Developing evidence-based clinicians

Evidence-based care has heralded an advancement for health with extensive rhetoric and incentives encouraging clinicians to become active participants in practice change. This paper explores two mechanisms-research utilization and systematic reviews--as processes to develop empowerment in clinicians, and develop an ethos of basing practice on research. The intent of these approaches is to create an environment that enables clinicians to seek solutions to practice problems, inform practice decisions and develop practice policy using evidence from research. The goal is to develop evidence-based clinicians who remain active and interested in their practice and who are committed to promoting the application of research to practice. The strengths and weaknesses of these methods are explored within two case studies where they are applied to the management of hypothermia and the efficacy of postoperative observations. Key points of application for each of the methods are outlined in the conclusions.

A role for fractalkine and its receptor (CX3CR1) in cardiac allograft rejection

The hallmark of acute allograft rejection is infiltration of the inflamed graft by circulating leukocytes. We studied the role of fractalkine (FKN) and its receptor, CX(3)CR1, in allograft rejection. FKN expression was negligible in nonrejecting cardiac isografts but was significantly enhanced in rejecting allografts. At early time points, FKN expression was particularly prominent on vascular tissues and endothelium. As rejection progressed, FKN expression was further increased, with prominent anti-FKN staining seen around vessels and on cardiac myocytes. To determine the capacity of FKN on endothelial cells to promote leukocyte adhesion, we performed adhesion assays with PBMC and monolayers of TNF-alpha-activated murine endothelial cells under low-shear conditions. Treatment with either anti-FKN or anti-CX(3)CR1-blocking Ab significantly inhibited PBMC binding, indicating that a large proportion of leukocyte binding to murine endothelium occurs via the FKN and CX(3)CR1 adhesion receptors. To determine the functional significance of FKN in rejection, we treated cardiac allograft recipients with daily injections of anti-CX(3)CR1 Ab. Treatment with the anti-CX(3)CR1 Ab significantly prolonged allograft survival from 7 +/- 1 to 49 +/- 30 days (p < 0.0008). These studies identify a critical role for FKN in the pathogenesis of acute rejection and suggest that FKN may be a useful therapeutic target in rejection.

Development of an instrument to assess readiness to recover in anorexia nervosa

OBJECTIVE

The degree to which patients with anorexia nervosa demonstrate readiness to recover from their illness has received scant theoretical or empirical attention. Investigating the prevalence and degree of amotivation for recovery in anorexia nervosa, its role in outcome, and the effectiveness of interventions designed to enhance readiness to recover necessitates the existence of a reliable and valid measure of motivational issues relevant to the disorder. The present study aimed to develop and evaluate an instrument for assessing readiness to recover in anorexia nervosa, namely, the Anorexia Nervosa Stages of Change Questionnaire (ANSOCQ), a 23-item self-report questionnaire based on Prochaska and DiClemente's stages of change model.

METHOD

Seventy-one inpatients with anorexia nervosa participated in the study. On several occasions during their admission, participants completed the ANSOCQ as well as questionnaires assessing readiness to recover, anorexic symptomatology, general distress, and social desirability.

RESULTS

The ANSOCQ demonstrated good internal consistency (.90) and 1-week test-retest reliability (.89). Various aspects of validity were also supported, such as significant relationships with other instruments assessing readiness to recover and the prediction of weight gain during different periods of treatment.

DISCUSSION

The results suggest that the ANSOCQ is a psychometrically sound instrument that may prove useful in investigating the role of readiness to recover in anorexia nervosa.

Possible role for the FosB/JunD AP-1 transcription factor complex in glutamate-mediated excitotoxicity in cultured cerebellar granule cells

