Mass balance: a quantitative guide to clinical nutritional therapy. I. The predialysis patient with renal disease.

Mass balance principles can be readily applied to the patient with chronic renal failure for the more structured management of his/her nutritional and clinical course. Urine values provide valuable information with respect to rates of protein catabolism and sodium intake; creatinine excretion rates provide a ready check on data accuracy and lean body mass; urea and creatinine clearance can be calculated, if blood levels of these solutes are known. With accurate data on creatinine generation and the ratio of urea to creatinine clearance, creatinine clearance, urea generation, and protein catabolism rates can be estimated from blood levels alone. These techniques then provide quantitative guidance for the nutritional/medical staff in its efforts to control the clinical course of the patient with severly diminished renal function.     

Protein consumption and hepatic encephalopathy in alcoholic hepatitis. VA Cooperative Study Group #275.

Patients with alcoholic hepatitis frequently have moderate or severe malnutrition. Dietary protein intake may be restricted in these patients because of concurrent hepatic encephalopathy. To further evaluate the relationship between dietary protein intake and hepatic encephalopathy in alcoholic hepatitis, we evaluated prospectively gathered data from a study of 136 placebo-treated patients with moderate or severe alcoholic hepatitis conducted at eight Department of Veterans Affairs Medical Centers.

Physical examination, laboratory tests, and grade of hepatic encephalopathy were recorded at entry and every seventh day for the first 28 days of study. Average daily protein intake was calculated from dietary evaluation obtained by a registered dietitian at entry and again three times a week.

Sixty-three percent of patients had hepatic encephalopathy at entry. Hepatic encephalopathy decreased over time. Time dependent regression analysis found low protein intake, along with high blood urea nitrogen (BUN) and high serum creatinine, to be independently associated with worsening hepatic encephalopathy. Similar analysis found low BUN and less malnutrition at entry into the study to be independently associated with improved hepatic encephalopathy. Higher protein intake was associated with improved hepatic encephalopathy in univariate (p = 0.01), but not multivariate, analysis.

In patients with alcoholic hepatitis who can be treated with standard anti-encephalopathy medications (e.g., lactulose and neomycin), low protein intake is associated with worsening hepatic encephalopathy while a higher protein intake correlates with improvement in hepatic encephalopathy.     

The role of the dietitian in a multicenter clinical trial of dialysis therapy: the Hemodialysis (HEMO) Study.

The Hemodialysis (HEMO) Study is a randomized multicenter prospective clinical trial, supported by the National Institute of Diabetes, Digestive, and Kidney Diseases of the National Institutes of Health. The trial is designed to assess the effects of a standard versus higher dialysis dose and low versus high dialysis membrane flux on morbidity and mortality of chronic hemodialysis patients. The role of the dietitian in the HEMO Study is to support and maintain the nutritional status of randomized participants. To ensure participant safety, nutritional status is closely monitored by a variety of biochemical and participant-reported parameters. Serum albumin and equilibrated normalized protein catabolic rates are obtained monthly. Appetite assessment and dietary energy and protein intakes using a 2-day diet diary assisted recall are ascertained at baseline and on a yearly basis. Consumption of vitamins, minerals, and nutritional supplements, including oral enterals, tube feedings, and parenteral nutrition, is obtained at least once a year. In addition, anthropometry is performed at baseline and on a yearly basis. Prespecified changes in serum albumin level or body weight trigger action by the dietitian to prevent protein calorie malnutrition. The HEMO Study dietitians play a vital role in carrying out the nutrition program for the trial. The HEMO Study should provide important information about the natural history of the nutritional status of chronic hemodialysis patients and the impact of dialysis dose and dialysis membrane flux on these parameters.     

