Malnutrition and Methods of Nutritional Assessment
Today, malnutrition is accepted as a common factor in clinical practice that result in an increased length of hospital stay, morbidity and mortality in patients hospitalized due to high risk of complications such as infection, phlebitis, pulmonary embolism, respiratory failure, low fistula healing and that they suffer. As a result, hospital stay and costs of therapy significantly increase. Nutritional status is normally the result of the balance between what is consumed and what was required, which is determined by the quality and quantity of dietary nutrients and their full utilization in the body.
In recent years, he had played down the nutritional assessment of patients, because the parameters so far have not been developed are approved, because in some cases affected by the response to the disease per se, also constitute a cost-benefit important to the patient. But now because of the impact of nutrition on clinical outcome has been increased interest in finding a precise marker of malnutrition. Nutritional assessment should be integral to any clinical evaluation to identify patients who require aggressive nutritional support early in order to reduce the risk of mortality secondary to preexisting malnutrition in hospitalized patients.
Methods of nutritional assessment
There are different methods to assess nutritional status, as is the questioning or the subjective global assessment, biochemical tests, body composition, immunological data and prognostic indices. The following describes each:
* Interrogation. Gives an estimate about eating habits, food intolerance, anorexia, vomiting, diarrhea, consequences of any surgical treatment, religious and cultural traditions that may influence a patient's nutrition. This method has the patient's age limitations, the ability to recall information, and the consciousness of the patient. Besides the possibility of under or over estimate the food ration, providing a significant miscalculation in its nutritional value.
* Subjective global assessment. It is a clinical technique that rapidly assesses the nutritional status according to the characteristics of the interrogation and physical examination found. Here patients are classified as normal, moderately malnourished and severely malnourished. This technique has not been formally evaluated in critically ill patients, lacks quantification and sensitivity is therefore limited in assessing changes in nutritional status after or during therapy of nutritional support.
* Biochemical tests.
* Total protein: protein synthesis may be regulated by many factors including the availability of amino acids and liver function. In acute disease there is an increased transcapillary escape of proteins for which there will changes in plasma concentrations do not reflect well and malnutrition. The critically ill patients may be affected by hydration status, the synthesis of acute phase proteins such as CRP and fibrinogen increase after severe illness or sepsis in association with a fall in albumin, prealbumin and transferrin, ignoring the state nutrition. The immune response to sepsis is very fast, mainly mediated by interleukins 1 and 6 and tumor necrosis factor, causing alteration in protein synthesis and thus changes in plasma levels independent of the effect of nutrition. Improve or normalizing levels of hypoproteinemia can make it harder for malnutrition and delay in recovering these plasma levels are reduced by adequate nutritional support, so their measurements may be useful in monitoring response to nutritional support.
* Albumin is the most common serum protein, within its functions is to maintain intravascular oncotic pressure, transport of amino acids, fatty acids, enzymes, hormones and drugs in plasma. It has been used in population studies as an indicator of Kwashiorkor or protein depletion, associated with decreased protein intake in the diets. It is an important test for predicting complications but its long half-life (20 days) and its sensitivity to nutritional depletion makes it a poor marker of nutritional status, values less than 3.5 g / dl at hospital admission is correlated with poor postoperative poor prognosis, increased hospital days and more time in the intensive care unit.
* Transferrin: A betaglobulina synthesized by the liver that is in the intravascular space which serves as carrier-binding and iron. Is directly measured by its ability to iron recombination and its levels can be evaluated in the context of iron stores as a decrease of this ends in increased levels of transferrin, which interferes with the interpretation of results.
* Prealbumin: transports thyroxine and retinol binding protein, in different studies proved a sensitive index of protein status and a large marker of response to nutritional support.
* Retinol binding protein: this protein has a half life of about twelve hours, is filtered by the glomerulus and metabolized by the kidney, which makes their use is limited in renal failure as it increases. It reflects acute changes in protein malnutrition and although it has high sensitivity levels and even minor stress changes is minimal use in clinical practice.
* Fibronectin: A glycoprotein found in blood and lymph with structural functions and defense. It has been found useful to be a great predictor of mortality i morbidity, in states of malnutrition were observed overall low levels, however critical the patient has a reduced ability to synthesize it.
* Somatomedin C: Also called growth factor 1 insulin-like, is a peptide synthesized in the liver that mediates the anabolic effects of growth hormone is regulated by dietary intake independently of the plasma hormone concentrations
* The total count of lymphocytes: An economic marker of immune function and nutritional risk is now commonly used, can be affected by surgery, chemotherapy, immunosuppressive agents and corticosteroids.