The potent excitatory and neurotoxic actions of glutamate are known to influence the expression of a variety of genes, including those encoding the AP-1 transcription factor, which comprises proteins belonging to the Fos and Jun families. However, the precise role of Fos- and Jun-like transcription factors in these events remains elusive. Here we demonstrate, using primary cultures of mouse brain cerebellar granule cells as an in vitro model system, a possible involvement of the FosB/JunD heterodimer in excitotoxicity. Granule cells were grown for either 2 or 7 days in vitro (DIV) before exposure to varying concentrations (1-3000 microM) of the excitotoxin glutamate. In 7-DIV cells, glutamate induced a concentration-dependent neuronal death, whereas, in 2-DIV cells, no glutamate-induced neuronal damage was seen. We were particularly interested in comparing the protein composition of the AP-1 transcription factor complex in cells exposed to excitotoxic and to nontoxic conditions. AP-1 DNA binding activity was demonstrated by gel shift analysis in nuclear extracts derived from 7-DIV cells following exposure to either a nontoxic (10 microM) or an excitotoxic (250 microM) dose of glutamate and was similarly observed in extracts of 2-DIV cells exposed to the same levels of glutamate. Gel supershift analysis using antibodies against the different Fos and Jun family members allowed differentiation between AP-1 DNA binding in nuclear extracts as a function of both 1) viability status and 2) the stage of development. Of major significance was the finding that FosB could be detected as a component of AP-1 in 7-DIV cells only under excitotoxic conditions, whereas c-Fos, Fra-2, and JunD proteins were detectable under both excitotoxic and nontoxic conditions in cells of this age. In 2-DIV cells (in which glutamate is nontoxic), AP-1 comprised combinations of only Fra-1, Fra-2, c-Jun, and JunD. Because Fos family members are unable to form homodimers, this finding raises the possibility that the FosB/JunD heterodimer may have special significance in the mechanism of excitotoxic neuronal death.

Development of a client-generated health outcome measure for community nursing

OBJECTIVE

To develop a client-generated outcome measure for use in community nursing.

METHOD

Participants for the study were identified from the case load of community health nurses, from a nursing home service and from residents of a retirement village. All participants had a diagnosis of venous leg ulcer (VLU) and/or type 2 diabetes. Preliminary development of the measure involved focus groups of community clients and health professionals, and pilot testing of an existing quality of life (QoL) measure, the Patient-Generated Index. The resulting Client-Generated Index was tested for reliability and validity.

RESULTS

The Pearson's correlation coefficient between administration of the CGI at T1 and T2 was 0.526 (n = 51; p = 0.0001). The CGI correlated significantly with four of eight dimensions of the SF-36, and with pain as a clinical marker for VLU r = 0.54 (p = 0.001). Overall, participants with VLU reported a lower QoL (mean CGI score 2.8) compared to those with diabetes (mean CGI score 4.1).

CONCLUSIONS

The CGI was developed to measure outcomes in community health settings. Some measures of its reliability and validity are demonstrated and further research is needed to validate the instrument using other client groups.

IMPLICATIONS

If routine assessment and evaluation is to contribute to measures of outcome, the instruments need to be concise and acceptable to health care providers. The CGI has all these properties.

Preliminary evaluation of an in vitro test for assessment of excitotoxicity by measurement of early gene (c-fos mRNA) levels

Using primary cultures of mouse cerebellar granule cells as an in vitro model system, it has been demonstrated that different profiles of temporal expression of the c-fos proto-oncogene are observed under non-excitotoxic and excitotoxic conditions. A ratio has been derived previously for the steady-state level of c-fos mRNA after 30 min and 240 min which suggests that a 240 min/30 min ratio of greater than 1 correlates with excitotoxicity, whereas a ratio of less than 1 correlates with a non-excitotoxic outcome. Moreover, a positive correlation is seen with abrogation of excitotoxicity in response to selective excitatory amino acid receptor antagonists. This test, proposed as a specific biomarker for excitotoxicity is undergoing prevalidation. Excitotoxicity is defined as neuronal cell death mediated by hyperactivation of glutamate receptor subtypes and therefore might be expected to be prevented by selective glutamate receptor antagonists. In preliminary evaluation studies, we have conducted work under the direction of the European Center for Validation of Alternate Methods (ECVAM) using compounds specified by ECVAM that have been subdivided into four groups based on known or presumed actions. These groups comprise: Group 1-endogenous/synthetic excitotoxins; Group 2-environmental, putative excitotoxins; Group 3-neurotoxic but non-excitotoxic compounds, and Group 4-non-toxic compounds. The results of this study support the proposal that the c-fos mRNA time-ratio test is a specific biomarker of excitotoxicity. Just as importantly, this test has the potential for application in screening newly-designed EAA receptor antagonists in the search for clinically relevant drugs to treat a variety of neuropathologies.

