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Biomedical subjects

J Lomas

Publications and source records attributed to J Lomas.

At least 55 records · Page 3Linked to original sources
PubMed1995

Lack of preservation of higher brain function during hypoglycaemia in patients with intensively-treated IDDM.

Severe hypoglycaemia with cognitive dysfunction is 3 times more common in intensively, rather than conventionally, treated insulin-dependent diabetes mellitus (IDDM). To investigate the effect of diabetes control on higher brain function during acute hypoglycaemia, we studied one of the earliest detectable changes in cognitive function, i.e. the four-choice reaction time, and symptomatic and hormonal responses during euglycaemic and hypoglycaemic clamping in human subjects. There were no changes in symptoms or counterregulatory hormones and four-choice reaction time was stable during 220 min of euglycaemic insulin clamping in five men with IDDM, with a coefficient of variation of less than 2.2% (1% for accuracy) for the cognitive function test. During stepped hypoglycaemic clamping however, hormonal responses and subjective awareness of hypoglycaemia occurred in all groups but started at much lower blood glucose concentrations in eight intensively-treated diabetic subjects (Group 1) than in ten conventionally-treated (Group 2) or in eight non-diabetic subjects (Group 3). For example, for adrenaline, plasma glucose thresholds were 2.7 +/- 0.2 vs 3.4 +/- 0.2 and 3.2 +/- 0.1 mmol/l, respectively, p < 0.05, Group 1 vs Groups 2 or 3 and for subjective awareness of hypoglycaemia 2.3 +/- 0.2 vs 3.0 +/- 0.1 and 3.2 +/- 0.1 mmol/l, p < or = 0.003), as in previous studies. In contrast, deterioration in reaction time occurred at 3.2 +/- 0.3, 3.2 +/- 0.2 and 3.0 +/- 0.2 mmol/l, respectively (p = NS), thus occurring at higher glucose levels than subjective awareness in the intensively-treated subjects only. The altered hierarchy of responses to hypoglycaemia in well-controlled intensively-treated diabetes explains the increased risk of severe hypoglycaemia without warning seen in such patients.

Adult↗
PubMed1995

Review of the multi-hospital arrangements literature: benefits, disadvantages and lessons for implementation.

The multi-hospital arrangements literature is reviewed for Canada and the United States. There is a notable lack of evaluations on the outcomes of these arrangements, especially in the Canadian context. For evaluations that do make it to the literature, generalizability of conclusions is difficult because most is based on case studies and relates to "for-profit" U.S. hospitals. We are forced to conclude, however, that there is little definitive evidence that quality of care is improved by multi-hospital arrangements or to support or refute the claims of better human resources deployment. The most striking organizational benefit appears to be that institutions considering merger or other arrangements are forced into explicit considerations of their mission and goals. Many of the potential disadvantages of multi-hospital arrangements may be ameliorated with appropriate strategic planning and attention to detail during negotiation of the arrangement. As new multi-institutional arrangements may cause harm as well as reap benefits, careful evaluation is needed.

Canada↗
PubMed1994

Restoration of hypoglycaemia awareness in patients with long-duration insulin-dependent diabetes.

Hypoglycaemia without warning is a dangerous complication of insulin-dependent diabetes mellitus and it limits the use of intensified insulin therapy to reduce chronic diabetic complications. To investigate the possibility of restoring awareness; symptomatic, cognitive, and hormonal responses to controlled hypoglycaemia were studied in insulin-dependent diabetic patients with long disease duration (6 with good glycaemic control and 6 with poor control) before and after hypoglycaemia avoidance. At the start of the study, all had loss of hypoglycaemia awareness. Responses to the initial challenge were small (pooled area under curve [AUC] adrenaline 5.75 [SE 0.07] nmol/L per 260 min, pooled AUC symptom score 80 [1.3]) and only started when plasma glucose was significantly lower than the 2.8 (0.1) mmol/L at which cognitive function deteriorated. After 4.1 (1.1) months' scrupulous hypoglycaemia avoidance, hormone and symptom responses to the challenge were increased (AUC adrenaline 15.9 [0.1] nmol/L per 260 min, p = 0.01; AUC symptom score 275 [7], p < 0.001), starting at plasma glucose concentrations significantly higher than that causing cognitive dysfunction. Glycosylated haemoglobin did not deteriorate significantly. We conclude that the normal hierarchy of subjective awareness before cognitive dysfunction during hypoglycaemia can be restored by avoiding hypoglycaemia. This is independent of disease duration or initial metabolic control.

