BMI (kg/m2)
Weight classification
<18.4
Underweight
18.5–24.9
Normal weight
25.0–29.9
Overweight
≥30.0
Obese
Table 6.2
Height assessment in bedridden patients
Females | 84.88 – (0.24 × age) + (1.83 × knee height) |
Males | 64.19 – (0.04 × age) + (2.02 × knee height) |
Females | (1.35 × demispan) + 60.1 |
Males | (1.40 × demispan) + 57.8 |
4.
Body composition can be altered as a result of physiological factors (age, sex, and physical activity) or pathological ones. It is important to determine the body composition during the nutritional assessment because malnutrition and cancer cachexia alter this composition. A reduced fat-free mass and alterations in intracellular and extracellular volumes are often seen in palliative care patients. Many techniques can be used to determine body composition. The most widely used are plicometry, bioelectrical impedance analysis, and dual-energy X-ray absorptiometry. Imaging techniques (ultrasound, computed tomography scans, and magnetic resonance imaging scans) and total body potassium measurement are expensive and generally not utilized in clinical practice. Body fat mass and hence body fat-free mass can be easily measured by plicometry. This method is inexpensive and very quick. Moreover, the triceps skinfold thickness and arm circumference can be used in formulas to give the arm muscle circumference and arm muscle area. Body impedance analysis measures the opposition of body tissues to the flow of a small alternating current and is used to determine total body water, fat-free mass, and fat mass. Dual-energy X-ray absorptiometry (DEXA) determines the body’s absorption of photons when irradiated by X-rays at two different energy levels. This technique is normally used to evaluate bone mineral density. It is a widely employed method and one of the most reliable techniques for assessing body composition [21].
5.
Laboratory analyses are also needed when evaluating nutritional status. Routine blood tests, urinalysis, nutrient levels, metabolic balances, immunological tests, and functional tests are used. Plasma protein levels are a part of the nutritional assessment. The levels of plasma proteins are generally lower than normal in malnutrition states since there is decreased protein synthesis in this condition. Serum albumin, transferrin, prealbumin, and retinol-binding protein are the proteins most frequently determined in a nutritional assessment. These proteins have different half-lives: albumin about 15–20 days, transferrin 8–10 days, prealbumin about 2 days, and retinol-binding protein about 10 h. Poor surgical outcomes are associated with hypoalbuminemia. Immunological tests are used in nutritional assessment since malnutrition causes immune system alterations. A lymphocyte count <1,500/mm3 is an indicator of malnutrition. Complement fraction 3 and skin test reactivity are also determined. Finally, measurements of the blood levels of vitamins, minerals, and trace elements are included in the nutritional assessment.
It is important to appreciate that the results of anthropometric and laboratory analyses should be interpreted carefully since many alterations can be due to the neoplastic disease itself rather than to malnutrition. Body weight, BMI, and weight loss can all be affected by the dehydration or edema often found in cancer patients receiving palliative care. Levels of plasma proteins could be lower than normal as a consequence of urine and bowel leakage and interactions with acute-phase proteins. Immunological parameters, e.g., lymphocyte count, could be altered by hepatic or renal impairment or drug therapies such as steroids or immunosuppressants.
No parameter alone, except perhaps loss of body weight, can make the diagnosis of malnutrition. The diagnosis is made on the basis of many parameters and the nutritionist’s experience is pivotal in this regard.
6.3.2 Nutritional Screening Tools
All patients undergoing surgery should be screened preoperatively to evaluate their nutritional status and nutritional risk, as recommended by international guidelines (American Society for Parenteral and Enteral Nutrition (ASPEN), European Society for Clinical Nutrition and Metabolism (ESPEN)). The screening is important to identify malnourished patients or those at nutritional risk. When such patients are identified, they should be addressed to nutrition specialists or to perioperative nutritional support. Nutritional status should be assessed weekly in all patients not only in the preoperative period but also after the surgical procedure. With proper nutritional support, this can help to avoid worsening of the nutritional status.
Nutritional screening tools utilize objective and subjective data to determine the patient’s nutritional state. These tools are easy to use by nurses, by nonexpert personnel, and even by patients themselves and should be used in every surgery department, but especially in cancer surgery departments.
For patients receiving anticancer treatment, the ASPEN guidelines [22] recommend the Subjective Global Assessment (SGA), the Patient-Generated Subjective Global Assessment (PG-SGA) [23], and the Nutrition Risk Index (NRI) [24], while the ESPEN guidelines [25] recommend the Malnutrition Universal Screening Tool (MUST) [26], the Nutritional Risk Screening 2002 (NRS-2002) [27], and the Mini Nutritional Assessment (MNA) [28].
