PubMed Health⌕ Search

Biomedical subjects

Keith Simpson

Publications and source records attributed to Keith Simpson.

11 recordsLinked to original sources
PubMed2006

Modifications to advanced life support in renal failure.

The outcome of cardiopulmonary resuscitation (CPR) has been reported to be worse in patients with renal failure compared with those with normal renal function. It is likely that this increased mortality may be at least partly attributable to sub-optimal and highly variable treatment strategies used in cardiac arrest in patients with renal failure, but this issue has not previously been explored. Such patients undoubtedly pose a challenge to advanced life support (ALS) providers, and renal unit staff are not trained to provide specialist advice after a patient has sustained a cardiac arrest. There are few studies investigating the epidemiology, safety or outcome of cardiac arrest in patients with renal failure and there are no generally accepted resuscitation guidelines for this special circumstance. In this article we discuss the unique problems of resuscitating patients with renal failure and propose a suitable management strategy.

Advance Directives↗
PubMed2006

International differences in dialysis mortality reflect background general population atherosclerotic cardiovascular mortality.

Existing national, racial, and ethnic differences in dialysis patient mortality rates largely are unexplained. This study aimed to test the hypothesis that mortality rates related to atherosclerotic cardiovascular disease (ASCVD) in dialysis populations (DP) and in the background general populations (GP) are correlated. In a cross-sectional, multinational study, all-cause and ASCVD mortality rates were compared between GP and DP using the most recent data from the World Health Organization mortality database (67 countries; 1,571,852,000 population) and from national renal registries (26 countries; 623,900 population). Across GP of 67 countries (14,082,146 deaths), all-cause mortality rates (median 8.88 per 1000 population; range 1.93 to 15.40) were strongly related to ASCVD mortality rates (median 3.21; range 0.53 to 8.69), with Eastern European countries clustering in the upper and Southeast and East Asian countries in the lower rate ranges. Across DP (103,432 deaths), mortality rates from all causes (median 166.20; range 54.47 to 268.80) and from ASCVD (median 63.39 per 1000 population; range 21.52 to 162.40) were higher and strongly correlated. ASCVD mortality rates in DP and in the GP were significantly correlated; the relationship became even stronger after adjustment for age (R(2) = 0.56, P < 0.0001). A substantial portion of the variability in mortality rates that were observed across DP worldwide is attributable to the variability in background ASCVD mortality rates in the respective GP. Genetic and environmental factors may underlie these differences.

Atherosclerosis↗
PubMed2006

Long-term quality of life and hospital mortality in patients treated with intermittent or continuous hemodialysis for acute renal and respiratory failure.

OBJECTIVE: To describe long-term quality of life, intensive care, and hospital mortality in patients with acute renal and respiratory failure treated with one of two methods of renal replacement therapy (RRT). DESIGN: Cross-sectional survey of long-term survivors from a prospective observational study of two methods of RRT. SETTING: A combined surgical and medical intensive care unit in a university hospital. PATIENTS AND PARTICIPANTS: One hundred and twenty-six patients with acute renal and respiratory failure who required treatment with RRT and mechanical ventilation. Interventions. (1) RRT for acute renal failure was with either continuous hemodialysis with ultrafiltration using biocompatible membranes and prostacyclin and heparin anticoagulation (CHDF) or intermittent hemodialysis using cuprophane membranes and heparin anticoagulation (IHD); (2) Health-related quality of life in long-term survivors was assessed with the SF-36 (HRQL) questionnaire. MEASUREMENTS AND MAIN RESULTS: (1) There was no difference in ICU mortality (73.5% [39/53] IHD vs. 71.8% [46/64] CHDF, P = NS) or hospital mortality (83% [44/53] IHD vs. 76.5% [49/64] CHDF, P = NS) between the two RRT treatment groups. By 1999, there were 16 surviving patients; (2) Twelve of these survivors completed SF-36 forms (10 CHDF vs. 2 IHD). The overall physical health summary score and scores for seven of the health domains were significantly reduced. The mental health summary score and the domain mental health score did not differ from the general population. CONCLUSIONS: (1) The method of RRT used in ICU patients with ARF had no influence on survival; (2) The long-term survivors of multi-organ failure have poor physical health.