Back to basics in anaesthesia

This is the last in the Back to Basics series of articles--for now at least. I would like to thank all the authors for their pieces. I've learnt and relearnt from each of them. The completed set of articles will be available as one document in October, and will be launched at Congress--yet another reason to attend! Bye for now.

Primary care groups. Serving from the shadows

A study of appointments to the boards of 59 PCGs covered by the 13 health authorities in the West Midlands found concerns about fairness, openness and transparency. There was concern about the lack of a competency framework for GP members. Health authorities questioned whether the lay members of boards were representative of the local population. Some health authorities provided no induction training for boards.

The 50-millilitre syringe as an inexpensive training aid in the application of cricoid pressure

A recent study in our department demonstrated that depressing the plunger of a 50-mL syringe was reliably and linearly related to the force applied between 20 N and 50 N. Using a 50-mL syringe we constructed a simple device to help train anaesthetic assistants to apply cricoid pressure correctly. We then tested anaesthetists, operating department practitioners (non-physicians) and nurses in our hospital to see if they could correctly apply forces of 20 and 40 N. All subjects were then trained using this apparatus and once confident were retested immediately afterwards, and again 1 week and 1 month later. The results show a wide variation in the force applied with only 30% of subjects applying appropriate force at 20 N, and 40% at 40 N. Training leads to a significant improvement in performance (P < 0.005 at 20 N and P < 0.001 at 40 N) which is maintained for 1 week for both 20 N (P < 0.05) and 40 N (P < 0.05) but not for 1 month. Therefore training should be practised on a weekly basis. This is an inexpensive and simple device that we believe to be useful in helping anaesthetic assistants to apply effective cricoid pressure.

Supportive pharmacology

We continue to explore the basics of anaesthesia with another article from Rachelle Griffiths, this month looking at supportive pharmacology. If you think this looks too complicated for a Back to Basics piece, read it in small chunks--and be grateful that you are not my spelling checker, which has gone berserk! This Back to Basics series is drawing to a close soon. However, if you have suggestions for any more articles, or perhaps an article itself, then do contact me via Headquarters.

A role for leukotrienes in cyclosporine nephrotoxicity

BACKGROUND

Nephrotoxicity associated with cyclosporine A (CsA) administration is characterized by marked renal vasoconstriction, interstitial fibrosis, and arteriolar hypertrophy. While the molecular mechanisms of CsA toxicity are not well characterized, previous studies have demonstrated that altered arachidonic acid (AA) metabolism plays a role its pathogenesis. Using a rat renal transplant model, the purpose of this study was to examine the effects of CsA on the 5-lipoxygenase (5-LO) pathway of AA metabolism.

METHODS

The PVG (RT1c) strain of rats underwent kidney transplantation, and recipients of nonrejecting kidney transplants were treated with either 50 mg/kg/day CsA or vehicle (N = 24). To determine the physiologic significance of increased leukotriene (LT) production, the peptidoleukotriene receptor antagonist SKF 106203 was administered to CsA-treated animals for six days.

RESULTS

CsA caused a substantial reduction in glomerular filtration rate (GFR) in the transplanted rats compared with the vehicle-treated controls (1.5 +/- 0.6 vs. 4.1 +/- 0.8 mL/min/kg, P < 0.05). The reduction in renal function was associated with enhanced urinary excretion of the peptidoleukotriene metabolites LTE4 (1431 +/- 207 vs. 953 +/- 125 pg/24 h, P < 0.05) and N-acetyl-LTE4 (4411 +/- 848 vs. 463 +/- 70 pg/24 h, P < 0.001). LT receptor blockade had a significant protective effect on renal transplant function in CsA-treated animals (GFR, 4.8 +/- 1.1 vs. 1.7 +/- 0.9 mL/min/kg, P < 0.05), such that CsA-treated animals that received SKF106203 maintained GFR at levels similar to controls that never received CsA (4.1 +/- 0.8 mL/min/kg). Peptidoleukotriene receptor blockade also prevented the histomorphological abnormalities caused by CsA, including tubular vacuolization.

CONCLUSIONS

These studies identify a critical role for LTs in the pathophysiology of CsA nephrotoxicity and suggest that LT antagonists may be useful in preventing CsA-associated kidney toxicity.

