The incidence, impact, and risk factors for moderate to severe persistent pain after breast cancer surgery: a prospective cohort study

BACKGROUND

Few Australasian studies have evaluated persistent pain after breast cancer surgery.

OBJECTIVE

To evaluate the incidence, impact, and risk factors of moderate to severe persistent pain after breast cancer surgery in a New Zealand cohort.

DESIGN

Prospective cohort study.

METHODS

Consented patients were reviewed at 3 timepoints (preoperative, 2 weeks and 6 months postoperative). Pain incidence and interference, psychological distress and upper limb disability were assessed perioperatively. Clinical, demographic, psychological, cancer treatment-related variables, quantitative sensory testing, and patient genotype (COMT, OPRM1, GCH1, ESR1, and KCNJ6) were assessed as risk factors using multiple logistic regression.

RESULTS

Of the 173 patients recruited, 140 completed the 6-month follow-up. Overall, 15.0% (n = 21, 95% CI: 9.5%-22.0%) of patients reported moderate to severe persistent pain after breast cancer surgery with 42.9% (n = 9, 95% CI: 21.9%-66.0%) reporting likely neuropathic pain. Pain interference, upper limb dysfunction and psychological distress were significantly higher in patients with moderate to severe pain (P < .004). Moderate to severe preoperative pain (OR= 3.60, 95% CI: 1.13-11.44, P = .03), COMT rs6269 GA genotype (OR = 5.03, 95% CI: 1.49-17.04, P = .009) and psychological distress at postoperative day 14 (OR= 1.08, 95% CI: 1.02-1.16, P = .02) were identified as risk factors. Total intravenous anesthesia (OR= 0.31, 95% CI: 0.10 - 0.99, P = .048) was identified as protective.

CONCLUSION

The incidence of moderate to severe persistent pain after breast cancer surgery is high with associated pain interference, physical disability, and psychological distress. Important modifiable risk factors were identified to reduce this important condition.

Trajectories of Pain and Function Outcomes up to 5 to 8 Years Following Total Knee Arthroplasty

BACKGROUND

There appears to be substantial variability in outcomes > 2 years following total knee arthroplasty (TKA) that is masked by whole group analyses. The goal of the study was to identify trajectories of pain and function outcomes up to 5 to 8 years post-TKA and to identify baseline factors that are associated with different trajectories of recovery.

METHODS

Baseline, 6-month, and 12-month pain and function data were collected in a previous study investigating predictors of outcome following primary TKA (n = 286), along with a variety of baseline predictor variables. The present study obtained pain and function data at 5 to 8 years following TKA in the same cohort (n = 201). Latent class linear mixed models were used to identify different classes of pain and functional trajectories over time. The extent to which differences across latent classes were explained by baseline predictor variables was determined.

RESULTS

Three classes of pain and two classes of function trajectory were identified. While most patients (84% to 93%) followed a trajectory that showed an initial rapid gain following surgery that was sustained through 5 to 8 years, both pain and function included at least one trajectory class that showed a meaningful change after 12 months. No predictor variables were significantly associated with either the pain or function classes.

CONCLUSIONS

Most patients follow a traditional trajectory of recovery in knee pain and function over 5 to 8 years. However, alternative trajectories are observed in an important minority of patients such that knee pain and function at 12 months after surgery does not always reflect outcomes at 5 to 8 years.

A combination of high preoperative pain and low radiological grade of arthritis is associated with a greater intensity of persistent pain 12 months after total knee arthroplasty

Aims

Despite new technologies for total knee arthroplasty (TKA), approximately 20% of patients are dissatisfied. A major reason for dissatisfaction and revision surgery after TKA is persistent pain. The radiological grade of osteoarthritis (OA) preoperatively has been investigated as a predictor of the outcome after TKA, with conflicting results. The aim of this study was to determine if there is a difference in the intensity of pain 12 months after TKA in relation to the preoperative radiological grade of OA alone, and the combination of the intensity of preoperative pain and radiological grade of OA.

Methods

The preoperative data of 300 patients who underwent primary TKA were collected, including clinical information (age, sex, preoperative pain), psychological variables (depression, anxiety, pain catastrophizing, anticipated pain), and quantitative sensory testing (temporal summation, pressure pain thresholds, conditioned pain modulation). The preoperative radiological severity of OA was graded according to the Kellgren-Lawrence (KL) classification. Persistent pain in the knee was recorded 12 months postoperatively. Generalized linear models explored differences in postoperative pain according to the KL grade, and combined preoperative pain and KL grade. Relative risk models explored which preoperative variables were associated with the high preoperative pain/low KL grade group.

Results

Pain 12 months after TKA was not associated with the preoperative KL grade alone. Significantly increased pain 12 months after TKA was found in patients with a combination of high preoperative pain and a low KL grade (p = 0.012). Patients in this group were significantly more likely to be male, younger, and have higher preoperative pain catastrophizing, higher depression, and lower anxiety (all p ≤ 0.05).

Conclusion

Combined high preoperative pain and low radiological grade of OA, but not the radiological grade alone, was associated with a higher intensity of pain 12 months after primary TKA. This group may have a more complex cause of pain that requires additional psychological interventions in order to optimize the outcome of TKA. Cite this article: Bone Joint J 2022;104-B(11):1202–1208.

The effect of intra-operative hypotension on acute kidney injury, postoperative mortality and length of stay following emergency hip fracture surgery

The association between intra-operative hypotension and postoperative acute kidney injury, mortality and length of stay has not been comprehensively evaluated in a large single-centre hip fracture population. We analysed electronic anaesthesia records of 1063 patients undergoing unilateral hip fracture surgery, collected from 2015 to 2018. Acute kidney injury, 3-, 30- and 365-day mortality and length of stay were evaluated to assess the relationship between intra-operative hypotension absolute values (≤ 55, 60, 65, 70 and 75 mmHg) and duration of hypotension. The rate of acute kidney injury was 23.7%, mortality at 3-, 30- and 365 days was 3.7%, 8.0% and 25.3%, respectively, and median (IQR [range]) length of stay 8 (6-12 [0-99]) days. Median (IQR [range]) time ≤ MAP 55, 60, 65, 70 and 75 mmHg was 0 (0-0.5[0-72.1]); 0 (0-4.4 [0-104.9]); 2.2 (0-8.7 [0-144.2]); 6.6 (2.2-19.7 [0-198.8]); 17.5 (6.6-37.1 [0-216.3]) minutes, and percentage of surgery time below these thresholds was 1%, 2.5%, 7.9%, 12% and 21% respectively. There were some univariate associations between hypotension and mortality; however, these were no longer evident in multivariable analysis. Multivariable analysis found no association between hypotension and acute kidney injury. Acute kidney injury was associated with male sex, antihypertensive medications and cardiac/renal comorbidities. Three-day mortality was associated with delay to surgery ? 48 hours, whilst 30-day and 365-day mortality was associated with delay to surgery ≥ 48 hours, impaired cognition and cardiac/renal comorbidities. While the rate of acute kidney injury was similar to other studies, use of vasopressors and fluids to reduce the time spent at hypotensive levels failed to reduce this complication. Intra-operative hypotension at the levels observed in this cohort may not be an important determinant of acute kidney injury, postoperative mortality and length of stay.