高蛋白饮食对腹膜透析病人营养状况影响的初步观察

目的观察过高蛋白质摄入进行饮食调整后对腹膜透析病人营养状况的影响。方法选取2005年7月至2006年11月期间规律随访的稳定腹透病人33例,其每日饮食蛋白质摄入(daily protein intake,DPI)均>1.2g/(kg·d)。由营养师为其制定食谱以减少蛋白质摄入。评估调整病人饮食DPI和热量摄入(daily energy intake,DEI)前后各营养指标的变化,包括血白蛋白(Alb)、瘦体重(LBM)、主观综合性营养评估(SGA),高钾、高磷和代谢性酸中毒发生的比例,以及病人生活质量和生活满意度(半定量评分方法,分为0～10分)。结果33例腹透病人6月后1人转血透,3人移植,1人死亡,共28人纳入研究。对象的平均年龄为61.4±12.3岁,男女比例分别为39.29%和60.71%。透析龄为8.8月(1～66月)。饮食调整半年内DPI,DEI下降具有统计学差异。所有病人饮食调整后不伴随胃肠道症状加重,生活质量和生活满意度无变化。饮食调整半年内,血ALB在3个月后明显上升为36.22±2.79g/L vs37.34±3.32g/L,P<0.05),血Scr半年后明显上升(753.91±311.02μmol/L vs835.93±283.39μmol/L,P=0.003),而LBM、SGA、高磷血症、高钾血症及酸中毒发生率在半年内变化均无统计学意义。结论过高蛋白质摄入的腹透病人经营养师制定食谱指导其合理摄入蛋白质和能量后,病人营养状况稳定,生活质量和生活满意度等无变化。     

Nutritional management of the adult patient undergoing peritoneal dialysis.

Until the last few years, maintenance peritoneal dialysis (PD) often was associated with progressive wasting due to frequent episodes of peritonitis, loss of considerable amounts of protein into the dialysate, and poor nutritional intake. Recently, available techniques have made PD a feasible alternative for the long-term care of the patient with end-stage renal failure. The incidence of peritonitis has been markedly reduced, and protein loss is only 4 to 20 gm. per dialysis treatment. Preliminary studies have shown no differences in the nutritional status of patients undergoing PD or hemodialysis, although both groups have evidenced malnutrition. In the patient undergoing PD, daily intakes of 1.2 to 1.5 gm. protein and 35 kcal per kilogram body weight are recommended. During times of stress, parenteral administration of nutrients may be necessary. Dietary supplements may often be required chronically. Careful studies are needed to difine the nutritional needs of the patient undergoing PD.     

Positive and Negative Aspects of Sodium Intake in Dialysis and Non-Dialysis CKD Patients

Sodium intake theoretically has dual effects on both non-dialysis chronic kidney disease (CKD) patients and dialysis patients. One negatively affects mortality by increasing proteinuria and blood pressure. The other positively affects mortality by ameliorating nutritional status through appetite induced by salt intake and the amount of food itself, which is proportional to the amount of salt under the same salty taste. Sodium restriction with enough water intake easily causes hyponatremia in CKD and dialysis patients. Moreover, the balance of these dual effects in dialysis patients is likely different from their balance in non-dialysis CKD patients because dialysis patients lose kidney function. Sodium intake is strongly related to water intake via the thirst center. Therefore, sodium intake is strongly related to extracellular fluid volume, blood pressure, appetite, nutritional status, and mortality. To decrease mortality in both non-dialysis and dialysis CKD patients, sodium restriction is an essential and important factor that can be changed by the patients themselves. However, under sodium restriction, it is important to maintain the balance of negative and positive effects from sodium intake not only in dialysis and non-dialysis CKD patients but also in the general population.     

Full protein alimentation and nitrogen equilibrium in a renal failure patient treated with continuous hemodiafiltration: a case report of 67 days of continuous hemodiafiltration.

Standard care for patients with renal failure while in an intensive care unit involves traditional hemodialysis or peritoneal dialysis and protein restriction. We present a case of a patient with renal failure supported with continuous arteriovenous hemofiltration with dialysis (CAVH-D) who was given full protein alimentation. Total daily urea clearance was measured from the CAVH-D output. Protein load was 196 +/- 34 g/day while receiving total parenteral nutrition and 164 +/- 30 g/day while receiving enteral alimentation. Serum blood urea nitrogen was controlled between 40 and 75 mg/dL, except during septic episodes. Nitrogen balance was estimated based upon known alimentation protein load and measurable and estimated nitrogenous losses. The patient was potentially in nitrogen equilibrium during most of the dialysis period. The cumulative nitrogen balance was positive by 5.2 g after 67 days of dialysis. Volume of alimentation was 3.49 +/- 0.7 liters/day. With CAVH-D, the renal failure patient can receive full alimentation without volume or protein load limitations. Furthermore, nitrogen balances can be estimated easily while the patient is on CAVH-D.     

