Cost of treating acute myocardial infarction in an Irish teaching hospital

Recent figures indicate that there are approximately 6,500 patients admitted to hospital following acute myocardial infarction (AMI) in Ireland each year. As hospital admission is frequently the most expensive component of healthcare we determined the costs associated with treatment of AMI in a teaching hospital. The costing evaluation was from the hospital perspective and the strategy used was a micro-costing detailed collection of resources used. The average cost of hospital admission for the treatment of AMI was Pound Sterling 3,976. The average cost per day was calculated at Pound Sterling 501. Approximately 50% of hospital costs were associated with ward costs. Procedures accounted for 35% of costs whereas medications contributed just 7% of total costs.

Treatment of surgical patients is evidence-based

OBJECTIVES

To assess the type of evidence that supported our management of surgical patients.

DESIGN

Retrospective audit.

SETTING

Teaching hospital, Republic of Ireland.

PATIENTS

All 222 patients admitted by two surgical teams during one month. Patients admitted for diagnostic procedures were included if they were treated as a result.

MAIN OUTCOME MEASURES

Diagnosis and treatment were established from the notes. Evidence for each intervention was then sought in MEDLINE 1986-1999, Best Evidence 1991-1999, and the Cochrane Database of Systematic Reviews Issue 3, 1999, and graded into one of five categories: systematic review, meta-analysis, randomised controlled trial, prospective study, or retrospective study.

RESULTS

Treatment was supported by systematic review in 14, by meta-analysis in 12, by randomised controlled trial in 75, by prospective studies in 55, by retrospective studies in 58, and by no evidence in 8.

CONCLUSIONS

Everyday surgical practice in our unit is supported by good quality evidence from recent publications.

The role of a nurse case manager in implementing a critical pathway for infrainguinal bypass surgery

BACKGROUND

A previous study showed the effectiveness of a clinical pathway for infrainguinal bypass surgery in reducing postoperative length of stay (LOS) in an acute care setting. Most of the deviations from the pathway were due to patient factors (50%) and/or external disposition problems (30%), but 20% were related to physician or system problems that could potentially be modified. The current study examined those factors influencing LOS following infrainguinal bypass surgery and the impact of daily rounds by a nurse case manager--a vascular nurse specialist--on LOS and pathway deviations.

METHODS

Data were collected through detailed chart review and prospective tracking of pathway deviations. LOS was compared in 58 patients on the modified pathway (with the nurse case manager) to 69 patients on the original pathway and 67 prepathway controls. Multivariate analysis was used to identify factors influencing postoperative LOS and to compare LOS among the three groups.

RESULTS

Use of a nurse case manager significantly reduced physician-related deviations, from the pathway from 10% to 0% (p = .015), and reduced system-related deviations from 3% to 0%. Median postoperative LOS was 7 days before the pathway was begun, 6 days with the original pathway, and 5 days after the introduction of a vascular nurse specialist (p = .0001). There were no differences in rates of complications, rates of readmission, or mortality.

CONCLUSIONS

Intervention by a nurse case manager facilitated implementation of a critical pathway for patients undergoing infrainguinal bypass surgery, especially by preventing patient deviations due to intrainstitutional factors.

Selective inhibition of COX-2 in humans is associated with less gastrointestinal injury: a comparison of nimesulide and naproxen

BACKGROUND

Selective inhibitors of cyclooxygenase (COX)-2 may provoke less gastric damage and platelet inhibition than conventional non-steroidal anti-inflammatory drugs.

AIMS

We compared the biochemical and gastrointestinal effects of nimesulide, a potent and selective COX-2 inhibitor, with naproxen which exhibits no selectivity.

SUBJECTS

Thirty six healthy volunteers were randomised to nimesulide 100 mg or naproxen 500 mg twice daily for two weeks in a double blind, crossover study with a washout between treatments.