Steroids to reduce the impact on delirium (STRIDE): a double-blind, randomised, placebo-controlled feasibility trial of pre-operative dexamethasone in people with hip fracture

Neuro-inflammation may be important in the pathogenesis of postoperative delirium following hip fracture surgery. Studies have suggested a potential role for steroids in reducing postoperative delirium; however, the potential efficacy and safety of pre-operative high-dose dexamethasone in this specific population is largely unknown. Conducting such a study could be challenging, considering the multidisciplinary team involvement and the emergency nature of the surgery. The aim of this study was to assess feasibility and effectiveness of dexamethasone given as early as possible following hospital admission for hip fracture, to inform whether a full-scale trial is warranted. This single-centre, randomised, double-blind, placebo-controlled study randomly allocated 79 participants undergoing hip fracture surgery to dexamethasone 20 mg or placebo pre-operatively. Eligibility and recruitment rates, timing of the intervention and adverse events were recorded. Incidence and severity of postoperative delirium were assessed using the 4AT delirium screening tool and the Memorial Delirium Assessment Scale. Postoperative pain, length of stay and mortality were also assessed. The eligibility rate for inclusion was 178/527 (34%), and 57/178 (32%) of eligible patients presented to hospital when no researcher was available (e.g. after-hours, weekends, public holidays). Recruitment was limited mainly by ethical limitations (not including patients with impaired cognition) and lack of weekend staffing. Median (IQR [range]) time from emergency department admission to drug administration was 13.3 (5.9-17.6 [1.8-139.6]) hours. There was a significant difference in delirium severity scores, favouring the dexamethasone group: median (IQR [range]) 5 (3-6 [3-7]) vs. 9 (6-13 [5-14]) in the placebo group, with the probability of superiority effect size being 0.89, p = 0.010. Delirium incidence did not differ between groups: 6/40 (15%) in the dexamethasone group vs. 9/39 (23%) in the placebo group, relative risk (95%CI) 0.65 (0.22-1.65), p = 0.360). A larger randomised controlled trial is feasible and ideally this should include people with existing cognitive impairment, seven days-a-week cover and a multicentre design.

The Prevalence, Impact, and Risk Factors for Persistent Pain After Breast Cancer Surgery in a New Zealand Population

OBJECTIVE

Few Australasian studies have assessed persistent pain after breast cancer surgery. This study aims to evaluate the prevalence, impact, and risk factors of moderate to severe persistent pain after breast cancer surgery in a New Zealand population.

METHODS

Retrospective cross-sectional study of patients who underwent breast cancer surgery between six and 48 months previously. Validated questionnaires were used to assess pain prevalence and impact, psychological distress, and upper limb function. Patients' clinical records were assessed for potential risk factors.

RESULTS

Of the 375 patients who were sent questionnaires, 201 were included in the study. More than half of the patients (N = 111, 55%) reported breast surgery related-persistent pain, with 46 (23%) rating the pain as moderate to severe. Neuropathic pain was reported by 21 (46%) patients with moderate to severe pain. Pain interference, upper limb dysfunction, and psychological distress were significantly higher in patients with moderate to severe pain (P < 0.001). Non-European ethnicity (odds ratio [OR] = 5.02, 95% confidence interval [CI] = 2.05-12.25, P < 0.001), reconstruction surgery (OR = 4.10, 95% CI = 1.30-13.00, P = 0.02), and axillary node dissection (OR = 4.33, 95% CI = 1.19-15.73, P < 0.03) were identified as risk factors for moderate to severe pain by multivariate logistic regression analysis.

CONCLUSIONS

Moderate to severe persistent pain after breast cancer surgery affects many New Zealand patients, and is associated with impaired daily life activities, physical disability, and psychological distress. Large numbers of patients undergo breast cancer surgery annually. This study emphasizes the importance of identification and management of these patients perioperatively.

Aspiration during anaesthesia in the first 4000 incidents reported to webAIRS

The first 4000 reports to the webAIRS anaesthesia incident reporting database were used to evaluate pulmonary aspiration in patients undergoing procedures under general anaesthesia or sedation. Demographic data, predisposing factors, outcome and potential preventative measures were evaluated. In these reports, 121 cases of aspiration were identified. Aspirated substances included gastric contents, bile type fluids, blood and solids; 60 (49.6%) patients were admitted to the intensive care unit/high dependency unit, and 43 (35.5%) required mechanical ventilation. Aspiration was associated with significant harm in >50% of reports, and eight (6.6%) patients died. Factors associated with a risk ratio of aspiration >1.5 and outside the 95% confidence interval for no event included: age >80 years, emergency procedure, procedure undertaken in freestanding day unit or gastroenterology department, procedure undertaken between 1800 and 2200 hours and endoscopy procedures. Only 11 (9%) cases appeared to be inadequately fasted, and 77 (64%) were definitely fasted. In the remaining 33 (27%), fasting was not mentioned. In 18 (14.9%) cases, aspiration occurred in the presence of cricoid pressure. Potential measures to prevent aspiration included using a cuffed endotracheal tube rather than a laryngeal mask airway in cases at high risk of aspiration and being made more aware of potential risk factors by improvements in team communication. Aspiration continues to be an important complication of anaesthesia, and one that can be difficult to predict and to prevent.

Incident Reporting in Anaesthesia: A Survey of Practice in New Zealand

A postal survey of anaesthetists practising in New Zealand assessed their practice and attitudes to anaesthetic incident reporting. 136 replies were received (57% response rate). Respondents indicated a high awareness of the Anaesthetic Incident Monitoring Study (AIMS) based incident monitoring yet individual utilization may be declining due to a perception that this system is ineffective. Seventy-five per cent of respondents used AIMS forms in their current institute, whilst 87% had at some time completed an AIMS form. Two-thirds of respondents used the forms for morbidity and mortality audit activities. Support for the continuing practice of incident reporting was high, yet opinion suggested that the present system was not being used productively. Almost half the anaesthetists felt that the AIMS reporting system had changed their practice. Common concerns with the system included a need to simplify the reporting process and to ensure that information is managed to provide a useful outcome. This study suggests that incident reporting in its present form needs to be re-evaluated in light of changing priorities in anaesthesia quality improvement activities.

