Alcohol, self-focus and complex reaction-time performance

The effects of alcohol, expectancy and state-trait varieties of public self-focus on complex reaction-time performance were evaluated. The procedure crossed a 2 (expectancy) X 2 (dose) modified balanced-placebo design with two levels of public self-awareness (normal versus high). A median split procedure performed on public and private self-consciousness scale scores served to evaluate trait effects. Results indicated that subject's task performance was best understood as an interaction between his subjective experience of intoxication-sobriety, his beliefs concerning what he had drunk and the salience of situational standards toward effortful performance. Public self-consciousness proved to mediate the behavioral expression of conventional expectancies concerning drunken comportment. Interactions between alcohol, expectancy and self-focus are discussed in terms of an interactive model of drunken comportment.

Flumazenil (Ro 15-1788) and physostigmine

The pharmacologic effects of benzodiazepines may be counteracted either by functional antagonists like physostigmine acting via cholinergic mechanisms or by competitive antagonists like flumazenil (Ro 15-1788) acting via GABAergic mechanisms (GABA = Gamma-AminoButyric Acid). The lipophilic choline esterase inhibitor physostigmine adjusts a relatively or absolutely decreased concentration of acetylcholine at central cholinergic synaptic sites. As the neuronal network is very complex, many lipophilic compounds may cause a central anticholinergic syndrome even if they primarily do not affect cholinergic but, like benzodiazepines, GABAergic synaptic sites. Prolonged and/or adverse effects of such drugs may therefore be treated with 1-2 mg physostigmine at a maximal rate of 1 mg/min. The onset of physostigmine action can be expected within 2-20 min. Furthermore, the benzodiazepine action can very effectively be counteracted by the specific antagonist flumazenil. It could be demonstrated in volunteer and clinical studies that the hypnotic effect of benzodiazepines could be antagonized within 1-2 min. However, the minimal duration of action proved to be about 2 h as could be demonstrated by clinical observations, EEG-studies and psychometric tests. In clinical practice, a flumazenil dose of 0.3-0.8 mg proved to be the optimal dose range. The indication to treat unwanted central effects of benzodiazepines either with flumazenil or with physostigmine after anaesthesia should be restricted to cases of distinctly prolonged sedation after adequate dosage or adverse side effects. In intensive care, special indications for flumazenil and/or physostigmine may result after high benzodiazepine dosage or to differentiate a coma of undefined origin if centrally acting drugs including benzodiazepines are involved.

The lack of response to suggestion under controlled surgical anesthesia

Thirty-two ASA I or II women undergoing abdominal hysterectomy were randomly allocated to four groups to determine what type, if any, of recorded intraoperative message they would receive. Groups I and II heard a neutral recording with no verbal content. Group III heard an experimental recording with a positive suggestion for a rapid recovery. Group IV had a self-prepared message. The tapes were played during general anesthesia when anesthetic depth was judged to be stable and adequate by vital signs, end-tidal anesthetic concentration and EEG compressed spectral array. No patient reported any recall of intraoperative messages when interviewed on the day after surgery. Chart review showed no difference in days of hospitalization, dose of analgesics required, time to beginning oral intake, or the amount of wound drainage (P greater than 0.05). We conclude that no awareness can be observed directly by recall or indirectly by response to suggestion given under stable and adequate general anesthesia.

Memory of cardiac anaesthesia. Psychological sequelae in cardiac patients of intra-operative suggestion and operating room conversation

Thirty patients scheduled for elective cardiopulmonary bypass surgery were interviewed pre-operatively and postoperatively to assess changes in their emotional state and recollections, both aware and unaware, of intra-operative events. A random selection of patients heard a prerecorded audio tape towards the end of bypass after they were rewarmed to 37 degrees C. The tape contained suggestions for patients to touch their chin during the postoperative interview, to remember three sentences and to recover quickly. The interviewers were blind to the experimental condition. The experimental group touched their chins significantly more often than the control group (p = 0.015). Sentence recognition did not reach significance and this may be due to the small numbers and low salience of the stimuli. Seven patients (23%) recalled intraoperative events, five with the aid of hypnosis. Three reports (10%) were corroborated. Pre-operative medication (p less than 0.01) and postoperative anxiety (p less than 0.05) were significant predictors of those patients who reported recall.

Retention of auditory information presented during anaesthesia. A study of children who received light general anaesthesia

Surgical procedures that involve a local anaesthetic block are often accompanied by light general anaesthesia. It is possible that under these circumstances, the patients are more likely to register auditory events while apparently unconscious. Two groups of children were exposed to auditory stimuli during surgery; one group received a lighter level of anaesthesia than the other. Retention of the stimuli was tested using a cued recall technique, and the performance of the two experimental groups was compared with a control group which had not been exposed to the material but was tested in the same way. The light anaesthesia group retained more items than did the other two groups but this difference was significant (p less than 0.05) only when compared with the other experimental group. This is not very strong evidence of auditory registration, but a greater effect might be found with exposure to emotionally significant material. It is suggested that patients should be protected from unfortunate theatre conversation.

