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Biomedical subjects

A F Merry

Publications and source records attributed to A F Merry.

At least 19 recordsLinked to original sources

Simulators for use in anaesthesia.

There are many simulators available for use in anaesthetic-related education and research. Those who wish to purchase a simulator or to establish a simulation facility face a daunting task in understanding the differences between simulators. Recent reviews have focused on narrower areas of simulation, such as airway management or basic life support, or on the application of simulators. It would be difficult to deal in detail with every simulator ever made for anaesthesia, but in the present review we cover the spectrum of currently available anaesthetic simulators, provide an overview of different types of simulator, and discuss a selection of simulators of particular interest, including some of historical significance and some examples of 'home made' simulators. We have found no common terminology amongst authors for describing or classifying simulators, and propose a framework for describing (or classifying) them that is simple, clear and applicable to any simulator.

Anesthesiology↗

A national survey of infection control practice by New Zealand anaesthetists.

Anaesthetists have an important role in preventing nosocomial infection. Failures in this role have resulted in critical reports in the media. We ascertained the current practices of New Zealand anaesthetists relating to infection control, by distributing a questionnaire to all 450 anaesthetists practising in New Zealand. Sixty-one percent responded. Just over half the respondents had never read their hospital policy on infection control and over a third had never read the Australian and New Zealand College of Anaesthetists policy document on infection control. It was found that 3.4% rarely changed gloves if they became contaminated and 2.2% occasionally used the same syringe to administer drugs to more than one patient. The majority (86.3%) of respondents split one drug ampoule between more than one patient, 41.3% used multidose vials for more than one patient and 2.2% used pre-filled syringes for more than one patient. The majority complied with the College infection control policy for performing arterial cannulation (85.7%), central venous cannulation (77.4%) and regional blockade (65.1%). Respondents ranked the overall risk of the anaesthetist contributing to the transmission of infectious agents on a scale from 0 to 10 (10=highest risk). The median response was 7, the modal response was 10 and interquartile range was 4 to 8. There was a high level of awareness of the risks of contributing to cross-infection inherent in anaesthesia, most anaesthetists reporting that they followed recommended guidelines in this context. However, these data suggest more effort is required to promote compliance with appropriate guidelines.

Anesthesia↗

Crises in clinical care: an approach to management.

A "crisis" in health care is "the point in the course of a disease at which a decisive change occurs, leading either to recovery or to death". The daunting challenges faced by clinicians when confronted with a crisis are illustrated by a tragic case in which a teenage boy died after a minor surgical procedure. Crises are challenging for reasons which include: presentation with non-specific signs or symptoms, interaction of complex factors, progressive evolution, new situations, "revenge effects", inadequate assistance, and time constraints. In crises, clinicians often experience anxiety- and overload-induced performance degradation, tend to use "frequency gambling", run out of "rules" and have to work from first principles, and are prone to "confirmation bias". The effective management of crises requires formal training, usually simulator-based, and ideally in the inter-professional groups who will need to function as a team. "COVER ABCD-A SWIFT CHECK" is a pre-compiled algorithm which can be applied quickly and effectively to facilitate a systematic and effective response to the wide range of potentially lethal problems which may occur suddenly in anaesthesia. A set of 25 articles describing additional pre-compiled responses collated into a manual for the management of any crisis under anaesthesia has been published electronically as companion papers to this article. This approach to crisis management should be applied to other areas of clinical medicine as well as anaesthesia.

Algorithms↗

A prospective, randomised clinical evaluation of a new safety-orientated injectable drug administration system in comparison with conventional methods.