Pain Catastrophizing is Not Associated With Spinal Nociceptive Processing in People With Chronic Widespread Pain

Objectives:

Pain catastrophizing has been associated with higher pain intensity, increased risk of developing chronic pain and poorer outcomes after treatment. Despite this, the mechanisms by which pain catastrophizing influences pain remain poorly understood. It has been hypothesized that pain catastrophizing may impair descending inhibition of spinal level nociception. The aims of this study were to compare spinal nociceptive processing in people with chronic widespread pain and pain-free controls and examine potential relationships between measures of pain catastrophizing and spinal nociception.

Materials and Methods:

Twenty-six patients with chronic widespread pain and 22 pain-free individuals participated in this study. Spinal nociception was measured using the nociceptive flexion reflex (NFR) threshold and NFR inhibition, measured as the change in NFR area during exposure to a second, painful conditioning stimulus (cold water immersion). Pain catastrophizing was assessed using the Pain Catastrophizing Scale and a situational pain catastrophizing scale.

Results:

Compared with pain-free controls, patients with chronic widespread pain had higher pain catastrophizing scores and lower NFR thresholds. Although NFR area was reduced by a painful conditioning stimulus in controls, this was not apparent in individuals with chronic widespread pain. No significant correlations were observed between measures of pain catastrophizing and spinal nociception.

Discussion:

Despite increased excitability and decreased inhibition of spinal nociception in patients with chronic widespread pain, we could find no evidence of a significant relationship between pain catastrophizing and measures of spinal nociceptive processing.

Crisis management during anaesthesia: regurgitation, vomiting, and aspiration

BACKGROUND

Regurgitation, vomiting and aspiration may occur unexpectedly in association with anaesthesia. "Aspiration/regurgitation" was ranked fifth in a large collection of previously reported incidents that arose during general anaesthesia. These problems are encountered by all practising anaesthetists and require instant recognition and a rapid, appropriate response. However, the diagnosis may not be immediately apparent as the initial presentation may vary from laryngospasm, desaturation, bronchospasm or hypoventilation to cardiac arrest.

OBJECTIVES

To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK", supplemented by a specific sub-algorithm for regurgitation, vomiting and aspiration, in the management of these complications occurring in association with anaesthesia.

METHODS

The potential performance of this structured approach for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual management as reported by the anaesthetists involved.

RESULTS

There were 183 relevant incidents of regurgitation, vomiting and aspiration among the first 4000 reports to the AIMS. Aspiration was documented in 96, was excluded in 69, and in 18 it could not be determined whether or not aspiration had occurred. It was considered that the correct use of an explicit algorithm would have led to earlier recognition and/or better management of the problem in 10% of all cases of regurgitation and vomiting and in 19% of those in which aspiration occurred.

CONCLUSION

Regurgitation and/or aspiration should always be considered immediately in any spontaneously breathing patient who suffers desaturation, laryngospasm, airway obstruction, bronchospasm, bradycardia, or cardiac arrest. Any patient in whom aspiration is suspected must be closely monitored in an appropriate perioperative facility, the acuity of which will depend on local staffing and workload. If clinical instability is likely to persist or if there are concerns by attending staff, the patient should be admitted to a high dependency unit or intensive care unit.

Crisis management during anaesthesia: water intoxication

BACKGROUND

Irrigation of closed body spaces may lead to substantial perioperative fluid and electrolyte shifts. A syndrome occurring during transurethral resection of prostate (TURP), and a similar syndrome described in women undergoing transcervical endometrial ablation (TCEA) are both characterised by a spectrum of symptoms which may range from asymptomatic hyponatraemia to convulsions, coma, and death. Such potentially serious consequences require prompt recognition and appropriate management of this "water intoxication" syndrome.

OBJECTIVES

To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK", supplemented by a specific sub-algorithm for water intoxication, in the management of this syndrome occurring in association with anaesthesia.

METHODS

The potential performance of this structured approach for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual management as reported by the anaesthetists involved.

RESULTS

From the first 4000 incidents reported to AIMS, 10 reports of water intoxication were identified, two from endometrial ablations under general anaesthesia and eight from male urological procedures under spinal anaesthesia. The "core" crisis management algorithm detected a problem in seven cases; however, it was deficient in dealing with neurological presentations. Diagnosis of the cause of the incident would have required a specific water intoxication sub-algorithm in eight cases and a hypotension algorithm in a further two cases. Corrective strategies also required a specific sub-algorithm in eight cases, while the hypotension and cardiac arrest sub-algorithms were required in conjunction with the water intoxication sub-algorithm in the remaining two.

CONCLUSION

This relatively uncommon problem is managed poorly using the "core" crisis management sub-algorithm and requires a simple specific sub-algorithm for water intoxication.

Crisis management during anaesthesia: pulmonary oedema

BACKGROUND

Pulmonary oedema may complicate the perioperative period and the aetiology may be different from non-operative patients. Diagnosis may be difficult during anaesthesia and consequently management may be delayed.

OBJECTIVES

To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK", supplemented by a specific sub-algorithm for pulmonary oedema, in its management occurring in association with anaesthesia.

METHODS

The potential performance of this structured approach for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual management as reported by the anaesthetists involved.

RESULTS

Pulmonary oedema was identified in 35 (<1%) of the first 4000 reports to AIMS. The most frequent presenting sign was hypoxia (46%) and the most specific sign was the presence of frothy sputum (23%). The core algorithm, although successful in the management of the initial physiological upset, was found to be inadequate for the ongoing management of pulmonary oedema. A specific sub-algorithm for the management of perioperative pulmonary oedema was devised, tested against the reports and would have been effective, if properly applied, in the management of all but one of the reported cases.

CONCLUSION

Successful recognition and management of perioperative pulmonary oedema is likely with the application of the structured algorithm and specific sub-algorithm approach outlined in this study.

Crisis management during anaesthesia: obstruction of the natural airway

BACKGROUND

Obstruction of the natural airway, while usually easily recognised and managed, may present simply as desaturation, have an unexpected cause, be very difficult to manage, and have serious consequences for the patient.

OBJECTIVES

To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK", supplemented by a specific sub-algorithm for obstruction of the natural airway, in the management of acute airway obstruction occurring in association with anaesthesia.

