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Biomedical subjects

N Mackenzie

Publications and source records attributed to N Mackenzie.

33 records · Page 2Linked to original sources
PubMed1987

Propofol for intravenous sedation.

This study investigated the properties of propofol when given by subanaesthetic infusion to provide sedation as an adjunct to spinal anaesthesia for lower limb surgery in 40 patients. Sedation, defined as sleep with preservation of eyelash reflex and purposeful reaction to verbal or mild physical stimulation, was satisfactorily achieved and maintained with minimal complications. The mean duration of infusion was 98 minutes and a mean infusion rate of 3.0 mg/kg/hour was required in patients over 65. This was significantly less (p less than 0.005) than the 4.1 mg/kg/hour required in younger patients. Recovery was impressively rapid; patients regained full consciousness approximately 4 minutes after the end of infusion, and were free from minor postoperative sequelae. Conversion to general anaesthesia was achieved in three patients where surgery encroached outside the analgesic field of the regional block, simply by increasing the infusion rate to approximately 10 mg/kg/hour.

Adolescent↗
PubMed1986

Immunological evidence for a carbamylphosphate synthetase lesion resulting in the formation of enzyme with altered sub-unit size.

A partial carbamylphosphate synthetase (CPS: EC 6.3.4.16) deficiency (McKusick 23730) was found in a male child who presented with generalized convulsions, rickets and apnoeic attacks at six months of age. By his second year he showed serious developmental delay and a gut biopsy revealed an absence of CPS activity with an elevated ornithine transcarbamylase activity. Analysis of the gut biopsy sample on SDS-polyacrylamide gels, followed by electrophoretic transfer to a nitrocellulose filter probed with monospecific antibodies to CPS showed that the child had normal levels of immunoreactive enzyme, but instead of one band corresponding to normal CPS with a subunit size of 165,000 u, the patient had three immunoreactive bands, one larger and two smaller than that found in normal controls. The genetic defect in this child therefore results in an unusual form of CPS being made which has markedly reduced enzyme activity.

Ammonia↗
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↗
PubMed1985

Comparison of a pulse oximeter with an ear oximeter and an in-vitro oximeter.

A pulse oximeter was compared with an ear oximeter for measurement of arterial hemoglobin saturation within the range of 70 to 100% in 11 healthy volunteer subjects. Two hundred seventy-seven pooled data points were obtained, and analysis was performed by means of linear regression. The accuracy was 3% (95% confidence limits). The pulse oximeter was also compared with an in-vitro oximeter, and accuracy was within 2%. The pulse oximeter was easy to use because, unlike the ear oximeter, it required no time-consuming instrument calibration or site preparation. In addition, the delays involved in taking an invasive sample, transporting it to the blood gas laboratory, and waiting for the results were eliminated. Saturation values were continually available, and placement and use of the pulse oximeter sensor caused no discomfort to the volunteer subjects.

Adult↗
PubMed1985

Comparison of propofol with methohexitone in the provision of anaesthesia for surgery under regional blockade.

Propofol was compared with methohexitone for provision of light general anaesthesia in patients undergoing surgery under spinal analgesia. Intermittent bolus administration of both agents proved a feasible way of maintaining anaesthesia, a mean infusion rate of 0.13 mg kg-1 min-1 being required for propofol and 0.089 mg kg-1 min-1 for methohexitone. Propofol produced smoother anaesthesia with significantly fewer excitatory side effects and less pain on injection, but cardiovascular and respiratory depression occurred commonly. Recovery was rapid with both agents, but minor postoperative sequelae occurred more frequently after methohexitone.

Adolescent↗
PubMed1985

Comparison of the new emulsion formulation of propofol with methohexitone and thiopentone for induction of anaesthesia in day cases.

The new emulsion formulation of di-isopropyl phenol (propofol) was compared with methohexitone and thiopentone for induction of anaesthesia in day cases. Propofol produced significantly smoother induction of anaesthesia, but caused more cardiovascular and respiratory depression. Pain on injection was significantly less than with methohexitone. Post-anaesthetic recovery was superior with propofol, with virtual absence of side effects, and rapid recovery with little impairment of psychomotor function 30 min after anaesthesia.

Adolescent↗
PubMed1985

Recovery following propofol ('Diprivan') anaesthesia--a review of three different anaesthetic techniques.

The effect of propofol, in the emulsion formulation, on post-anaesthetic recovery was studied in 80 patients anaesthetized using one of three different techniques. Propofol was administered to 20 day case patients for induction of anaesthesia, to 20 patients for induction and maintenance by intermittent bolus injection to supplement spinal blockade, and to 40 patients for induction and maintenance by continuous infusion with spontaneous ventilation. Its effects were compared with those of methohexitone (all three techniques) and thiopentone (day case study only). The assessment of post-operative recovery included measurement of the speed of immediate recovery, psychometric testing comprising choice reaction time and critical flicker fusion threshold and the incidence of post-operative sequelae. In all three techniques, propofol was associated with rapid and symptom-free recovery from anaesthesia. With the day case and infusion techniques immediate recovery was more rapid after propofol than after methohexitone and thiopentone. Recovery of psychomotor function was more rapid after propofol in the day case study. The frequency of sequelae such as nausea and vomiting (5% of cases), headache (1%) and confusion/restlessness (2.5%) was considerably lower overall after propofol and in each individual study than with the other agents.

Ambulatory Care↗
PubMed1985

Propofol ('Diprivan') for continuous intravenous anaesthesia. A comparison with methohexitone.

The properties of propofol in emulsion given by continuous intravenous infusion to spontaneously breathing patients have been studied. Forty premedicated patients were anaesthetized with propofol infusion supplemented by nitrous oxide in oxygen. Induction and maintenance were uniformly smooth with no excitatory effects. Dose-related cardiovascular and respiratory depression allowed easy control of anaesthetic depth by adjusting the infusion rate. The mean duration of infusion was 51 min and the mean infusion rate 0.26 mg/kg/min. Recovery times were clinically acceptable and complications minimal. An attempted comparative study involving the use of methohexitone was abandoned after 10 cases when the latter agent proved unsuitable for use in this manner. The findings suggest that propofol may well be the agent of choice for continuous intravenous anaesthesia.

Adolescent↗
PubMed1985

Patient monitoring in the operating theatre. A comparison of practice between 1976 and 1983.

The vital importance of patient monitoring during anaesthesia is well recognised. There is little information available, however, on the actual practice of instrumental monitoring in the operating theatre. This study examined present-day practice and compared it with that of 1976. The main findings were an increase in frequency of electrocardiographic monitoring, especially for non-major surgery, and a smaller increase in blood pressure recording. Monitoring of other variables remained essentially unchanged. Possible reasons for this are given and suggestions made for improvements.

Adolescent↗
PubMed1979

Possible effect of time on renal allograft rejection.

The change in plasma creatinine concentrations from decreasing values after successful renal transplantation to increasing values after the onset of rejection occurs as a sudden event. Twenty-two such episodes in 16 renal allograft recipients were studied by extrapolating sequential measurements of plasma creatinine concentrations to see when the change occurred. Seventeen of the episodes occurred between 2300 and 1100 and the rest at other times. This difference was significant. The results suggest that rejection is more common at night and apparently has a circadian rhythm, being likely to first influence creatinine clearance at around 0600.

Circadian Rhythm↗
PubMed1971

Life and living it.

Explore the source record for details and available documents.

Abortion, Induced↗