The effect of transmucosal 0.2 mg/kg midazolam premedication on dental anxiety, anaesthetic induction and psychological morbidity in children undergoing general anaesthesia for tooth extraction.

BACKGROUND: The project aims were to evaluate the benefit of transmucosal midazolam 0.2 mg/kg pre-medication on anxiety, induction behaviour and psychological morbidity in children undergoing general anaesthesia (GA) extractions. METHOD: One hundred and seventy-nine children aged 5-10 years (mean 6.53 years) participated in this randomised, double blind, placebo-controlled trial. Ninety children had midazolam placed in the buccal pouch. Dental anxiety was recorded preoperatively and 48 hours later using a child reported MCDAS-FIS scale. Behaviour at anaesthetic induction was recorded and psychological morbidity was scored by the parent using the Rutter Scale preoperatively and again one week later. Subsequent dental attendance was recorded at one, three and six months after GA. RESULTS: While levels of dental anxiety did not reduce overall, the most anxious patients demonstrated a reduction in anxiety after receiving midazolam premedication (p = 0.01). Neither induction behaviour nor psychological morbidity improved. Irrespective of group, parents reported less hyperactive (p = 0.002) and more pro-social behaviour (p = 0.002) after the procedure; older children improved most (p = 0.048). Post-GA dental attendance was poor and unaffected by premedication. CONCLUSION: 0.2 mg/kg buccal midazolam provided some evidence for reducing anxiety in the most dentally anxious patients. However, induction behaviour, psychological morbidity and subsequent dental attendance were not found to alter.

A randomised placebo-controlled trial of the effects of midazolam premedication on children's postoperative cognition.

This randomised, placebo-controlled study assessed the effects of midazolam premedication on children's postoperative cognition and physical morbidity. In all, 179 children aged 5-10 years were randomly assigned to receive buccal midazolam (0.2 mg x kg(-1)) or placebo before sevoflurane-nitrous oxide anaesthesia for multiple dental extractions. They performed tests of choice reaction time, attention, psychomotor co-ordination and memory pre-operatively (baseline), before discharge and at 48 h. The reaction time of both groups was significantly slower before discharge compared to baseline, with the midazolam group being significantly slower than placebo. Psychomotor co-ordination was also significantly impaired postoperatively after midazolam. Performance on both tests had recovered to baseline by 48 h. Midazolam was also associated with significant anterograde amnesia, both postoperatively and at 48 h, for information presented in the interval between premedication and surgery. The results show significant short-term impairment of children's cognitive function and amnesia enduring for 48 h after low-dose midazolam premedication.

The effects of brief sevoflurane-nitrous oxide anaesthesia upon children's postoperative cognition and behaviour.

This study assessed the effects of brief sevoflurane-nitrous oxide anaesthesia on children's postoperative cognition, behaviour and physical morbidity. Forty-eight children aged 5-10 years undergoing anaesthesia without premedication for multiple dental extractions, and 48 control children, performed tests of choice reaction time, attention, psychomotor co-ordination and memory pre-operatively (baseline), prior to discharge and at 48 h (anaesthesia group only). Physical and psychological morbidity were recorded at 1 week. Mean choice reaction time and psychomotor co-ordination were significantly impaired postoperatively but had recovered at 48 h. However, measures of performance variability suggested the presence of residual impairment. Profound retrograde amnesia affected postoperative and 48-h recall of pictorial stimuli presented prior to anaesthesia, but recognition memory was unimpaired. Attention-seeking, tantrums, crying and nightmares were occurring more frequently in some 8-20% of children 1 week after the procedure.

Interobserver reliability between a nurse and anaesthetist of tests used for predicting difficult tracheal intubation.