METHODS

Gastrointestinal side effects were assessed by endoscopy, and by estimation of small intestinal absorption-permeability and inflammation. Comparisons were made between variables at the end of each treatment phase.

RESULTS

Nimesulide caused significantly less gastric injury using the modified Lanza score (p<0.001) as well as reduced duodenum injury (p=0.039). Nimesulide had lower visual analogue scores (VAS) for haemorrhage and erosive lesions in the stomach (p<0.001) and for mucosal injection in the duodenum (p=0.039). Naproxen increased excretion of calprotectin, a marker of intestinal inflammation (5.5 (1.2) to 12.1 (2.1) mg/l) while nimesulide had no effect (treatment difference p=0.03). Naproxen abolished platelet aggregation to arachidonic acid and suppressed serum thromboxane B(2) (TXB(2)) by 98%, indices of COX-1 activity. In contrast, nimesulide had no significant effect on platelet aggregation, although it reduced serum TXB(2) by 29%. Production of prostaglandin E(2) and prostacyclin by gastric biopsies, also COX-1 dependent, was inhibited by naproxen, but not by nimesulide. COX-2 activity, determined as endotoxin induced prostaglandin E(2) formation in plasma, was markedly suppressed by both treatments.

INTERPRETATION

Nimesulide has preferential selectivity for COX-2 over COX-1 in vivo at full therapeutic doses and induces less gastrointestinal damage than that seen with naproxen in the short term.

Quantitative measurement of apoptosis induced by cytotoxic T lymphocytes

Cytotoxic T lymphocytes destroy virus-infected and malignant cells through the induction of apoptosis. This form of cell death is characterized by a number of cellular changes including cell shrinkage and membrane blebbing, chromatin condensation and DNA fragmentation, externalization of phosphatidylserine to the outer leaflet of the plasma membrane, and disruption of the inner mitochondrial transmembrane potential (delta psi m). Cell death induced by cytotoxic T lymphocytes is associated with similar morphological and biochemical features. Here we demonstrate how methods typically employed to detect apoptotic cells can be adapted to monitor cell death mediated by cytotoxic T lymphocytes. We have specifically selected techniques that allow quantitative evaluation of death including membrane changes, DNA fragmentation, and mitochondrial depolarization.

Poor agreement in recognition of abnormal mitoses: requirement for standardized and robust definitions

AIMS

The finding of abnormal mitoses is a helpful feature in differentiating between benign and malignant neoplasia and has prognostic significance for some tumours. As the use of a histopathological variable is limited by the reproducibility of its recognition, we tested the interobserver agreement in the classification of abnormal mitoses among histopathologists. METHODS adn

RESULTS

Ten practising histopathologists were shown 30 potential mitotic figures and were asked to classify these as 'normal mitoses', 'abnormal mitoses' or 'not mitoses' according to the criteria each pathologist used in their routine practice. The results were analysed using kappa statistics. Overall agreement was only fair with a combined kappa of 0.31 and there was unanimous categorization of only four of 30 test items, none of which was called abnormal. The poorest result was obtained for the category 'abnormal mitosis' with only slight agreement (kappa 0.19). Agreement for the other categories varied from moderate (kappa = 0.45) for 'not a mitosis' to fair (kappa = 0.26) for 'normal mitosis'. Comparison of the results for observer pairs showed that for 12 out of the 45 possible pairings, there was no more agreement than might be expected by chance alone.

CONCLUSION

Agreement is poor among practising histopathologists in the recognition of abnormal mitoses. A standardized and robust definition is needed if diagnostic and prognostic significance is accorded to the finding of an abnormal mitosis in the context of neoplasia.

