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Biomedical subjects

E G Lowrie

Publications and source records attributed to E G Lowrie.

At least 55 records · Page 3Linked to original sources
PubMed1991

Increased serum aluminum. An independent risk factor for mortality in patients undergoing long-term hemodialysis.

The annual mortality rate among patients receiving long-term hemodialysis has been rising over the past decade. The prevalences of known risk factors such as older age, male sex, duration of dialysis, presence of diabetes, coronary artery disease, or hypertension do not seem to have changed during this time. However, evidence suggests that an increased body aluminum level may have an adverse effect on survival even in the absence of overt aluminum toxic reaction. Therefore, we evaluated the correlation between serum aluminum levels and mortality in 10 646 patients undergoing long-term hemodialysis. Mortalities were 18% higher for patients with serum aluminum levels between 1520 and 2220 nmol/L and progressively increased to 60% higher for patients with aluminum levels above 7410 nmol/L. Serum aluminum level was an important predictor of survival even after other known risk factors had been controlled. These data strongly suggest that patients undergoing long-term hemodialysis should have periodic surveillance of the serum aluminum levels, and in those patients who have plasma levels of 1520 to 2220 nmol/L or higher, one should seriously consider discontinuing aluminum salts and giving therapy to decrease body aluminum level if it is found to be increased.

Age Factors↗
PubMed1990

Death risk in hemodialysis patients: the predictive value of commonly measured variables and an evaluation of death rate differences between facilities.

Logistic regression analysis was applied to a sample of more than 12,000 hemodialysis patients to evaluate the association of various patient descriptors, treatment time (hours/treatment), and various laboratory tests with the probability of death. Advancing age, white race, and diabetes were all associated with a significantly increased risk of death. Short dialysis times were also associated with high death risk before adjustment for the value of laboratory tests. Of the laboratory variables, low serum albumin less than 40 g/L (less than 4.0 g/dL) was most highly associated with death probability. About two thirds of patients had low albumin. These findings suggest that inadequate nutrition may be an important contributing factor to the mortality suffered by hemodialysis patients. The relative risk profiles for other laboratory tests are presented. Among these, low serum creatinine, not high, was associated with high death risk. Both serum albumin concentration and creatinine were directly correlated with treatment time so that high values for both substances were associated with long treatment times. The data suggest that physicians may select patients with high creatinine for more intense dialysis exposure and patients with low creatinine for less intense treatment. In a separate analysis, observed death rates were compared with rates expected on the basis of case mix for these 237 facilities. The data suggest substantial volatility of observed/expected ratios when facility size is small. Nonetheless, a minority of facilities (less than or equal to 2%) may have higher rates than expected when compared with the pool of all patients in this sample. The effect of various laboratory variables on mortality is substantial, while relatively few facilities have observed death rates that exceed their expected values. Therefore, we suggest that strategies designed to improve the overall mortality statistic for dialysis patients in the United States would be better directed toward improving the quality of care for all patients, particularly high-risk patients, within their usual treatment settings rather than trying to identify facilities with high death rate for possible regulatory intervention.

Adult↗
PubMed1985

The quality of life of patients with end-stage renal disease.

We assessed the quality of life of 859 patients undergoing dialysis or transplantation, with the goal of ascertaining whether objective and subjective measures of the quality of life were influenced by case mix or treatment. We found that 79.1 per cent of the transplant recipients were able to function at nearly normal levels, as compared with between 47.5 and 59.1 per cent of the patients treated with dialysis (depending on the type). Nearly 75 per cent of the transplant recipients were able to work, as compared with between 24.7 and 59.3 per cent of the patients undergoing dialysis. On three subjective measures (life satisfaction, well-being, and psychological affect) transplant recipients had a higher quality of life than patients on dialysis. Among the patients treated with dialysis, those undergoing treatment at home had the highest quality of life. All quality-of-life differences were found to persist even after the patient case mix had been controlled statistically. Finally, the quality of life of transplant recipients compared well with that of the general population, but despite favorable subjective assessments, patients undergoing dialysis did not work or function at the same level as people in the general population.

Adult↗
PubMed1985

Formaldehyde kinetics and bacteriology in dialyzers.

The kinetics of formaldehyde washout in new and reused dialyzers with 2% (w/v) and 4% formaldehyde solution was studied. Using a standard method of rinsing, the concentration of formaldehyde decreases exponentially, but the rate of decrease and the steady-state level depends on the type of dialyzer. The residual quantity of formaldehyde using a 4% solution is more than twice that seen with a 2% solution in similar dialyzers. Bacteriological tests on water-adapted, formaldehyde-resistant organisms indicate that a significant proportion of these organisms can survive a 4-hr incubation with 4% formaldehyde at 20 degrees C. However, increasing the temperature of incubation to 40 degrees C or the addition of ethanol up to 8% (v/v) improved the bacteriological efficacy of formaldehyde. Under these conditions, a 1% formaldehyde solution allows eradication of all organisms tested. Similar results were observed in multiple-use dialyzers inoculated with the same organisms. There was no effect of incubation at 40 degrees C on the in vitro clearance determinations of new and reused dialyzers.