Altered intragraft immune responses and improved renal function in MHC class II-deficient mouse kidney allografts

BACKGROUND

During renal allograft rejection, expression of MHC class II antigens is up-regulated on the parenchymal cells of the kidney. This up-regulation of MHC class II proteins may stimulate the intragraft alloimmune response by promoting their recognition by recipient CD4+ T cells. In previous studies, absence of donor MHC class II antigens did not affect skin graft survival, but resulted in prolonged survival of cardiac allografts.

METHODS

To further explore the role of MHC class II antigens in kidney graft rejection, we performed vascularized kidney transplants using donor kidneys from A(beta)b-deficient mice that lack MHC class II expression.

RESULTS

At 4 weeks after transplant, GFR was substantially depressed in control allografts (2.18+/-0.46 ml/min/kg) compared to nonrejecting isografts (7.98+/-1.62 ml/min/kg; P<0.01), but significantly higher in class II- allografts (4.38+/-0.60 ml/min/kg; P<0.05). Despite the improvement in renal function, class II- allograft demonstrated histologic features of acute rejection, not unlike control allografts. However, morphometric analysis at 1 week after transplantation demonstrated significantly fewer CD4+ T cells infiltrating class II- allografts (12.8+/-1.2 cells/mm2) compared to controls (25.5+/-2.6 cells/mm2; P=0.0007). Finally, the intragraft profile of cytokines was altered in class II- allografts, with significantly reduced expression of Th2 cytokine mRNA compared to controls.

CONCLUSIONS

These results support a role of MHC class II antigens in the kidney regulating immune cells within the graft. Further, effector pathways triggered by class II antigens promote renal injury during rejection.

Anaesthetic drugs

A mere glance at a BNF will demonstrate the huge variety of drugs which are now available to us. In this piece, Rachelle Griffiths takes us step by step through the basics of anaesthetic drugs. I am very aware of the enormity of this topic, and would recommend that you take the time to consider carefully the information provided in this piece. There will be further articles on drugs and their effects in this series.

Evaluation of the use of accelerated infusions for the determination of pharmacokinetic linearity

Accelerated infusions are potentially useful in the investigation of pharmacokinetic linearity. However, little information exists to validate this technique or to demonstrate its limitations. This investigation was performed to determine whether accelerated infusion regimens reliably estimate the range of pharmacokinetic linearity for molecules of varying pharmacokinetic properties, to evaluate the ability of accelerated infusions to identify pharmacokinetic nonlinearity, and to validate the accelerated infusion technique using compounds with known pharmacokinetic parameters. Simulations incorporating accelerated infusion as the input function resulted in the anticipated concentration-time profiles that contained an initial lag phase before reaching a linear slope. This lag phase increased with increasing distributional volume and in some instances was sufficiently great to obscure or prevent the linear portion of the profile. These simulations also revealed that clearance estimated from the apparently linear portion of the concentration-time profile can be erroneous under some conditions, as for large-volume compounds. Simulations of structured nonlinearity produced the predicted profiles for compounds with low to moderate volumes of distribution while demonstrating that modeling of data derived from compounds with large volumes of distribution may be inaccurate. Finally, experiments using accelerated infusions with various test compounds further demonstrated the usefulness of this technique while presenting limits imposed on the interpretation of the data. The results of this investigation indicate that the accelerated infusion may be used to determine pharmacokinetic linearity for compounds within certain pharmacokinetic boundaries, but that appropriate caution should be exercised in the extent of interpretation that should be extracted from such studies.

Perceived expressed emotion in the siblings and parents of hospitalized patients with anorexia nervosa

OBJECTIVE

The present study investigated the relationship between the level of perceived Expressed Emotion (EE) of the siblings and parents of patients hospitalized with anorexia nervosa and its effect on weight gain and psychological functioning.

METHOD

The Level of Expressed Emotion (LEE) Scale was administered on admission to 19 patients with anorexia nervosa who completed the LEE three times so as to identify their perceptions of their relationship with their closest age sibling, mother, and father. They were also required to complete the Eating Disorder Inventory 2 (EDI-2). Patients' closest age sibling completed the Family Attitude Scale (FAS). The patients' body mass index (BMI) was calculated 6 weeks later, and the EDI-2 readministered.

RESULTS

Perceived EE was not predictive of BMI change after 6 weeks of hospitalization. A composite perceived family EE score was a significant predictor of change on the Interpersonal Distrust, Maturity Fears, and Perfectionism subscales of the EDI-2.