Granzyme B-mediated cytochrome c release is regulated by the Bcl-2 family members bid and Bax

Cytotoxic T lymphocytes (CTLs) destroy target cells through a mechanism involving the exocytosis of cytolytic granule components including granzyme B (grB) and perforin, which have been shown to induce apoptosis through caspase activation. However, grB has also been linked with caspase-independent disruption of mitochondrial function. We show here that cytochrome c release requires the direct proteolytic cleavage of Bid by grB to generate a 14-kD grB-truncated product (gtBid) that translocates to mitochondria. In turn, gtBid recruits Bax to mitochondria through a caspase-independent mechanism where it becomes integrated into the membrane and induces cytochrome c release. Our results provide evidence for a new pathway by which CTLs inflict damage and explain the caspase-independent mechanism of mitochondrial dysfunction.

Mannose 6-phosphate/insulin-like growth factor II receptor is a death receptor for granzyme B during cytotoxic T cell-induced apoptosis

The serine proteinase granzyme B is crucial for the rapid induction of target cell apoptosis by cytotoxic T cells. Granzyme B was recently demonstrated to enter cells in a perforin-independent manner, thus predicting the existence of a cell surface receptor(s). We now present evidence that this receptor is the cation-independent mannose 6-phosphate/insulin-like growth factor receptor (CI-MPR). Inhibition of the granzyme B-CI-MPR interaction prevented granzyme B cell surface binding, uptake, and the induction of apoptosis. Significantly, expression of the CI-MPR was essential for cytotoxic T cell-mediated apoptosis of target cells in vitro and for the rejection of allogeneic cells in vivo. These results suggest a novel target for immunotherapy and a potential mechanism used by tumors for immune evasion.

Cost of treating heart failure in an Irish teaching hospital

BACKGROUND

The prevalence of heart failure is 3 to 20 per 1,000 population, but may exceed 100 per 1,000 in the over 65 age group. Some 1-2% of the total healthcare budget is consumed in the management of heart failure.

AIM

As hospital costs account for approximately 70% of this expenditure we determined the cost of treating heart failure in an Irish teaching hospital.

METHODS

Cost evaluation was from the hospital perspective using a microcosting detailed collection of resources used.

RESULTS

The average cost of a hospital admission for cardiac failure was IR 2,146 Pounds. The average cost per day was IR 193 Pounds. Approximately 75% of hospital costs were associated with ward costs. Medications accounted for 3.5% of total costs.

CONCLUSION

The availability of Irish cost data is essential for the assessment of the cost-effectiveness of therapeutic interventions for the treatment of heart failure in our healthcare system.

The tolerability of efavirenz after nevirapine-related adverse events

Eight patients who were infected with human immunodeficiency virus, and who had each sustained an adverse drug reaction while following a regimen including nevirapine, were switched to a regimen including efavirenz. None of the patients experienced adverse events identical to that which necessitated discontinuation of nevirapine. This study demonstrates that adverse events related to nevirapine are not a class-specific effect.

Pharmacokinetics of single-dose oral stavudine in subjects with renal impairment and in subjects requiring hemodialysis

Two open-label studies assessed the pharmacokinetics of single orally administered doses of 40 mg of stavudine in subjects with renal impairment. In one study (study I), 15 subjects with selected degrees of renal impairment, but not requiring hemodialysis, were stratified into three groups of five subjects each according to creatinine clearance (CL(CR)) normalized by body surface area (ml/min/1.73 m(2)): mild (CL(CR), 60 to 80), moderate (30 to 50), and severe (/= 90) were also enrolled. The stavudine area under the curve from 0 h to infinity (AUC(0-infinity)) increased nonlinearly with declining renal function: 1,864, 2,215, 3,609, and 5,928 ng. h/ml for normal renal function and for mild, moderate, and severe renal impairment, respectively (P = 0.0001 between renal impairment groups). The following stavudine dosage recommendations for renal impairment were proposed for subjects weighing >/=60 kg: CL(CR) of >50 ml/min/1.73 m(2), 40 mg every 12 h; CL(CR) of 21 to 50 ml/min/1. 73 m(2), 20 mg every 12 h; and CL(CR) of 10 to 20 ml/min/1.73 m(2), 20 mg every 24 h. For subjects weighing <60 kg, the proposed doses were 30, 15, and 15 mg, respectively, with the same dosing intervals specified above. In a second study (study II), 12 subjects with end-stage renal disease requiring hemodialysis three times a week were enrolled in a randomized, open-label crossover study (dialysis 2 h after dosing and lasting 4 h or dosing without dialysis). There were no statistically significant differences for AUC(0-infinity), AUC(2-6), time to maximum concentration of drug in serum, half-life, or apparent oral clearance when the two treatment dosage regimens were compared. As a result of study II, the recommended dosing rate for subjects requiring hemodialysis was the same as that proposed for those with severe renal impairment not requiring hemodialysis; however, dosing was recommended to follow hemodialysis and to occur at the same time each day.