* Skin sensitivity tests: These tests are affected by various clinical conditions as atiinflamatorias drugs, corticosteroids, edema, poor techniques in the application of antigen, and so on. Altering its interpretation and not always showing total anergy by malnutrition, a situation that must be taken into account if there is to be used. Currently are unusual because they are impractical for routine use and high cost.
* Measurement of body nitrogen: The quantification of body nitrogen excretion should be performed in order to ensure that the protein supplied is fulfilling the function of cellular regeneration and healing, not as a source of bodily energy which ends up in protein repletion. In the nitrogen balance is measured intake and excretion of the same, the difference of the amount withheld or lost by the body. Nitrogen is excreted through the urine as urea nitrogen, which represents 90% of total urinary nitrogen, and the remaining as non-urea. It is considered the "golden rule" and is used by the nutrition support group for assessing the adequacy of support system. It is subject to errors in urine collection, over-intake or change in the interpretation and must be recalled that the estimator only or "raw" nitrogen retention.
* Urinary Excretion of Creatinine: Creatinine is a protein product of protein metabolism, which is derived from creatine which is synthesized in the liver, pancreas and kidney. Creatine degrades to creatinine, a reusable product that is excreted in the urine. So, being a muscle product. Reflects the general state of muscle mass and decreases in protein depletion states, 1 g of urinary creatinine is approximately 18 g of muscle mass. Creatinine excretion decreases with age, increases in acute infection, trauma, high-protein diets and is not valid in renal failure, likewise, there is individual variation in excretion up to 20% from one day to another, so its safer means for obtaining a strict collection of urine for 24 hours for three consecutive days.
* Body composition. The body components (total fat and fat-free mass) can be measured with different methods or calculated based on these other areas. Commonly used methods are:
* Anthropometry: The muscular circumference and subcutaneous skinfolds (biceps, triceps, subscapular and suprailiac) were used to measure somatic protein and fat reserve total, including Body Mass Index or Quetelet also stopped for the latter. The derivation is quick, easy, painless, immediate analysis is not expensive nor invasive. The extent of the folds mainly estimate the duration and severity of poor intake over a long period of time. Its use is limited because it requires expensive equipment.
* Imaging: Different techniques such as ultrasound, magnetic resonance imaging and computed tomography have emerged as measuring body composition. In the case of computed tomography transverse sectional area of adipose tissue, bone, muscle or visceral organs can be determined by sophisticated software programs. Because the thickness of the cuts is known, one can calculate the relative surface area or volume occupied by each organ or tissue in the reconstructed images.
Bioelectrical Impedance: Based on the electrical properties of tissues in the body, this pipe is connected with the free ion content of various salts, acids and bases, water and electrolytes intraextracelulares. While muscle mass is highly conductive, fat and bone are very little. In general, the impedance measured fat-free mass by determining the difference in driving between fat and muscle mass. It offers a real estimation of body composition under conditions of normal hydration, except in the critically ill due to changes in hydration status and changes in the fluids is presented.
* Total Body Potassium: Potassium is an intracellular cation that is not present in the fat reserve. Naturally abundant in the body exists an isotope of potassium, called K40, which emits radiation spontaneously to 1.46 Mev. It can be measured using a meter full body in order to estimate total body potassium and therefore muscle mass. Their quantification requires specially built quarter and protected to reduce external radiation, with systems of gamma detection. After determining the K40, muscle mass can be estimated with a constant potassium content of fat-free mass. The concentration of potassium can vary with age and adiposity, in obese potassium concentration in muscle tissue is lower than in non-obese.
* In vivo neutron activation: It is the only technique capable of measuring body composition multielemental as easily measured the total content of calcium, sodium, chlorine, phosphorus and nitrogen, which emit gamma radiation measured when the patient is irradiated, allowing quantify the content of each body. The energy level identifies the element and level of activity indicates its abundance.
* Total Body Water: This method is based on the principle that water is not present in the fat reserves and occupies a constant fraction of fat-free mass, hence their determination serves as an indicator of body composition. Have been used for hydrogen isotopes, deuterium and tritium to quantify the amount of body water by isotope dilution in diseased and healthy individuals. The mass of muscle tissue is calculated by the difference between the result of total body water, lean body mass and body weight.
* Tests functionality. In a malnourished patient are structural and metabolic changes in skeletal muscle. The cellular mechanisms responsible for this decline have not been widely demonstrated. Based on the above, there have been studies that have shown that a functional test as a test to evaluate nutritional status is more sensitive than the same amount of muscle mass present. Then to measure functional status using two methods: the dynamometry, which is measured muscle strength, and electrical stimulation from muscle fatigue.