Adult↗
PubMed1994

Protection by lactate of cerebral function during hypoglycaemia.

Severe hypoglycaemia with brain dysfunction limits intensified therapy in patients with insulin-dependent diabetes mellitus, despite evidence that such therapy reduces the risk of chronic complications of the disease. We have investigated the effect of infusing lactate (a potential non-glucose fuel for brain metabolism) on protective, symptomatic neurohumoral responses and on brain function during hypoglycaemia in seven healthy men. Elevation of lactate (within a physiological range) substantially diminished catecholamines, growth hormone, cortisol, and symptomatic responses to hypoglycaemia and lowered the glucose level at which these responses began. Glucagon responses were unaffected. Lactate was also associated with a significant lowering of the glucose level at which brain function deteriorated, suggesting that brain function was protected during the hypoglycaemia. The defect in counter-regulation is similar to that seen in hypoglycaemia-prone diabetic patients. Initiation of the protective responses to hypoglycaemia (except glucagon) can be delayed by supporting metabolism with an alternative metabolic fuel. Cerebral cortical dysfunction of severe hypoglycaemia is also delayed. Our demonstration that higher brain function can be protected during hypoglycaemia may have therapeutic potential.

Adult↗
PubMed1994

Evaluating the message: the relationship between compliance rate and the subject of a practice guideline.

To explore the relationship between providers' compliance and some key aspects of the clinical messages in practice guidelines, studies published in the English language medical literature between 1980 and 1991 were retrieved through MEDLINE and through relevant review articles in the field. All published studies providing compliance rates with practice guidelines and endorsed by official organizations were eligible for the study. The clinical content and the reported compliance rate were gathered for each recommendation in the 23 studies selected. The medical and surgical procedures addressed by 143 recommendations were identified according to specialty area, type of procedure (diagnostic, surgical, etc.) and were independently classified by the authors as being high or low on characteristics thought to influence diffusion:complexity, trialability and observability. The mean compliance rate with the 143 clinical recommendations was 54.5% (95% CI: 50.2%-58.9%), with those in the specialty areas of cardiology and oncology showing the highest compliance (mean 63.6% and 62.2%, respectively). Recommendations concerning procedures with high complexity had lower compliance rates than those low on complexity (41.9% vs. 55.9%; P = 0.05), and those judged to be high on trialability had higher compliance rates than those low on trialability (55.6% vs 36.8%; P = 0.03). Overall, all the characteristics of the clinical recommendations considered in the practice guidelines could account for no more than 47% of the observed variability in compliance rates. The target area of practice and the complexity and trialability of the recommended procedure appear to be useful, if partial, predictors of the level of compliance with a practice guideline.

Cardiology↗
PubMed1993

Diffusion, dissemination, and implementation: who should do what?

The concepts of diffusion, dissemination, and implementation are distinguished as progressively more active steps in the process of flowing valid and reliable research information into clinical practice. Using a staged model of behavior change, diffusion is seen as a precursor for dissemination activities, which in turn "predispose" physicians to consider change in their practices. Local implementation activities capitalize on this by "enabling" and subsequently "reinforcing" the desired behavior change. Different skills are needed for each activity. Biomedical journals, with some improvements, are identified as diffusion agents. Collaboration between academics and medical organizations is best suited to the dissemination stage. Local agents, empowered by resources, are best equipped for implementation activities.

