Stoffwechselveränderungen und Ernährungstherapie von Patienten nach großen viszeralchirurgischen Eingriffen und bei chirurgischen Intensivpatienten

Changes of Metabolism and Nutrition Therapy in Patients with Major Visceral Surgical Interventions and in Surgical Intensive Care Patients Surgical injury results in a variety of hormonal and immunologic reactions causing characteristic temporary metabolic changes (hyperglycemia, muscle protein catabolism). Although useful during the dawn of mankind, these metabolic changes are counterproductive in times of modern medicine. Perioperative nutrition tends to limit such secondary metabolic complications as much as possible, thereby improving patient prognosis. The cornerstone of each nutritional therapy is the supplementation of sufficient amounts of protein or amino acids (1.2-1.5 g/kg/day). Furthermore, hyperglycemia (>180 mg/dl) should be prevented by reducing the provision of carbohydrates during the postoperative acute phase. Oral/enteral nutrition should always be the application mode of choice. It is essential, however, that the upper and lower gastrointestinal tract is functioning properly. Therefore, a close surveillance regarding a potential deterioration of motility as well as absorption is mandatory. Quantity and quality of oral/enteral foods depends on the particularities of the surgical procedure. Patients with malignant diseases will profit from a preoperative nutritional conditioning (immunonutrition). Only patients with gastrointestinal dysfunction, who are simultaneously malnourished, benefit from postoperative parenteral nutrition. Malnutrition can be identified preoperatively by subjective global assessment. During parenteral nutrition, it is particularly important to closely monitor concentrations of blood glucose, triglycerides, and electrolytes. In critically ill patients, additional glutamine should be provided during all periods of parenteral substrate supply, whereas supplementation of intravenous fat is restricted to patients requiring a prolonged parenteral nutrition

Feeding Patients with Severe Abdominal Infections: Special Aspects

Background: Feeding patients with severe abdominal infections isparticularly demanding. Method: The authors electronically searched theMEDLINE, EMBASE and Cochrane databases (using the keywords‘peritonitis’, ‘severe sepsis’, ‘nutrition’, ‘practice parameter’, and‘guideline’) and reviewed their personal databases for articles relevantto the issue which have been published between 2002 and 2012. Results:Patients suffering from abdominal sepsis are at a high risk for severehyperglycemia and insulin resistance. Due to an excessive proteincatabolism which cannot be overcome by standard nutritional therapy,these patients are malnourished and require a particularly carefulnutritional support. The latter is not guided by the actual energyexpenditure (which markedly increases during the acute phase) but by thecapacity of the organism to utilize exogenous substrates (this capacityusually decreases during the acute phase). It is of outmost importanceto supply sufficient amounts of protein or amino acids. Ideally, thepatients should be fed enterally. Even in patients with severe abdominalcomplications (anastomotic leakage), modern tube and jejunostomytechniques as well as surgical strategies allow an adequate enteralsupply of calories. However, patients suffering from a severe abdominalsepsis often exhibit a delayed gastrointestinal passage (delayed gastricemptying, small bowel paralysis, colonic pseudo-obstruction). Thesepathologies restrict enteral nutrition and should be recognized as earlyas possible by appropriate clinical surveillance. Besides a clinicalexamination of the abdomen, measurement of gastric residual volumerepresents the best control parameter when providing food into thestomach. Delayed gastrointestinal passage should be treated asaggressively as possible. Primary objective is the cure of the abdominalfocus. In addition, use of drugs with an antiperistaltic action shouldbe restricted as much as possible. Severe cases may profit frommedications with a properistaltic action combined with specific physicalmeasures. Conclusion: Feeding patients suffering from an abdominalinfection requires an individualized, patient-centered approach whichrequires a profound nutritional and special gastroenterologicalknowledge

Acute and long-term survival in chronically critically ill surgical patients: a retrospective observational study

Introduction Various cohort studies have shown that acute ( short-term) mortality rates in unselected critically ill patients may have improved during the past 15 years. Whether these benefits also affect acute and long-term prognosis in chronically critically ill patients is unclear, as are determinants relevant to prognosis. Methods We conducted a retrospective analysis of data collected from March 1993 to February 2005. A cohort of 390 consecutive surgical patients requiring intensive care therapy for more than 28 days was analyzed. Results The intensive care unit ( ICU) survival rate was 53.6%. Survival rates at one, three and five years were 61.8%, 44.7% and 37.0% among ICU survivors. After adjustment for relevant covariates, acute and long-term survival rates did not differ significantly between 1993 to 1999 and 1999 to 2005 intervals. Acute prognosis was determined by disease severity during ICU stay and by primary diagnosis. However, only the latter was independently associated with long-term prognosis. Advanced age was an independent prognostic determinant of poor short-term and long-term survival. Conclusion Acute and long-term prognosis in chronically critically ill surgical patients has remained unchanged throughout the past 12 years. After successful surgical intervention and intensive care, long-term outcome is reasonably good and is mainly determined by age and underlying disease

The Native 3D Organization of Bacterial Polysomes

SummaryRecent advances have led to insights into the structure of the bacterial ribosome, but little is known about the 3D organization of ribosomes in the context of translating polysomes. We employed cryoelectron tomography and a template-matching approach to map 70S ribosomes in vitrified bacterial translation extracts and in lysates of active E. coli spheroplasts. In these preparations, polysomal arrangements were observed in which neighboring ribosomes are densely packed and exhibit preferred orientations. Analysis of characteristic examples of polysomes reveals a staggered or pseudohelical organization of ribosomes along the mRNA trace, with the transcript being sequestered on the inside, the tRNA entrance sites being accessible, and the polypeptide exit sites facing the cytosol. Modeling of elongating nascent polypeptide chains suggests that this arrangement maximizes the distance between nascent chains on adjacent ribosomes, thereby reducing the probability of intermolecular interactions that would give rise to aggregation and limit productive folding