We examined the interobserver reliability, between a nurse and anaesthetist, of five tests used to predict difficult tracheal intubation: mouth opening; thyromental distance; head and neck movement; mandibular luxation; and assessment of oropharyngeal view. For each test, an anaesthetic nurse and a specialist registrar anaesthetist were trained to use a standard method of examination. Most of the tests had either good or very good reliability. Assessment of mouth opening demonstrated only moderate reliability and assessment of oropharyngeal view demonstrated poor reliability. The interobserver reliability estimates between a nurse and an anaesthetist are similar to those previously demonstrated between two anaesthetists.

Validation of a pre-anaesthetic screening questionnaire.

We developed a screening questionnaire to be used by nurses to decide which patients should see an anaesthetist for further evaluation before the day of surgery. Our objective was to measure the accuracy of responses to the questionnaire. Agreement between questionnaire responses and the anaesthetist's assessment was assessed. For questions with a prevalence of 5 to 95%, the Kappa coefficient was used; percentage agreement was used for all other questions. Criterion validity was excellent/good for all questions with a prevalence between 5 and 95%, except for the question 'Do you have kidney disease?' For questions with prevalence < 5%, all demonstrated adequate criterion validity except the questions 'Has anyone in your family had a problem following an anaesthetic?' and 'If you have been put to sleep for an operation were there any anaesthetic problems?' Therefore, it is reasonable for nurses to use this questionnaire to determine which patients an anaesthetist should see before the day of surgery.

Pre-operative screening: criteria for referring to anaesthetists.

Nurses assess patients pre-operatively using screening questionnaires and locally-developed protocols. Our objectives were to determine which questions might identify patients who should be seen by an anaesthetist before the day of surgery. A review of the literature and a preliminary questionnaire to establish questions to be tested was followed by a modified, two-round Delphi questionnaire to determine the level of agreement by anaesthetists. There was agreement for referring patients who gave a positive response to questions that query: restricted exercise tolerance; previous anaesthetic problems; family history of anaesthetic problem; pathology affecting neck movement; angina; arrhythmia; heart failure; asthma; epilepsy; insulin-dependent diabetes mellitus; liver disease and unspecified kidney disease. There was equivocal agreement on questions that report a myocardial infarction over one year ago, cerebrovascular accident, non insulin-dependent diabetes mellitus and thyroid disease. Nurses should use these criteria during pre-operative assessment to decide the timing of evaluation by an anaesthetist.

Pre-existing cognitive impairment as a factor influencing outcome after cardiac surgery.

Conventional methodology to investigate cognitive impairment after coronary artery bypass graft (CABG) surgery leaves unclear the potential for pre-existing cognitive deficits to influence outcome. Individuals with pre-existing deficits may be more vulnerable to the effects of CABG, hence biasing the results of a typical prospective trial if account is not taken of their state. The present study examined the effect of pre-existing cognitive impairment upon cognitive outcome in 81 patients undergoing CABG. Patients performed the Stroop Neuropsychological Screening Test and other psychometric assessments prior to and at 6 days and 6 months after CABG. Those with pre-existing cognitive deficits were significantly more likely to display impairment at 6-day and 6-month follow-ups than were those without pre-existing deficits. Greater age and lower pre-morbid intelligence were also significant predictors of post-CABG deficit, confirming earlier findings. The results imply both that pre-existing cognitive impairments may render patients more vulnerable to post-operative deficits and that, in the absence of such pre-existing impairments, CABG surgery does not inevitably lead to later deficits. The study also replicated previous findings showing a similar influence of pre-existing depression upon emotional state after CABG. Overall, the results confirm the importance both of a patient's pre-existing cognitive and emotional states, and the methodology to assess them, in influencing outcome after cardiac surgery and the conclusions to be drawn as to the supposed adverse effects of the procedure.

Theatre monitor alarm settings: a pilot survey in Scotland and Belgium.