METHODS

The potential performance for this structured approach for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual management as reported by the anaesthetists involved.

RESULTS

There were 62 relevant incidents among the first 4000 reports to the AIMS. It was considered that the correct use of the structured approach would have led to earlier recognition of the problem and/or better management in 11% of cases.

CONCLUSION

Airway management is a fundamental anaesthetic responsibility and skill. Airway obstruction demands a rapid and organised approach to its diagnosis and management and undue delay usually results in desaturation and a potential threat to life. An uncomplicated pre-learned sequence of airway rescue instructions is an essential part of every anaesthetist's clinical practice requirements.

Crisis management during anaesthesia: laryngospasm

BACKGROUND

Laryngospasm is usually easily detected and managed, but may present atypically and/or be precipitated by factors which are not immediately recognised. If poorly managed, it has the potential to cause morbidity and mortality such as severe hypoxaemia, pulmonary aspiration, and post-obstructive pulmonary oedema.

OBJECTIVES

To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK", supplemented by a specific sub-algorithm for laryngospasm, in the management of laryngospasm occurring in association with anaesthesia.

METHODS

The potential performance of this structured approach for the relevant incidents amongst the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual management as reported by the anaesthetists involved.

RESULTS

There were 189 reports of laryngospasm among the first 4000 incidents reported to AIMS. These were extracted and analysed. In 77% of cases laryngospasm was clinically obvious, but 14% presented as airway obstruction, 5% as regurgitation or vomiting, and 4% as desaturation. Most were precipitated by direct airway stimulation (airway manipulation, regurgitation, vomiting, or blood or secretions in the pharynx), but patient movement, surgical stimulus, irritant volatile agents, and failure to deliver the anaesthetic were also precipitating factors. Desaturation occurred in over 60% of cases, bradycardia in 6% (23% in patients aged <1 year), pulmonary oedema in 4%, and pulmonary aspiration in 3%. It was considered that, correctly applied, the combined core algorithm and sub-algorithm recommended for the diagnosis and management of laryngospasm would have led to earlier recognition of the problem and/or better management in 16% of cases.

CONCLUSION

Laryngospasm may present atypically and, if not promptly managed effectively, may lead to morbidity and mortality. Although usually promptly recognised and appropriately managed, the use of a structured approach is recommended. If such an approach had been used in the 189 reported incidents, earlier recognition and/or better management may have occurred in 16% of cases.

Crisis management during anaesthesia: the development of an anaesthetic crisis management manual

BACKGROUND

All anaesthetists have to handle life threatening crises with little or no warning. However, some cognitive strategies and work practices that are appropriate for speed and efficiency under normal circumstances may become maladaptive in a crisis. It was judged in a previous study that the use of a structured "core" algorithm (based on the mnemonic COVER ABCD-A SWIFT CHECK) would diagnose and correct the problem in 60% of cases and provide a functional diagnosis in virtually all of the remaining 40%. It was recommended that specific sub-algorithms be developed for managing the problems underlying the remaining 40% of crises and assembled in an easy-to-use manual. Sub-algorithms were therefore developed for these problems so that they could be checked for applicability and validity against the first 4000 anaesthesia incidents reported to the Australian Incident Monitoring Study (AIMS).

METHODS

The need for 24 specific sub-algorithms was identified. Teams of practising anaesthetists were assembled and sets of incidents relevant to each sub-algorithm were identified from the first 4000 reported to AIMS. Based largely on successful strategies identified in these reports, a set of 24 specific sub-algorithms was developed for trial against the 4000 AIMS reports and assembled into an easy-to-use manual. A process was developed for applying each component of the core algorithm COVER at one of four levels (scan-check-alert/ready-emergency) according to the degree of perceived urgency, and incorporated into the manual. The manual was disseminated at a World Congress and feedback was obtained.

RESULTS

Each of the 24 specific crisis management sub-algorithms was tested against the relevant incidents among the first 4000 reported to AIMS and compared with the actual management by the anaesthetist at the time. It was judged that, if the core algorithm had been correctly applied, the appropriate sub-algorithm would have been resolved better and/or faster in one in eight of all incidents, and would have been unlikely to have caused harm to any patient. The descriptions of the validation of each of the 24 sub-algorithms constitute the remaining 24 papers in this set. Feedback from five meetings each attended by 60-100 anaesthetists was then collated and is included.

CONCLUSION

The 24 sub-algorithms developed form the basis for developing a rational evidence-based approach to crisis management during anaesthesia. The COVER component has been found to be satisfactory in real life resuscitation situations and the sub-algorithms have been used successfully for several years. It would now be desirable for carefully designed simulator based studies, using naive trainees at the start of their training, to systematically examine the merits and demerits of various aspects of the sub-algorithms. It would seem prudent that these sub-algorithms be regarded, for the moment, as decision aids to support and back up clinicians' natural responses to a crisis when all is not progressing as expected.

Drug error in anaesthetic practice: a review of 896 reports from the Australian Incident Monitoring Study database

Eight hundred and ninety-six incidents relating to drug error were reported to the Australian Incident Monitoring Study. Syringe and drug preparation errors accounted for 452 (50.4%) incidents, including 169 (18.9%) involving syringe swaps where the drug was correctly labelled but given in error, and 187 (20.8%) due to selection of the wrong ampoule or drug labelling errors. The drugs most commonly involved were neuromuscular blocking agents, followed by opioids. Equipment misuse or malfunction accounted for a further 234 (26.1%) incidents; incorrect route of administration 126 (14.1%) incidents; and communication error 35 (3.9%) incidents. The outcomes of these events included minor morbidity in 105 (11.7%), major morbidity in 42 (4.7%), death in three (0.3%) and awareness under anaesthesia in 40 (4.4%) incidents. Contributing factors included inattention, haste, drug labelling error, communication failure and fatigue. Factors minimising the events were prior experience and training, rechecking equipment and monitors capable of detecting the incident. The information gained suggests areas where improved guidelines are required to reduce the incidence of drug error. Further research is required into the effectiveness of preventive strategies.

