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Biomedical subjects

J N Lunn

Publications and source records attributed to J N Lunn.

At least 37 records · Page 2Linked to original sources
PubMed1984

Computer assistance in the control of depth of anaesthesia.

A control system was used to bring the tension of anaesthetic in the brain to any value specified (in MAC units) by the anaesthetist and then maintain it constant until a new value was specified. The control was applied to a volatile agent but allowance was automatically made for the anaesthetic effect of any nitrous oxide concomitantly administered by the anaesthetist. The inspired concentration required to achieve the desired brain tension was calculated from a model of the patient and set automatically on the vaporizer. The quantification of the model was matched to the patient on the basis mainly of body mass and periodic non-invasive measurements of alveolar ventilation and cardiac output. In order to adapt the model to the patient an arterial blood sample was taken every 30 min to obtain the arterial tension of halothane for use as feedback. The system has been tested on eight Alsatian dogs. After omitting results affected by avoidable errors, the SD of the measured-to-computed arterial tension ratio was less than 10%.

Anesthesia, Inhalation↗
PubMed1984

Epidemiology in anaesthesia: a method for predicting hospital mortality.

Data on 13 043 operations were abstracted from 108 878 anaesthetic records in the Cardiff Anaesthetic Record System. Nine groups of surgical operations with high mortality in hospital were identified. These records were analysed using a logistic regression model to determine the probability of death in hospital. Variables included in the model were age, sex, elective or emergency operation and five intercurrent diseases. The significance of individual variables was assessed: age was the most important single variable in six of the nine operation groups. The model was used to calculate the risk of death in hospital for individuals with specific characteristics. With further development, this technique might be used by clinicians at other centres to predict the outcome for patients under their care.

Age Factors↗
PubMed1983

Anaesthesia-related surgical mortality.

This is the report of the second of two studies conducted by the Association of Anaesthetists of Great Britain and Ireland based on anonymous reports of deaths within 6 days of anaesthesia. One hundred and ninety-seven detailed reports were received during 1981; 43% were found by assessors to have nothing to do with anaesthesia, 41% to be partly due to, and 16% totally due to anaesthesia. These figures confirm earlier results reported by the same system. It is important to have the opinion of the two clinicians (anaesthetist and surgeon) separately and not to ignore either in a study which attempts to identify aspects of clinical medicine which might be improved.

Aged↗