Anaesthesia dissociative

Miscellaneous Intra-arterial injection —> crystallization Fit threshold Toxic in children (metabolic acidosis and bradycardia) Salivation dissociative anaesthesia Adrenal suppression... 

Phencyclidine ( angel dust ) was made in a search for a better intravenous anaesthetic. It is structurally related to pethidine. Phencyclidine was found to induce analgesia without unconsciousness, but with amnesia, in man (dissociative anaesthesia). The postoperative course, however, was complicated... 

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. 

Ketamine is a phencyclidine (hallucinogen) derivative and an antagonist of the NMDA-receptor. In anaesthetic doses it produces a trance-like state known as dissociative anaesthesia (sedation, amnesia, dissociation, analgesia). 

Ketamine produces a different effect to other intravenous anaesthetics analgesia, sensory loss, amnesia and muscle paralysis are produced without loss of consciousness, so-called dissociative anaesthesia, and with minimal respiratory depression. 

S. Mamtell, G. Nyman and P. Funkquist, Dissociative anaesthesia during field and hospital conditions for castration of colts, Acta Vet. Scand., 2006, 47, 1 11. 

Phencyclidine (PCP) was first developed as a dissociative anaesthetic in the 1950s, but its use was mainly confined to veterinary anaesthesia after it had... 

Iselin-Chaves IA, Willems SJ, Jermann FC, Forster A, Adam SR, Van der Linden M. Investigation of implicit memory during isoflurane anaesthesia for elective surgery using the process dissociation procedure. Anesthesiology. 2005 103(5) 925-33. 

Halothane has the highest blood/gas partition coefficient of the volatile anaesthetic agents and recovery from halothane anaesthesia is comparatively slow. It is pleasant to breathe and is second choice to sevoflurane for inhalational induction of anaesthesia. Halothane reduces cardiac output more than any of the other volatile anaesthetics. It sensitises the heart to the arrhythmic effects of catecholamines and hypercapnia arrhythmias are common, in particular atrioventricular dissociation, nodal rhythm and ventricular extrasystoles. Halothane can trigger malignant hyperthermia in those who are genetically predisposed (see p. 363). 

Most local anaesthetics are used in the form of the acid salts, as these are both soluble and stable. The acid salt (usually HCI) dissociates in the tissues to liberate the free base, which is biologically active. This dissociation is delayed in abnormally acid, e.g. inflamed, tissues but the risk of spreading infection makes local anaesthesia undesirable in infected areas. 

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