Management guidelines for hypotensive pelvic fracture patients

Pelvic fractures are common in blunt trauma patients and are often associated with other system injuries. Most studies describe the type of pelvic fractures and classify them by the forces creating the injury. Mortality from these fractures is due most often to other system injuries or to hemorrhage. Mortality ranges from 5 to 20 per cent depending on complexity and number of systems injured. We studied 692 cases of pelvic fractures and analyzed the seriously ill patients. They were identified by blood pressure (BP) less than 90 systolic on presentation to the trauma room and having a complex pelvic fracture. The management of these patients was by a protocol used by a group of eight trauma surgeons. This group of 75 hypotensive pelvic fracture patients were analyzed to identify significant factors in their management that predicted mortality. Patients with base excess (BE) values < or =-5 were significantly more likely to die (P<0.05). Patients with BP < or =90 on leaving the trauma room had a significantly higher mortality (P<0.01). Injury Severity Score predicted mortality and can be useful as a tool for quality assurance and process improvement. The early operative intervention to fix associated fractures within 24 hours was not detrimental to patient outcome. Overall mortality in this very sick population was 14.7 per cent. Emergent angiography was used successfully on 14 patients. Seven patients died of continued bleeding. The most important management guidelines for these seriously injured, complex patients are: 1) resuscitate with BE used as a monitor; 2) keep patient blood volume as close to normal as possible; 3) use BP, BE, and ISS to evaluate management of these patients.

The potential for drug interactions with statin therapy in Ireland

BACKGROUND

Seven percent of acute hospital admissions result from adverse drug reactions, of which 25% are due to drug interactions. Adverse effects of statin drugs occur in 3% of patients, mainly due to co-prescribing with other lipid-lowering agents or agents that alter their metabolism.

AIM

The aim of this study was to investigate co-prescribing of the frequently-used statin medications with interacting drugs.

METHODS

Data from the General Medical Services (GMS) scheme of the Eastern Health Board from January to December 1998 were used in this study. Using the coding index for statins, co-prescribing was identified when concomitant medications were administered under the same GMS claim number.

RESULTS

Of 7,602 patients prescribed statins, co-prescribing of simvastatin, atorvastatin and fluvastatin with competing substrates or inhibitors of their metabolism occurred in 32, 26 and 13.4% of prescriptions issued. Thirty-four per cent of patients on simvastatin, 28% on atorvastatin and 16% on fluvastatin were prescribed medications with drug interaction potential.

CONCLUSION

Co-prescribing of statins with competing substrates or inhibitors of their metabolism occurred in up to one-third of prescriptions issued. When statins are co-prescribed with recognised inhibitors of drug metabolism, pravastatin, which does not undergo significant hepatic metabolism, is the statin of choice.

