Impact of preoperative serum creatinine on short- and long-term mortality after cardiac surgery: a cohort study.

BACKGROUND: Preoperative renal insufficiency is an important predictor of mortality after cardiac surgery. This retrospective cohort study was designed to identify the optimal cut-off for baseline serum creatinine (bSCr) and estimated glomerular filtration rate (eGFR) to predict survival. Furthermore, we investigated the potential confounding effect of other perioperative risk indicators on short- and long-term survival. METHODS: Data of 9490 cardiac surgical patients were prospectively collected between 1997 and 2008 (follow up to 2010) at the Medical University Vienna. We identified bSCr cut-off values and calculated uni- and multivariate hazard models for short- and long-term survival and compared the results with a validation set from Zurich. The estimated survival curves defined a distinct period of increased mortality until 150 days. RESULTS: Cut-off values of >115 µmol litre(-1) for bSCr and ≤50 ml min(-1) for eGFR were identified. Increased bSCr, associated with higher mortality [hazard ratio (HR) 2.61, 95% confidence interval (CI) 2.43-2.80, P<0.0001], was present in 19.5% of patients and remained predictive for short- (HR 1.59, 95% CI 1.38-1.83, P=0.0027) and long-term survival (HR 1.46, 95% CI 1.32-1.62, P<0.0001) in the multivariate hazard models. A cut-off of >120 µmol litre(-1) for bSCr was determined for the validation set. Decreased eGFR was present in 23.6% (HR 2.86, 95% CI 2.67-3.06, P<0.0001). CONCLUSIONS: In our patients, increased bSCr was an independent predictor of mortality, which may critically influence risk evaluation and perioperative treatment guidance.

Peritransplant immunoadsorption for positive crossmatch deceased donor kidney transplantation.

Various desensitization protocols were shown to enable successful living donor kidney transplantation across a positive complement-dependent cytotoxicity crossmatch (CDCXM). Positive crossmatch transplantation, however, is less well established for deceased donor transplantation. We report a cohort of 68 deceased donor renal allograft recipients who, on the basis of broad sensitization (lymphocytotoxic panel reactivity ≥40%), were subjected to a protocol of peritransplant immunoadsorption (IA). Treatment consisted of a single session of immediate pretransplant IA (protein A) followed by posttransplant IA and antilymphocyte antibody therapy. Twenty-one patients had a positive CDCXM, which could be rendered negative by pretransplant apheresis. Solid phase HLA antibody detection revealed preformed donor-specific antibodies (DSA) in all 21 CDCXM-positive and in 30 CDCXM-negative recipients. At 5 years, overall graft survival, death-censored graft survival and patient survival were 63%, 76% and 87%, respectively, without any differences between CDCXM-positive, CDCXM-negative/DSA-positive and CDCXM-negative/DSA-negative recipients. Furthermore, groups did not differ regarding rates of antibody-mediated rejection (24% vs. 30% vs. 24%, p = 0.84), cellular rejection (14% vs. 23% vs. 18%, p = 0.7) or allograft function (median 5-year serum creatinine: 1.3 vs. 1.8 vs. 1.7 mg/dL, p = 0.62). Our results suggest that peritransplant IA is an effective strategy for rapid desensitization in deceased donor transplantation.

[Fever in the critically ill : To treat or not to treat]. / Fieber bei Intensivpatienten : Senken oder nicht senken?

Fever, arbitrarily defined as a core body temperature >38.3 °C, is present in 20-70 % of intensive care unit patients. Fever caused by infections is a physiologic reset of the thermostatic set-point and is associated with beneficial consequences, but may have negative sequelae with temperatures >39.5 °C. Fever of non-infectious and neurologic origin affects about 50 % of patients with elevated body temperature, presents as a pathologic loss of thermoregulation, and may be associated with untoward side effects at temperatures above 38.5-39.0 °C. Cooling can be achieved by physical and pharmacologic means. Evidence-based recommendations are not available. The indication for a cooling therapy can only be based on the physiologic reserve and the neurologic, hemodynamic, and respiratory state. The temperature should be lowered to the normothermic range. Hyperthermia syndromes require immediate physical cooling (and dantrolen when indicated).