In general the ideal method for diagnosing the nutritional status has not been identified and among those available so far none have actually been accepted as safe. Find an easy method that is highly specific and sensitive with a proper cost-benefit ratio remains a subject of research. In clinical practice should be suspected impaired nutritional status of a patient when you have a weight loss percentage less than 10% without cause established, this prolonged anorexia, albumin less than 3.5 mg / dl and decreased work capacity.
Structure and function of a metabolic nutritional support unit
There is an excellent mechanism to identify patients who need nutritional support, reducing the complications associated with enteral nutrition and parenteral nutrition support and provide cost-effective in hospitals. Expressed in the simplest form, the purpose of providing nutritional support team nutritional care, usually performed in three ways:
1. Identification of patients affected nutritionally.
2. Implementation of a nutritional assessment that can adequately guide nutritional therapy.
3. Provision of safe and effective nutritional support.
To achieve these goals, you have to develop a service project that includes the following:
* Question of the hospitalized patients. Metabolic and Nutritional assessment and management of patients requiring nutrition scheduled monitoring and monitoring through the round of the nutrition support team.
* Educational programs. Conferences and meetings at the departments, aimed at medical, nursing, nutrition and pharmacy clinical rotations for residents, developing educational material to be used by professionals in the medical field with patients.
* Ensure quality. Development of hospital guidelines, policies and procedures for parenteral and enteral nutrition, standing orders and orders of standardized formats.
* Research. Development and evaluation of new products for nutrition and metabolic support, development and evaluation of tracking parameters.
* Program of nutritional support at home. Patient Education and training; planning hospital discharge; policies to interact with external commercial vendors, follow-up clinics.
The special nutritional support should be provided through a group consisting multidisciplinary the physician, a nurse, a dietitian and a pharmacist expert in the area.
The proper functioning of this service that integrates disparate disciplines requires optimal organization should be based on written rules and procedures and centralized on a physical area within a hospital that has appropriate conditions for the preparation of solutions, equipment and components assessment of patients.
These services or units in addition to offering this therapy, should help with the hospital administration in streamlining costs and promote continuing education programs and research is this field.
The application of special nutritional support for a group multidisciplinary is an accepted fact, having been shown the benefits of individual therapy by the treating physician about clinical benefits, reducing complications and costs, expanding coverage, creation of outpatient programs continuing education and research. Once the group consisting of metabolic and nutritional support, the only hospital authorized to initiate and discontinue specialized nutritional support by parenteral nutrition. To achieve adequate control in this sense the group recorded in the hospital pharmacy patients who were started on parenteral nutrition special and only they were allowed the administration of this therapy.
Once enrolled the patient, the pharmacy staff made clear the order marked on the corresponding day. Of thus can not be given more than one formula per day for the same patient and this event occurs, a person of the group must personally authorize.
Members of the group of metabolic and nutritional support will have the following functions:
* Doctor: is responsible for decisions regarding diagnosis and treatment plan; define assessment procedures or nutritional assessment, performs vascular access procedures, formulates and prescribes the regime of support and follow up leads and monitors the patient, and suspended or modify the treatment according to the changing needs of the patient.
* Nurse: Responsible for the continued and ongoing management of the patient, both physical and material aspects, such as appearance, emotional and psychological. It is responsible for preparing parenteral nutrition solutions, except for hospitals where a pharmacist. Must keep in constant availability of equipment, materials recovery, and so on. It takes meticulous and accurate recording of fluid balance against the infusion rates, substrates for food and generally oversees all nursing care by patient care. also is responsible for education and training of technical staff that handles nutritional support.
* Dietician nutritionist: is responsible for determining the individual needs of patients through nutritional assessment protocol, making the interpretation of the findings in the light of careful nutritional history, recommends and implements nutritional regimes, implementing the requirements of medical evaluates the effectiveness of nutritional support, assesses the patient's progress. Prepare parenteral mixtures where the QFB or nurse is not available.
* Physical Therapist: Execute an exercise program to ensure the best use of the system of support and help to restore muscle tone and general rehabilitation of the patient.
* Chemical pharmaceutical: is responsible for permanently maintaining availability and provide timely parenteral solutions with all components and additives necessary for the mixtures used in parenteral nutrition. Must be familiar with biochemical and pharmacological aspects of such solutions. Furthermore, materials should be chosen with the best conditions of quality, safety and economy. Shall prepare parenteral nutrition mixtures and provide recommendations on the compatibility of solutions, stability of these. etc.
The personnel working in the preparation of the solutions should be subjected to an annual checkup (at least) for control of communicable diseases.
With the advent of intravenous administration in 1968 and demonstration of the prevalence of malnutrition in hospital populations and benefit of nutritional replenishment in these patients drive the development of a new field in medicine, clinical nutrition support. Research in this area has progressed rapidly in recent years and the new science has become an important specialty of medicine.