The use of alarms on operating theatre equipment was explored in a questionnaire to anaesthetists in Belgium and Scotland. They were presented with a scenario of a fit male having an anaesthetic for an abdominal operation. The overall response rate was 72%, giving 100 records for analysis. The responses from Scottish and Belgian anaesthetists were similar except for views on setting an upper limit for systolic arterial pressure; Scottish anaesthetists seemed relatively unwilling to set an upper systolic arterial pressure limit. Beyond this, the respondents considered alarms to be a method of detecting problems before they occur and they readjust alarms for each patient. They would set systolic arterial pressure alarms 30 mmHg above and below the patients normal pressure, the heart rate alarms 30 bpm above and 20 bpm below the actual rate, and the peripheral oxygen saturation lower alarm limit to 90%.

A system for psychomotor evaluation; design, implementation and practice effects in volunteers.

This paper describes the design, implementation and assessment of PsychE, psychomotor evaluation system. Six standard tests are included: numeric vigilance, a dual task, probed memory recall, simple reaction time, choice reaction time and semantic long-term memory. The test presentations are described in detail. Practice effects were assessed in 10 healthy volunteers and were only evident in the performance measures for the simple reaction time test. For the remaining five tests, stable performance was reached within a single test session. The volunteers were healthy and most were regular users of computers. Therefore, the lack of practice effects cannot be assumed for the general population. A control group is essential for all studies using these tests. The system is implemented on an IBM-compatible personal computer and includes a database shell for the convenient collection, storage and analysis of performance data.

How would patients prefer to spend the waiting time before their operations?

Many surgical patients are anxious while waiting to go to the operating theatre in spite of the best preparation with drugs, information and reassurance. It is possible that patients could be more comfortable if allowed a choice of activities before operations. The objective of this study was to find out how pre-operative patients might prefer to occupy their time. We distributed 200 questionnaires to elective surgery patients and 184 (92%) were available for analysis. Of the respondents, 54.1% wanted to be slightly sleepy, 72.0% preferred not to be fast asleep and 57.2% preferred not to be wide awake. Reading (56.8%), listening to music (57.1%) and chatting with other patients (39.9%) were preferred activities. It might be appropriate to ask patients how sedated they would wish to be before their surgery and perhaps have alternatives to sedation available.

The effect of music on anaesthetists' psychomotor performance.

Music is frequently played in operating theatres, but may prove distracting to anaesthetists. We undertook a laboratory-based study of the effects of music on the psychomotor performance of 12 anaesthetic trainees. Using part of the computer-based PsychE psychomotor evaluation programme, we were unable to demonstrate any effect of self-chosen music, silence, white noise or classical music on their performance in these tests.

Pressure changes over the anterior neck during tracheal and oesophageal intubation.

Pressure changes were measured on the skin over the cricoid and thyroid cartilages during intubation of the oesophagus or trachea in 21 consenting patients. A 100-ml bag of saline was firmly fixed to the anterior neck and the pressure changes in the bag recorded. Typical and distinctively different pressure patterns for tracheal and oesophageal intubation were recorded. Oesophageal intubation was accompanied by a statistically significantly higher and longer pressure rise and, most characteristically, by an obvious and sustained rise in baseline pressure. This method is, however, neither practical nor recommended for clinical use in detecting accidental oesophageal intubation. Capnography should always be used during tracheal intubation as an ongoing capnographic waveform provides the only guarantee of correct tracheal placement.

Detection of accidental oesophageal intubation. Role of the anaesthetic assistant.

Three situations in which an anaesthetic assistant might be able to detect accidental oesophageal intubation during or immediately after intubation were assessed. These were: firstly, whilst applying cricoid pressure, secondly, whilst applying gentle palpation over the trachea just above the suprasternal notch and, thirdly, after intubation by means of a 'roll test'. During cricoid pressure, tracheal intubation was correctly diagnosed in all of 10 cases. However, deliberate oesophageal intubation was only detected in six out of 10 cases. During suprasternal palpation, three cases out of 10 oesophageal and three cases out of 10 tracheal intubation were misdiagnosed. In the 'roll test', two out of 10 tracheal and five out of 10 oesophageal intubations were misdiagnosed. In conclusion, no method could be relied on entirely and may indeed give false reassurance. Nonetheless, any doubt expressed about the tracheal tube position by the assistant should be taken seriously and a careful check made.