Use of urea kinetics in the nutritional care of the acutely ill patient

In acutely ill patients nitrogen balance is often assessed clinically from measurements of protein intake and urinary urea nitrogen. We have utilized urea kinetic modeling to measure urea generation rates, protein catabolic rates and nitrogen balance in 19 acutely ill patients with varying degrees of renal dysfunction and have studied the effect of varying caloric intake on protein balance during a period of fixed protein intake. In patients with measured creatinine clearances equal to or greater than 50 ml/min there was a highly significant correlation between nitrogen balance estimates derived from urea kinetic modeling and those obtained from urinary urea nitrogen (R = 0.939; p less than 0.001). When creatinine clearance measurements were between 20 to 50 ml/min the correlation between the two estimates was poorer (R = 0.337; p less than 0.001). In patients whose creatinine clearance was below 20 ml/min the correlation between measurements was worse still (R = 0.229; p less than 0.002). To determine the effects of increasing caloric intake on protein catabolic rate seven acutely ill patients were studied. When caloric intake was increased from 27.8 to 34.2 kcal/kg/day while on a fixed protein intake of 1.27 g/kg/day there was a significant fall in protein catabolic rate from 1.39 to 0.99 g/kg/day (p less than 0.002). As urea kinetic modeling takes into account changes in blood urea nitrogen, extrarenal losses of urea and the urinary urea pool, it is the preferred method for measuring protein balance in acutely ill patients particularly those with poor renal function. Serial monitoring of protein catabolic rates permits easy continuous assessment of the effect of increasing caloric intake on protein sparing during parenteral hyperalimentation.     

Intradialytic nutritional support

PURPOSE OF REVIEW: Intradialytic nutritional support has been used for more than 30 years both in critically ill patients with acute renal failure and during maintenance hemodialysis. Present knowledge allows better estimation of its metabolic and nutritional efficacy, as well its effect on patient outcome. RECENT FINDINGS: Recent data showed that intradialytic nutritional support is able to counteract these effects of dialysis on protein metabolism and to improve both nitrogen and energy balance. In maintenance hemodialysis patients, the improvement of nutritional status during nutritional support was shown to improve long-term survival. In critically ill patients with acute renal failure, protein sparing is one of the main therapeutic goals. The effect of nutritional support on patient outcome is not demonstrated. Recent data, however, showed that the improvement of nitrogen balance may be associated with a better outcome. SUMMARY: Current information helps to better assess the effects of intradialytic nutritional support, to clarify the nutritional management of renal failure patients and to provide recommendations. Future research should focus on the possible means to improve the efficacy of nutritional support, either by modifying its components of by associating anabolic or anticatabolic agents.     

A baseline audit to evaluate the quality of nutritional provision delivered to fractured neck of femur inpatients

