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Biomedical subjects

R McCloy

Publications and source records attributed to R McCloy.

At least 19 recordsLinked to original sources
PubMed2000

Counterfactual thinking about controllable events.

When people think about what might have been, they mentally undo controllable rather than uncontrollable events. We report the results of two experiments in which we examined this controllability effect in counterfactual thinking. The experiments show that the mutability of controllable events is influenced by the perceived appropriateness or inappropriateness of the events. The first experiment shows that people change inappropriate controllable actions more than appropriate controllable ones. The second experiment shows that people mutate inappropriate controllable events whether the outcome is exceptional or normal with respect to intrapersonal habitual norms, and whether the outcome is positive or negative. We discuss the implications for alternative theories of counterfactual thinking.

Adult↗
PubMed1999

Learning rate for laparoscopic surgical skills on MIST VR, a virtual reality simulator: quality of human-computer interface.

Acquiring laparoscopic surgical skills involves initial learning of cognitive and motor skills followed by refinement of those skills. The successful use of a virtual reality simulator depends on the quality of the interface for the human-computer interaction and this can be determined by the initial learning rate. MIST VR, a part-task virtual reality laparoscopic simulator, provides objective assessment of psychomotor skills and can generate an overall score for performance, based upon errors made and time taken for six different tasks. This study analysed the rate of early task/instrument/computer familiarization on consecutive scores achieved by surgically experienced and naive individuals. Eleven surgeons, 18 medical students and seven non-medical personnel were tested on the simulator up to ten consecutive times, within a 2-week period. Performance data from every task and repetition were analysed to obtain individual scores of task performance. The calculation of overall score penalized errors far more heavily than total time taken, with high scores indicating poor performance. The surgeon-computer interface generated a rapid and significant early familiarization curve up to the third session on the simulator, with significant reductions in both time taken and total contact errors made. These results suggest that MIST VR represents a high quality interface. Surgeons scored consistently and significantly better than other subjects on all tasks. For surgically naive individuals, it was possible to predict the level of laparoscopic skills performance that would be attained after overcoming initial simulator learning curve, by studying their initial score. Overall scores reflected surgical experience and suggest that the simulator is measuring surgically relevant parameters. MIST VR provides a validated and much needed method for objective assessment of laparoscopic skills, for a variety of surgical disciplines.

Adult↗
PubMed1998

Chronic pancreatitis at Manchester, UK. Focus on antioxidant therapy.

The Manchester 'oxidant stress' hypothesis for the development of pancreatitis accommodates published information on both chronic pancreatitis and acute pancreatitis. Oxidant stress, mainly from reactive xenobiotic metabolites, is perceived as the pivotal pre-morbid problem in chronic pancreatitis and, by depleting glutathione, targets the exocytosis mechanism of the pancreatic acinar cell. Inhalation exposure to petrochemical products is identified as an independent risk factor in patients at Manchester Royal Infirmary, where some 50% of patients referred have non-alcoholic disease. This paper describes the development of antioxidant therapy, using supplements of methionine, vitamin C and selenium, and its validation in a placebo-controlled trial, followed by a retrospective cross-sectional study in 94 consecutive patients for an average of 30 months. Antioxidant therapy emerges as a safe and effective medical alternative to surgery for painful chronic pancreatitis.

Antioxidants↗
PubMed1997

Lessons learned during the INSURRECT project (INteractive SURgical Teaching at REmote CeNtres).

The INSURRECT project began in 1993 as a collaboration between six UK universities in distance teaching of undergraduate surgery. The first year was spent in testing the network and preparing the course material. This was followed by a two-year pilot teaching course. During this phase, 108 teaching sessions were conducted, involving more than 1300 students in all. It was found that successful teaching depended on increasing the amount of audience interaction was much as possible and transmitting high-quality video pictures. Although the time taken to deliver material by interactive video was greater than for conventional lectures, both students and teachers responded favourably to the project.

Academic Medical Centers↗
PubMed1997

MIST VR. A laparoscopic surgery procedures trainer and evaluator.

The key bimanual instrument tasks involved in laparoscopic surgery have been abstracted for use in a virtual reality surgical skills evaluator and trainer. The trainer uses two laparoscopic instruments mounted on a frame with position sensors which provide instrument movement data that is translated into interactive real time graphics on a PC (P133, 16 Mb RAM, graphics acceleration card). An accurately scaled operating volume of 10 cm3 is represented by a 3D cube on the computer screen. "Camera" position and size of target objects can be varied for different skill levels. Targets appear randomly within the operating volume according to the skill task and can be grasped and manipulated with the instruments. Accuracy and errors during the tasks and time to completion are logged. Mist VR has tutorial, training, examination, analysis and configuration modes. Six tasks have been selected and include combinations of instrument approach, target acquisition, target manipulation and placement, transfer between instruments, target contact with optional diathermy, and controlled instrument withdrawal/replacement. Tasks can be configured for varying degrees of difficulty and the configurations saved to a library for reuse. Specific task configurations can be assigned to individual students. In the examination mode the supervisor can select the tasks, repetitions and order and save to a specific file for that trainee. Progress can be assessed and there is the option for playback of the training session or examination. Data analyses permit overall, including task, and right or left hand performances to be quantified. Mist VR represents a significant advance over the subjective assessment of training performances with existing "plastic box" basic trainers.