Disinfection↗
PubMed1982

Hemodialysis-associated neutropenia and hypoxemia: the effect of dialyzer membrane materials.

The fall in white blood cells (WBC) and arterial oxygen pressure that occurs during hemodialysis was investigated as a function of different dialysis membranes and different sterilization methods. 8 chronic hemodialysis patients were studied and each was dialyzed with three different membranes: cellulosic hollow fiber, polyacrylonitrile flat sheet and polymethylmethacrylate hollow fiber. Each dialyzer was studied with a dry sterilization method and after formalin treatment. Arterialized blood gas, bicarbonate and WBC were drawn at various intervals throughout dialysis. The effect of the sterilization method was minimal. Cellulosic membranes were shown to cause significantly more neutropenia (p less than 0.001) and hypoxemia (p less than 0.01) than the other two membranes. No significant differences was seen in pH, PCO2 and bicarbonate. The results indicate differences in biocompatibility between different membranes. Clinical implications are discussed.

Adult↗
PubMed1982

Which mathematical model to study uremic toxicity? National Cooperative Dialysis Study.

Mathematical modelling advantages and limitations to study dialysis adequacy are evaluated, the use of the single pool urea model in the guidance of the National Cooperative Dialysis Study (NCDS) is described, and therapeutic control results from the Control phase of the NCDS are reported. The relevance of using urea as a target compound and the practicality of modelling its levels in clinical settings using a single pool model are discussed. The NCDS involves intensive participation of 8 geographically separate centers to control BUN at two weekly time averaged concentrations (50 +/- 5 and 100 +/- 5 mg/dl) using standard clinical dialyzers and two different lengths of dialysis (3 and 4.5 hr) in the presence of .8-1.4 g/kg/day protein intake. Control phase data on 195 patients indicates a remarkable level of clinical precision and method reproducibility as well as a high degree of patient compliance. Patient urea volumes averaged 39.8 +/- 8.9 liters, net rates of daily protein catabolism were 1.06 +/- .17 g/kg; daily weight gain: .96 +/0 .43 kg; and dialyzer clearances to maintain patients in the control phase for 3 to 6 months were 168 +/- 44 ml/min. Clearances required to randomize patients into four experimental groups ranged 40-250 ml/min. Less than 1/4 of dialyzers were larger than 1.8 m2 and were not specific to any experimental group.

Blood Urea Nitrogen↗
PubMed1981

Effect of the hemodialysis prescription on patient morbidity: report from the National Cooperative Dialysis Study.

This report summarizes morbidity in 151 patients in a cooperative trial designed to evaluate the clinical effects of different dialysis prescriptions. Four treatment groups were divided along two dimensions: dialysis treatment time (long or short), and blood urea nitrogen (BUN) concentration averaged with respect to time (TACurea) (high or low). Dietary protein was not restricted. There was no difference in mortality between the groups. Withdrawal of patients from the high-BUN groups for medical reasons was significantly greater than withdrawal from the low-BUN groups. Hospitalization was also greater in the high-BUN groups, but dialysis treatment time had no significant effects. The data indicate that the occurrence of morbid events is affected by the dialysis prescription. Increased morbidity appears to accompany prescriptions associated with a relatively high BUN. Conversely, morbidity may be decreased by prescriptions associated with more efficient removal of urea if the dietary intake of protein and other nutrients is adequate.

Adolescent↗
PubMed1981

The success of medicare's end-stage renal-disease program: the case for profits and the private marketplace.

The 92nd Congress extended Medicare benefits to patients with end-stage renal disease (ESRD), sparing patients the financial burden of treating this catastrophic illness. The costs of the ESRD program have been contained better than those of health care generally; payment was originally limited by a screen of $138 per dialysis but could be higher if higher cost was documented. About 48 per cent of patients receive dialysis in units outside hospitals. The majority of these units are operated for profit, in which physicians share. The payment to these facilities has remained constant while payment to the nonprofit hospitals' unit has increased markedly. Physicians in for-profit units have a strong incentive to learn about costs and control them. They are involved in medical economic management as well as clinical management; this results in integrated administration of health care. The success of the ESRD program in expanding service to meet demand while controlling costs and maintaining quality has been due primarily to the combined effect of setting a price and creating a system of incentives that involves physicians in the medical marketplace.

Adult↗