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Biomedical subjects

J I Lawson

Publications and source records attributed to J I Lawson.

At least 19 recordsLinked to original sources
PubMed1990

Reversal of midazolam sedation with flumazenil following conservative dentistry.

The purpose of this double-blind randomized study was to assess recovery of mental function following reversal of midazolam-induced sedation with the specific antagonist flumazenil (R015-1788) or placebo following conservative dental procedures. Recovery was assessed using choice reaction time and critical flicker fusion threshold, both objective tests of psychomotor function; linear analogue sedation scores and simple memory tests. Assessments were repeated up to 3 h after administration of flumazenil or placebo to discover whether recovery was sustained or whether resedation occurred due to the short duration of action of flumazenil. Flumazenil in doses from 0.5 to 1.0 mg rapidly reversed the sedative and amnesic effects of a mean dose of 8.2 mg of midazolam without apparent evidence of subsequent resedation. Since recovery of mental function in the control group had ordinarily occurred 45 min after administration of placebo, routine reversal of midazolam sedation with flumazenil cannot be justified. Nevertheless, in cases of undue sedation persisting after dental treatment, flumazenil may be used with minimal risk of resedation occurring.

Adolescent↗
PubMed1986

I.v. sedation for conservative dentistry. A comparison of midazolam and diazepam.

Midazolam and the emulsion formulation of diazepam were compared in a cross-over study in 50 patients undergoing out-patient conservative dentistry, with particular regard to sedation and the quality of recovery. Both agents proved effective, but sedation was achieved more rapidly with midazolam (P = 0.001) and was more effective (P less than 0.02). Significantly greater anterograde amnesia for the dental procedure (P less than 0.001) and a more rapid return to normal activities (P less than 0.02) were found with midazolam. Psychometric testing, however, failed to show any objective differences between the treatments. A mean dose of midazolam 0.14 mg kg-1 was required to achieve sedation equating to 0.29 mg kg-1 of diazepam, although there was considerable variation between individual patients.

Adolescent↗
PubMed1983

Effect of anaesthesia and surgery on the pre-S-phase cell cycle kinetics of mitogen-stimulated lymphocytes of previously healthy people.

The influence of general anaesthesia, and of operative surgery, on immune responsiveness was studied in blood obtained from 26 women undergoing laparoscopic sterilization (minor operation group) and in 14 women undergoing abdominal hysterectomy (major operation group). Since immunity depends ultimately on clonal expansion of lymphocytes, the growth potential of peripheral blood lymphocytes was studied in tissue culture by mitogen stimulation. There was no evidence of any change in either the number of responding cells (those that have left the resting G0-phase and responded to mitogen stimulation by entering the G1-phase of the first cycle of growth) or in the rate at which cells grow in volume during the period of study. It was concluded that there was no evidence that anaesthesia, or surgery, impaired this aspect of the immune response in our patients, but the design of the experiments does not allow comment on other aspects of the immune response such as antigen presentation, immunoregulation and effector mechanisms, which are superimposed on the basic clonal expansion mechanisms studied in this investigation. Incidentally, we noted that the standard method for isolation of lymphocytes from peripheral blood frequently yielded highly contaminated preparations: if this fallacy was not appreciated, tests with contaminated lymphocytes could be misinterpreted as showing depression.

Adult↗
PubMed1979

Reports by anaesthetists to procurators-fiscal: analysis of "anaesthetic deaths" over 10 years in four Scottish teaching hospitals.

Review of 489 "anaesthetic deaths" reported to procurators-fiscal over 10 years disclosed only 30 that were thought to justify such reporting. Most of the remainder occurred in patients so desperately ill at the time of operation that death was expected. Postmortem examinations ordered by the Crown authorities in nearly all cases were probably largely unrewarding and mostly unnecessary. The results suggest that the present regulation on reporting should be revised to focus more attention on the few deaths that occur in patients who have no apparent contraindication to anaesthesia or operation.

Adult↗