Intravenous administration of calories, nitrogen and other nutritive elements in sufficient quantities for tissue synthesis and anabolism is called total parenteral nutrition (TPN). Originally this procedure was called hyperalimentation.
Manage development technique for total parenteral nutrition fluid by the subclavian vein to the superior vena cava, where the solution is quickly diluted by the large volume of circulating blood and minimizes the hypertonicity of the solution. TPN is indicated in patients who can not take food by carcinoma or extensive burns, patients who refuse to eat, as in the case of young people who are depressed or suffering from anorexia nervosa and surgical patients or those who can not feed by mouth.
* Parenteral Nutrition: A generic term that refers to agents provided by routes other than the gastrointestinal tract, usually through the circulatory system.
* Central parenteral nutrition: Parenteral nutrition delivered via a large diameter vein, usually the superior vena cava.
* Peripheral parenteral nutrition: Parenteral nutrition delivered via a small vein, usually the hand or forearm.
* Whole Food Intravenous: Therapy in which all nutrients are delivered by the intravenous route. Usually we use the central route.
* Partial Parenteral Nutrition Support: therapy in which some nutrients, usually amino acids, glucose and fats are administered by intravenous route. You can use the central or peripheral route.
The proper functioning of the unit required parenteral nutrition support that there is a specific area in the hospital where this work. This unit should include areas suitable for the preparation of parenteral nutrition and whole wardrobe for a change of clothes for the technicians working on these sites, bathroom, office to centralize the management of the unit and a clinical examination room.
* Characteristics of the mixtures preparation area.
You must have a number of features in its design and construction designed to minimize microbial contamination during the preparation of these solutions.
These features are:
* Circulation restricted. It can only enter the technicians who are preparing the mixtures.
* Dress appropriately and intended solely for this purpose including: clothing, leggings, hat and scarf. The technician should change their clothes for working in a dressing room adjacent to the preparation area. Used to prepare sterile gloves after hand washing.
* These areas may not have other access non-apparel. It can be stored in them nothing other than preparation of each particular day.
* Once prepared mixes are delivered through a window to be stored on a site earmarked for this purpose.
* Items to be waived are delivered to the washing area and re-sterilization and transported to areas of preparation time to do them.
* Sterile and nonsterile areas.
They identified two areas: the preparation of enteral and parenteral mixtures, independent of one another and which are referred sterile thus indicating that bacterial contamination is minimal and other so-called non-sterile areas.
* Construction of sterile areas.
The rules for constructing the sterile areas are:
* Surface Material: will be non-porous, smooth and hard, without additions, joints, or crevices must withstand washing abundant. The junction of the wall to the floor, must be concave or curved to facilitate proper cleaning. The floor should be of granite tile. Walls covered with smooth, washable paint, like the ceiling. Mesons are coated granite tile above and below, built into the wall with joint or concave curves. Stainless steel can be equally smooth, seamless or factors that hinder cleaning.
* Ventilation system: the ideal preparation for mixing zones the existence of unidirectional ventilation, ie positive pressure of 10% in these areas in relation to others. This system has proven to be optimal in reducing microorganisms suspended in the atmosphere. The air must have suitable filters. Alternatively can be used laminar flow chambers.
* Lighting: It is has neon lamp base located on the roof and easy to clean.
* Access doors: washable.
* No longer drains: water on the floor in these areas.
* Toilets: for technicians who are preparing the mixtures.
* Procedures performed in each of the areas requiring the maximum asepsis, including hand washing before the procedure, without moving to other places to do so.
Large volumes of parenterals
IV solutions are sterile solutions of chemicals such as sugars, amino acids or electrolytes. There are currently centralized programs mixed in 70% of U.S. hospitals with 300 beds or more.
The large volume parenteral infusion for intravenous solutions are often called IV. They come in packs of 1000, 500, 250, 150 and 100 ml., These containers are glass or flexible plastic type 1 and contain no preservatives .. The systems of the recipients are recognized worldwide for companies that have innovated.
One of the critical parameters to consider in evaluating a large volume parenteral is the particle content. Which are defined in the USP as foreign matter, mobile, undissolved. The solution meets the requirements for determining if it contains no more than 50 particles per ml. of the same size or smaller than 10 microns and no more than 5 particles of a size up to 25 microns.
Intravenous Liquid containers must be constructed so as to maintain sterility and pyrogen clarity of the solution from the time they are dosed during storage and clinic administration. The closures of the containers should be designed to facilitate insertion into the socket through which the solution is administered to a regulated flow in veins previously selected.
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