The management of patients with ischaemic heart disease undergoing non-cardiac elective surgery: a survey of Australian and New Zealand clinical practice

Improvements in patient risk stratification and peri-operative beta-blockade have been suggested as methods which can reduce cardiovascular risk in patients with known cardiac risk factors. A postal questionnaire was sent to all Australian and New Zealand teaching hospitals to identify patterns of pre-operative cardiac risk evaluation and methods of peri-operative beta-blocker use. In all, 67 replies were evaluated (64% response rate). Specialist anaesthetists are present in the majority of pre-admission clinics (78%), with a designated peri-operative physician in 9%. Further cardiological referral was possible in almost all institutions (96%), and specific peri-operative physician referral in 54%. Waiting times for specialist consultation were < 7 days in the majority of cases. Whilst 79% of institutions used peri-operative beta-blockade, specific protocols were available in only 10%. In 60% of institutions, beta-blockers were administered to high-risk patients, and in 25% they were given to intermediate risk group patients. There was a wide range in the duration of pre- and postoperative beta-blocker administration. Whilst peri-operative risk assessment appears to be consistent, the pattern of beta-blockade, a known beneficial intervention, is variable. Reasons need to be identified, protocols developed and consistent administration targeted for further improvements to be made.

Job satisfaction, stress and burnout in Australian specialist anaesthetists

A postal survey was sent to specialist anaesthetists in Australia looking at aspects of job satisfaction, dissatisfaction and stress. Burnout was measured using the Maslach Burnout Inventory. The response rate was 60% (422/700) with the majority of respondents being male (83%). Stressful aspects of anaesthesia included time constraints and interference with home life. Experienced assistants and improved work organisation helped to reduce stress. The high standard of practice and practical aspects of the job were deemed satisfying, whereas poor recognition and long hours were the major dissatisfying aspects of the job. With respect to burnout, high emotional exhaustion, high levels of depersonalisation and low levels of personal achievement were seen in 20, 20 and 36% of respondents, respectively. Female anaesthetists reported higher stress levels than males (p = 0.006), but tended to prioritise home/work commitments better than males (p = 0.05). Private practitioners rated time issues of high importance compared with public hospital doctors, whereas public hospital doctors rated communication problems as being more significant than with private specialists. Although burnout levels are high in anaesthetists, they compare favourably with other medical groups. There are, however, aspects of the anaesthetist's job that warrant further attention to improve job satisfaction and stress.

Recovery room incidents: a review of 419 reports from the Anaesthetic Incident Monitoring Study (AIMS)

Four hundred and nineteen incidents that occurred in the recovery room were extracted from the Anaesthetic Incident Monitoring Study database, representing 5% of the total database of 8372 reports. Incidents were reported mainly in daylight hours, with over 50% occurring in ASA 1-2 patients. The most common presenting problems related to respiratory/airway issues (183; 43%), cardiovascular problems (99; 24%) and drug errors (44; 11%). One hundred and twenty-two events (29%) led to a major physiological disturbance and required management in the High Dependency Unit or Intensive Care Unit. Contributing factors cited included error of judgement (77; 18%), communication failure (57; 14%) and inadequate pre-operative preparation (29; 7%), whilst factors minimising the incident included previous experience (97; 23%), detection by monitoring (72; 17%) and skilled assistance (54; 13%). Staffing and infrastructure of the recovery room needs to be supported, with ongoing education and quality assurance programmes developed to ensure that such events can be reduced in the future.

Awareness during general anaesthesia: a review of 81 cases from the Anaesthetic Incident Monitoring Study

Because of recent studies suggesting that awareness is still a major issue in anaesthetic practice, we reviewed 8372 incidents reported to the Anaesthetic Incident Monitoring Study. There were 81 cases in which peri-operative recall was consistent with awareness. There were 50 cases of definite awareness and 31 cases with a high probability of awareness. In 13 of the 81 incidents, the patients appeared to receive adequate doses of anaesthetic drugs. Where the cause could be determined, awareness was mainly due to drug error resulting in inadvertent paralysis of an awake patient (n = 32) and failure of delivery of volatile anaesthetic (n = 16). Less common causes included prolonged attempts at intubation of the trachea (n = 5), deliberate withdrawal of volatile anaesthetic (n = 4) or muscle relaxant apnoea with inadequate administration of hypnotic (n = 3). An objective central nervous system depth of anaesthesia monitor may have prevented 42 of these incidents and an improved drug administration system may have prevented 32. On the basis of these reports, we have developed guidelines that may have prevented the majority of these incidents.

Personality testing and profiling for anaesthetic job recruitment: attitudes of anaesthetic specialists/consultants in New Zealand and Scotland

Specialist/consultant anaesthetists based in New Zealand and Scotland were sent a reply paid postal questionnaire asking about their attitudes to personality testing and personality types in the recruitment process for registrars and specialists. The questionnaire consisted of nine Likert-style questions and 14 visual analogue questions. The overall response rate was 65% (523/808). The responses to all the questions were broadly similar in the two countries. Personality testing was deemed of use in recruiting trainees and specialists, with a slightly greater proportion considering personality traits more important than academic achievement. An overwhelming majority believed the presence of an adverse personality trait would influence an appointment process, but few believed that the personality makeup of anaesthetists influenced the way in which they react to stressful situations. A slight majority considered the interview process a poor predictor of personality. New Zealand anaesthetists rated independence, orderliness, compassion, empathy, reflectiveness and patience higher than did anaesthetists in Scotland. In contrast, anaesthetists in Scotland rated pragmatism, as opposed to perfection, as a more important characteristic than did the New Zealand specialists. Personality assessment, although not effective as the sole tool for candidate selection, may have a role in the process of anaesthetic job recruitment and warrants further investigation.

The bispectral index during an anaphylactic circulatory arrest

A 47-year-old woman with Cushing's syndrome suffered a severe anaphylactic reaction on induction of anaesthesia, resulting in circulatory arrest. A spontaneous cardiac output appeared after 25 minutes of chest compression and she regained consciousness three hours later, with no neurological deficit. A Bispectral Index monitor demonstrated values greater than 40 throughout the whole period of resuscitation. Possible implications for this observation are discussed.

Inadequate pre-operative evaluation and preparation: a review of 197 reports from the Australian incident monitoring study

The Australian Incident Monitoring Study database was examined for incidents involving inadequate pre-operative patient preparation and/or evaluation. Of 6271 reports, 727 had appropriate keywords, of which 197 (3.1%) were used for subsequent analysis. All surgical categories were represented. In 10% of reports the patient was not reviewed pre-operatively by an anaesthetist, whilst in 23% the anaesthetist involved in the operating theatre had not performed the pre-operative assessment. Death followed in seven cases, major morbidity in 23 cases, admission to a high-dependency unit or intensive care unit in 17 cases, and surgery was cancelled in nine cases. Poor airway assessment, communication problems and inadequate evaluation were the most common contributing factors. Respondents indicated that the incident was preventable in 57% of cases. Proposed corrective strategies include improved communication, quality assurance activities, development of protocols and additional training. A structured assessment of the airway, along with improvements in information exchange, patient assessment, and use of clearly defined patient management plans and pathways would prevent most of the incidents reported.