[Overtreatment in intensive care medicine]. / Übertherapie in der Intensivmedizin.

Overtreatment, which is therapy that is neither indicated nor desired by the patient ("non-beneficial"), presents an inherent and huge problem of modern medicine and intensive care medicine in particular. Overtreatment concerns all aspects of intensive care medicine, may start already before admission at the emergency scene, the inappropriate admission to the intensive care unit, overuse in diagnostics and especially in blood sampling, in invasive procedures and in organ support therapies. It manifests itself as "too much" in sedation, relaxation, volume therapy, hemodynamic support, blood products, antibiotics and other drugs and nutrition. Most importantly, overtreatment concerns the care of the patients at the end of life when a causal therapy is no longer available. Overtreatment also has important ethical implications and violates the four fundamental principles of medical ethics. It disregards the autonomy, dignity and integrity of the patient, is by definition nonbeneficial and increases pain, suffering, prolongs dying, increases sorrow of relatives, imposes frustration for the caregivers, disregards distributive justice and harms society in general by wasting principally limited resources. Overtreatment has also become an important legal issue and because of imposing inappropriate suffering may lead to prosecution. Overtreatment is poor medicine, is no trivial offence, all must continuously work together to reduce or avoid overtreatment.

[Intestinal cross-talk : The gut as motor of multiple organ failure]. / Intestinaler Crosstalk : Der Darm als Motor des Multiorganversagens.

The central role of the organ system "gut" for critically ill patients has not been acknowledged until the last decade. The gut is a crucial immunologic, metabolic and neurologic organ system and impairment of its functions is associated with morbidity and mortality. The gut has a central position in the cross-talk between organs and dysfunction of the gut may result in impairment of other intra-abdominal and extra-abdominal organ systems. The intestinal tract is the most important source of endogenous infections and determines the inflammatory status of the organism. Gut failure is an element of the multiple organ dysfunction syndrome (MODS). The leading mechanism in the evolution of endogenous infections is the intestinal translocation of microbes. A dysbiosis and damage of the intestinal mucosa leads to a disorder of the mucosal barrier function, increases the permeability and promotes translocation (leaky gut hypothesis). A further crucial mechanism of organ interactions is the increase in intra-abdominal pressure. Intra-abdominal hypertension promotes further injury of the gut, increases translocation and inflammation and causes dysfunction of other organ systems, such as the kidneys, the cardiovascular system and the lungs. Maintaining and/or restoring intestinal functions must be a priority of any intensive care therapy. The most important measure is early enteral nutrition. Other measures are the preservation of motility and modulation of the intestinal microbiome. Intra-abdominal hypertension must be reduced by an individually adapted infusion therapy, positioning of the patient, administration of drugs (abdominal compliance) and decompression (by tubes, endoscopically or in severe cases surgically).

[Metabolic management and nutrition in critically ill patients with renal dysfunction : Recommendations from the renal section of the DGIIN, ÖGIAIN, and DIVI]. / Metabolische Führung und Ernährung von Intensivpatienten mit renaler Dysfunktion : Empfehlungen der Sektionen Niere der DGIIN, ÖGIAIN und DIVI.

