The common contraindications to spinals and epidurals are:
Patient Refusal
Absolute patient refusal is an absolute contraindication. Ignoring it could constitute assault.
However, patients often have misconceptions and allaying their fears may provoke a change of mind. Some common reasons given (with responses) are:
- 'I don’t want to be awake/hear/see/remember anything' (sedation can be given)
- 'I’ve got back problems' (there is no evidence that a regional technique will make them worse)
- 'It will cause backache' (good evidence exists showing no link)
- 'It will hurt' (not usually – provided enough local infiltration is used)
- 'I don’t want to end up paralysed' (vanishingly small risk)
However, a competent patient is quite entitled to disregard your reassurances.
Coagulation disorder
If a patient has disordered coagulation, either because of drug therapy or disease, spinal or epidural could cause spinal haematoma.
Generally, the techniques should only be performed if the following criteria are satisfied:
Low dose aspirin is not considered a contraindication, but other antiplatelet drugs (e.g. clopidogrel) will require a period of abstinence before neuraxial techniques are considered safe.
Hypovolaemia
In hypovolaemic patients, blood pressure may be maintained only by the presence of sympathetic tone. Abolishing such tone with a regional technique can cause disastrous cardiovascular collapse.
A regional technique may be appropriate in a hypovolaemic patient who has been fluid resuscitated and in whom there is no continuing loss.
Local sepsis
Unless the area of local sepsis overlies the area of the back where the injection is to be made, it is not a contraindication.
Systemic sepsis
In this case, as with hypovolaemia, the abrupt removal of sympathetic tone that accompanies these techniques makes them inadvisable. In addition, placement of an epidural catheter theoretically provides a focus around which systemic infection could become seeded, leading to epidural abscess.
Fixed cardiac output disorders
In conditions such as aortic stenosis or hypertrophic obstructive cardiomyopathy (HOCM), decreased systemic vascular resistance is poorly tolerated. This is because the hypertrophied myocardium relies on a high-normal diastolic blood pressure to perfuse the coronary arteries in diastole, and the stiff heart requires a reasonable preload to maintain forward flow. Both of these are decreased by the vasodialtion which accompanies spinal/epidural anaesthesia.
However, the techniques can sometimes be safely used by experienced practitioners in such individuals, if:
Raised intracranial pressure
If the intracranial pressure is increased (for example because of haematoma or tumour) and a dural puncture is made, cerebrospinal fluid can leak from the thecal sac. The resultant pressure gradient can cause uncal herniation through the foramen magnum, with subsequent neurological injury, including coning and death.
Acute neurological disease
Clearly this encompasses a wide variety of diseases. However, it is generally best to avoid administering drugs to the neuraxis in this circumstance, as any subsequent deterioration in disease may be, rightly or wrongly, attributed to the technique.
Stable neurological diseases in isolation, such as multiple sclerosis or neurofibromatosis, are not usually a contraindication to spinal or epidural.
Inability to consent
If a patient is unable, for whatever reason, to consent to a regional technique, then by implication neither are they able to consent to a general anaesthetic. Therefore, 'inability to consent' is not a valid contraindication to regional anaesthesia.
A patient who lacks capacity may be unable to understand or obey instructions, or may present difficulties in assessing adequacy of block. These are valid contraindications.
Language barrier
'Language barrier' generally means it is impossible or difficult to:
However, all of these can be overcome with an interpreter or by using other methods. If a regional technique is truly in the patient’s best interest, it is important not to default to general anaesthesia just for want of seeking an interpreter.