Effect of bolus dose of remifentanil on haemodynamic response to tracheal intubation

A randomized placebo-controlled double-blinded study was conducted in 40 ASA 1 and 2 patients to determine the dose response of remifentanil in attenuating the haemodynamic response to tracheal intubation. Patients were allocated to one of four groups: placebo, remifentanil 1 microgram.kg-1, remifentanil 2 micrograms.kg-1 and remifentanil 4 micrograms.kg-1. A propofol target-controlled infusion was started at 4 micrograms.ml-1 and incrementally titrated to loss of verbal contact. Muscle relaxation was provided by cisatracurium. The study drug was given three minutes later over 30 seconds, and 90 seconds later the patient's trachea was intubated under direct laryngoscopy. Baseline noninvasive blood pressure and heart rate recordings were made prior to starting target-controlled infusion, then at one-minute intervals after loss of verbal contact for the duration of the study. Demographic data and target-controlled infusion rate at intubation was similar for the groups. Following intubation, heart rate increased by 15% in the placebo group, 10% in 1 microgram.kg-1 group, with no changes in 2 micrograms.kg-1 and 4 micrograms.kg-1 groups. Systolic blood pressure following intubation increased by 30% in the placebo group, 10% in the 1 microgram.kg-1 group and remained unchanged in the 2 micrograms.kg-1 and 4 micrograms.kg-1 groups. Remifentanil 1 microgram.kg-1 attenuated the rise in heart rate and systolic blood pressure. Remifentanil 2 micrograms.kg-1 blocked the haemodynamic response completely: no further benefit was shown from increasing the dose to 4 micrograms.kg-1.

Erythromycin improves gastric emptying in critically ill patients intolerant of nasogastric feeding

OBJECTIVE

To evaluate the effect of intravenous erythromycin on gastric emptying and the success of enteral feeding in mechanically ventilated, critically ill patients with large volume gastric aspirates.

DESIGN

Prospective, double-blind, randomized, and placebo-controlled trial.

SETTING

General intensive care unit in a university hospital.

PATIENTS

Twenty critically ill, mechanically ventilated patients intolerant of nasogastric feeding (indicated by a residual gastric volume of > or =250 mL during feed administration at > or =40 mL/hr).

INTERVENTIONS

After a gastric aspirate of > or =250 mL, which was discarded, the enteral feeding was continued at the previous rate for 3 hrs. Intravenous erythromycin (200 mg) or placebo was then administered over 20 mins. The residual gastric contents were again aspirated and the volume was recorded 1 hr after the infusion began.

MEASUREMENTS AND MAIN RESULTS

Gastric emptying was calculated as volume of feed infused into the stomach over 4 hrs minus the residual volume aspirated. Mean gastric emptying was 139+/-37 (+/-SEM) mL after erythromycin and -2+/-46 mL after placebo (p = .027). Nasogastric feeding was successful in nine of ten patients treated with erythromycin and five of ten who received placebo 1 hr after infusion (chi-square p = .05).

CONCLUSION

In critically ill patients who have large volumes of gastric aspirates indicating a failure to tolerate nasogastric feeding, a single small dose of intravenous erythromycin allows continuation of feed in the short term.

The relationship between change in blood pressure, blood pressure and time

Physiological homeostatic mechanisms and interventions by anaesthetists attempt to moderate excessive change in many biological variables during anaesthesia. These mechanisms may have fast or slow response times. This study describes how mean arterial blood pressure changes with time and how the change is dependent upon the pre-existing blood pressure. The results demonstrate the 'regression towards the mean' concept; low arterial blood pressures increase and high pressures decrease. The data are the result of all interactions and have been used to produce an 'envelope' into which 80% of all changes fall. Alarm systems using this envelope could warn of excessive changes that occur within short time intervals.

Personality traits of anaesthetists and physicians: an evaluation using the Cloninger Temperament and Character Inventory (TCI-125)

The personality profiles of Specialist Anaesthetists, Trainee Anaesthetists and Specialist Physicians were examined using Cloninger's Temperament and Character Inventory. These were compared with validated Community Sample 'average values' and a historical Norwegian Physician sample. Completed forms were returned from 364 doctors (Specialist Anaesthetists 222, Trainee Anaesthetists 75, Physicians 67), an overall response rate of 71%. Specialist Anaesthetists were more Cooperative, Harm Avoidant and Self-Directed than the Community Sample but less Reward Dependent, Novelty Seeking and Persistent than the Community Sample. Physicians were more Cooperative than their Specialist Anaesthetist colleagues, but both more so than were the general population. Trainee anaesthetists appear to be more Novelty Seeking and Reward Dependent than the Specialist Anaesthetists, this factor being predominately age related. Extreme/Mild personality traits were identified in 33% of Specialists, 41% of Trainees and 33% of Physicians, whilst personality disorders were found at the expected rates (Specialist Anaesthetists 9%, Trainee Anaesthetists 10%, Physicians 2%). Personality assessment has implications for recruitment, crisis management and professional development within anaesthesia.

Anaesthetic assistants: their role in the development and resolution of anaesthetic incidents

Trained anaesthetic assistants are considered essential for the safe conduct of anaesthesia. Data from 5837 AIMS (Anaesthetic Incident Monitoring Study) reports were evaluated for issues concerning anaesthetic assistants in the generation and resolution of anaesthetic incidents. "Inadequate assistance" as a contributing factor was identified in 187 reports, whilst "skilled assistance" which minimized the incident was present in 808 cases. One hundred and seventy-two reports specifically commented on anaesthetic assistants in the narrative section of the AIMS form. All surgical specialties were represented. In 147 of these reports the assistant actually contributed to or failed to assist with the incident. Although the majority of outcomes from the reports were uneventful, prolonged stay, awareness and ICU admission did ensue in a small number of cases. The most common incidents were related to problems with equipment, communication and inadequate staffing levels (number and/or skill mix). Results from this study have implications for anaesthetic assistant staffing levels and the orientation of course content.