The SGA is a questionnaire incorporating information about medical history (weight change, dietary intake, gastrointestinal symptoms and functional impairment changes in food intake) and physical examination (muscle wasting, subcutaneous fat loss, and edema) and classifies patients into being well nourished (A), mildly to moderately undernourished (B), and severely undernourished (C). Among patients receiving palliative care, a strong correlation was found between the SGA score and nutritional status determined by the objective method [29]. The PG-SGA is an adaptation of the SGA and was developed specifically for patients with cancer. The medical history can be provided by the patient using a format of checking four boxes (weight, food intake, symptoms, activity, and functions). The physical examination (fat stores, muscle, and fluid status) is performed by a physician, nurse, or dietitian. Patients are classified as well nourished, moderately malnourished, and severely malnourished.
The NRI is based on a mathematical equation: NRI = [1,519 × albumin (g/L)] + [41.7 × (present weight – usual weight)]. An NRI >100 implies no malnutrition, between 97.5 and 100 mild malnutrition, between 83.5 and 97.5 moderate malnutrition, and <83.5 severe malnutrition.
The NRS-2002 involves an initial screening (BMI, weight loss, dietary intake, and severe illness) and a final screening considering nutritional status (weight loss, body mass index, and food intake; 1–3 points) and severity of disease (1–3 points) and patient’s age (1 point if >70 years). Patients undergoing major abdominal surgery are assigned 2 points. Patients are classified as not at risk (≤3 points) or nutritionally at risk (≥3 points) and a nutritional care plan should be initiated.
The MUST considers BMI, unintentional weight loss, and the presence of an acute illness and classifies the risk of malnutrition as low (0 points), medium (1 point), or high (≥2 points).
The MNA is validated to evaluate the nutritional status of the elderly. It consists of 18 items: anthropometric data (weight, height, and weight loss), general data (medications, lifestyle, mobility), dietary data (food and fluid intake, number of meals), and autonomy of eating. Patients are classified as well nourished (≥24 points), at risk of malnutrition (17–23.5 points), or malnourished (<17 points). A Mini Nutritional Assessment short form (MNA-SF) was recently validated [30].
Every nutrition assessment should be followed by a plan of nutritional intervention or reassessment in patients at risk of malnutrition [31]. Nutritional screening tools are summarized in Table 6.3.
Table 6.3
Screening tools
Tool | Items (N) | Anthropometry | Diet | Others |
|---|---|---|---|---|
MUST | 3 | BMI, weight loss | Presence of acute illness | |
NRS-2002 | 4 + 2 | BMI, weight loss | Food intake | Severity of disease |
NRI | 3 | Present weight, usual weight | Albumin | |
MNA | 6 + 12 | BMI, weight loss, mid-arm and calf circumference | Food intake (3 items), fluid intake, mode of feeding | Mobility, psychological stress, drugs, pressure sores, independence, self-consideration of health and nutritional status |
SGA | 7 | Weight loss | Food intake | Gastrointestinal symptoms, functional impairment, physical examination (muscle and fat loss, edema) |
PG-SGA | 4 + 3 | Weight history, height | Food intake | Symptoms, activities and function, disease, metabolic demand, physical examination |
6.4 Perioperative Nutrition
Surgical procedures cause the production of stress hormones and inflammatory substances [32]. The neuroendocrine response to stress is proportional to the extent of the surgical injury and is characterized by inflammation, reduced immune responses, and oxidative stress [33]. The metabolic response to surgical trauma is mainly characterized by an increase in basal metabolic rate (BMR), a negative nitrogen balance, increased gluconeogenesis, and increased synthesis of acute-phase proteins [34]. These changes lead to a depletion of body compartments which can impair healing and increase the risk of postoperative complications. This risk is higher in malnourished patients.
Pancreatic surgery, advanced age, weight loss, low serum albumin, and nutritional support are factors correlated with postoperative complications [35].
6.4.1 Perioperative Nutritional Support
Fast track surgery and less invasive techniques have changed the approach to the surgical patient, especially in the preoperative period. This kind of surgery allows rapid recovery of bowel function and a quick return to natural feeding within 1–3 days after surgery. The duration of preoperative fasting should be 2 h for liquids and 6 h for solids (grade A recommendation), and oral nutritional supplements should be prescribed (approximately 200 mL, energy dense, 2–3 times daily) from the day of surgery until normal food intake is achieved (grade A recommendation) [36].
