Absence of priming coupled with substantially preserved recognition in lorazepam-induced amnesia.

Two experiments are reported on priming when subjects are in an amnesic state induced by lorazepam. The primed tasks were completion of word-stems and generation of words from specified categories. In both experiments, lorazepam subjects showed no evidence of priming; whereas control subjects showed substantial priming. Recognition by the amnesic subjects of items produced in the priming tests, although impaired, was well above the chance level. These findings contrast with those obtained with organic amnesic subjects, for whom priming is typically normal but recognition is grossly impaired. The theoretical implications of this double dissociation between priming and recognition are discussed.

Changes in memory following general or spinal anaesthesia for hip arthroplasty.

Patients scheduled for hip arthroplasty were anaesthetised using either general or spinal anaesthesia. Each patient's memory was tested for both recall and recognition by using lists of 10 words each of a different category. This testing for memory extended from the pre-operative visit to one week after operation. Memory was not tested on the day of operation. There was little overall change of memory after either spinal or general anaesthesia although there was an inexplicable but significant decrease in the ability to recognize words after spinal anaesthesia.

Long-term tracheal intubation practice in the United Kingdom.

A questionnaire was circulated to members of the Intensive Care Society and hospitals with more than 120 acute beds in the United Kingdom. The object was to determine the usage of the various types of cuffs on tracheal tubes and the practice of long-term tracheal intubation in contrast to tracheostomy. One hundred and fifty two replies were received (a 55% response rate). The majority of units favoured the high volume cuff for long term ventilation (61% for tracheal tubes and 69.2% for tracheostomy tubes). The cuffs were mainly inflated to 'no-leak' ventilation and pressure was not measured. The majority of units changed from tracheal tubes to tracheostomy after about one week but, for children, a longer period of tracheal intubation is employed. The results are discussed.

Effects of lorazepam on rate of forgetting, on retrieval from semantic memory and on manual dexterity.

Using a double-blind procedure, 16 out of 32 volunteer subjects (students) each took 2.5 mg of lorazepam (Ativan) orally and the remainder took a placebo. To overcome the problem of wide variation in individual tolerance to the drug, impairment on a task unrelated to memory (a manual dexterity task) was used to divide drug subjects into a group appreciably affected by the drug, subgroup 1, and a group minimally affected, subgroup 2. Only subgroup 1 showed consistent impairment of episodic memory. Both subgroups showed some impairment in a semantic memory task (generation of words from a specified category), but this was confined to the rate at which the task was carried out. The main aim of the experiment was to examine the effect of lorazepam on the rate of forgetting of word lists when drug and control subjects' initial recall levels were equalized. There was no evidence that the drug affected rate of forgetting: this suggests that it does not affect retention. There was also no evidence that it affected retrieval, since there was no impairment in the recall of material presented before administration of the drug. Hence its locus of action is attributed to input, specifically to impaired encoding of contextual information.

A comparison between transient amnesias induced by two drugs (diazepam or lorazepam) and amnesia of organic origin.

The transient amnesias produced by drugs may have much in common with the more permanent amnesias associated with organic brain damage. This possibility was investigated using two benzodiazepines, diazepam and lorazepam, with medical student volunteers. In Experiment 1, 27 subjects received a 2ml intravenous injection of either diazepam (7.5 mg) or of lorazepam (3.0 mg) or of normal saline. In Experiment 2, a further 13 subjects were given lorazepam (2.5 mg) or saline. A double blind procedure was used. Neither drug had an appreciable effect on span-type short-term memory (except with 2-channel presentation). Both drugs produced severe anterograde amnesia in other forms of memory test: the amnesic effect of lorazepam lasted for several hours. This amnesia was not attributable to failures of perception. Lorazepam appeared to affect recognition even more than recall. In a test with lorazepam no evidence was obtained that the drug increases susceptibility to proactive interference. With both drugs, recall and recognition were unimpaired of material presented about 10 min before the injection; this shows that the drugs did not affect retrieval mechanisms.

Atropine and hyoscine.

The drugs atropine and hyoscine are reviewed in the context of their use by anaesthetists. The results of recent studies are stressed and guidelines given for use of these drugs in modern anaesthetic practice.

Amnesic effects of intravenous diazepam and lorazepam.

The amnesic effects of 2 benzodiazepine drugs, diazepam (Valium) and lorazepam (Ativan), have been investigated. Some of the effects were similar to those of certain clinical amnesic syndromes. The effects were more extensive than previous work has indicated.

Experimental appraisal of factors involved in provision of donor livers.

The results of a series of porcine orthotopic liver homotransplants have shown that hepatic damage is related almost entirely to the period of warm ischaemia following death. Low flow perfusion with modified plasma would seem to be a satisfactory method of preserving cadaveric livers for at least six hours.In man it would appear possible to use cadaver livers derived from patients who had or had not been treated with artificial ventilation during life, provided the period of warm ischaemia is not longer than 25 to 30 minutes.