Acute Kidney Injury↗
PubMed2005

The ERA-EDTA cohort study--comparison of methods to predict survival on renal replacement therapy.

BACKGROUND: Accurate prediction of patient survival from the time of starting renal replacement therapy (RRT) is desirable, but previously published predictive models have low accuracy. We have attempted to overcome limitations of previous studies by conducting an ambidirectional inception cohort study in patients on RRT from centres throughout Europe. A conventional multivariate regression (MVR) model, a self-learning rule-based model (RBM) and a simple co-morbidity score [the Charlson score modified for renal disease (MCS)] were compared. METHODS: In 1996, all 3640 dialysis centres registered with the ERA-EDTA were invited to identify all patients on RRT for end-stage renal failure (ESRF) who died during the 28 days of February 1997 (training cohort) and all patients who started RRT in the same period (validation cohort). Fifty-four clinical and laboratory variables from the time of starting RRT were collected in both cohorts using a two-page questionnaire. The data from the training cohort were given to statisticians at the Amsterdam Academic Medical Centre to create the MVR model and to engineers in Strathclyde University to create the RBM. They were then given the baseline data from patients in the validation cohort to predict how long each patient would survive. Follow-up questionnaires were sent to the centre of each patient in the validation cohort to determine actual survival. RESULTS: A total of 2310 patients from 793 centres in 37 countries in the ERA-EDTA area were used to construct and validate the models. For predicting 1-year survival, the RBM had the highest positive predictive value (PPV) (84.2%), the MVR model had the highest negative predictive value (NPV) (47%) and the RBM had the highest likelihood ratio (1.59). For predicting 5-year survival, the MCS had the highest PPV (79.4%), the RBM had the highest NPV (74.3%) and the MCS had the highest likelihood ratio (7.0). The proportion of explained variance in survival for MCS, MVR and RBM was 14.6, 12.9 and 3.95%, respectively. CONCLUSION: Using the ambidirectional inception cohort design of this ERA-EDTA Registry survey, we have been able to create and validate two novel instruments to predict survival in patients starting RRT and compare them with a simple scoring model. The models tended to predict 5-year survival with more accuracy than 1-year survival. Examples of potential applications include informing clinical decision making about the likely benefit of starting RRT and listing for transplantation, adjusting for baseline risk in comparative studies and identifying specific risk groups to participate in clinical trials.

Comorbidity↗
PubMed2005

Renal replacement therapy in the over-80s.

BACKGROUND: The incidence of chronic renal failure rises dramatically with age, which is no longer seen as a contraindication to treatment. AIM: To characterise Scottish dialysis patients aged 80 years and over at the time of their first treatment and to compare their outcomes with those of patients with other serious illnesses. DESIGN AND METHODS: Retrospective survey of all older patients starting dialysis in Dumfries and Galloway between 1 January 1994 and 31 December 2003, and of all older chronic renal failure patients starting dialysis in Scotland between 1 January 1994 and 31 December 2001. Comparison with 4,565 Scottish Lung Cancer and 14,398 myocardial infarction (MI) patients of similar age. RESULTS: 213/3,944 Scottish dialysis patients were aged 80 years or over at the time of their first treatment, representing 5.4% of all new patients and 9.2% of all new starts in 2001. Ninety per cent of older patients received haemodialysis as their first mode of renal replacement therapy. The most common diagnosis was chronic renal failure of unknown cause in 41% of cases. Quality of life, measured in a subset of Dumfries patients, suggested similar social functioning and mental health, but poorer physical health than their younger dialysis counterparts. Early mortality was high in all three diagnostic groups. Median survival from 90 days after the start of treatment, registration or hospital admission was 459 days (95% CI, 375, 543) for the older Scottish CRF patients, compared to 141 days (128, 154) for lung cancer and 1242 days (1192, 1292) for MI patients. CONCLUSIONS: Dialysis can be an effective treatment modality for at least a proportion of octogenarians with end-stage renal failure.