Fifteen anaesthetists were observed while providing anaesthesia for 15 pairs of adult cardiac surgical operations, using conventional methods for one of each pair and a new drug administration system designed to reduce error for the other. Aspects of each method were rated by users on 10-cm visual analogue scales (10 being best). The new system was rated more favourably than conventional methods in terms of safety (median [range] = 8.1 [6.8-9.7] vs. 7.1 [2.6-9.3] cm; p = 0.001) and usability (8.5 [5.9-9.4] vs. 7.5 [3.2-9.8] cm; p=0.027). The new system saved preparation time both before anaesthesia (median [range] = 180 [32-480] vs. 360 [120-600] s; p=0.013) and during anaesthesia (10 [2-38] vs. 12 [10-60] s; p=0.009). Prefilled syringes for the new system increased costs by euro 23.00 per anaesthetic (p = 0.041), but this increase is likely to be offset by the potential of the new system to decrease costly iatrogenic harm by preventing drug error.

Adult↗

Evidence-based strategies for preventing drug administration errors during anaesthesia.

We developed evidence-based recommendations for the minimisation of errors in intravenous drug administration in anaesthesia from a systematic review of the literature that identified 98 relevant references (14 with experimental designs or incident reports and 19 with reports of cases or case series). We validated the recommendations using reports of drug errors collected in a previous study. One general and five specific strong recommendations were generated: systematic countermeasures should be used to decrease the number of drug administration errors in anaesthesia; the label on any drug ampoule or syringe should be read carefully before a drug is drawn up or injected; the legibility and contents of labels on ampoules and syringes should be optimised according to agreed standards; syringes should (almost) always be labelled; formal organisation of drug drawers and workspaces should be used; labels should be checked with a second person or a device before a drug is drawn up or administered.

Anesthesia, Intravenous↗

A prospective clinical audit of central venous catheter use and complications in 1000 consecutive patients.

We conducted a prospective audit of central venous catheter (CVC) use in 1000 consecutive patients to better define the rates of postoperative complications (particularly vascular perforation) and the pattern of CVC and pulmonary artery catheter (PAC) usage (particularly the number of lumens inserted and utilized). Details of CVCs, complications, and the number of lumens in place and used, were recorded daily until all CVCs were removed. A total of 1546 CVCs and 223 PACs were placed in study patients. Two non-fatal perforations occurred: a perforated right atrium in a patient who received an Arrow triple-lumen CVC (previously reported), and a perforated pulmonary artery in a patient upon withdrawal of a Baxter PAC. The risk per patient of any CVC-related perforation was 0.2% (95% confidence interval (CI): 0.02% to 0.7%). The rates of CVC-related sepsis and local infection were 3% (95% CI: 2% to 4%) and 2% (95% CI: 1% to 3%) respectively. At the peak of CVC use (day 1 in the ICU) the overall number of lumens placed was significantly correlated with lumens used (r = 0.53), endorsing clinical judgement in the anticipation of the needs of the patient. The modal number of lumen uses in adults and children was four. However, in children, fewer catheters were inserted per patient than in adults (1.28 vs 1.63, P = 0.01), and placed lumens were used more intensively (P < 0.001). Data appear to justify the routine selection of a triple-lumen CVC in adult patients, but not of a quad-lumen CVC.

Adolescent↗

Evaluation in an anaesthetic simulator of a prototype of a new drug administration system designed to reduce error.

Ten anaesthetists were observed while providing anaesthesia for two simulated surgical procedures, twice using conventional methods and twice using a prototype of a new drug administration system designed to reduce error. Aspects of each method were rated by users on 10-cm visual analogue scales (10 being best) and comments were invited. Median safety scores were 7.7 cm (range 4.3-8.9) for the new system and 4.6 cm (1.3-8.2) for conventional methods (p = 0.009). The new system was compared favourably with conventional methods in respect of safety (p = 0.005), clinical acceptability (p = 0.008), organisation and layout (p = 0.047), and acceptability for use on patients (p = 0.005). The new system saved time in the preparation of drugs both before anaesthesia (105 vs. 346 s; p < 0.001) and during anaesthesia (20 vs. 104 s; p < 0.001). Comments facilitated development of the system and the evaluation endorsed proceeding to a clinical trial.