Feedback control in anaesthesia.

This review considers the some of the methods of automatic control which are usable in medicine. The features of each type of control system are explained and the advantages and disadvantages summarised. The author has attempted to maintain a balance between what is possible with the excellence of modern engineering, and what is feasible in the clinical area, and practical when working with patients. The problem of lack of knowledge of an individual patient is emphasised, as is the potential of fuzzy logic methods in the future.

Music in theatre: not so harmonious. A survey of attitudes to music played in the operating theatre.

Music played to staff in the operating theatre is thought to improve surgeons' concentration but its effects on other theatre staff are unknown. We surveyed 200 anaesthetists to determine the prevalence of music playing in the operating theatre and anaesthetists' attitudes to it. The response rate was 72% and of these 72% (104) worked in a theatre where music was played regularly. Around 26% of the sample felt that music reduced their vigilance and impaired their communication with other staff while 11.5% felt that music might distract their attention from alarms. Fifty-one per cent felt that music was distracting when a problem was encountered during the anaesthetic.

Gas leakage and the laryngeal mask airway. A comparison with the tracheal tube and facemask during spontaneous ventilation using a circle breathing system.

The ability of the laryngeal mask airway, tracheal tube and facemask to provide a leak free seal in a clinical setting was assessed by measuring the minimal fresh gas flows needed in a closed circle system during spontaneous ventilation on 60 subjects. The fresh gas flow was reduced until no spillage occurred from the pop-off valve. This fresh gas flow was taken to represent the sum of gas uptake by the subject and gas leakage from the circuit. The median fresh gas flow after 20 minutes was 350 ml.min-1 in the laryngeal mask airway group, 350 ml.min-1 in the tracheal tube group and 450 ml.min-1 in the facemask group. The fresh gas flow required for the facemask group was significantly higher than that for the laryngeal mask airway or tracheal tube groups (p < 0.01). There was no significant difference between the fresh gas flows required for the tracheal tube and laryngeal mask airway group. We conclude that the laryngeal mask airway provides as good a gas tight seal as a tracheal tube in this context and would be of benefit in reducing anaesthetic gas pollution.

Comparison of patient-controlled sedation with either methohexitone or propofol.

We studied 42 patients undergoing oral surgery under local anaesthesia with i.v. sedation, allocated randomly to receive either methohexitone (group M) or propofol (group P) for patient-controlled sedation (PCS). Group M patients self-administered 2.5-mg (0.5 ml) bolus doses of methohexitone and group P, 5-mg (0.5 ml) doses of propofol, without a lockout. The 0.5-ml bolus dose was delivered over 7.2 s for both drugs. The procedure was completed satisfactorily in all patients. Patients in both groups achieved their desired levels of sedation. No patient lost verbal contact. Group M patients had higher heart rates during the procedure. The lowest SpO2 values recorded were 92% and 95% for group P and group M, respectively. Immediately after operation patients in group M reported that they felt more sleepy than those in group P (P < 0.01) but there were no differences at subsequent times. The results of the psychomotor tests were comparable for the two groups after operation, except for the "posting box task" at 15 min after operation when the mean decrement (compared with preoperative performance) was -3% for group P and -13% for group M (P < 0.05). More patients in group P complained of pain in their hand. We conclude that methohexitone is a suitable alternative drug to propofol for PCS.

The Glasgow Pain Questionnaire: a new generic measure of pain; development and testing.