BACKGROUND: Intensive care patients with renal failure or insufficiency comprise a heterogeneous group of subjects with widely differing metabolic patterns and nutritional requirements. They include subjects with various stages of acute kidney injury (AKI), acute-on-chronic renal failure (A-CKD), without/with renal replacement therapy (RRT), chronic kidney disease (CKD), and subjects on regular hemodialysis or peritoneal dialysis therapy (HD/PD). GOALS: Development of recommendations by the renal section of DGIIN (Deutsche Gesellschaft für Internistische Intensivmedizin und Notfallmedizin), ÖGIAIN (Österreichische Gesellschaft für Internistische und Allgemeine Intensivmedizin und Notfallmedizin) and DIVI (Deutsche Interdisziplinäre Vereinigung für Intensiv- und Notfallmedizin) for the metabolic management and the planning, indication, implementation, and monitoring of nutrition therapy in this heterogeneous group of patients. MATERIALS AND METHODS: The recommendations are based on recent evidence and current recommendations of DGEM (Deutsche Gesellschaft für Ernährungsmedizin), ASPEN (American Society for Parenteral and Enteral Nutrition) and ESPEN (European Society for Clinical Nutrition and Metabolism) and also the KDGIO (Kidney Disease: Improving Global Outcomes) clinical practice guidelines for AKI and the expert knowledge and clinical experience of the authors. RESULTS: Nutrition support in these patient groups is not fundamentally different from that in other disease states but must consider the multiple variations in metabolism and nutrient requirements. Nutrition therapy must be adapted to the stage of disease and especially, in those patients on RRT. Nutritional needs can differ widely between patients but also in the same patient during the course of the disease. CONCLUSIONS: Thus, the patient with renal failure requires an individualized approach in nutrition support and because of the altered metabolism of many nutrients and intolerances for electrolytes and fluids, the nutrition support in patients with renal insufficiency requires close clinical and laboratory monitoring.

[Prevention of acute kidney injury in critically ill patients : Recommendations from the renal section of the DGIIN, ÖGIAIN and DIVI]. / Prävention der akuten Nierenschädigung beim kritisch kranken Patienten : Empfehlungen der Sektionen Niere der DGIIN, ÖGIAIN und DIVI.

BACKGROUND: Acute kidney injury (AKI) has both high mortality and morbidity. OBJECTIVES: To prevent the occurrence of AKI, current recommendations from the renal section of the DGIIN (Deutschen Gesellschaft für Internistische Intensivmedizin und Notfallmedizin), ÖGIAIN (Österreichischen Gesellschaft für Internistische und Allgemeine Intensivmedizin und Notfallmedizin) and DIVI (Deutschen Interdisziplinären Vereinigung für Intensiv- und Notfallmedizin) are stated. MATERIALS AND METHODS: The recommendations stated in this paper are based on the current Kidney Disease Improving Global Outcomes (KDIGO) guidelines, the published statements of the "Working Group on Prevention, AKI section of the European Society of Intensive Care Medicine" and the expert knowledge and clinical experience of the authors. RESULTS: Currently there are no approved clinically effective drugs for the prevention of AKI. Therefore the mainstay of prevention is the optimization of renal perfusion by improving the mean arterial pressure (>65 mm Hg, higher target may be considered in hypertensive patients). This can be done by vasopressors, preferably norepinephrine and achieving or maintaining euvolemia. Hyperhydration that can lead to AKI itself should be avoided. In patients with maintained diuresis this can be done by diuretics that are per se no preventive drug for AKI. Radiocontrast enhanced imaging should not be withheld from patients at risk for AKI; if indicated, however, the contrast media should be limited to the smallest possible volume.

[Extracorporeal renal replacement therapy in acute kidney injury : Recommendations from the renal section of the DGIIN, ÖGIAIN and DIVI]. / Extrakorporale Nierenersatztherapie bei akuter Nierenschädigung : Empfehlungen der Sektionen "Niere" der DGIIN, ÖGIAIN und DIVI.

