General anaesthesia involves the patient being put into a medication-induced state which, when deep enough, means that the patient will not respond to pain and includes changes in breathing and circulation.
Under general anaesthetic, a patient is in a state of carefully controlled unconsciousness.
A local anaesthetic numbs a small part of the patients body. It is used when the nerves can easily be reached by drops, sprays, ointments or injections. It can be a sole technique for minor surgery or combined with sedation or general anaesthesia in more major procedures.
Conscious sedation is defined as a medication-induced state that reduces the patient’s level of consciousness during which the patient may respond purposefully to verbal commands or light touch. Common procedures include eye surgery or nitrous oxide during childbirth.
Procedural sedation is used for procedures where general anaesthesia is not required. It allows patients to tolerate procedures that may otherwise be uncomfortable or painful. Patients often lose consciousness and respond only to painful touch. The patient may occasionally have difficulty with breathing normally and their heart function may be affected.
The anaesthetist is trained to manage these situations. Common procedures using procedural sedation are gastroscopy, colonoscopy, excision of larger skin lesions and dc cardio version.
Regional anaesthesia is anaesthesia affecting a large part of the body, such as a limb or the lower half of the body. Regional anaesthetic techniques can be divided into central and peripheral techniques.
The central techniques include neuraxial blockade (epidural and/or spinal anaesthesia). The peripheral techniques can be divided into plexus blocks e.g. brachial plexus blocks and single nerve blocks.
It can be used as a sole form of analgesia (pain relief) or combined with sedation or a general anaesthetic. The blockade of pain sensation can last up to 24 hours. Whilst many regional anaesthetics involve a single injection, a catheter can sometimes be inserted through the needle and left in place in the tissue surrounding the nerve so that local anaesthetic solution can be infused over several days.