Computer-Assisted Instruction↗
PubMed1994

Laparoscopic cholecystectomy in England and Wales: results of an audit by the Royal College of Surgeons of England.

The results of an audit of open and laparoscopic cholecystectomy conducted by the Comparative Audit Service of The Royal College of Surgeons of England are presented. Data were submitted by 124 consultant surgeons on 3319 attempted laparoscopic and by 227 consultant surgeons on 8035 open cholecystectomies performed in England and Wales during the 2 years 1990 and 1991. These were contrasted with 9322 attempted laparoscopic cholecystectomies reported in 21 series reported in the world literature between 1991 and 1992, and with five other nations' audit studies. Among attempted laparoscopic cases, conversion to an open procedure was necessary in 175/3319 (5.2%) of cases and overall mortality was 0.15% (5/3319). Major complications were reported in 2.1% and minor complications in 5.9% of cases. Bile duct injury was reported to be significantly more common after attempted laparoscopic cholecystectomy (11/3319, 0.33%) than after open cholecystectomy (4/8035, 0.06%) (95% confidence intervals -0.48 to 0.08), but it was not significantly different from that reported for laparoscopic cholecystectomy in the combined world literature (28/9322, 0.3%) (95% confidence intervals -0.19 to 0.25). Most systemic complications were significantly more common after open cholecystectomy. For open cholecystectomy, the mortality was 55/8035 (0.76%), with major complications reported in 3.2% and minor complications in 9.8% of patients. Adoption of the laparoscopic approach was associated with a four-fifths reduction in the mortality of cholecystectomy, and a 40% reduction in the overall complication rate when compared with the open operation. While laparoscopic cholecystectomy has an impressively low mortality and morbidity profile during the first 2 years of its introduction into the UK, prevention of bile duct injury is the most important issue to be addressed in all laparoscopic cholecystectomy training programmes.

Bile Ducts↗
PubMed1992

Through the keyhole.

Surgically speaking, history is likely to dub the 1990s as 'the laparoscopic years', as changes in surgical practice cause one of the biggest revolutions in our hospitals since the arrival of general anaesthesia. As a result, surgeons are having to re-examine their skills and training, while managers need to update their infrastructure for budgets and funding. Both purchasers and providers of surgical services need to ensure that they are not tied down to 'historic' contracts.

Capital Expenditures↗
PubMed1992

Is endoscopy helpful in patient monitoring?

The safety issues involved in patients on long-term treatment with omeprazole will determine whether endoscopic monitoring is necessary. In a review of 646 patients who have undergone regular gastric biopsies during continuous treatment with omeprazole, 10-120 mg daily, for periods of up to 5.5 years, there were no overall patterns to the changes in gastric endocrine cells. Apparent gastric endocrine cell hyperplasia in 72% of patients correlated with the development of chronic atrophic corpus gastritis. The only macroscopic changes to be reported were endocrine tumours in 4 out of 184 patients on long-term omeprazole for Zollinger-Ellison syndrome, and at least 3 of these patients had multiple endocrine neoplasia (MEN) type 1 syndrome. In patients with other low acid states, such as pernicious anaemia or after gastric irradiation or gastric surgery, in which drug therapy is not a confounding factor, there is a very low risk of developing macroscopic lesions within the stomach, and endoscopic surveillance is not routine practice. In conclusion, upper gastrointestinal endoscopic monitoring to identify microscopic or macroscopic changes cannot be justified during at least the first 5 years of continuous treatment with omeprazole.

Biopsy↗
PubMed1992

Asleep on the job: sedation and monitoring during endoscopy.

Gastrointestinal endoscopic procedures are invasive and carry a significant morbidity and mortality, even for diagnostic procedures (mortality of 1 in 2000 for upper gastrointestinal endoscopy). The commonest causes of death are cardiopulmonary complications, which may in part be related to sedative techniques. The clinical end-points for sedation need to be reappraised and should aim to induce amnesia rather than hypnosis. Endoscopists need to be familiar with the pharmacokinetic and pharmacodynamic properties of the benzodiazepines used for sedation. This applies particularly to the protracted half-lives of some benzodiazepines and the major drug interaction with significant synergy that occurs if opioids are used in combination with benzodiazepines. Thus appropriate doses of these drugs should be administered. The use of supplemental oxygen and pulse oximetry, combined with continuous intravenous access during the procedure should be standard practice. Endoscopists should be aware of national guidelines for safe endoscopic practice.

Procedural Sedation↗
PubMed1992

Laparoscopic gastrointestinal surgery.

The growth and scope of laparoscopic gastrointestinal surgery are outstripping the ability of medical journals to print series and reports of experience, and much data remain anectodal and preliminary. Laparoscopic cholecystectomy has become established, although, unfortunately, peroperative cholangiography has not yet become normal practice, despite convincing published evidence that it is likely to reduce the increased number of bile ducts that are damaged by laparoscopic surgeons. Imaging the bile ducts and the overall management of choledocholithiasis need re-evaluation, and the approach will change as more surgeons explore the bile ducts laparoscopically. Laparoscopic hiatal anti-reflux surgery will soon be routine, and a whole range of laparoscopically assisted operations on the oesophagus, colon, and rectum will become commonplace. Operations on the liver remain anecdotal. Throughout this rapid progress, surgeons must not forget the principles of (open) surgical practice, whilst carefully kept registers and regular audit of operations will provide new surgical standards.

Cholecystectomy, Laparoscopic↗