BACKGROUND: Acute kidney injury (AKI) is a common complication in intensive care unit (ICU) patients. The incidence of AKI in ICU patients exceeds 50% and the associated morbidity and mortality rates increase with severity of AKI. In addition, long-term consequences of AKI are underestimated and several studies show impaired long-term outcome after AKI. In about 5-25% of ICU patients with AKI renal replacement therapy (RRT) is required. OBJECTIVES: To assist in indication, timing, modality and application of renal replacement therapy of adult patients, current recommendations from the renal sections of the DGIIN (Deutschen Gesellschaft für Internistische Intensivmedizin und Notfallmedizin), ÖGIAIN (Österreichischen Gesellschaft für Internistische und Allgemeine Intensivmedizin und Notfallmedizin) and DIVI (Deutschen Interdisziplinären Vereinigung für Intensiv- und Notfallmedizin) are stated. MATERIALS AND METHODS: The recommendations stated in this paper are based on the current KDIGO (Kidney Disease: Improving Global Outcomes) guidelines, recommendations from the 17th Acute Disease Quality Initiative (ADQI) Consensus Group, the French Intensive Care Society (SRLF) with the French Society of Anesthesia Intensive Care (SFAR) and the expert knowledge and clinical experience of the authors. RESULTS: Today, different treatment modalities for RRT are available. Although continuous RRT and intermittent dialysis therapy as well as continuous dialysis therapy have comparable outcomes, differences exist with respect to practical application as well as health-economic aspects. Individualized risk stratification might be helpful to choose the right time to start and the right treatment modality for patients.

Abnormal cation transport in uremia. Mechanisms in adipocytes and skeletal muscle from uremic rats.

The cause of the abnormal active cation transport in erythrocytes of some uremic patients is unknown. In isolated adipocytes and skeletal muscle from chronically uremic chronic renal failure rats, basal sodium pump activity was decreased by 36 and 30%, and intracellular sodium was increased by 90 and 50%, respectively, compared with pair-fed control rats; insulin-stimulated sodium pump activity was preserved in both tissues. Lower basal NaK-ATPase activity in adipocytes was due to a proportionate decline in [3H]ouabain binding, while in muscle, [3H]ouabain binding was not changed, indicating that the NaK-ATPase turnover rate was decreased. Normal muscle, but not normal adipocytes, acquired defective Na pump activity when incubated in uremic sera. Thus, the mechanism for defective active cation transport in CRF is multifactorial and tissue specific. Sodium-dependent amino acid transport in adipocytes closely paralleled diminished Na pump activity (r = 0.91), indicating the importance of this defect to abnormal cellular metabolism in uremia.

Prevention of acute kidney injury and protection of renal function in the intensive care unit: update 2017 : Expert opinion of the Working Group on Prevention, AKI section, European Society of Intensive Care Medicine.

BACKGROUND: Acute kidney injury (AKI) in the intensive care unit is associated with significant mortality and morbidity. OBJECTIVES: To determine and update previous recommendations for the prevention of AKI, specifically the role of fluids, diuretics, inotropes, vasopressors/vasodilators, hormonal and nutritional interventions, sedatives, statins, remote ischaemic preconditioning and care bundles. METHOD: A systematic search of the literature was performed for studies published between 1966 and March 2017 using these potential protective strategies in adult patients at risk of AKI. The following clinical conditions were considered: major surgery, critical illness, sepsis, shock, exposure to potentially nephrotoxic drugs and radiocontrast. Clinical endpoints included incidence or grade of AKI, the need for renal replacement therapy and mortality. Studies were graded according to the international GRADE system. RESULTS: We formulated 12 recommendations, 13 suggestions and seven best practice statements. The few strong recommendations with high-level evidence are mostly against the intervention in question (starches, low-dose dopamine, statins in cardiac surgery). Strong recommendations with lower-level evidence include controlled fluid resuscitation with crystalloids, avoiding fluid overload, titration of norepinephrine to a target MAP of 65-70 mmHg (unless chronic hypertension) and not using diuretics or levosimendan for kidney protection solely. CONCLUSION: The results of recent randomised controlled trials have allowed the formulation of new recommendations and/or increase the strength of previous recommendations. On the other hand, in many domains the available evidence remains insufficient, resulting from the limited quality of the clinical trials and the poor reporting of kidney outcomes.

ESPEN Guidelines on Enteral Nutrition: Adult renal failure.

