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Biomedical subjects

N D Barber

Publications and source records attributed to N D Barber.

At least 19 recordsLinked to original sources
PubMed1999

A validated, reliable method of scoring the severity of medication errors.

A method of scoring the severity of medication errors that does not require knowledge of patient outcomes was developed and tested. Thirty health care professionals from four U.K. hospitals scored 50 medication errors in terms of potential patient outcomes on a scale of 0 to 10, where 0 represented a case with no potential effect and 10 a case that would result in death. Sixteen error cases reported in the literature with actual patient outcomes were included among the cases to assess the validity of the scores. Ten of the errors were scored twice. The severity of the error cases, the occasion on which they were scored, the judge, each judge's profession, and the interactions between these were considered as potential sources of variability in scoring. The data were analyzed by applying generalizability theory to two models: one based on the 10 cases that were scored twice and ignoring the effect of differences in profession and one based on all 50 cases and ignoring the effect of the occasion of scoring. Generalizability coefficients for different numbers of judges and scoring occasions were calculated. A generalizability coefficient of 0.8 or more was considered to represent acceptable reliability. Most of the variance was attributable to differences in the cases. The analysis showed that, to achieve a generalizability coefficient of more than 0.8, at least four judges would have to score each case, each on one occasion, with the mean score used as a severity indicator. A reliable, valid method of scoring the severity of medication errors that did not require knowledge of patient outcomes was developed; at least four judges were required in order to achieve reliable scores, and reliability was not affected by the professions of the judges or the number of occasions on which the errors were scored.

Hospitals, Public↗
PubMed1997

Mathematical modeling of pharmacy systems.

Mathematical modeling and its potential applications in pharmacy are discussed. A model is a simplified representation of the real world. As an experimental approach, modeling minimizes expense, risk, and disruption, but its validity can be hard to ascertain. Mathematical models describe numerically the relationships among elements of a system and are a powerful tool in making decisions affecting that system. There are two types of mathematical models: analytical models, which directly describe the relationships between system inputs and outputs using mathematical equations (such as pharmacokinetic models), and simulation models, which involve the replication, usually with a computer, of events as they occur in the real world. Analytical models are easier to develop but are not appropriate for describing highly complex systems. In continuous-time simulation, the system is represented as an uninterrupted flow of material; in discrete-event simulation, it is assumed that events occur only at distinct times. Various simulation programs are commercially available. The stages of a mathematical modeling study are (1) formulate the problem, (2) determine the model's structure, (3) collect and analyze initial data, (4) develop the model further, (5) validate the model, (6) experiment using the model, and (7) use the results. There have been many applications of modeling in health care, but relatively few have involved the study of pharmacy systems. Mathematical modeling offers pharmacists a low-risk, low-cost tool for aiding decisions about pharmacy systems by predicting alternative futures.

Models, Organizational↗
PubMed1997

Predicting the rate of physician-accepted interventions by hospital pharmacists in the United Kingdom.

Pharmacists' clinical interventions in a group of British hospitals were counted, and a model to determine factors that affected the intervention rate was developed. All pharmacists who visited patient wards in 27 acute care hospitals recorded their daily ward visits and their clinical interventions during five consecutive days (Monday through Friday) in June 1993. An intervention was defined as any recommendation made with the intent of changing drug treatment. Mixed-model Poisson regression was used to try to explain variations in the intervention rate, defined as the number of physician-accepted interventions divided by the number of occupied-bed days. Possible predictors of intervention rate considered were characteristics of the hospitals, the wards, and the pharmacists. During the study period, 248 pharmacists visited 10,478 beds and proposed 3,501 interventions. Of these interventions, 3371 were accepted, 56 were rejected, and 74 were unresolved. The most frequent reasons for the interventions involved the dose (29%), the need for therapy (21%), the choice of drug (14%), and the route (12%). Ward type, pharmacist grade, and the total time the pharmacist spent on the wards were significant predictors of the intervention rate. To validate the model, data were collected during the same period in 1994; the model predicted the number of interventions within 1 of the actual number in 82% of cases. In a model explaining the factors that affected the rate of physician-accepted pharmacist interventions in acute care hospitals in the United Kingdom, ward type, pharmacist grade, and total time spent on the ward by the pharmacist were significant predictors of the intervention rate.

Drug Monitoring↗
PubMed1997

Economic evaluation of the use of nadroparin calcium in the prophylaxis of deep vein thrombosis and pulmonary embolism in surgical patients in Italy.