Background: Fractured neck of femur patients are often malnutrition (Lumbers et al., 2001). Studies have found 30–50% of patients are malnourished on admission, and dietary intake during recovery in hospital is frequently suboptimal resulting in a deterioration of nutritional status, and impaired recovery. The aim was to baseline the nutritional care given to this patient group, and objectives were set to evaluate initial nutritional screening, nutritional interventions delivered and nutritional monitoring. Methods: Data were collected on all fractured neck of femur patients present on an orthopaedic ward on two separate dates in February 2010. Audit standards were set for clinical care, and data were collected using information from the medical/ nursing notes, as well as from observations made on the ward throughout the day. The audit form was designed to capture data on use of nutrition screening and monitoring, delivery of nutritional care and dietetic referrals. In addition, an estimate of the energy and protein intake of each patient was made for the day of the audit, and this was compared with the estimated requirement based on 125 kJ kg^?1 (30 kcal kg^?1) and 1g protein kg^?1. Results: A total of 33 patients were included, the mean age was 83 years (range 49–94 years), 85% were female, and 24% had dementia. Twenty‐seven (81%) patients had an initial Malnutrition Universal Screening Tool (MUST) score (BAPEN, 2003) calculated. It was calculated using a measured weight in 18% of these, and nine patients had a previous weight recorded for score calculation. Of these, 51% (17 patients) were given an initial MUST score of zero, indicating a low risk of malnutrition. First‐line nutritional care was poorly documented, and often not observed. Assistance was given to 11 (33%) patients but not all these had a red tray. Fifteen (45%) patients were referred to the dietitian. Of those not referred 74% were taking ≤50% of their daily energy requirement; 78.5% patients referred to the dietitian were seen within two working days of referral. Oral nutritional supplements (ONS) were prescribed for 39% patients; this was following dietetic referral in all cases. Fourteen (42%) patients had food record charts in their notes to monitor food intake, and 60% of patients with a MUST score ≥1 were monitored in this way. Only 14% patients who were inpatients for more that 7 days had weight and MUST score repeated weekly. Twenty‐one (63%) patients were getting ≤50% of their daily energy requirement, and 45% patients were getting ≤50% of their daily protein requirement on the day of the audit. Discussion: This audit showed that many of the standards of nutritional care were not met, and many patients were not consuming enough energy or protein on the day of the audit. Although evidence suggests that routine supplements are of benefit in this patient group (Volkert et al., 2006), 61% did not have ONS prescribed. These findings were used to devise a dedicated nutritional care pathway, in the form of a flow diagram, to highlight the importance of nutrition in this patient group throughout their hospital stay, and promote best practice in nutritional assessment, delivery and monitoring, as well as trigger routine blanket ONS twice a day, an extra daily snack, and appropriate dietetic referral. Conclusions: This audit has highlighted nutritional care in this high‐risk group of patients and that greater dietetic involvement is needed to improve their nutritional status. References: BAPEN (2003) Malnutrition Universal Screening Tool (MUST). http://www.bapen.org.uk/must_tool.html (accessed on 28 February 2010). Lumbers, M., New, S.A., Gibson, S. & Murphy, M.C. (2001) Nutritional status in elderly female hip fracture patients: comparison with an age matched home living group attending day centres. Br. J. Nutr. 85 , 733–740. Volkert, D., Berner, Y., Berry, E., Cederholm, T., Coti Bertrand, P., Milne, A., Palmblad, J., Schneider, St., Sobotka, L. & Stanga, Z. (2006) ESPEN guidelines on enteral nutrition: geriatrics. Clin. Nutr. 25 , 330–369.     

The effects of megestrol acetate on nutritional parameters in a dialysis population.

OBJECTIVE: To examine the effect of megestrol acetate on nutritional parameters in a hemodialysis population. DESIGN: Prospective case studies of hemodialysis patients. SETTING: A freestanding, nonprofit, hemodialysis unit. SUBJECTS: Seventeen patients were studied. They were included regardless of gender, age, or cause of renal disease. They had to be on dialysis for at least 2 months, had a serum albumin <3.5 g/dL for these 2 months, and had to be at high nutritional risk. There were 8 women and 9 men. Ages were 44 to 87 years. Eight were diabetics, and 9 were nondiabetics. INTERVENTIONS: Megestrol acetate 400 mg orally twice daily was prescribed, and patients were studied for 6 months. OUTCOME MEASURES: Pre-evaluation and postevaluation were performed by patient questionnaire, Subjective Global Assessment (SGA), dry weight, and anthropometric measurements. Monthly laboratory monitoring included albumin, prealbumin, blood urea nitrogen (BUN), cholesterol, triglycerides, carbon dioxide, platelets, hematocrit, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gammaglutamyl transpeptidase (GGT), lactate dehydrogenase (LDH), alkaline phosphatase, and glucose. Glycohemoglobin and hemoglobin A1c were monitored in diabetic patients. RESULTS: Three patients were able to take megestrol acetate for 5 to 6 months. They reported improved appetite and showed an increase in dry weight. The annualized mortality rate was about 59%. Side effects included diarrhea, confusion, hyperglycemia, headaches, dizziness, and elevated LDH. CONCLUSION: Megestrol acetate may help stimulate appetite in the hemodialysis patient, but it is risky and must be monitored closely. Eight hundred milligrams per day is probably too large a dose for the end-stage renal disease (ESRD) patient.     

