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Biomedical subjects

L S Knox

Publications and source records attributed to L S Knox.

11 recordsLinked to original sources
PubMed1993

Ethics and nutritional support in the intensive care unit.

Provision of nutrition and hydration through artificial means is an invasive medical intervention. As such, procedures for supplying nutrition and hydration impose burdens as well as provide benefits and may, under certain circumstances, be foregone. However, in the intensive care unit, the needs of most patients are best served by providing nutritional support. For many critically ill patients, the long-term prognosis and potential for response to treatment are uncertain. For these reasons, the presumption should be in favor of providing nutrition and hydration.

Beneficence↗
PubMed1989

Ethical issues in nutritional support nursing. Withholding and withdrawing nutritional support.

A new and controversial debate in bioethics concerns the question, "Is it ever acceptable to withhold or withdraw specialized nutritional support from the dying adult patient?" In the opinion of many, the answer to this question is yes, but for only a very small number of patients. Provision of nutrition through artificial means is an invasive medical intervention. As such, procedures for supplying nutritional support impose burdens as well as provide benefits and may, under certain circumstances, be foregone. However, the needs of the vast majority of dying patients will best be served by providing specialized nutritional support.

Adult↗
PubMed1988

Study protocol: a randomized clinical trial of total parenteral nutrition in malnourished surgical patients.

CSP #221 is a randomized multiinstitutional clinical trial to assess the efficacy of 10 d of perioperative total parenteral nutrition (TPN) in reducing morbidity and mortality in malnourished patients undergoing intraperitoneal and/or intrathoracic operations. In this paper a detailed protocol for the clinical efficacy trial is presented primarily as a reference document for use in interpretation of the results of the clinical trial. It is also anticipated, however, that review of this protocol may be useful to other investigators planning future clinical nutrition intervention trials.

Clinical Trials as Topic↗
PubMed1987

Caloric requirements in total parenteral nutrition.

Resting energy expenditure (REE) was measured in 100 consecutive total parenteral nutrition (TPN) patients. Only forty-eight percent of the measured REEs were within 90-110% of the predicted Harris-Benedict values. A literature review revealed 191 published guidelines for non-protein caloric requirements of hospitalized TPN patients. These guidelines were appropriately matched and applied to the 100 individual TPN patients. The relationship between the recommended caloric supply and measured caloric expenditure was minimal. The recommendations exceeded measured REE by an average of 1076 +/- 660 kcal/day. These published guidelines were substantially above and below caloric requirements based on measured REE for both fat maintained (130% REE) and fat depleted (150% REE) patients. Following published guidelines rather than standards based on measured REE results in the administration of 6947 excess liters of TPN per year. Improvement in the precision of TPN caloric prescription can be accomplished by using measured REE as a reference base. When published guidelines were compared to prescriptions based on measured REE it was found that published guidelines were inaccurate both overall and individually and a substantial cost savings justifies actual measurement of energy needs.

Adipose Tissue↗
PubMed1986

Energy expenditure in malnourished patients with colorectal cancer.

To evaluate energy expenditure in patients who have colorectal cancer with varying stages of disease and to examine the possible determinants of energy expenditure in a group of patients with cancer who have the same type of tumor, we studied 73 patients with biopsy proven and pathologically staged adenocarcinomas of the colon and rectum. Resting energy expenditure (REE) was measured by indirect calorimetry and compared with predicted energy expenditure (PEE), which was calculated from the Harris-Benedict formulas. Nutritional and tumor characteristics were examined. Forty-nine percent of patients had abnormal REE (normal = PEE +/- 10%). One quarter of the patients were hypometabolic (REE less than 90% PEE). The abnormalities persisted despite normalization of REE to metabolic body size (kg0.75) or predicted values based on weight, height, age, and sex. There were no differences in nutritional status, as judged by the percent of weight loss and visceral protein levels, between those patients in the hypometabolic, normometabolic, or hypermetabolic categories, and there were no significant relationships between energy expenditure and the tumor burden. The mean duration of disease in the normometabolic group was 4.5 months, while the hypometabolic and hypermetabolic groups had mean durations of 9.5 and 14.2 months, respectively. The tumor site and duration of the disease are important variables in studies of energy expenditure in patients with cancer.

Adenocarcinoma↗
PubMed1984

Energy expenditure in malnourished gastrointestinal cancer patients.