Granzyme B short-circuits the need for caspase 8 activity during granule-mediated cytotoxic T-lymphocyte killing by directly cleaving Bid

Cytotoxic T lymphocytes (CTL) can trigger an apoptotic signal through the Fas receptor or by the exocytosis of granzyme B and perforin. Caspase activation is an important component of both pathways. Granzyme B, a serine proteinase contained in granules, has been shown to proteolytically process and activate members of the caspase family in vitro. In order to gain an understanding of the contributions of caspases 8 and 3 during granule-induced apoptosis in intact cells, we have used target cells that either stably express the rabbitpox virus-encoded caspase inhibitor SPI-2 or are devoid of caspase 3. The overexpression of SPI-2 in target cells significantly inhibited DNA fragmentation, phosphatidylserine externalization, and mitochondrial disruption during Fas-mediated cell death. In contrast, SPI-2 expression in target cells provided no protection against granzyme-mediated apoptosis, mitochondrial collapse, or cytolysis, leading us to conclude that SPI-2-inhibited caspases are not an essential requirement for the granzyme pathway. Caspase 3-deficient MCF-7 cells were found to be resistant to CTL-mediated DNA fragmentation but not to CTL-mediated cytolysis and loss of the mitochondrial inner membrane potential. Furthermore, we demonstrate that granzyme B directly cleaves the proapoptotic molecule Bid, bypassing the need for caspase 8 activation of Bid. These results provide evidence for a two-pronged strategy for mediating target cell destruction and provide evidence of a direct link between granzyme B activity, Bid cleavage, and caspase 3 activation in whole cells.

RasGRP links T-cell receptor signaling to Ras

Stimulation of the T-cell receptor (TCR) alters a number of intracellular signaling pathways including one that involves protein tyrosine kinases, phospholipase C-gamma1 (PLC-gamma1), diacylglycerol (DAG), and calcium messengers. By a divergent pathway, TCR-stimulated protein tyrosine kinase activity is thought to result independently in recruitment of the Ras activator Sos to the plasma membrane, leading to Ras activation. Here we show that RasGRP, a Ras activator that contains calcium-binding EF hands and a DAG-binding domain, is expressed in T cells. A PLC-gamma1 inhibitor diminished activation of Ras following TCR stimulation. Membranes from TCR-stimulated Jurkat T cells exhibited increased RasGRP and increased Ras-guanyl nucleotide association activity that was inhibited by antibodies directed against RasGRP. Overexpression of RasGRP in T cells enhanced TCR-Ras-Erk signaling and augmented interleukin-2 secretion in response to calcium ionophore plus DAG analogues phorbol ester myristate or bryostatin-1. Thus, RasGRP links TCR and PLC-gamma1 to Ras-Erk signaling, a pathway amenable to pharmacologic manipulation.

Post-translational modification of the myxoma-virus anti-inflammatory serpin SERP-1 by a virally encoded sialyltransferase

SERP-1 is a secreted serpin (serine-proteinase inhibitor) encoded by myxoma virus, a poxvirus pathogen of rabbits. SERP-1 is required for myxoma-virus virulence, and the purified protein has been shown to possess independent anti-inflammatory activity in animal models of restenosis and antigen-induced arthritis. As an inhibitor of serine proteinases, SERP-1 acts against tissue-type plasminogen activator, urokinase-type plasminogen activator, plasmin, thrombin and Factor Xa. In the present study, examination of SERP-1 glycosylation-site mutants showed that the N-linked glycosylation of Asn(172) was essential for SERP-1 secretion, whereas mutation of Asn(99) decreased secretion efficiency, indicating that N-linked glycosylation plays an essential role in the processing and trafficking of SERP-1. Furthermore, comparison of SERP-1 from wild-type myxoma virus and a virus containing a targeted disruption of the MST3N sialyltransferase locus demonstrated that SERP-1 is specifically modified by this myxoma-virus-encoded sialyltransferase, and is thus the first reported viral protein shown to by modified by a virally encoded glycosyltransferase. Sialylation of SERP-1 by the MST3N gene product creates a uniquely charged species of secreted SERP-1 that is distinct from SERP-1 produced from other eukaryotic expression systems, though this has no apparent effect upon the kinetics of in vitro proteinase inhibition. Rather, the role of viral sialylation of SERP-1 likely relates to masking antigenicity or targeting SERP-1 to specific sites of action in vivo.