Nutritional support of the critically ill. Part II--Guidelines for clinical dietitians.

The second of a two part article, this section focuses on aspects of dietetic practice in a general adult Intensive Care Unit (ICU). Current recommendations for nutritional support are briefly outlined. Techniques of nutritional assessment and monitoring of nutritional support are reviewed, with a case study example taken from actual practice in the ICU at the University of Alberta Hospitals. The results of an audit of nutritional support in ICU patients at the University of Alberta Hospitals are presented. The audit provided documentation of the benefits of expanded dietitian involvement in the nutritional care of adult ICU patients.     

Compliance of orthopaedic patients with postoperative oral nutritional supplementation

BACKGROUND: Studies have shown clinical benefits of nutritional supplementation in orthopaedic and elderly patients in both under and well nourished groups. However, patient compliance with the supplementation has not been reported. AIM: To assess level of patient compliance with nutritional supplementation when prescribed postoperatively to unselected orthopaedic patients as part of a large controlled trial researching the clinical benefits of non-targeted nutritional supplementation. METHODS: Patients in the intervention group were prescribed two oral supplements each day of their hospital stay, in addition to usual meals. Information describing the supplements was given by the dietitian. Supplements were issued on drug rounds and the proportion of each drink consumed was recorded and collated. Patients could choose to change the type of drink or to discontinue the supplements completely at any time. Twenty-four hour food intake was analysed for a random sub-sample of 48 patients. RESULTS: Eighty-four patients (27 men, 57 women; mean age, 72 years) were prescribed supplements. Median length of stay was 14.4 days. Supplements were taken for a mean of 6.7 days. Median compliance was 14.9%. Despite this, median energy intake in the study group was 1523 kcal/day and 1289 kcal/day in the control (P= 0. 0214). CONCLUSION: Compliance with non-targeted, postoperative nutritional supplementation is poor in unselected orthopaedic patients but even low levels of supplementation significantly increase energy intake.     

Nutritional effects of peritonitis in continuous ambulatory peritoneal dialysis (CAPD) patients

Peritonitis, a major complication of end-stage renal disease patients treated with continuous ambulatory peritoneal dialysis (CAPD), enhances peritoneal protein losses by increasing protein and energy requirements while simultaneously decreasing appetite, usually causing a negative nitrogen balance. The influence of peritonitis on the nutritional status of CAPD patients was evaluated. Fourteen end-stage renal disease patients being treated with CAPD and presenting with peritonitis were randomized to one group with and one without a nutritional supplement. Four CAPD patients without peritonitis served as controls. Anthropometric measurements, laboratory determinations, dietary protein intake, and protein catabolic rate were obtained. The control group lost an average of 9.6 gm protein per 24 hours in the peritoneal fluid vs. an average of 15.1 gm protein per 24 hours lost by patients with peritonitis (p less than .01). Serum albumin did not decrease except in two diabetic patients in whom it dropped an average of 42% and remained low. Nitrogen balance remained positive in all patients except one with diabetes who had very low daily protein intake and caloric intake. The catabolism produced by short uncomplicated peritonitis did not create a negative nitrogen balance in patients eating at least 1 gm protein per kilogram ideal body weight (IBW) and 25 kcal/kg IBW.     

Enteral nutrition in patients with an open peritoneal cavity.

