Malnutrition in cancer patients results from multifactorial events and is associated with an alteration of quality of life and a reduced survival. A simple nutritional assessment program and early counselling by a dietitian are essential to guide nutritional support and to alert the physician to the need for enteral (EN) or parenteral nutrition (PN). A daily intake of 20–35 kcal/kg, with a balanced contribution of glucose and lipids, and of 0.2–0.35 g nitrogen/kg is recommended both for EN and PN, with an adequate provision of electrolytes, trace elements and vitamins. EN, always preferable for patients with an intact digestive tract, and PN are both safe and effective methods of administering nutrients. The general results in clinical practice suggest no tumor growth during nutritional support. The indiscriminate use of conventional EN and PN is not indicated in well-nourished cancer patients or in patients with mild malnutrition. EN or PN is not clinically efficacious for patients treated with chemotherapy or radiotherapy, unless there are prolonged periods of GI toxicity, as in the case of bone marrow transplant patients. Severely malnourished cancer patients undergoing major visceral surgery may benefit from perioperative nutritional support, preferably via enteral access. Nutritional support in palliative care should be based on the potential risks and benefits of EN and PN, and on the patient’s and family’s wishes. Research is currently directed toward the impact of nutritional pharmacology on the clinical outcome of cancer patients. Glutamine-supplemented PN is probably beneficial in bone marrow transplant patients. Immune diets are likely to reduce the rate of infectious complications and the length of hospital stay after GI surgery. Further studies are needed to determine the efficacy of such novel approaches in specific populations of cancer patients, and should also address the question of the overall cost-benefit ratio of nutritional pharmacology, and the effect of nutritional support on length and quality of life.

Nutritional support of the cancer patient: issues and dilemmas

THE wasting syndrome is one of the most devastating aspects of the acquired immunodeficiency syndrome (AIDS). Until therapies are developed that eradicate the human immunodeficiency virus (HIV) or halt its replication, wasting will be a major cause of morbidity and mortality in AIDS.1 2 3 This paper will review the metabolic disturbances that occur during AIDS, put them in the context of studies of cachexia with infection and cancer, and attempt to define the role of these disturbances in the pathogenesis of wasting. Weight Loss and Death from Inanition In the absence of disease, starvation leads to death at 66 percent of . . .

https://www.nejm.org/doi/pdf/10.1056/NEJM199207303270506?listPDF=true

Metabolic disturbances and wasting in the acquired immunodeficiency syndrome.

Cancer cachexia: Metabolic alterations and clinical manifestations

Direct calorimetry is the gold standard means of measuring human metabolic rate and its use has been fundamental for understanding metabolism in health and disease. While metabolic rate is now more commonly estimated indirectly from measures of the oxygen consumed during respiration, direct calorimetry provides the user with the unique capacity to quantify the heat produced from aerobic and anaerobic metabolism by measuring heat exchange between the body and the environment. This review provides a brief historical overview of the fundamental concepts which underlie direct calorimetry, of pioneer scientists which developed these concepts into functional pieces of equipment and the subsequent use of direct calorimetry to advance our understanding of energy balance, nutrition, and the pathogenesis of metabolic diseases. Attention is directed to seminal studies that successfully employed direct calorimetry to verify that the law of energy conservation also applies to human beings and to establish the validity of indirect calorimetry. Finally, we discuss the more recent use of direct calorimetry for the measurement of whole-body heat exchange and body heat storage in the study of human thermoregulation.

Direct calorimetry: a brief historical review of its use in the study of human metabolism and thermoregulation.

Background: There is no consensus regarding the optimal duration of measurement or time of day to perform indirect calorimetry (IC). Energy expenditure (EE) varies at different times of day and with different activity levels. We sought to assess the variability of EE in mechanically ventilated patients over a 24-hour period and the accuracy of 30-minute IC studies in predicting the 24-hour energy expenditure (EE24). Methods: The study was a prospective comparison between the resting EE obtained by 30-minute measurement of IC and EE values obtained from 24-hour measurements. Tests were performed in the Medical Intensive Care Unit (MICU) of a tertiary care, university hospital. Oxygen consumption (VO2) and carbon dioxide production (VCO2) were measured for 24 hours in eight ventilated patients. Measurements were made every 3 minutes and used to calculate 30-minute and 24-hour oxygen consumption values. EE24 was calculated using the modified Weir equation. Each 30-minute interval was compared with the value ...