Can drugs be used to enhance the psychotherapeutic process?

Many preindustrial cultures traditionally use certain psychedelic plants to enhance a procedure that resembles psychotherapy--an idea that was also tested in Western psychiatry in the 1950s and 1960s. LSD and related drugs were used to facilitate the production of memories, fantasies and insights and to enhance the therapeutic alliance. The results were inconclusive, and research was largely abandoned after the drugs became difficult to obtain. It may now be possible to revive this research, using new drugs that do not have some of the disadvantages of the old ones. The drug now of most interest is MDMA (3,4-methylenedioxymethamphetamine) a relatively mild and short-acting substance that is said to give a heightened capacity for introspection and intimacy without the perceptual changes, emotional unpredictability, and occasional adverse reactions associated with LSD. Therapists who have used the drug claim that it can enhance the therapeutic alliance by inviting self-disclosure and promoting trust. Whether MDMA fulfills this promise or not, other drugs may eventually prove useful in psychotherapy. Research on their potential should not be curtailed because of fear that they will be subject to illicit abuse.

Stimulus processing during apparent unconsciousness in anesthetized volunteers

Return of motor-responses upon request as an indicator of stimulus processing during apparent unconsciousness in general anesthesia was studied in 8 healthy, male volunteers during prolonged inhalation of nitrous oxide. First the minimal effective concentration of nitrous oxide was established for each volunteer, based upon continued absence of motor-responses to repeated verbal commands. One week later this concentration of nitrous oxide was administered for a 3-hr. period; return of motor-responses after at least 30 min. of absence was considered a sign of so-called unconscious perception. Four volunteers showed return of motor-response within the 3 hr. of exposure, but two of these had been rather restless throughout the session. Results indicate that unexpected processing of information by patients may occur during presumed unconsciousness after a prolonged inhalation of nitrous oxide in general anesthesia.

Alfentanil's analgesic, respiratory, and cardiovascular actions in relation to dose and plasma concentration in unanesthetized dogs

Relationships between plasma concentrations of alfentanil and its analgesic, respiratory, and cardiovascular effects were determined in dogs. To avoid drug interaction, trained, unanesthetized, spontaneously breathing dogs were used. After a control period in the awake state, alfentanil was injected in increasing amounts (10, 20, 80, 160, and 320 micrograms/kg) at 5-min intervals to a total dose of 590 micrograms/kg administered over 20 min. The effects were observed on pain responses (heart rate and blood pressure changes and somatic reactions to tail clamping), respiration (respiratory rate, oxygen consumption [VO2], blood gas tensions) and circulation (heart rate and blood pressure). The plasma concentration-effect curves, derived by relating the changes in multiple variables from the awake state to the corresponding plasma concentrations (range 8-5079 ng/ml), plateaued at and around 200 ng/ml during the injection period but were displaced in parallel to two-fold higher concentrations during recovery, which resembles acute tolerance. At maximally effective analgesic concentrations, which precipitated profound cardiorespiratory slowing with conspicuous hypoxemia, the VO2 of 4.4 +/- 0.3 ml X kg-1 X min-1 corresponded with the calculated metabolic rate but increased to 6.3 +/- 1.6 ml X kg-1 during recovery. The analgesic action of alfentanil, which cannot be separated from its depressant cardiorespiratory effects and maximally effective analgesic concentrations (between 200 and 400 ng/ml), apparently does not jeopardize the adequacy of tissue oxygenation in dogs.

Cocaine update: from bench to bedside

The aim of this paper is to review and explore the psychopharmacology of cocaine from two divergent points of view--the chronic user and the laboratory. Cocaine's behavioral effects will be correlated with neurophysiological, neurochemical events, and reports by users of consequences of chronic use. These studies and reports when pieced together offer considerable promise in the development of a natural history of compulsive cocaine use. Additional neurochemical and neurophysiological research investigations are needed to allow for the development of non-addicting treatments for detoxification (à la clonidine) and prophylaxis (à la naltrexone). In the absence of these data cocaine treatment programs have been developed borrowing heavily from self help, contingency contracting and inpatient programs for working addicts.