Communication Barriers↗
PubMed1993

Double blind clinical and laboratory study of hypoglycaemia with human and porcine insulin in diabetic patients reporting hypoglycaemia unawareness after transferring to human insulin.

OBJECTIVES: To compare awareness of hypoglycaemia and physiological responses to hypoglycaemia with human and porcine insulin in diabetic patients who reported loss of hypoglycaemia awareness after transferring to human insulin. DESIGN: Double blind randomised crossover study of clinical experience and physiological responses during slow fall hypoglycaemic clamping with porcine and human insulin. SETTING: Clinical investigation unit of teaching hospital recruiting from diabetes clinics of five teaching hospitals and one district general hospital. SUBJECTS: 17 patients with insulin dependent diabetes mellitus of more than five years' duration who had reported altered hypoglycaemia awareness within three months of transferring to human insulin. MAIN OUTCOME MEASURES: Glycaemic control and frequency of hypoglycaemic episodes during two months' treatment with each insulin. Glucose thresholds for physiological and symptomatic responses during clamping. RESULTS: Glycaemic control did not change with either insulin. 136 hypoglycaemic episodes (eight severe) were reported with human insulin and 149 (nine severe) with porcine insulin (95% confidence interval -4 to 2.5, p = 0.63). 20 episodes of biochemical hypoglycaemia occurred with human insulin versus 18 with porcine insulin (-0.8 to 1, p = 0.78). During controlled hypoglycaemia the mean adrenaline response was 138 nmol/l/240 min for both insulins; neurohormonal responses were triggered at 3.0 (SE 0.2) versus 3.1 (0.2) mmol/l of glucose for adrenaline and 2.5 (0.1) versus 2.5 (0.1) mmol/l for subjective awareness. CONCLUSIONS: These data suggest that human insulin per se does not affect the presentation of hypoglycaemia or the neurohumoral, symptomatic, and cognitive function responses to hypoglycaemia in insulin dependent diabetic patients with a history of hypoglycaemia unawareness.

Adult↗
PubMed1993

Making clinical policy explicit. Legislative policy making and lessons for developing practice guidelines.

Promulgation of practice guidelines in medicine has increased interest in the structure of clinical policy making. It is argued that with a generic definition of policy as "the rules governing the behavior of individuals or institutions," clinical policy making is analogous to legislative policy making. Practice guidelines emphasize the advantages of making clinical policy more explicit. The structure of legislative policy making has evolved over many years to meet the challenge of making both the policies and the process of policy making explicit. Processes to promulgate clinical policies may be able to exploit this experience to improve clinical policy making and thereby retain control of the process within medicine. Generic steps are outlined for making decisions with incomplete information; synthesis of facts, vested interests, and values; involvement of stakeholders; and implementation of policy. An illustration of the use of the generic steps to make and implement a clinical policy for cesarean birth follows, with evaluations of its impact on the behavior and satisfaction of clinical stakeholders.

Canada↗
PubMed1993

Retailing research: increasing the role of evidence in clinical services for childbirth.

A current review of the structures and assumptions of research transfer for clinical care reveals some progress from "passive diffusion" to "active dissemination" models, but little or no progress has been made toward targeting local influences on practitioner behavior for "coordinated implementation" of clinically relevant research into childbirth (or other) medical practices. The implementation of scientifically valid research syntheses, such as Effective Care in Pregnancy and Childbirth (ECPC), is therefore constrained by a poorly developed marketplace for retailing research information to practitioners. A survey in Canada of the four most significant potential retailing groups demonstrated that whereas clinical and community groups were adopting the necessary knowledge and attitudes, public policy makers and administrators trailed well behind them. To increase the probability of thorough retailing of ECPC, a three-phase plan could be instituted that would identify product champions within potential retailing groups, develop implementation activities for each retailing group, and convene annual conferences.

Canada↗
PubMed1991

Opinion leaders vs audit and feedback to implement practice guidelines. Delivery after previous cesarean section.