Enteral nutrition (EN) by means of oral nutritional supplements (ONS) and tube feeding (TF) offers the possibility of increasing or ensuring nutrient intake in cases where normal food intake is inadequate. These guidelines are intended to give evidence-based recommendations for the use of ONS and TF in nephrology patients. They were developed by an interdisciplinary expert group in accordance with officially accepted standards and are based on all relevant publications since 1985. They were discussed and accepted in a consensus conference. Because of the nutritional impact of renal diseases, EN is widely used in nephrology practice. Patients with acute renal failure (ARF) and critical illness are characterized by a highly catabolic state and need depurative techniques inducing massive nutrient loss. EN by TF is the preferred route for nutritional support in these patients. EN by means of ONS is the preferred way of refeeding for depleted conservatively treated chronic renal failure patients and dialysis patients. Undernutrition is an independent factor of survival in dialysis patients. ONS was shown to improve nutritional status in this setting. An increase in survival has been recently reported when nutritional status was improved by ONS.

Loss of normal circadian profile of urine excretion in idiopathic restless legs syndrome.

BACKGROUND: This study was performed to elucidate preliminary observations of excessive nighttime urine excretion in idiopathic restless legs syndrome (iRLS). METHODS: Seventeen patients, with normal serum creatinine, blood urea nitrogen, and urate, and 11 healthy controls were examined. We measured excretory renal function parameters (urine volume, osmolarity, sodium, chloride, potassium, calcium, phosphate, microalbumin, aldosterone, creatinine) between 7:00 am and 10:00 pm and between 10:00 pm and 7:00 am. RESULTS: During the nighttime, volume (P=0.006), sodium (P=0.009), and chloride excretion (P=0.001) were significantly higher, and osmolarity (P=0.025) was significantly lower in patients as compared to controls. In comparing daytime to nighttime, controls showed the physiological reduced nocturnal excretion of volume (P=0.009) and chloride (P=0.023), and an increased osmolarity (P=0.026), but patients showed similar excretion rates of these parameters (all differences ns). CONCLUSIONS: These data indicate a loss of normal circadian profile of urine excretion in iRLS. The elevated nighttime excretion, with values similar to those in the daytime, hint at a possibly elevated fluid, sodium, and chloride intake during daytime.

An European survey of structure and organisation of nutrition support teams in Germany, Austria and Switzerland.

BACKGROUND & AIMS: Nutritional support teams (NST) have been demonstrated to be an excellent mechanism for identifying patients in need of nutrition support, improving the efficacy of nutrition support in a variety of hospital environments. Focus of this study was the investigation of function, structure and organisation of NST in Germany (D), Austria (A) and Switzerland (CH). METHODS: Prospective investigation of the function, structure and organisation of NST in D, A and CH, using standardised questionnaires. RESULTS: From a total of 3071 hospitals in D, A and CH, NST have been established at 98 hospitals (3.2%). Their main activities were creating nutritional regimes (100%), education (87%) and monitoring nutrition therapy (92%). In general, the NST are not independently operating units but are affiliated to a special discipline. Seventy-one per cent of the physicians, 40% of the nurses and 69% of the dieticians in the NST held a nutrition-specific additional qualification. A total of 12% of the physicians, 37% of the nurses and 46% of the dieticians are exclusively responsible for the NST. A reduction of complications (88%) and cost saving (98%) were indicated since their establishment. The NST received in 32% funding support. CONCLUSION: In D, A, CH neither a uniform nor comprehensive patient care by NST existed in 2004. Standards of practice, development of guidelines in clinical nutrition and better documentation in NSTs are necessary. Special efforts should be aimed at education of NST members and financing of teams.

Amino acid kinetics in patients with sepsis.