Tolerance to nitrous oxide in volunteers

Nociception and loss of awareness during exposure to anaesthetic concentration of nitrous oxide (N2O) were studied in eight male medical students. The cold water nociception test, where a hand is immersed in 0 degree C stirred water, was used for measurement of nociception. At irregular intervals an auditory command was given to oppose two fingers, and this served to monitor consciousness. The selected inspiratory concentration of N2O used per individual was sufficient to induce a loss of consciousness for more than 2.5 min, within 10 min of exposure to N2O. This concentration of N2O varied from 60% to 80%. The experimental exposure to N2O lasted 3 h. In all volunteers significant antinociception was observed within 2 min of exposure to N2O. The maximal analgesic effect was observed between 20 and 30 min of exposure to N2O. The analgesic effect of N2O gradually decreased and was absent in all eight volunteers within 150 min. Two volunteers regained consciousness at 77 and 91 min of exposure, whilst still breathing 60 and 80% N2O. These results show that tolerance to antinociceptive effects of N2O in man rapidly develops and that awareness may occur in some volunteers during prolonged exposure to N2O.

Study of awareness during noninhalational anaesthesia

Forty-five adult patients underwent a noninhalational anaesthetic method for investigation of awareness during surgery and recall of events associated with surgery in postoperative period. All the patients were divided into two groups. The first group of patients were male and had upper abdominal operations. The second group were female and had lower abdominal operations. No significant difference was found between these two groups either in requirements of depth of anaesthesia or in the evidence of per-operative awakefulness. Eighty percent patients of both the groups showed various signs of peroperative awakefulness but did not recall any events associated with surgery in the postoperative period. There was no report of dream either.

Opioid analgesics in anesthesia: with special reference to their use in cardiovascular anesthesia

In this article, an attempt has been made to review the use of receptor stimulating pure agonist opioids in anesthesia, especially in patients with cardiovascular disease. Particular emphasis has been placed on the use of opioids in high doses to produce anesthesia, techniques that recently have become popular in cardiovascular anesthesia. A major benefit of opioid anesthesia is the cardiovascular stability obtained during induction and throughout operation, even in patients with severely impaired cardiac function. There is a considerable body of evidence to support this claim when fentanyl is used. Anesthetic doses of morphine are associated with a higher incidence of cardiovascular disturbances and other problems, and, therefore, more attention to detail is required in order to achieve adequate anesthesia and hemodynamic stability. Although other opioids have been used as sole or principal agents in anesthesia for cardiovascular surgery, none have gained widespread acceptance. Meperidine, for example, which is widely used in lower (nonanesthetic) doses as a supplement to nitrous oxide in cardiac and noncardiac surgery, has proved unsuitable because of severe hemodynamic disturbances when high doses are given. However, initial reports concerning two of the newer agonist opioids, sufentanil and alfentanil, suggest that they may prove to be suitable alternatives and perhaps provide advantages over morphine and fentanyl in patients with or without cardiovascular disease. Although cardiovascular stability usually can be assured in the chronically sick cardiac patient with opioid anesthesia, this is not always so with the healthier patient, particularly those presenting for coronary artery surgery. A frequently occurring problem in these patients is hypertension during or after sternotomy, which can result in myocardial ischemia and infarction. The incidence of severe hypertension (increases in systolic blood pressure greater than 20% of control values) can be reduced drastically by increasing the dose of opioid, e.g., up to 140 micrograms/kg of fentanyl. However, despite such large doses, some patients will continue to need treatment with vasodilators, inhalation anesthetics, or other supplements at certain periods during cardiovascular operations. The use of very large doses of opioids also will prolong postoperative respiratory depression. High doses of opioids can reduce or prevent the hormonal and metabolic responses to the stress of surgery. However, even very large doses of fentanyl or its newer analogues do not prevent marked increases in plasma catecholamine concentrations in response to cardiopulmonary bypass.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison between midazolam and thiopentone-based balanced anaesthesia for day-case surgery

In a randomized study of 100 women (ASA 1-2) undergoing termination of pregnancy as outpatients, the combination of midazolam-fentanyl-nitrous oxide was compared with thiopentone-fentanyl-nitrous oxide. The induction time (the time recorded until disappearance of the palpebral reflex) was significantly longer in the midazolam group (40 s) than in the thiopentone group (31 s). There were no significant differences in heart rate or arterial pressure between the two groups. Thirty minutes after the termination of surgery the degree of awareness, estimated by means of Glasgow Coma Scale, was lower in the midazolam group. After 60 and 180 min the scores were equal. During recovery more patients experienced side-effects in the thiopentone group than in the midazolam group, the difference being statistically significant 72 h after discharge when 66% and 34% of the patients complained of side-effects, respectively. Midazolam is as suitable as thiopentone for the induction of anaesthesia in day-case surgery.

Alcohol's effects on self-awareness

The results of two studies were reanalyzed to examine the effect of alcohol and expectations about intoxication on measures of self-awareness. The first study evaluated alcohol's effects on perception of negative interpersonal feedback and self-evaluation; the second analyzed alcohol's impact on the interaction of couples in which one of the spouses was an alcoholic. In neither study did intoxication result in decreased use of self-focused statements or first person pronouns as predicted by Hull's self-awareness model of alcohol consumption.