A randomized controlled trial with 76 physicians in 16 community hospitals evaluated audit and feedback and local opinion leader education as methods of encouraging compliance with a guideline for the management of women with a previous cesarean section. The guideline recommended clinical actions to increase trial of labor and vaginal birth rates. Charts for all 3552 cases in the study groups were audited. After 24 months the trial of labor and vaginal birth rates in the audit and feedback group were no different from those in the control group, but rates were 46% and 85% higher, respectively, among physicians educated by an opinion leader. Duration of hospital stay was lower in the opinion leader education group than in the other two groups. The overall cesarean section rate was reduced only in the opinion leader education group. There were no adverse clinical outcomes attributable to the interventions. The use of opinion leaders improved the quality of care.

Cesarean Section↗
PubMed1991

Obstetrical attitudes and practices before and after the Canadian Consensus Conference Statement on Cesarean Birth.

This paper describes one aspect of a research program aimed at reducing the incidence of cesarean section in Ontario for women with a previous cesarean section or a breech presentation. Using data from multiple sources--surveys of obstetricians, and hospital administrators, and hospital record statistics, the authors attempt to assess the response of obstetricians to pressure to change their practice. This pressure comes principally from the Canadian Consensus Conference Statement on Cesarean Birth, released in June 1986 and subsequently endorsed by a number of professional organizations. The Statement provides clear guidelines for the management of labour in women with previous cesarean section or a breech presentation. The findings present a number of interpretive challenges. Based on their response to hypothetical cases obstetricians are favourably disposed to considering a trial of labour for women with previous cesarean section and breech presentation. However, both their reported practices, as well as hospital statistics indicate the continued high prevalence of cesarean section, though there is a small decline in cesareans for previous cesarean section. There was no evidence that hospitals lacked appropriate facilities for a trial of labour or had unduly restricted formal policies. Furthermore, although awareness of and agreement with the Consensus Statement recommendations was high, when questioned on the actual details of the recommendations, obstetrician's recall was surprisingly low. Respondents tended to err in the direction of choosing more conservative measures than those recommended by the Statement.(ABSTRACT TRUNCATED AT 250 WORDS)

Attitude of Health Personnel↗
PubMed1991

Words without action? The production, dissemination, and impact of consensus recommendations.

When existing evaluations find little or no evidence of consensus recommendations leading to action, one can justifiably ask why so much of this review was dedicated to analyzing alternative ways of producing such "words without action." There are, however, at least two reasons why consensus recommendations should be produced with care and attention to validity. First, recommendations do sometimes have an impact on behavior as a consequence of mere dissemination activity--the Dutch program, for instance, was more successful than most. This success may occur when the target audience is already particularly receptive to change and the message is timely and delivered by a credible source in a clinically relevant way. Thus, although "such a conjunction of favorable conditions is probably the exception rather than the rule for consensus topics" (46, 240) it does happen. Second, the output from consensus processes is increasingly a potential input to other processes. Consensus recommendations can be used as the criteria for evaluation and appraisal aimed at changing practice behavior, making administrative decisions on resource allocation, or defining research protocols. For instance, quality assurance activities, such as peer assessment, practitioner certification, or utilization review, are actively seeking criteria with which to make judgments and elicit changes in practice to improve the quality of care. Funding agencies are looking for information to help make reimbursement, capital expenditure, or fee-for-service decisions on cessation of insurance for particular procedures or approaches. These uses of the consensus criteria are potentially major and controversial. Therefore, even if dissemination rarely leads to action, consensus processes should still be done carefully and with valid techniques. The use of their recommendations embedded within other activities may well lead to (forced) changes in behavior. On ethical grounds alone, we should be as sure as possible that the behavior changes being implied and encouraged are indeed advisable. For these reasons, the review describes the decision points in the production process for consensus recommendations as a start on the development of a set of recognized standards. The review offers a critical appraisal of the various methodological choices available at each decision point. The seven decision points are selecting a topic, picking the consensus group, providing background preparation, identifying information inputs, choosing a group judgment process, defining the criteria for recommendations, and choosing a report preparation procedure and format. At least two important points emerged from this review. First, the research is often not well enough developed to give clear indications for many of the choices on what is the "best" alternative.(ABSTRACT TRUNCATED AT 400 WORDS)

Canada↗
PubMed1990

Do health service organizations and community health centres have higher disease prevention and health promotion levels than fee-for-service practices?