Anesthesiology↗

Tenoxicam 20 mg or 40 mg after thoracotomy: a prospective, randomized, double-blind, placebo-controlled study.

Forty-five adults undergoing thoracotomy were randomized to receive placebo, tenoxicam 20 mg or tenoxicam 40 mg IV during chest wall closure. All patients received intraoperative fentanyl and intercostal blocks followed by morphine by patient-controlled analgesia. Patient numbers 13 to 45 also received thoracic epidural analgesia by continuous infusion of bupivacaine 0.125%, patient numbers 25 to 45 having fentanyl 2 microg/ml added to the epidural infusion. Efficacy parameters and adverse reactions were assessed over the first 24 hours postoperatively. On a 100 mm visual analogue scale, mean (SD) pain at rest (adjusted area under curve for hours 1 to 24) was 25.8 (12.5), 17.4 (14.8) and 16.5 (13.3) mm for groups receiving placebo, 20 mg and 40 mg tenoxicam, respectively (ANOVA: P<0.05). There were no significant differences between study groups postoperatively in pain on coughing, opioid consumption, blood gas measurements, nausea, vomiting, sedation, blood loss, haemoglobin or serum creatinine. One patient in each tenoxicam group reported epigastric pain, rated moderate. These data support the inclusion of tenoxicam 20 mg IV in the management of pain at rest for patients undergoing thoracotomy, but do not show additional benefit for a higher dose.

Analgesia, Patient-Controlled↗

Cost-effectiveness of spinal cord stimulation in patients with intractable angina.

AIM: To review the cost of healthcare utilisation by patients suffering from intractable angina, unsuitable for coronary revascularisation, before and after treatment with spinal cord stimulation. METHODS: Data were collected for eight patients treated for intractable angina with spinal cord stimulation at Green Lane Hospital before April 1999. Information on consumption of specified medica resources for the twelve months preceding implantation, the implantation period, and the twelve months following implantation was collected. Where available, data were also collected for the eighteen months preceding and following treatment. RESULTS: In six patients successful permanent stimulation was established; in two it proved technically impossible to implant a stimulator. The six patients with successful stimulation spent fewer days in hospital (p=0.028) and consumed fewer resources (p=0.046) following implantation than in the period before implantation. The two patients for whom spinal cord stimulation was unsuccessful spent more days in hospital and consumed more resources in the twelve months following, than in the twelve months preceding attempted implantation. Extrapolation of data for all eight patients suggests that, on average, the cost of implanting a spinal cord stimulator will be recovered in approximately fifteen months. CONCLUSION: Spinal cord stimulation is a cost-effective treatment for intractable angina pectoris.

Aged↗

Touch contamination levels during anaesthetic procedures and their relationship to hand hygiene procedures: a clinical audit.

After different methods of hand preparation, volunteers rolled segments of sterile central venous catheter between their fingertips, and bacterial transfer was evaluated by standardized quantitative culture. The number of bacteria transferred differed between methods (P<0.001). Comparisons were made with the control group (no preparation at all; median, third quartile and maximum count=6.5, 24, 55). Bacterial transfer was greatly increased with wet hands (1227, 1932, 3254; P<0.001). It was reduced with a new rapid method, based on thorough drying with a combination of 10 s using a cloth towel followed by either 10 or 20 s with a hot-air towel (0, 3, 7 and 0, 4, 30, respectively; P=0.007 and 0.004, respectively). When asked to follow their personal routines, 10 consultant anaesthetists used a range of methods. Collectively, these were not significantly better than control (7.5, 15, 55; P=0.73), and neither was an air towel alone (2.5, 15, 80; P=0.176) nor the hospital's standard procedure (0, 1, 500; P=0.035). If hand preparation is needed, an adequate and validated method should be used, together with thorough hand drying.

Bacteria↗

A new, safety-oriented, integrated drug administration and automated anesthesia record system.