The objective of this study was to compare the costs, from the perspective of the payer, of using nadroparin calcium, a low-molecular-weight heparin, instead of unfractionated heparin in the prophylaxis of venous thromboembolism in patients undergoing orthopaedic surgery or major general surgery in Italy. The methods used were based on a published meta-analysis and a survey of clinical practice. We constructed a model of the prophylaxis and management of venous thromboembolism in Italy. Resource use associated with individual events was estimated on the basis of the clinical survey. Unit costs, not available from published sources, were taken from charges made by hospitals and from direct observation. A sensitivity analysis was conducted to examine whether the results were robust to changes in key variables. In the base case, compared with unfractionated heparin, prophylaxis with nadroparin calcium reduced the expected costs of managing thromboembolism by 267,226 Italian lire (L, 1994 values; $US1 = L1600 approx.) per patient undergoing orthopaedic surgery, and by L45,588 per patient undergoing major general surgery. Therefore, switching from unfractionated heparin to nadroparin calcium in these patients offers the possibility of significant cost savings to the Italian healthcare system.

Fibrinolytic Agents↗
PubMed1996

Factors influencing the provision of clinical pharmacy services in United Kingdom National Health Service hospitals.

There is much variation in the provision of clinical pharmacy services in U.K. National Health Service hospitals. Some services are provided in groups and there are differences in the extent to which barriers exist to the provision of services. Factors that linked services included efficient use of resources; barriers involved a requirement for pharmacists to participate in multidisciplinary teams. The strong resemblances between service uptake by hospital pharmacies and the technology diffusion model provides insight into the future development of services in this era of evidence-based care.

Pharmacy Service, Hospital↗
PubMed1995

Comparison of medication errors in an American and a British hospital.

Medication errors in a hospital in the United States and a hospital in the United Kingdom were compared. The study was conducted in wards with a high oral-drug-related workload in two large university hospitals. The U.S. hospital was studied in August 1993 and the U.K. hospital in May and June 1993. The U.S. hospital had a typical unit dose drug distribution system, and the U.K. hospital had the ward-based system commonly used in that country, in which a pharmacist visits each ward several times daily and reviews each patient's medication chart. The medication chart is used by the physician to order drugs and obviates the need for transcription of orders. A disguised-observation technique was used to determine frequencies and types of medication errors. Medication errors were identified retrospectively in the U.S. hospital by comparing the observer's notes with the original drug orders made in the patient's chart by the physician. In the U.K. hospital, identification of errors took place concurrently; as doses were administered, they were compared with the orders on the medication chart. In the U.S. and U.K. hospitals, 919 and 2756 opportunities for error were observed, respectively. The medication error rate in the U.S. hospital was 6.9% (95% confidence interval [CI], 5.2% to 8.5%), significantly higher than the 3.0% rate observed in the U.K. hospital (95% CI, 2.4% to 3.7%) (95% CI for the difference, 2.1% to 5.7%). Omitted doses and incorrect doses were the most common types of errors in the U.K. hospital; incorrect doses and unordered doses were the most common types in the U.S. hospital. An American hospital with a unit dose distribution system had a significantly higher medication error rate than a British hospital with a ward-based supply system.

Hospitals, University↗
PubMed1995

Medication errors during hospital drug rounds.

Objective--To determine the nature and rate of drug administration errors in one National Health Service hospital. Design--Covert observational survey be tween January and April 1993 of drug rounds with intervention to stop drug administration errors reaching the patient. Setting--Two medical, two surgical, and two medicine for the elderly wards in a former district general hospital, now a NHS trust hospital. Subjects--37 Nurses performing routine single nurse drug rounds. Main measures--Drug administration errors recorded by trained observers. Results--Seventy four drug rounds were observed in which 115 errors occurred during 3312 drug administrations. The overall error rate was 3.5% (95% confidence interval 2.9% to 4.1%). Errors owing to omissions, because the drug had not been supplied or located or the prescription had not been seen, accounted for most (68%, 78) of the errors. Wrong doses accounted for 15% (17) errors, four of which were greater than the prescribed dose. The dose was given within two hours of the time indicated by the prescriber in 98.2% of cases. Conclusion--The observed rate of drug administration errors is too high. It might be reduced by a multidisciplinary review of practices in prescribing, supply, and administration of drugs.

Aged↗
PubMed1994

Survey of clinical pharmacy services in United Kingdom National Health Service hospitals.