We interviewed health care providers representing 23 fee-for-service (FFS) practices, 19 health service organizations (HSOs) and 11 community health centres (CHCs) in Ontario to compare self-reported approaches to disease prevention and health promotion. Few significant differences were found across practice types in the presence of recall systems for screening or in knowledge of, compliance with or estimated coverage for selected preventive maneuvers recommended by the Canadian Task Force on the Periodic Health Examination. CHCs reported a significantly greater variety of formal health promotion programs and a greater tendency to use nonphysician health care personnel to carry out both prevention and health promotion activities. The results must be interpreted with caution because of the use of self-reported data, the low response rate for FFS practices and the use of a restrictive definition of disease prevention tied to evidence from the reports of the task force. Thus, the results cast some doubt on the common assumption that increasing the population served by alternative modes of delivery such as HSOs and CHCs necessarily increases the level of disease prevention and health promotion activity.

Aged↗
PubMed1990

Flat on your back or back to your flat? Sources of increased hospital services utilization among the elderly in British Columbia.

Between 1969 and 1985, the British Columbia hospital system allocated an increasing proportion of the province's total hospital days to elderly patients who stayed for 60 days or more. By 1985/86, long stay patients accounted for almost 50% of all days. In this paper, we explore the diagnoses which contributed the greatest number of patient days of increase among the elderly as a first step in evaluating the appropriateness of this response to the pressures of an aging population. Patient days of increase were not distributed smoothly across a large number of diagnoses, but could be explained by a small number of chronic conditions. Most important were conditions related to senility and senile dementia, the chronic sequelae of heart disease and stroke, and persons awaiting admission to adequate facilities elsewhere. Eighty percent of the increases were seen in extended care and rehabilitation beds and 20% in acute care beds. Seventy-seven percent of the increased patient days were attributable to females and only 23% to males. Since the major sources of increase in patient days were not related to conditions for which new, effective hospital care modalities are available, they call into question the appropriateness of the system's response to the health care needs of the elderly population.

Aged↗
PubMed1990

Quality assurance and effectiveness in health care: an overview.

Increasing interest in quality assurance and effectiveness in health care has been generated by three major things: about 20% of care is consistently demonstrated to be inappropriate, variations in practice cannot be explained by patient or facility factors, and decreased utilization as a result of changing economic and regulatory incentives seems to lead to both inappropriate care and appropriate care reduction. This interest has led to at least three changes in the approach to quality assurance. First, a move from measuring practitioner competence to measuring population health outcomes. Second, less use of implicit judgements and greater attention to explicit standards (e.g. practice guidelines) and explicit processes to establish the standards. Third, less organizational isolation of quality assurance and greater efforts to integrate it into everyday activities and across levels of health care delivery.

Canada↗
PubMed1990

Finding audiences, changing beliefs: the structure of research use in Canadian health policy.

The impact of research information depends on its ability to change beliefs or policy assumptions within the relevant audiences. As a hybrid of American and British systems, Canada's chosen decision-making structure for policy-making and its legislative framework for health insurance make these audiences unclear and not readily accessible. This factor and historical characteristics of the research community which made them only partially responsive to the values of decisionmakers provide an explanation for the limited past use of research information in Canadian health policy. More recently, improved responsiveness by researchers and an emerging definition of the audiences by legislative policymakers are bringing about a gradual increase in the potential impact of research at the levels of administrative and clinical policy. Because of continuing decision-making constraints on legislative policy, however, impact at this level is predicted to remain diffuse, with only cautious acceptance of the changes in beliefs implied by research.

Attitude to Health↗