DISCUSSION

These findings suggest that patients' perceptions of their relationships with their closest aged sibling, mother, and father are poor predictors of weight gain and improvement in psychological functioning following 6 weeks of inpatient treatment.

General versus regional anaesthesia for hip fracture surgery: a meta-analysis of randomized trials

Hip fracture surgery is common and the population at risk is generally elderly. There is no consensus of opinion regarding the safest form of anaesthesia for these patients. We performed a meta-analysis of 15 randomized trials that compare morbidity and mortality associated with general or regional anaesthesia for hip fracture patients. There was a reduced 1-month mortality and incidence of deep vein thrombosis in the regional anaesthesia group. Operations performed under general anaesthesia had a reduction in operation time. No other outcome measures reached a statistically significant difference. There was a tendency towards a lower incidence of myocardial infarction, confusion and postoperative hypoxia in the regional anaesthetic group, and cerebrovascular accident and intra-operative hypotension in the general anaesthetic group. We conclude that there are marginal advantages for regional anaesthesia compared to general anaesthesia for hip fracture patients in terms of early mortality and risk of deep vein thrombosis.

Circulation and invasive monitoring

Circulation is very important to theatre nurses everywhere. (Excuse the pun, but 2000 - or YK2 as we are now to call it - has got to me.) Rachelle Griffiths continues our Back to Basics series with a consideration of cardiovascular circulation and monitoring. What topics would you like to see in the future in this series? Let me know via the editorial staff at NATN Headquarters.

General versus spinal/epidural anaesthesia for surgery for hip fractures in adults

BACKGROUND

The majority of hip fracture patients are treated surgically, requiring anaesthesia.

OBJECTIVES

To compare different types of anaesthesia for surgical repair of hip fractures (proximal femoral fractures) in adults. This is primarily regional (spinal or epidural) anaesthesia versus inhalation general anaesthesia, but also includes ketamine anaesthesia versus inhalation general anaesthesia.

SEARCH STRATEGY

We searched the Cochrane Musculoskeletal Injuries Group trials register, Medline, selected orthopaedic and anaesthetic journals and conference proceedings, and reference lists of relevant articles. Date of the most recent search: August 1998.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing different methods of anaesthesia for hip fracture surgery in skeletally mature persons. Trials comparing the use of local nerve blocks are not considered in this review. Neither are trials using different types of drugs or techniques with one type of anaesthesia. The primary outcome was mortality.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality, using a nine item scale, and extracted data. The other two reviewers independently checked these results. Wherever appropriate and possible, results were pooled.

MAIN RESULTS

Fifteen trials, involving 2162 patients, which compared regional anaesthesia with general anaesthesia, were included. All trials had methodological flaws. Regional anaesthesia was associated with a decreased mortality at one month (49/766 (6.4%) versus 76/812 (9.4%)) of borderline statistical significance (Peto odds ratio 0.66, 95% confidence interval 0.46 to 0.96)). The results for three month mortality were not statistically significant, although the confidence interval does not exclude the possibility of a clinically relevant reduction (86/726 (11.8%) versus 98/765 (12.8%), Peto odds ratio 0.91, 95% confidence interval 0.67 to 1.24). The reduced numbers at one year, coming exclusively from two studies, preclude any useful conclusions for long term mortality (80/354 (22.6%) versus 78/372 (21.0%), Peto odds ratio 1.10, 95% confidence interval 0.77 to 1.57). Regional anaesthesia was associated with a tendency to a longer operation (weighted mean difference 4.8 minutes, 95% confidence interval 1.1 to 8.6 minutes), and a reduced risk of deep venous thrombosis (39/129 (30%) versus 61/37(76%); Peto odds ratio 0. 41, 95% confidence interval 0.23 to 0.72), although this conclusion is insecure due to possible selection bias in the subgroups in whom this outcome was measured. No other statistically significant differences in outcome were identified. There was insufficient evidence to draw any conclusions from a further two included trials, involving a total of 100 patients, which compared other types of anaesthesia.

REVIEWER'S CONCLUSIONS

Regional anaesthesia and general anaesthesia appear to produce comparable results for most of the outcomes studied. Regional anaesthesia may reduce short-term mortality but no conclusions can be drawn for longer term mortality.