Complications of regional anaesthesia - Incidence and prevention

The complications of failure. neural injury and local anaesthetic toxicity are common to all regional anaesthesia techniques, and individual technique s are associated with specific complications. All potential candidates for regional anaesthesia should be thoroughly evaluated and informed of potenti al complications. If there is significant risk of injury, then these techni ques should he avoided. Central neural blockade (CNB) still accounts for more than 70% of regional anaesthesia procedures. Permanent neurological injury is rare (0.02 to 0.07 %); however transient injuries do occur and are more common (0.01 to 0.8%). Pain oil injection and paraesthesiae while performing regional anaesthesia are danger signals of potential injury and must not be ignored. The incidence of systemic toxicity to local anaesthetics has significantly reduced in the past 30 years, from 0.2 to 0.01%. Peripheral nerve blocks ar e associated with the highest incidence of systemic toxicity (7.5 per 10 00 0) and the lowest incidence of serious neural injury (1.9 per 10 000). Intravenous regional anaesthesia is one of the safest and most reliable for ms of regional anaesthesia for short procedures on the upper extremity. Bra chial plexus anaesthesia is one of the most challenging procedures. Axillar y blocks are performed most frequently and are safer than supraclavicular a pproaches. Ophthalmic surgery is particularly suited to regional anaesthesia. Serious risks include retrobulbar haemorrhage, brain stem anaesthesia, and globe pe rforation, but are uncommon with skilled practitioners. Postdural puncture headache remains a common complication of epidural and s pinal anaesthesia; however, the incidence has decreased significantly in th e past 2 to 3 decades from 37 to approximately 1% largely because of advanc es in needle design. Backache is frequently linked with CNB; however, other causes should also b e considered. Duration of surgery, irrespective of the anaesthetic techniqu e, seems to be the most important factor. The syndrome of transient neurolo gical symptoms is a form of backache that is associated with patient positi on and use of lidocaine (lignocaine). Disturbances of micturition are a common accompaniment of CNB,especially in elderly males. Hypotension is the most common cardiovascular disturbance a ssociated with CNB. Severe bradycardia and even cardiac arrest have been re ported in healthy patients following neuraxial anaesthesia, with a reported incidence of cardiac arrest of 6.4 per 10 000 associated with spinal anaes thesia. Prompt diagnosis, immediate cardiopulmonary resuscitation and aggre ssive vasopressor therapy with epinephrine (adrenaline) are required. New complications of regional anaesthesia emerge occasionally, e.g. cauda e quina syndrome with chloroprocaine, microspinal catheters and 5% hyperbaric lidocaine, and epidural haematoma formation in association with low molecu lar weight heparin. Even so, after 100 years of experience, most discerning physicians appreciate the benefits of regional anaesthesia.