Anaesthesia hypnosis

Balanced surgical anaesthesia (hypnosis with analgesia and muscular relaxation) with a single drug requires high doses that will cause adverse effects such as slow and unpleasant recovery, and depression of cardiovascular and respiratory function. In modem practice, different drugs are used to attain each objective so that adverse effects are minirnised. 

Barbiturates are the derivatives of barbituric acid. They are general CNS depressants. They can cause sedation, hypnosis and general anaesthesia depending upon the particular barbiturates used and its dose. 

Sedation and hypnosis (sleep from which arousal is easy) represent lower levels of CNS depression, and increasing doses of sedative-hypnotic drugs will produce sedation, hypnosis, anaesthesia and death from respiratory depression. Like anaesthesia, sedation is produced by compounds of varied structure and the involvement of a specific receptor is improbable, but at lower doses some of these drugs affect specific centers in the brain before others are depressed. 

Dissociative anaesthesia is a state of profound analgesia and anterograde amnesia with minimal hypnosis during which the eyes may remain open (see ketamine, p. 353). It is particularly useful where modem equipment is lacking or where access to the patient is limited, e.g. at major accidents or on battlefields. 

In general, the barbiturates exert a significant depressant action on the cerebrospinal axis. The relative degrees of depression, sedation, hypnosis or anaesthesia are exelusively dependent on the nature of the barbiturate, its dose and route of administration. 

It is a barbiturate of choice for rapid action, administered intravenously, for causing anaesthesia, supplementing general anaesthetic agents, short surgical trauma and induction of hypnosis. 

B. Several studies suggest that beta blockers, such as atenolol and esmolol, given before induction reduce the anaesthetic dose requirement and may potentiate hypnosis. However, there are concerns that reducing the dose of anaesthetic may increase the risk of intra-operative awareness and it has been suggested that the use of BIS to predict the depth of anaesthesia in the presence ofbeta blockers may not be valid.There is a possibility that acute as well as chronic administration ofbeta blockers may prevent perioperative cardiac complications, but more study is needed on this. ... 

For hypnosis or general anaesthesia in mammals, the maximum effect is... 

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