Plakoglobin regulates the expression of the anti-apoptotic protein BCL-2

Plakoglobin is a cytoplasmic protein and a homologue of beta-catenin and Armadillo of Drosophila with similar adhesive and signaling functions. These proteins interact with cadherins to mediate cell-cell adhesion and associate with transcription factors to induce changes in the expression of genes involved in cell fate determination and proliferation. Unlike the relatively well characterized role of beta-catenin in cell proliferation via activation of c-MYC and cyclin D1 gene expression, the signaling function of plakoglobin in regulation of cell growth is undefined. Here, we show that high levels of plakoglobin expression in plakoglobin-deficient human SCC9 cells leads to uncontrolled growth and foci formation. Concurrent with the change in growth characteristics we observe a pronounced inhibition of apoptosis. This correlates with an induction of expression of BCL-2, a prototypic member of apoptosis-regulating proteins. The BCL-2 expression coincides with decreased proteolytic processing and activation of caspase-3, an executor of programmed cell death. Our data suggest that the growth regulatory function of plakoglobin is independent of its role in mediating cell-cell adhesion. These observations clearly implicate plakoglobin in pathways regulating cell growth and provide initial evidence of its role as a pivotal molecular link between pathways regulating cell adherence and cell death.

[Cholera in Guinea: the 1994-1995 epidemic]

Since the first outbreak in 1970, cholera epidemics have occurred regularly in Guinea. Until 1994, epidemics recurred every 8 years and were confined to the capital and coastal areas. The first cases in every epidemic were observed in coastal lagoons near the Sierra Leone border. In 1994, the disease demonstrated its migratory ability as the first cases were reported in towns located in far eastern inland areas. Spread of the disease from war-torn Sierra Leone and Liberia where epidemics have also been reported cannot be ruled out. Control measures have gradually been implemented to deal with these outbreaks and a treatment facility was built at the University of Conakry in 1994. Bacteriological studies including antibiotic susceptibility tests carried out at this center showed that the offending bacteria was Vibrio cholerae El Tor of the Ogawa group. Although this strain is relatively sensitive to all antibiotics, analysis of epidemiological data revealed high mortality rates at the beginning of every outbreak probably due to delays in organizing appropriate care. A major effort is now being made to improve the response time particularly in remote inland areas.

Infantile hypertrophic pyloric stenosis in a regional centre

BACKGROUND

It has been suggested that only specialist paediatric surgeons should manage infantile hypertrophic pyloric stenosis (IHPS).

AIM

The aim of this retrospective study was to ascertain whether the majority of these infants might be managed in a well-equipped regional centre.

METHODS

Using the Hospital Inpatient Enquiry database, all cases of IHPS within a single administrative health region were identified over a six-year period. A chart review was performed to obtain demographic and clinical information for each patient. Reports from the Central Statistics Office were used to obtain data on population and live births for the region.

RESULTS

Seventy patients with IHPS were identified from this region from 1991 to 1996, 63 (90%) of which were treated in the region. Of the remaining seven, four were referred directly to specialised paediatric surgical hospitals because of prematurity (n = 1), low birth weight (n = 1), capillary haemangioma (n = 1) and severe metabolic derangement (n = 1) while three were assessed and treated in general hospitals outside the region. Of the 63 infants undergoing pyloromyotomy in this region, the duodenal mucosa was breached in four (6%); there were wound complications in three (5%); and one required a re-pyloromyotomy. The mean postoperative stay was eight days (range 2-42 days).

CONCLUSION

The majority of infants with IHPS may be safely managed in regional centres with transfer to specialist paediatric centres reserved for 'high risk' cases. The management of IHPS at a regional level has important implications and presents opportunities for surgical training.