Acute Kidney Injury↗
PubMed2003

End-stage renal disease in Scotland: outcomes and standards of care.

BACKGROUND: The number of patients starting renal replacement therapy (RRT) for end-stage renal disease (ESRD) in the United Kingdom rises annually. Patients are increasingly elderly with a greater prevalence of comorbid illness. Unadjusted survival, from the time of starting RRT, is not improving. The United Kingdom Renal Association has published recommended standards of treatment, which all United Kingdom nephrologists strive to attain. This study was devised to define the impact of attaining recommended treatment standards, adjusting for patient age and comorbid illnesses, upon survival on RRT in the United Kingdom population. METHODS: A prospective, registry based, observational study of all patients starting RRT in Scotland over a 1-year period, followed for the first 2 years of RRT. RESULTS: Of the 523 patients who were studied, 217 (41.5%) had died by 2 years of follow-up, 32% excluding deaths within the first 90 days. Age, comorbidity, weight when starting RRT, and attaining the recommended standards for albumin and hemoglobin had a significant impact upon survival. CONCLUSION: This study has emphasized the very high mortality of patients starting RRT in Scotland. By paying close attention to the attainment of recommended standards of care for patients with ESRD, it may be possible to improve upon current mortality figures. The monitoring of such success is only possible if correction is made for age and comorbidity.

Adolescent↗
PubMed2003

Trends in the incidence of renal replacement therapy for end-stage renal disease in Europe, 1990-1999.

BACKGROUND: The epidemiology of renal replacement therapy (RRT) for end-stage renal disease (ESRD) varies considerably worldwide, but we have lacked reliable quantitative estimates of trends in the incidence by age, sex and cause in Europe over the last decade. METHODS: We analysed data from nine countries participating in the ERA-EDTA registry: Austria, Belgium, Denmark, Finland, Greece, The Netherlands, Norway, Spain and UK (Scotland). Adjusted incidence rates for age and sex were studied for 2 year periods between 1990 and 1999. Average annual changes (%) were estimated by Poisson regression. RESULTS: The adjusted incidence rate of RRT increased from 79.4 per million population (pmp) (range: 58.4-101.0) in 1990-1991 to 117.1 pmp (91.6-144.8) in 1998-1999, i.e. 4.8% (3.1-6.4%) each year. This increase did not flatten out at the end of the decade, except in The Netherlands, and was greater in men than women, 5.2 vs 4.0%/year. In most countries, the incidence rate remained stable for those younger than 45 years; it rose by 2.2%/year on average in the 45-64 year age group and by 7.0% among those 65-74 years; it tripled over the decade in those 75 years or older, and by 1998-1999 it ranged from 140.9 to 540.4 pmp between countries. The incidence of ESRD due to diabetes, hypertension and renal vascular disease nearly doubled over 10 years; in 1998-1999, it varied between countries from 10.2 to 39.3 pmp for diabetes, from 5.8 to 21.0 for hypertension, and from 1.0 to 15.5 for renal vascular disease. CONCLUSION: RRT incidence continues to rise but at various rates in the European countries studied, tending to widen the gap between them. This mainly results from enlarging differences in incidence in the elderly and, to a lesser extent, in that due to diabetes, hypertension and renal vascular disease.

Adolescent↗
PubMed2002

Hemodynamic changes during hemodialysis: role of nitric oxide and endothelin.

