minihep (low dose standard heparin (SH), 5,000units bd s/c is not associated with an increased risk of epidural haematoma. Wait for 4 hours after a dose before performing epidural. Minihep/SH should not be given until 1 hour following epidural injection. These guidelines also apply for removal of epidural catheters.
LMWH (<40mg enoxaparin and dalteparin): allow 12hr interval between LMWH administration and epidural; this also applies to removal of epidural catheters.
NSAID's (including aspirin) do not increase the risk of epidural haematoma.
Intraoperative anticoagulation using 5000units i/v heparin following epidural/spinal injection appears safe, but careful postoperative observations are recommended. Bloody tap or blood in epidural catheter is controversial. Some teams delay surgery for 12hr, others (if pre-op coagulation normal) delay i/v bolus of heparin for 1hour.
Fibrinolytic and thrombolytic drugs: avoid epidural block for 24 hrs, check clotting prior to insertion.
Thrombocytopaenia: epidurals are relatively contraindicated below platelet count of 100,000/mm3.
An epidural haematoma should be suspected in patients who complain of severe back pain a few hours/days following any central neuraxial block or with any prolonged or abnormal neurological deficit (including. sensory loss, paraesthesiae, muscle weakness and disturbance of bladder control and anal sphincter tone). A high index of suspicion is required, with early orthopaedic or neurosurgical referral for decompression of the haematoma. Even with early recognition, the morbidity of this condition is still very high.