Cancer cachexia, a common finding in patients with gastrointestinal (GI) malignancy, is frequently attributed to tumor-induced aberrations in host energy expenditure. To characterize the frequency and severity of aberrations in energy expenditure in GI cancer patients, and to identify the potential influence of tumor characteristics in this group, the authors measured resting energy expenditure (REE) by indirect calorimetry in 173 patients and compared REE to predicted-energy expenditure (PEE) from the Harris-Benedict formulae based on current body weight. Fifty-eight percent of patients had abnormal REE (normal REE = +/- 10% PEE); 36% (62 of 173) were hypometabolic (REE less than 90% PEE), and 22% (39 of 173) were hypermetabolic (REE greater than 110% PEE). Host and tumor factors were compared between metabolic groups to identify potential determinants of abnormal energy expenditure. Differences between groups cannot be explained by differences in patient age, sex, body size, nutritional status, tumor burden, or duration of disease. Resting energy expenditure does not correlate with percent of weight loss, serum albumin, or duration of disease. Analysis by tumor site reveals patients with pancreatic or hepatobiliary tumors to be predominantly hypometabolic; gastric cancer patients tend to be hypermetabolic, whereas patients with colorectal or esophageal neoplasms are more evenly distributed across metabolic groups, the largest portion being normometabolic (X2 = 20.7, P less than 0.02). The majority of GI cancer patients have abnormal REE which is unpredictable and not uniformly hypermetabolic. The determinants of these abnormalities do not appear to be age, sex, body size, nutritional status or tumor burden. Primary tumor site is a major determinant of energy expenditure in GI cancer patients.

Age Factors↗
PubMed1983

Energy expenditure in malnourished cancer patients.

It is widely believed that the presence of a malignancy causes increased energy expenditure in the cancer patient. To test this hypothesis, resting energy expenditure (REE) was measured by bedside indirect calorimetry in 200 heterogeneous hospitalized cancer patients. Measured resting energy expenditure (REE-M) was compared with expected energy expenditure (REE-P) as defined by the Harris-Benedict formula. The study population consisted of 77 males and 123 females with a variety of tumor types: 44% with gastrointestinal malignancy, 29% with gynecologic malignancy, and 19% with a malignancy of genitourinary origin. Patients were classified as hypometabolic (REE less than 90% of predicted), normometabolic (90-110% of predicted) or hypermetabolic (greater than 110% of predicted). Fifty-nine per cent of patients exhibited aberrant energy expenditure outside the normal range. Thirty-three per cent were hypometabolic (79.2% REE-P), 41% were normometabolic (99.5% REE-P), and 26% were hypermetabolic (121.9% REE-P) (p less than 0.001). Aberrations in REE were not due to age, height, weight, sex, nutritional status (% weight loss, visceral protein status), tumor burden (no gross tumor, local, or disseminated disease), or presence of liver metastasis. Hypermetabolic patients had significantly longer duration of disease (p less than 0.04) than normometabolic patients (32.8 vs. 12.8 months), indicating that the duration of a malignancy may have a major impact upon energy metabolism. Cancer patients exhibit major aberrations in energy metabolism, but are not uniformly hypermetabolic. Energy expenditure cannot be accurately predicted in cancer patients using standard predictive formulae.

Aged↗
PubMedDate not supplied

Treatment effects of parenteral vitamins in total parenteral nutrition patients.

To determine the prevalence of abnormal vitamin levels in an adult hospitalized population requiring total parenteral nutrition (TPN) and to assess the effect of routine parenteral vitamin therapy on vitamin levels, we studied 35 general surgical patients. Assays for 12 vitamins were performed both before and after a standard 10-day course of TPN. Patients were given nothing by mouth. The first 25 patients received a daily parenteral vitamin mixture tailored to the recommendations of the Nutrition Advisory Group of The American Medical Association (maintenance dose). The final 10 patients were given a parenteral multivitamin dose providing substantially greater amounts of most vitamins (repletion dose). Only 58% (190/324) of pre-TPN vitamin levels were normal, 25% were low, and 17% were high. No patient had fewer than two abnormal baseline levels. Vitamin levels did not correlate with serum albumin, body weight, or nitrogen balance. After 10 days of treatment, only 39% of low pre-TPN vitamin levels improved; most (45/62) of the low posttreatment levels were low at baseline. The higher repletion dose resulted in a significantly (p less than 0.01) greater percent increase in vitamin A, C, and pyridoxine levels. The prevalence of abnormal vitamin levels in this population is high (42%). Standard parenteral vitamin therapy leads to marginal improvement in abnormally low pre-TPN vitamin levels.

25-Hydroxyvitamin D 2↗