The extent to which clinical pharmacy services are provided in National Health Service (NHS) hospitals in the United Kingdom was studied by means of a questionnaire. Questionnaires inquiring whether and to what extent certain clinical pharmacy services were provided were mailed to all NHS hospital pharmacies in 1992. The questionnaires also requested information about the hospital and the number and qualifications of pharmacists employed. The results were compared with those of a survey of pharmaceutical services in the United States. Of 508 questionnaires mailed, 416 usable responses were returned. Services commonly provided were inpatient drug therapy monitoring (96%), clinical trials support (92%), formulary management (89%), participation in drug and therapeutic committees (97%), and an on-site drug information center (60%). Services infrequently provided were therapeutic drug monitoring (21%), medication history-taking (16%), and a 24-hour on-site pharmacist (10%). Several services were associated with pharmacies that employed many pharmacists, pharmacists with advanced education, or specialist clinical pharmacists and pharmacies located in medical school teaching hospitals. U.K. hospital pharmacies provided fewer patient-oriented services and more drug information, therapy monitoring, and pharmacist education services than U.S. hospital pharmacies. Provision of clinical pharmacy services in the United Kingdom was associated with employment of many pharmacists, pharmacy clinical specialists, and pharmacists with advanced education.

Clinical Trials as Topic↗
PubMed1994

Educational intervention in pharmacy students' attitudes to HIV/AIDS and drug misuse.

By providing injecting equipment to drug misusers, community pharmacists in the UK may become involved in preventing the spread of HIV via the intravenous route. Over 60% of pharmacy graduates from the School of Pharmacy enter community pharmacy and, as part of their undergraduate course, attend a series of lectures and seminars on HIV/AIDS and drug misuse. The aim of this research was to: (1) investigate students' attitudes to these subjects; (2) assess the students' knowledge of HIV/AIDS; (3) evaluate any change in level of knowledge or of attitude after attending the course; and (4) investigate students' attitudes towards the teaching of these subjects. A questionnaire was administered to students before and after their undergraduate course. The level of knowledge increased significantly after attending the course. Students were asked their opinion on the teaching of HIV/AIDS and drug misuse at the School of Pharmacy. After the course, significantly more responded 'good' or 'very good' with regard to teaching on social issues in drug misuse, rehabilitation and treatment of drug misusers, and health education on HIV/AIDS. There was no significant change in attitude, after the course. Attitude to HIV/AIDS and drug misuse was found to be unassociated with previous experience of working in pharmacies supplying injecting equipment and prescribed methadone. Both attitude and pre-course assessed knowledge were significantly associated with race and religion. These results indicate that attending the course had the effect of increasing knowledge of HIV/AIDS and increasing confidence in counselling clients. The perception of the teaching was also seen to be more positive.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Comparison of the cost-effectiveness of administering heparin subcutaneously or intravenously for the treatment of deep vein thrombosis.

The cost-effectiveness of subcutaneous heparin (20,000 iu, twice daily, prefilled syringes), a continuous intravenous infusion of 24,000 iu heparin in 24 h, and the intravenous infusion of 48,000 iu heparin as two consecutive 12-h infusions of 24,000 iu, were compared. The costs were calculated by timing and observing staff in three hospitals, and by noting the costs of what they used. Cannulation of a vein by a doctor took a mean of 4 min 16 s and cost 2.61 pounds. To prepare and administer the 24,000 iu of heparin in a 24-h infusion took a mean of 22 min 42 s/day and cost 9.52 pounds. If a 48,000 iu in 24-h infusion was used it took a mean of 36 min 3 s/day and cost 16.81 pounds. The use of heparin syringes, 20,000 iu subcutaneously twice daily, took 2 min 53 s/day and cost 4.80 pounds. A generic cost formula was calculated to allow for variation in staff or drug costs. The subcutaneous and intravenous routes were assumed to be equally effective on the basis of the medical literature. This study shows that subcutaneous heparin therapy is significantly more cost-effective than intravenous heparin therapy. The reduction in cost and liberation of nursing time mean that the subcutaneous route should be preferred.

Cost-Benefit Analysis↗
PubMed1991

Low-flow anaesthesia. Practice, cost implications and acceptability.