However, artificial nutrition, whether enteral or parenteral, can also play an important role in improving clinical outcomes in fast track surgery. Since artificial feeding is not without risks, it should be reserved only for those patients who are malnourished or at risk of malnutrition, i.e., patients who cannot be adequately fed by mouth for 7–14 days in the postoperative period [22, 37]. Artificial nutrition is not required in well-nourished patients or in patients who do not have surgical complications and are expected to eat orally in the postoperative period.
6.4.2 Route of Administration of Nutritional Support
The first choice of route for administering nutrients in surgical patients is enteral feeding. This kind of nutrition is easiest; is less expensive than parenteral nutrition; is associated with fewer complications, particularly infectious ones; and, moreover, stimulates anastomotic healing [38]. Early enteral nutrition improves gut function and wound healing in surgical patients [39, 40]. Possible side effects of enteral nutrition are diarrhea and vomiting, which can usually be controlled with a reduction of the infusion rate and are almost always well tolerated.
Parenteral nutrition should be prescribed in cases of intestinal failure (intestinal occlusion, intestinal ischemia, etc.) or when enteral nutrition is impossible to ensure.
6.4.3 Preoperative Nutritional Support
Malnutrition worsens and increases postoperative complications, surgical risk, and mortality. The ESPEN guidelines [41, 42] recommend preoperative nutritional support for at least 7–10 days in malnourished patients and in patients at high risk of malnutrition.
A high nutritional risk is defined by the presence of one or more of the following parameters: (1) weight loss >10–15 % within the preceding 6 months, (2) a BMI <18.5 kg/m2, (3) albumin <30 g/L, and (4) severe undernutrition determined by the SGA. If dietary supplements are insufficient to meet the patient’s nutrient requirements, artificial nutrition is needed.
The main goals of perioperative nutritional support are to minimize negative protein balance by avoiding starvation and maintaining muscle, immune, and cognitive function and to enhance postoperative recovery [42].
6.4.4 Postoperative Nutritional Support
Oral feeding and oral nutritional supplements can generally be started within 1–3 days after surgery, limiting the use of artificial nutrition. Nutritional supplements enable greater energy and protein intakes in a small volume. Artificial nutrition is needed in the presence of postoperative complications such as bowel obstruction, intestinal failure, impaired gastrointestinal function, and dysphagia. This nutritional therapy is recommended in the postoperative period for patients who had severe preoperative malnutrition, metabolic stress or a septic state, an inadequate food intake (<60 % of requirements) for more than 10 days, or when there has been no oral feeding for more than 7 days (Grade C recommendation) [41].
Parenteral nutrition should be reserved for patients who cannot be fed adequately either orally or enterally. Enteral nutrition is the first choice of artificial nutrition and should be started as soon as possible. The gastric route of enteral feeding (by a nasogastric tube) is easier to achieve than post-pyloric tube feeding (by naso-jejunal or jejunostomy inserted during surgery). This latter form of enteral feeding should be started when there is a high risk of aspiration and delayed gastric emptying or when there is an intestinal anastomosis in the upper gastrointestinal tract, and it is preferable to administer the nutrients downstream of the anastomosis.
The administration of nutrients should be initiated at a low flow rate (10–20 mL/h) and increased progressively according to the patient’s tolerance [41]. It can take a few days to reach the target amounts of calories and protein. If the calories that can be tolerated enterally are not sufficient, partial or peripheral parenteral nutrition should be integrated.
6.4.5 Nutritional Requirements in the Perioperative Period
Energy requirements should be 25 kcal/kg/ideal body weight but in patients with severe stress requirements may approach 30 kcal/kg/ideal body weight [42]. Energy requirements are better determined by indirect calorimetry, but it is often difficult to perform this examination in patients receiving palliative care, so BMR is almost always determined using the Harris-Benedict formula [43]. This formula is reported in Table 6.4. The BMR can be normal, decreased, or increased in cancer patients depending on the type of cancer and body composition [44].
Table 6.4
Harris-Benedict formula for calculating the basal metabolic rate in adults
Males | 66.4730 + (13.7516 × weight in kg) + (5.0033 × height in cm) − (6.7550 × age in years) |
Females | 655.0955 + (9.5634 × weight in kg) + (1.8496 × height in cm) − (4.6756 × age in years) |
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