Medicina intensiva
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Nutritional metabolic management, together with other treatment and support measures used, is one of the mainstays of the treatment of septic patients. Nutritional support should be started early, after initial life support measures, to avoid the consequences of malnutrition, to provide adequate nutritional intake and to prevent the development of secondary complications such as superinfection or multiorgan failure. As in other critically-ill patients, when the enteral route cannot be used to ensure calorie-protein requirements, the association of parenteral nutrition has been shown to be safe in this subgroup of patients. ⋯ Routine use of omega-3 fatty acids cannot be recommended until further evidence has been gathered, although the use of lipid emulsions with a high omega-6 fatty acid content should be avoided. Septic patients should receive an adequate supply of essential trace elements and vitamins. Further studies are required before the use of high-dose selenium can be recommended.
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Electrical impedance tomography has been described as a new method of monitoring critically ill patients on mechanical ventilation. It has recently gained special interest because of its applicability for monitoring ventilation and pulmonary perfusion. ⋯ This review explains the physical concept of bioimpedance and its clinical application, and summarizes the scientific evidence published to date with regard to the implementation of electrical impedance tomography as a method for monitoring ventilation and perfusion, mainly in the patient with acute lung injury, and other possible applications of the technique in the critically ill patient. The review also summarizes the limitations of the technique and its potential areas of future development.
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Nutritional support in acute renal failure must take into account the patient's catabolism and the treatment of the renal failure. Hypermetabolic failure is common in these patients, requiring continuous renal replacement therapy or daily hemodialysis. In patients with normal catabolism (urea nitrogen below 10 g/day) and preserved diuresis, conservative treatment can be attempted. ⋯ Depending on their hemofiltration flow, continuous renal replacement systems require high daily nitrogen intake, which can sometimes reach 2.5 g protein/kg. The amount of volume replacement can induce energy overload and therefore the use of glucose-free replacement fluids and glucose-free dialysis or a glucose concentration of 1 g/L, with bicarbonate as a buffer, is recommended. Monitoring of electrolyte levels (especially those of phosphorus, potassium and magnesium) and of micronutrients is essential and administration of these substances should be individually-tailored.
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Patients with cardiac disease can develop two types of malnutrition: cardiac cachexia, which appears in chronic congestive heart failure, and malnutrition due to the complications of cardiac surgery or any other type of surgery in patients with heart disease. Early enteral nutrition should be attempted if the oral route cannot be used. When cardiac function is severely compromised, enteral nutrition is feasible, but supplementation with parenteral nutrition is sometimes required. ⋯ Routine polymeric or high protein formulae should be used, according to the patient's prior nutritional status, with sodium and volume restriction according to the patient's clinical situation. The major energy source for myocytes is glutamine, through conversion to glutamate, which also protects the myocardial cell from ischemia in critical situations. Administration of 1 g/ day of omega-3 (EPA+DHA) in the form of fish oil can prevent sudden death in the treatment of acute coronary syndrome and can also help to reduce hospital admission for cardiovascular events in patients with chronic heart failure.
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Gastrointestinal surgery and critical illness place tremendous stress on the body, resulting in a series of metabolic changes that may lead to severe malnutrition, which in turn can increase postsurgical complications and morbidity and mortality and prolong the hospital length of stay. In these patients, parenteral nutrition is the most widely used form of nutritional support, but administration of enteral nutrition early in the postoperative period is effective and well tolerated, reducing infectious complications, improving wound healing and reducing length of hospital stay. Calorie-protein requirements do not differ from those in other critically-ill patients and depend on the patient's underlying process and degree of metabolic stress. ⋯ When proximal sutures are used, tubes allowing early jejunal feeding should be used. Pharmaconutrition is indicated in these patients, who benefit from enteral administration of arginine, omega 3 and RNA, as well as parenteral glutamine supplementation. Parenteral nutrition should be started in patients with absolute contraindication for use of the gastrointestinal tract or as complementary nutrition if adequate energy intake is not achieved through the enteral route.