BACKGROUND: The study set out to develop and test a measure of perceived pain suitable for use in community studies and in the evaluation of clinical care. METHOD: The work had three parts; (1) generation and selection of items, (2) weighting of the items and (3) testing for reliability and validity. Potential items were obtained from 230 informal interviews conducted in a variety of settings. These were reviewed to produce a draft questionnaire, and this was used in a pilot study of 60 volunteers to determine the final item selection. Item weights were calculated using ratings of severity as judged by subjects in the pilot study and the validity testing. Weights are used so that questions referring to more severe pains have higher scores than those about milder pains. Reliability and validity testing was carried out using three groups: 100 rheumatoid arthritis outpatients; 37 attenders at an occupational health clinic and 178 chronic pain clinic patients. Scores from the three different patient groups were compared, scores were compared with a visual analogue measure of pain, and scores from the same individuals from two consecutive months were compared. DEVELOPMENT: The main product was the new measure itself, the Glasgow Pain Questionnaire (GPQ). This has a total of 24 items in five categories; pain frequency, intensity, emotional reaction, ability to cope and restrictions of daily activity. TESTING: Validity; scores were significantly different in the three groups. The GPQ scores were significantly related to the visual analogue measure of pain. Reliability; scores of the same respondents on two consecutive months were significantly associated and had a modal value of zero. CONCLUSIONS: The project has produced a new measure of self-rated pain suitable for use in large-scale population surveys. This instrument assesses not only pain intensity but affective dimensions of pain. It is considered that the validity and reliability testing carried out to date show the measure as acceptable for use in future studies.

Patient-controlled analgesia with morphine and droperidol following caesarean section under spinal anaesthesia.

BACKGROUND: The addition of droperidol to morphine for patient-controlled analgesia reduces the incidence of nausea and vomiting, but may result in unwanted side effects. METHOD: We studied 40 women randomised to receive morphine sulphate with or without added droperidol (10mg droperidol/60 mg morphine) by patient-controlled analgesia following elective caesarean section under spinal anaesthesia. RESULTS: Median morphine demand in the 20 h after surgery was 74 mg with morphine alone, and 53 mg with added droperidol, the median consumption of which was 8.8 mg. The incidence of nausea was reduced from 80% to 38.8% (P < 0.01), and that of emesis from 55% to 16.7% (P < 0.05) by the addition of droperidol. Psychomotor function was significantly impaired to a similar degree in both groups and there was no significant difference in sedation scores or pain scores. Subjective drowsiness which resulted in withdrawal from the study occurred in two patients, both of whom were receiving droperidol, and though all patients who completed the study were satisfied with their analgesia overall, significantly more of those receiving unsupplemented morphine (11/19 compared with 4/18, P < 0.05) described it as excellent. CONCLUSION: The addition of droperidol 10 mg to morphine 60 mg for PCA following caesarean section under spinal anaesthesia reduces the incidence of nausea and emesis, but may result in drowsiness, limiting the usefulness of the technique.

Comparison of the effect of two dose schedules of oral omeprazole with oral ranitidine on gastric aspirate pH and volume in patients undergoing elective surgery.

We have compared gastric aspirate pH and volume at induction of anaesthesia in 222 patients who had received either omeprazole or ranitidine before elective operations. Omeprazole was given orally either as 40 mg on the evening before and 40 mg on the morning of surgery or as 80 mg on the morning of surgery. Ranitidine 150 mg was given orally on the evening before surgery and 2 h before anaesthesia. Treatment success was defined as aspirate pH > or = 2.5 and volume < 25 ml at induction of anaesthesia. Treatment was successful in 84% (95% confidence interval (CI) 73-91%) of patients in the omeprazole 40 + 40 mg group, 84% (95% CI 73-91%) in the ranitidine group and 73% (95% CI 61-83%) in the omeprazole 80 mg group. There were no statistically significant differences between the groups. Twelve patients in the omeprazole 80 mg group had gastric pH < 2.5 and four had volume > 25 ml. Only three patients had a gastric pH < 2.5 in the omeprazole 40 + 40 mg group and none had volume > 25 ml, which compared well with the ranitidine group. Omeprazole, given as 40 mg in the evening and 40 mg on the morning of operation, has a potential role for use in patients at risk for aspiration during general anaesthesia.