An 8-week survey was conducted to determine whether the introduction of low-flow anaesthesia (a fresh gas flow of 4 litres/minute or less) into routine use would be acceptable to members of a representative anaesthetic department and if the consequent reduction in use of volatile anaesthetics would result in financial savings. The hourly consumption of the volatile agents was measured during anaesthesia conducted using either conventional or low fresh gas flows. Anaesthetists' acceptance of low-flow anaesthesia was assessed using a questionnaire. Data were gathered on 286 patients undergoing inhalational anaesthesia for routine operative procedures. A 54.7% reduction in the consumption of isoflurane and a 55.9% reduction in that of enflurane was found. Of the 28 anaesthetists at the hospital, 21 would use low-flow anaesthesia routinely. The routine use of low-flow anaesthesia would therefore be acceptable and could result in annual savings of 26,870 pounds at Northwick Park Hospital.

Anesthesia, Inhalation↗
PubMed1983

Effect of aspirin treatment on the hypotensive effect of clonidine in rats.

Rats were pretreated with aspirin (5 mg/kg i.p. 5 days) or saline, anaesthetized with pentobarbitone, and blood pressure recorded from the carotid artery. Clonidine (30 micrograms/kg) was injected intravenously via a cannula inserted into the femoral vein. Aspirin pretreatment significantly reduced the hypotensive effect of clonidine. Spleen, heart brain, kidneys and lung were removed from the animals 60 min after clonidine administration. Prostaglandin biosynthesis from endogenous substrate was determined by homogenizing tissues (1:4 w/v) in either Tris buffer (pH 7.4) or in 1 M formic acid: ethanol (1:V/v). Prostaglandins were extracted into ethyl acetate and bioassayed on the rat stomach strip. Clonidine administration significantly increased the prostaglandin formation in heart, brain and kidney. Animals pretreated with aspirin showed a reduction in the clonidine-induced increase in prostaglandin synthesis in heart, brain and spleen. The results suggest that the hypotensive effect of clonidine in anaesthetized rats may in part be secondary to stimulation of central prostaglandin biosynthesis.

Animals↗
PubMed1982

Comparison of the actions of centrally and peripherally administered clonidine and guanfacine in the rabbit: investigation of the differences.

1 Guanfacine was administered intravenously to rabbits and produced a dose-dependent lowering of blood pressure. 2 Clonidine and guanfacine, administered to rabbits intravenously (30 micrograms/kg and 300 micrograms/kg respectively) and intracisternally (3 micrograms/kg and 12 micrograms/kg respectively) caused a similar degree of hypotension, apparently of central origin. 3 Saliva flow in vivo was estimated. Clonidine (30 micrograms/kg, i.v.) caused a significant decrease in salivation (P less than 0.05) for the first 50 min after injection. Guanfacine caused a significant fall (P less than 0.05) only at 50 and 180 min after injection. 4 Apparent partition coefficients for an octanol/buffer system at pH 7.4 for clonidine and guanfacine were 5.4 and 21.2 respectively. 5 Measurement of guanfacine levels concurrently in both plasma and brain showed that guanfacine had higher brain than plasma levels and that the brain levels were fairly constant over the 3 h measured. Brain:plasma ratios were 2.1:1, 5.3:1 and 13.6:1 after 15, 90 and 180 min respectively. 6 These results suggest that the long duration of action of guanfacine is due to its persistence at its central site of action.

Animals↗
PubMed1982

A homozygote for pericentric inversion of chromosome 4.

A child with developmental and language delay was found to be homozygous for a pericentric inversion of chromosome 4 (inv(4) (p15 X 2q12)). Her normal mother and aunt are inversion heterozygotes. It is suggested that the phenotypic abnormalities may have resulted from damage at chromosomal breakpoints or from a position effect which is expressed only in homozygous form.

Abnormalities, Multiple↗
PubMed1982

Studies on clonidine and guanfacine withdrawal after short term treatment in the rat.

Abrupt cessation of chronic, but not acute, clonidine treatment has been shown to produce a withdrawal syndrome in man. Guanfacine, its analogue, causes little or no such effect. Some animal models of clonidine and guanfacine withdrawal have shown significant changes in blood pressure and heart rate after both acute and chronic administration of the drugs. We administered both drugs to rats using a dosage schedule which we had shown to produce hypertension and tachycardia when clonidine, but not guanfacine, was stopped after 3 weeks treatment. After 3 days treatment both drugs were withdrawn. There was no significant alteration of blood pressure in either group. A small (3%) tachycardia in the clonidine treated group was the only significant variation from control. This suggests that in this animal model, as in man, clonidine withdrawal phenomena can be seen only after stopping chronic, not acute treatment. Guanfacine withdrawal phenomena were not observed.

Animals↗