Biomedical subjects

P A Isaac

Publications and source records attributed to P A Isaac.

7 recordsLinked to original sources

PubMed1991

Reversal of benzodiazepine sedation with the antagonist flumazenil.

The effectiveness of the benzodiazepine antagonist, flumazenil, was evaluated in a randomized double-blind clinical study in which diazepam 0.2 mg kg-1 or midazolam 0.1 mg kg-1 was used for i.v. sedation. We studied 120 day-case patients undergoing gastroscopy and treated with either flumazenil 0.1-2 mg or placebo after the procedure. Psychometric assessment of four aspects of recovery over a 3-h period showed that flumazenil attenuated the sedative effects of the benzodiazepines, but did not antagonize the sedation completely. For patients sedated with diazepam, there was a significant effect of flumazenil on speed of motor co-ordination after 90 min (P less than 0.01), and for those given midazolam a similar effect was found at 20 min (P less than 0.01). However, after 3 h all four groups of patients had not returned to baseline performance in accuracy of motor co-ordination (P less than 0.01) and cortical arousal (P less than 0.05), and the two groups sedated with diazepam still displayed memory deficits (P less than 0.05). Flumazenil did not attenuate the subjective experience of sedation as measured by visual analogue scales. These results indicate that sedation is multidimensional, differentially affecting the hierarchy of cognitive functions. In day-cases, antagonism of benzodiazepine sedation with flumazenil would not hasten the safe discharge of patients.

Adolescent↗

PubMed1990

Lower oesophageal contractility and detection of awareness during anaesthesia.

We have investigated the value of lower oesophageal contractility (LOC) in detecting awareness during anaesthesia in 20 human volunteer patients. LOC was measured either with subjects awake or after induction with propofol, during induction with propofol, and then as consciousness returned. Statistically significant changes were observed in the frequency of spontaneous contractions, peak and mean amplitude of spontaneous and provoked contractions, and the oesophageal contractility index as subjects lost consciousness and also as it was regained. The differences in LOC which occurred when subjects were conscious and unconscious support the view that LOC is related to the depth of anaesthesia, but its unreliability at the interface between consciousness and unconsciousness prevents selective detection of awareness, although the response in the presence of painful stimuli has not been tested.

Anesthesia, General↗

PubMed1990

A jet nebuliser for delivery of topical anesthesia to the respiratory tract. A comparison with cricothyroid puncture and direct spraying for fibreoptic bronchoscopy.

Topical anesthesia of the respiratory tract for fibreoptic bronchoscopy was compared, in a single-blind study, inhaled from a simple and inexpensive jet nebuliser, administered by cricothyroid injection or by a 'spray-as-you-go technique'. Each technique was supplemented by spraying lignocaine through the fibrescope and intravenous fentanyl-droperidol sedation. Inhaled nebulisation was successfully used for 96% (46 of 48) of patients, was safe, effective and acceptable to the patient and bronchoscopist. The cricothyroid injection method produced better conditions than nebulisation in patients who had diagnostic bronchoscopy. The nebuliser technique is as satisfactory as the spraying technique in patients for diagnostic bronchial lavage in whom bleeding from a cricothyroid puncture is unacceptable. Patients who used the nebuliser were more satisfied. This technique may also be a useful method for 'awake' intubation.

Administration, Inhalation↗

PubMed1990

Esmolol attenuates cardiovascular responses to extubation.

Changes in heart rate and systolic blood pressure were measured during extubation and emergence from anesthesia in 40 ASA physical status I and II patients in a double-blind study to assess the effect of three doses of esmolol (1, 1.5, and 2 mg/kg) given as a bolus 2 min after reversal of neuromuscular blockade. Heart rate (P less than 0.01), systolic blood pressure (P less than 0.02), and rate-pressure product (P less than 0.01) increased significantly during extubation of the control group. All doses of esmolol attenuated the increases in heart rate, but 1 mg/kg was insufficient to control the increase in systolic blood pressure. Doses of 1.5 and 2 mg/kg controlled both systolic blood pressure and heart rate, but the larger dose produced significant decreases in systolic blood pressure.

Adolescent↗

PubMed1989

Propofol-induced anaesthesia. Double-blind comparison of recovery after anaesthesia induced by propofol or thiopentone.

Postoperative psychomotor and cognitive recovery were assessed after anaesthesia induced by either propofol or thiopentone, and maintained with nitrous oxide and halothane in 40 unpremedicated dental patients. Performance was shown to be impaired one hour postoperatively for the whole sample in hand-eye coordination (p less than 0.001), reaction time (p less than 0.001) and digit span (p less than 0.05). There was evidence of impairment at 3 hours postoperatively in reaction time (p less than 0.05) and ataxia (p less than 0.01). Performance also deteriorated in the dexterity and aiming tasks. Patients reported significantly less clumsiness by 24 hours in blurred vision and shivering (p less than 0.05) and by 48 hours less coughing (p less than 0.05). However, there was no significant difference between groups. No evidence showed that recovery in the propofol group was faster, so it was concluded that induction with propofol offered no advantage when anaesthesia is maintained with nitrous oxide and halothane for the periods of time reported in this study.

Adolescent↗

PubMed1989

A possible hazard.

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Catheterization, Central Venous↗

PubMed1988

Miliary tuberculosis presenting as adult respiratory distress syndrome.

We report the history of a 27-year-old Caucasian girl who died of adult respiratory distress syndrome secondary to miliary tuberculosis (MTB), after treatment with antibiotics to which the organism was sensitive, and a long period of ventilation. This case emphasises the importance of considering MTB as the cause of respiratory failure when another aetiology is not apparent.

Adult↗