Personality profiles of Australian anaesthetists

Identification of personality traits in anaesthetists has potential implications for selection of trainees, assessment of coping strategies during times of stress and may have a role in the analysis of critical incidents. A 24 question postal questionnaire based on the Cattell 16PF inventory was sent to specialist anaesthetists in Australia. One hundred and sixty-seven replies were received (33% response rate). Personality traits did not differ when the anaesthetists were grouped for age, number of years qualified and country of qualification. City practitioners rated themselves more inquisitive than country practitioners did (P = 0.052). Female anaesthetists self-reported they were calm (P = 0.02), patient (P = 0.02) and tolerant (P = 0.02) more often than their male counterparts, whilst more males reported themselves as highly conscientious (P = 0.01). Although some traits were consistent, personality profiles showed significant heterogeneity. Further examination of how personality and coping mechanisms interact may be central to the management of stress and critical incident generation.

Aspiration during anaesthesia: a review of 133 cases from the Australian Anaesthetic Incident Monitoring Study (AIMS)

Two-hundred and forty incidents of vomiting/regurgitation and aspiration were reported to the Anaesthetic Incident Monitoring Study database consisting of 5000 reports. Of these, 133 cases of aspiration were recorded. Passive regurgitation occurred three times more commonly than active vomiting. Aspiration was reported twice as often in elective compared with emergency surgery, with 56% of incidents taking place during induction of anaesthesia. Anti-aspiration prophylaxis was prescribed in 14% of patients who subsequently aspirated; however, the majority of cases had at least one predisposing factor for regurgitation, vomiting or aspiration evident peri-operatively. While a major immediate physiological disturbance was common, long-term morbidity was not. Death ensued in five cases, all of whom had significant co-morbidities. Factors reported as contributing to the incident included error of judgement and fault of technique, while clinical experience and anaesthetic assistance tended to minimise the incident. Aspiration remains an important anaesthetic-related morbidity. The application of simple guidelines may have prevented the incident in 60% of all cases of aspiration. Ensuring airway security may be as important as chemoprophylaxis in its prevention.

With what certainty can post-anaesthetic outcome be predicted?

Prediction of outcome is an important aspect of anaesthetic practice. In populations prediction systems are well developed, but systems capable of identifying individuals at risk are still lacking. Importantly, anaesthesia outcome cannot be considered in isolation and must include patient, surgical, and social factors.

Trainees' attitudes to research as part of anaesthetic training

The formal project has been a requirement for the F.A.N.Z.C.A. diploma for the past few years. A questionnaire was sent to all registrars on a formal program asking questions relating to the formal project, perceived advantages, disadvantages, value of formal research teaching methodology and future career intentions. All years of training were represented. Forty-nine of the fifty-six (86%) respondents replied to the survey. Of these 15% felt the formal project had no value, 54% found it possibly useful whilst 31% perceived is as very useful. Advantages of the formal project included appreciation of research skills and the ability to critically appraise research. Disadvantages included lack of dedicated time, space and funding and production of poor quality research. A majority (63%) favoured formal teaching of research methods for the F.A.N.Z.C.A. diploma, which ideally should be taught before the Primary (30%) or in the Provisional Fellowship year (36%). Few respondents indicated a willingness to undertake a major commitment to research in the future (4%) but 46% wanted some contact with research and teaching as part of their normal work practice. A more structured teaching in research methodology, assessment of published work and presentation skills may be more suited to the longterm goals of the majority of clinical anaesthetists.

Anti-aspiration prophylaxis in New Zealand: a national survey

A postal questionnaire was sent on two occasions to specialist anaesthetists within New Zealand. Questions were related to fasting status, anti-aspiration prophylaxis, incidence of aspiration, definition of high risk groups for aspiration pneumonitis, and identification of departmental guidelines. Two-hundred-and-twenty-three replies were received (72% response rate). Most adults, children and infants were fasted for 6 hours for solids, whilst the majority fasted for 2 to 4 hours for liquids. Two-thirds indicated that they would delay emergency surgery (not life/limb threatening) to optimize gastric emptying. Histamine type 2 receptor antagonists, metoclopramide and cricoid pressure were used commonly, more so in the obstetric population compared to non-obstetric surgery. Preinduction nasogastric intubation and suction were used infrequently. Anti-aspiration prophylaxis was deemed important in morbidly obese patients, those in the third trimester of pregnancy and those with a hiatus hernia, whilst diabetes mellitus, sepsis and renal failure were not considered risk factors for aspiration pneumonitis. 71% of respondents had at least one episode of aspiration (range 0-10), with an overall mortality rate of 5%. Half of these cases of aspiration were deemed to be preventable by the respondent.

The effect of oral cisapride premedication on fasting gastric volumes

The aim of this study was to determine whether fasting gastric volumes could be reduced by preoperative administration of cisapride. One hundred and twenty-one patients undergoing elective general anaesthesia were randomly allocated to receive either cisapride 20 mg plus diazepam 10 mg or placebo tablets plus diazepam 10 mg, two hours prior to induction. Immediately following induction blind gastric aspiration was performed using a 16Fr multiorificed orogastric tube. Gastric volume, pH, and cisapride blood concentration were measured at this time. Gastric volumes were significantly smaller in the cisapride group, 20.5 (SD 22.2) ml compared to placebo 28.2 (SD 26.0) ml but there was no significant difference with respect to pH. Some patients in both groups had large gastric volumes despite fasting. No significant adverse effects were noted with cisapride.

Background infusion with patient-controlled analgesia: effect on postoperative oxyhaemoglobin saturation and pain control

The aim of this study was to determine whether the addition of a background infusion (BI) to patient-controlled analgesia (PCA) would lead to significantly improved pain control or poorer oxyhaemoglobin saturation (SpO2) after gynaecological surgery. Sixty-two patients were studied for 24 hours postoperatively; pain scores and morphine dose were recorded hourly, SpO2 was recorded every 10 seconds. Administration of the BI resulted in a significant increase in total morphine dose received although there was no difference in the severity of postoperative desaturation between the therapies. Despite the increased morphine dose pain scores also were similar in the two groups. Addition of a BI at 1 mg/hr did not confer any advantage over PCA alone and is not recommended when PCA is used in this patient group.

The effect of fentanyl administered epidurally by patient-controlled analgesia, continuous infusion, or a combined technique of oxyhaemoglobin saturation after abdominal surgery

The aims of this study were to determine the effect of three different modes of epidural administration of fentanyl on oxyhaemoglobin saturation and pain control. Forty-three patients undergoing elective abdominal surgery were randomly allocated to the following groups: (1) continuous infusion of fentanyl at a rate of 50 micrograms.h-1 with additional epidural boluses (25 micrograms) as required; (2) patient-controlled analgesia using a 25 microgram epidural bolus of fentanyl with a 15 min lock-out period; (3) a combination of patient-controlled analgesia and continuous infusion. Oxyhaemoglobin saturation was measured by continuous computerised pulse oximetry for 48 h after operation together with pain and sedation scores. In the first 24 h after surgery patients in the continuous infusion group spent a significantly greater proportion of time below oxygen saturations of 94% and 85% than those in the other two groups. On day 2 all oxygen saturation measurements were worse than during day 1, but differences between groups were not significant. Those patients receiving patient-controlled analgesia required significantly less fentanyl than patients in either of the other groups (p < 0.05). However, the mean pain and sedation scores did not differ significantly between the three treatment groups. There was no association between total fentanyl dose and oxygen saturation values. Overall, self-administered fentanyl appeared to cause less oxyhaemoglobin desaturation than nurse-administered analgesia without any loss of analgesic effect.