BACKGROUND: Etiology of dialysis induced hypotension and hypertension remains speculative. There is mounting evidence that nitric oxide (NO) and endothelin (ET-1) may play a vital role in these hemodynamic changes. We examined the intradialytic dynamic changes in NO and ET-1 levels and their role in the pathogenesis of hypotension and rebound hypertension during hemodialysis (HD). METHODS: The serum nitrate + nitrite (NT), fractional exhaled NO concentration (FENO), L-arginine (L-Arg), NGNG-dimethyl-L-arginine (ADMA) and endothelin (ET-1) profiles were studied in 27 end-stage renal disease (ESRD) patients on HD and 6 matched controls. The ESRD patients were grouped according to their hemodynamic profile; Group I patients had stable BP throughout HD, Group II had dialysis-induced hypotension, and Group III had intradialytic rebound hypertension. RESULTS: Pre-dialysis FENO was significantly lower in the dialysis patients compared to controls (19.3 +/- 6.3 vs. 28.6 +/- 3.4 ppb, P < 0.002). Between the experimental groups, pre-dialysis FENO was significantly higher in Group II (24.1 +/- 6.7 ppb) compared to Group I (17.8 +/- 5.6 ppb) and Group III (16.1 +/- 4.2 ppb; P < 0.05). Post-dialysis, FENO increased significantly from the pre-dialysis values (19.3 +/- 6.3 vs. 22.6 +/- 7.9 ppb; P=0.001). Pre-dialysis NT (34.4 +/- 28.2 micromol/L/L) level was not significantly different from that of controls (30.2 +/- 12.3 micromol/L/L). Serum NT decreased from 34.4 +/- 28.2 micromol/L/L at initiation of dialysis to 10.0 +/- 7.4 micormol/L/L at end of dialysis (P < 0.001). NT concentration was comparable in all the three groups at all time points. Pre-dialysis L-Arg (105.3 +/- 25.2 vs. 93.7 +/- 6.0 micromol/L/L; P < 0.05) and ADMA levels were significantly higher in ESRD patients (4.0 +/- 1.8 vs. 0.9 +/- 0.2 micromol/L/L; P < 0.001) compared to controls. Dialysis resulted in significant reduction in L-Arg (105.3 +/- 25.2 vs. 86.8 +/- 19.8 micromol/L/L; P < 0.005) and ADMA (4.0 +/- 1.8 vs. 1.6 +/- 0.7 micromol/L/L; P < 0.001) concentrations. Pre-dialysis ET-1 levels were significantly higher in ESRD patients compared to the controls (8.0 +/- 1.9 vs. 12.7 +/- 4.1 pg/mL; P < 0.002), but were comparable in the three study groups. Post-dialysis ET-1 levels did not change significantly in Group I compared to pre-dialysis values (14.3 +/- 4.3 vs.15.0 +/- 2.4 pg/mL, P=NS). However, while the ET-1 concentration decreased significantly in Group II (12.0 +/- 4.0 vs. 8.7 +/- 1.8 pg/mL, P < 0.05), it increased in Group III from pre-dialysis levels (12.8 +/- 3.8 vs. 16.7 +/- 4.5 pg/mL, P=0.06). CONCLUSION: Pre-dialysis FENO is elevated in patients with dialysis-induced hypotension and may be a more reliable than NT as a marker for endogenous NO activity in dialysis patients. Altered NO/ET-1 balance may be involved in the pathogenesis of rebound hypertension and hypotension during dialysis.

Adult↗
PubMed2002

Early initiation of dialysis fails to prolong survival in patients with end-stage renal failure.

There is a trend to start dialysis earlier in patients with chronic renal failure. Studies that suggest improved survival from earlier initiation of dialysis are flawed in that they have measured survival from start of dialysis rather than from a time point before dialysis, when patients have the same renal function. This flaw is termed lead-time bias. Using the electronic patient record at the renal unit of Glasgow Royal Infirmary, all patients were identified who had received dialysis for chronic renal failure and who had sufficient data to calculate the time point at which they reached an estimated creatinine clearance (eC(Cr)) of 20 ml/min (n = 275). This date was used to time survival. The patients were divided into early and late start groups by the median eC(Cr) for all patients at initiation of dialysis, which was 8.3 ml/min. There was no significant benefit in patient survival from earlier initiation of dialysis. A Cox proportional hazards model demonstrated a significant inverse relationship between eC(Cr) at start of dialysis and survival (hazard ratio, 1.1; P = 0.02), i.e., patients who started dialysis with a lower eC(Cr) tended to survive longer. This relationship retained significance when gender, age, weight, presence of diabetes, mode of first dialysis, initial dialysis access, hemoglobin, serum albumin, blood leukocyte count, Wright/Khan index, and eC(Cr) at the start of dialysis were taken into account. This study fails to support a policy of earlier initiation of dialysis for patients with end-stage renal failure.

Female↗