Accuracy of 30-minute indirect calorimetry studies in predicting 24-hour energy expenditure in mechanically ventilated, critically ill patients

Elevated resting energy expenditure (REE) is a possible mechanism of cancer cachexia. We measured REE by whole-body direct calorimetry in patients with colon and non-small cell lung cancer and compared the results with REE in groups of healthy subjects and in patients with anorexia nervosa, with nonmalignant gastrointestinal (GI) disease, with miscellaneous reasons for weight loss, and with chronic lung disease. The mean REE of the cancer patients was not different from healthy subjects, those with GI disease, miscellaneous causes of cachexia, and chronic lung disease, and there was no significant difference in REE between those cancer patients with weight loss and controls with weight loss, except for the anorexia nervosa patients. The REE of the anorexia nervosa patients (female) was significantly lower than the REE of females with lung cancer. Weight loss correlated with REE in female lung cancer patients. Serial comparison of REE of ten cancer patients who lost 5% to 18% of their body weight during study showed no consistent change in REE. We conclude that patients with colon and non-small cell lung cancer, including those with weight loss, have REE similar to normal controls. Relative hypermetabolism may contribute to cancer cachexia, as may absolute hypermetabolism in some subsets of cancer patients.

Resting energy expenditure in lung and colon cancer

An indirect calorimetry system was assembled from three readily available major components: a digital pneumotachograph, an oxygen analyzer, and a carbon dioxide analyzer. A one-way valve, face mask, and meteorological balloon completed the system. Accuracy was assessed by comparison to direct calorimetry in hospitalized patients undergoing enteral hyperalimentation. Each subject was on continuous infusion of formula during a 7-day metabolic balance. Direct and indirect calorimetry was performed over the last 4 days of the balance. The overall agreement between the two methods was within 1%. A simple and inexpensive calorimetry system can therefore be assembled to provide an accurate measure of resting energy expenditure. (Journal of Parenteral and Enteral Nutrition 8:45-48, 1984)

A Simple and Accurate Indirect Calorimetry System for Assessment of Resting Energy Expenditure

A whole body gradient-layer calorimeter was designed for thermophysiologic studies in hospitalized patients. The instrument was assembled in a room adjoining a metabolic ward. The patient lies recumbent on a stretcher which is wheeled into the calorimeter on tracks. Once inside, the patient's head extends through one wall into a clear plastic canopy. The canopy is partially open on one side and is the entry point for fresh air into this open-circuit system. Heat flux transducers in the calorimeter walls, a thermopile in the exit air stream, and a platemeter in conjunction with wet and dry bulb thermometers allow measurement of total, wet, and dry heat losses from the subject. All calorimeter output signals are routed to a microcomputer system which processes the data and provides real-time output of results. A mannequin heat source is used to calibrate the gradient layer. Testing with a variety of wet/dry heat sources indicate total, wet, and dry heat measurements are accurate to within 2-3%. A typical study of resting energy expenditure requires 1 hr, and protocols of up to 6 hr are well tolerated. The calorimeter has proven to be reliable, accurate, and easy to operate. These qualities, combined with good patient tolerance, make it ideal for metabolic studies.

Human Gradient-Layer Calorimeter: Development of an Accurate and Practical Instrument for Clinical Studies

Respiratory, cardiovascular, and metabolic changes were monitored during balance studies in undernourished patients receiving continuous enteral formula feeding. The nutrient solutions, either high carbohydrate (83% of kcal) or high fat (50% of kcal), were administered at doses ranging from 2.7 to 6.0 x 10_2 kcal.kg fat free body mass� #{149}min�. For both formulas, the observed physiological changes between fasting and the lower rates of energy infusion (ie, maintenance-slow growth) were either zero or relatively small. As formula dose was advanced into the rapid repletional range, physiological changes were more pronounced; there were linear increases in oxygen consumption, carbon dioxide production, minute ventilation, heat production, heat release, nitrogen balance, and change in heart rate from base-line (all p < 0.05 for both formulas). The rate at which carbon dioxide production, minute ventilation, and heat production increased with advancing energy infusion rate was also greater for the high carbohydrate formula relative to the high fat formula (p < 0.02, <0.07, and <0.06, respectively). The physiological changes caused by continuous intragastric feeding are therefore a function of formula infusion rate and composition. Knowledge of these changes can be applied to patients treated for semistarvation who suffer respiratory or cardiac insufficiency. Am J Clin Nuir l984;40:l 16-130.

Respiratory, cardiovascular,and metaboliceffects of enteral hyperalimentation:influenceof formula dose and composition13

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Resting energy expenditure in lung and colon cancer

A Simple and Accurate Indirect Calorimetry System for Assessment of Resting Energy Expenditure

Human Gradient-Layer Calorimeter: Development of an Accurate and Practical Instrument for Clinical Studies

Respiratory, cardiovascular,and metaboliceffects of enteral hyperalimentation:influenceof formula dose and composition13