UNLABELLED: Medication errors are an important cause of patient morbidity and mortality and excessive costs, including in anesthesia. Conventional methods of injectable drug administration in anesthesia make little use of technology to support manual checking and are idiosyncratic and relatively error prone. Similarly, conventional anesthesia records are handwritten, time-consuming to make, and often unreliable. There are automated record systems, but they do not provide support for checking drugs. Therefore, by using a multifaceted approach based on established principles of systems design and human factors psychology, we have developed a system that includes trays that promote a well-organized anesthetic workspace, color- and bar-coded labeling of syringes, and automatic visual and auditory verification of the syringe labels by computer just before each drug administration. In addition, documentation of drugs administered and a traditional anesthetic case record are generated automatically. The system has been successfully deployed for 25 mo and has been used by 35 anesthesiologists in 1148 diverse cases, including cardiopulmonary bypass procedures, heart and lung transplants, and orthopedic and otorhinolaryngologic operations. It is in daily use in a tertiary teaching center and in a private hospital. IMPLICATIONS: Traditional methods of drug administration and record keeping in anesthesia are relatively error prone. By using sound principles of systems design and human factors psychology, we have designed and deployed a system with the aim of improving patient safety by facilitating correct drug administration and accurate anesthesia record making.

Adolescent↗

The frequency and nature of drug administration error during anaesthesia.

We aimed to establish the frequency and nature of drug administration error in anaesthesia (a significant subset of error in medicine) at two hospitals. Anaesthetists were asked to return a study form anonymouslyfor every anaesthetic, indicating whether or not a drug administration error or pre-error (defined as any incident with potential to become an error) had occurred. Further details were sought if the response was affirmative. From 10,806 anaesthetics, 7794 study forms were returned, representing response rates of 80% from Hospital A and 57% from Hospital B (72% overall). The frequency (95% confidence intervals) of drug administration error; of any type, per anaesthetic was 0.0075 (0.006 to 0.009), of i.v. bolus errors was 0.005 (0.0035 to 0.006) and of pre-errors was 0.004 (0.003 to 0.005), with no significant difference between hospitals. Overall, one drug administration error was reported for every 133 anaesthetics. The two largest individual categories of error involved incorrect doses (20%) and substitutions (20%) with i.v. boluses of drug. Of the i.v. bolus substitutions, 69% occurred between different pharmacological classes. One patient was aware while under muscle relaxation, and two required prolonged ventilation. In addition, 47 transient physiological effects were reported, of which five required intervention. We conclude that drug administration error during anaesthesia is considerably more frequent than previously reported.

Anesthesia↗

Attitudes and practices of New Zealand anaesthetists with regard to emergency drugs.

A postal survey of anaesthetists practising in New Zealand assessed practices with regard to the preparation of pre-drawn syringes of emergency drugs in theatre, and attitudes towards the drawing up of drugs by non-medically qualified assistants. Opinion and practice varied widely; a quarter of respondents routinely draw up such drugs and a third either never or very infrequently do so. The drugs most commonly drawn up in this way were suxamethonium, atropine, syntocinon, ephedrine and metaraminol. Providing anaesthesia single-handed, anaesthesia involving paediatric, obstetric or vascular cases, the use of major regional techniques and laryngeal mask anaesthesia were reported as factors which prompted a number of respondents to draw up one or more of these drugs. The majority (68.5%) had received no teaching on the issue and nearly all (83.5%) reported that there was no institutional policy in their workplace(s). "Syringe swap" or "wrong drug" errors related to such pre-drawn drugs were reported by 26.5%, while delay in drawing up a drug in an emergency was reported by 37%. Nearly all (98%) respondents believed that it was acceptable for an anaesthetic technician (or similar assistant) to draw up drugs in an emergency but only 14% approved of assistants drawing up drugs routinely. We conclude that there is no uniformity of opinion amongst New Zealand anaesthetists about which if any drugs should be pre-drawn for possible emergency use, and that few would endorse the drawing up of drugs by non-medically qualified assistants, except in emergency, or under other clearly delineated circumstances.

Anesthesiology↗