Recent surgical advances have led to the increased survival of critically ill patients requiring postoperative nutritional supplementation. One technique, which has been increasingly used, is that of the open peritoneal cavity. In these cases, the peritoneum is left open, and the viscera are protected with a temporary dressing until the abdomen can be closed. The aim of this study was to evaluate the efficacy and tolerance of enteral nutrition in patients who need open peritoneal cavity management techniques. Patients at a tertiary referral center requiring the use of open peritoneal cavity management who received at least 4 days of enteral nutrition were included in the study. Retrospective data were collected on patients admitted between January 1999 and December 2000, and prospective data were collected on patients between January and May 2001. Energy expenditure and actual caloric and protein intake were determined in all patients. Prealbumin levels and nitrogen balance studies were analyzed when available. Intolerance, defined as diarrhea or gastric reflux, was also evaluated. Average daily total caloric intake was 77 +/- 27%, and average daily protein intake was 68 +/- 24% of estimated needs. Initial serum prealbumin levels were low and remained below normal but increased in some patients during the study. Average nitrogen balance studies from 3 patients was -15 +/- 9.7 g/d. Diarrhea and gastric reflux occurred in 42% and 36% of patients, respectively, and were easily treated. Enteral nutrition can be effectively used in patients requiring open peritoneal cavity management after laparotomy. Overall, enteral nutrition is relatively well tolerated in this patient population.     

Can malnutrition in predialysis patients be prevented by dietetic intervention?

OBJECTIVE: This study aimed to discover if the documented decline in nutritional status in predialysis patients could be prevented by dietetic intervention. DESIGN: Longitudinal prospective interventional study. SETTING: General hospital nephrology clinic. PATIENTS: Eleven patients with progressive chronic renal failure not yet requiring dialysis, all with creatinine clearance below 25 mL/min were studied. Mean age was 63.9 +/- 14.5 years. INTERVENTION: Patients received nutritional counseling from a renal dietitian on at least 3 occasions over a period of 6 months. Following assessment, patients were advised on dietary changes according to individual need, aiming for adequate energy intake to achieve or maintain a body mass index of 20 to 25 and protein intake of 0.8 to 1.0 g/kg/d. Dietary supplements were prescribed when necessary. OUTCOME MEASURES: Changes in nutritional status were assessed by Subjective Global Assessment, anthropometric measures (weight, triceps skinfold thickness, mid arm muscle circumference, and grip strength), and biochemical markers (serum albumin, serum transferrin, and insulin-like growth factor-1). RESULTS: None of the patients showed decline in Subjective Global Assessment category, and 2 of the patients improved. All anthropometric and biochemical measures of nutritional status were stable or increased over the course of the study, and mid arm muscle circumference increased significantly (P <.05), contrasting with published data showing a decline in these measures in patients not receiving dietetic intervention. CONCLUSION: With dietetic intervention, it may be possible to maintain or improve nutritional status in this group.     

Hepatic proteins and nutrition assessment

Serum hepatic protein (albumin, transferrin, and prealbumin) levels have historically been linked in clinical practice to nutritional status. This paradigm can be traced to two conventional categories of malnutrition: kwashiorkor and marasmus. Explanations for both of these conditions evolved before knowledge of the inflammatory processes of acute and chronic illness were known. Substantial literature on the inflammatory process and its effects on hepatic protein metabolism has replaced previous reports suggesting that nutritional status and protein intake are the significant correlates with serum hepatic protein levels. Compelling evidence suggests that serum hepatic protein levels correlate with morbidity and mortality. Thus, serum hepatic protein levels are useful indicators of severity of illness. They help identify those who are the most likely to develop malnutrition, even if well nourished prior to trauma or the onset of illness. Furthermore, hepatic protein levels do not accurately measure nutritional repletion. Low serum levels indicate that a patient is very ill and probably requires aggressive and closely monitored medical nutrition therapy.     

Nutritional monitoring of a pediatric burn patient.

The pediatric burn patient presents a particular challenge nutritionally. Nutritional reserves are limited, and excesses are often poorly tolerated. Ongoing monitoring is essential for discovering at an early stage the dynamic shifts in energy, protein, and other nutrients that may be occurring. Adequate enteral intake may be difficult to achieve as a result of repeated holding of feedings on surgery days and gastrointestinal tolerance problems such as poor gastric emptying and abdominal distention. This case report illustrates techniques, such as the nutritional assessment record and parenteral nutrition evaluation form, which may assist the clinician in optimizing the nutritional management of the patient.