Oxyhaemoglobin saturation following elective abdominal surgery in patients receiving continuous intravenous infusion or intramuscular morphine analgesia

Oxygen saturation was continuously measured using computerised pulse oximetry for 8 h overnight pre-operatively and for the first 24 h postoperatively in 40 patients receiving intermittent intramuscular morphine or continuous infusion of morphine following elective upper abdominal surgery. The proportion of time with an oxygen saturation less than 94% was used as an index of desaturation. Patients receiving continuous infusion analgesia received a larger morphine dose and achieved better analgesia than the intramuscular group. Postoperatively, the duration of desaturation increased 10-fold over pre-operative values, 'intramuscular' patients spending 39.0% (SD, 37.0%) and 'continuous infusion' patients 40.0% (SD, 37.5%) of the time below 94% saturation. Although newer therapies (e.g. epidural analgesia and patient-controlled analgesia) are currently receiving greater attention, the sequelae of these more traditional analgesic techniques warrant further study.

The influence of rectal cisapride on morphine-induced gastric stasis

The effect of a new formulation of the gastric prokinetic agent cispride on opioid-induced gastric stasis was investigated. Forty patients were randomly allocated to one of four therapies administered as premedication; group A, placebo suppositories only; group B, placebo suppositories and intramuscular morphine 10 mg; group C, rectal cisapride 30 mg and intramuscular morphine 10 mg and group D, rectal cisapride 60 mg and intramuscular morphine 10 mg. Gastric emptying was assessed from the small bowel absorption of paracetamol following oral absorption. The kinetics of the suppository formulation were determined from venous blood samples. Rectal cisapride in the two doses used did not prevent opioid-induced gastric stasis. This may reflect an inability of this formulation to produce adequate plasma concentrations.

Patient-controlled analgesia: can it be made safer?

Patient-controlled analgesia (PCA) has been shown to provide superior pain relief when compared with standard therapy options for postoperative analgesia. If PCA is to be implemented widely in teaching, private and country hospitals, its effectiveness needs balanced with a high safety profile. This can be achieved by consideration of patient selection, comprehensive education of patients, medical and nursing staff and equipment familiarisation. Continuous clinical audit allows identification of problem areas along with monitoring analgesic efficacy.

Peri-operative drug prescribing pattern and manufacturers' guidelines. An audit

Many patients admitted for surgery are receiving regular drug therapy. Adverse effects may occur, either as a result of these drugs being stopped suddenly or because staff are unaware of significant interactions between certain drugs and anaesthetic agents or techniques. This study aimed to find out how regular drug medication is actually given in the peri-operative period. In addition, pharmaceutical companies were contacted and asked for information about the effects of sudden withdrawal of their products and potential interactions with anaesthetic agents. We found that many drugs were omitted peri-operatively with potentially significant effects. Pharmaceutical companies do not seem to appreciate the importance of this problem and not all of them give clear recommendations relevant to practising anaesthetists.

Assessment of a new infusion pump for epidural PCA

The use of epidural fentanyl by patient-controlled analgesia (PCA) may be a useful method of providing high-quality postoperative analgesia on the general surgical ward. The successful use of this technique requires an infusion pump with specific characteristics. Three Provider 5500, newly-developed, battery-powered PCA pumps, were tested to determine their accuracy, threshold of occlusion alarm limits and stored volume characteristics. These measurements were repeated following the in-line addition of an 18 gauge epidural catheter and two 0.2 micron filters. Pumps delivered on average within 3% of stated infusion rates and within 3% of bolus dose size. Occlusion pressures generated were between 1200 and 1360 mmHg, while the mean stored volume was 0.12 ml. Accuracy of delivery was maintained at lower voltage inputs. Addition of the catheter failed to alter the accuracy of the pumps tested. Siphoning of fluid was possible on disconnection of cartridge from pump. This problem did not occur with the addition of an epidural catheter and filter. This device has features which make it suitable for the safe delivery of epidural PCA. Care, however, needs to be taken on changing cartridges to prevent accidental administration of a drug bolus to the patient.

Premedication: an audit

A prospective study of routine premedication management was carried out at a large teaching hospital. Many patients received their premedication at times inappropriate for it to be effective. Several patients receiving regular medication had this suddenly stopped pre-operatively. Prolonged fasting occurred in both elective and emergency groups of patients. Benzodiazepines and opioids were prescribed most frequently and drying agents were used widely. Antacids, H2-blockers and agents to promote gastric emptying were used very little despite the potential of aspiration in many groups of patients. This audit of activity has revealed several areas of practice that can either be improved immediately or warrant detailed investigation.

Antireflux valves in patient-controlled analgesia

Antireflux valves are widely used in conjunction with patient-controlled analgesia devices. It is important to appreciate the limitations and dangers of these systems. They can achieve a potential 'stored volume' if occluded and they may, as part of the administration set, retard fluid administration. Seven antireflux systems currently available were tested in conjunction with three patient-controlled analgesia pumps. The systems' volume, time to occlusion alarm and flow rates were measured. Results showed that the sets with low stored volumes were less efficient as administration sets. A potentially dangerous bolus could result after release of occlusion if sets with large stored volumes were used in conjunction with pumps that utilised concentrated solutions of opioid. This study has identified the ideal antireflux valve system.

Patients' expectations of patient-controlled analgesia

Patient-controlled analgesia is an increasingly popular method of postoperative pain relief. However, patients often worry about new therapies. Eighty ASA 1 and 2 patients aged 18-65 years were asked to list the advantages and disadvantages of using patient-controlled analgesia. The most important advantage as perceived by patients was the reduced time spent by nurses in giving medication, but there was concern that direct personal contact would also be lessened. Preservation of self control, autonomy, rapid onset of analgesia, ability to titrate analgesia and lack of injections were seen as an advantage. Addiction and machine faults were seen as minimal problems. Preservation of patient-nurse contact is of great importance to ensure success of postoperative analgesia.