BACKGROUND: In patients with sepsis and systemic inflammatory response syndrome, amino acid extraction by the liver is enhanced, resulting in decreased plasma amino acid concentrations. Systematic investigations of the elimination of intravenously infused amino acids have not been performed. OBJECTIVE: The objective of this study was to compare the elimination of 17 amino acids in patients with sepsis and in healthy control subjects. DESIGN: Elimination of amino acids was evaluated in 9 patients with sepsis and in 8 healthy control subjects by using a combined loading and maintenance infusion of 375 mg amino acids/kg body wt for 60 min. Pharmacokinetic variables were analyzed from plasma curves. RESULTS: With the exception of lysine, methionine, glutamate, ornithine, phenylalanine, and tyrosine, plasma concentrations of amino acids were lower in the patients with sepsis than in the control subjects; phenylalanine was the only amino acid whose plasma concentration increased (P < 0.001). In patients with sepsis, whole-body clearance (Cl(tot)) of total amino acids was 74% higher than in control subjects (x +/- SEM: 13,161 +/- 1659 and 7566 +/- 91 mL/min, respectively; P < 0.01), the Cl(tot) of essential amino acids was 64% higher (P < 0.02), that of nonessential amino acids was 82% higher (P < 0.01), and that of both branched-chain amino acids and glucogenic amino acids was 97% higher (P < 0.001). With the exception of phenylalanine, ornithine, proline, and glutamate, the Cl(tot) of all amino acids was elevated. The Cl(tot) of phenylalanine and ornithine decreased slightly (NS). CONCLUSIONS: In patients with sepsis, plasma concentrations of most amino acids are greatly decreased and the elimination of amino acids from the intravascular space during intravenous infusion is greatly enhanced.

Fat elimination in chronic hepatic failure: long-chain vs medium-chain triglycerides.

Elimination and hydrolysis of fat emulsions containing long-chain (LCT) or long- and medium-chain triglycerides (MCT, 50:50) were compared in eight patients with advanced chronic hepatic failure (CHF) and six healthy control subjects by using a two-stage constant infusion protocol. In control subjects clearance of MCT was slightly higher than that of LCT (1.93 +/- 0.34 vs 1.55 +/- 0.3 mL.kg-1.min-1, P < 0.05). The rise in plasma triglycerides was similar and the release of free fatty acids was higher during MCT (P < 0.02). In CHF patients, clearance of both LCT and MCT was comparable with that in healthy subjects and the rise in plasma triglycerides and release of free fatty acids was identical. We conclude that a clinically relevant infusion rates the elimination of lipid emulsions containing LCT or LCT and MCT and the release of free fatty acids thereof is not altered in patients with CHF and that intravenous lipids are a suitable source of energy and essential fatty acids (and phospholipids) for parenteral nutrition.

Elimination of amino acids in renal failure.

The elimination of intravenously infused amino acids was evaluated in six patients with acute renal failure (ARF), 6 with conservatively treated chronic renal failure (CRF), 6 subjects receiving regular hemodialysis treatment (RDT), and 5 healthy control subjects. In ARF, CRF, and RDT groups, whole-body clearance (Cltot) of the 10 amino acids was elevated (113.5 +/- 1.5; 94.2 +/- 1.5 and 127.6 +/- 12.4, respectively, vs 85.2 +/- 4.8 mL.kg-1.min-1 in control subjects, P < 0.001). In ARF, Cltot of histidine, lysine, and methionine was higher and Cltot of phenylalanine and valine was lower as compared with control subjects. In CRF, Cltot of tryptophan and histidine was elevated and Cltot of phenylalanine was reduced; in RDT, Cltot of histidine, methionine, tryptophan, lysine, isoleucine, and leucine was raised. In all groups the relative clearance (% of total clearance) of phenylalanine and valine was reduced, and relative clearance of histidine and tryptophan was elevated. We conclude that in renal failure the elimination of amino acids from the intravascular space is profoundly altered and that the pattern of metabolic aberrations is similar in ARF, CRF, and RDT groups.

Fat elimination in acute renal failure: long-chain vs medium-chain triglycerides.

Elimination and hydrolysis of fat emulsions containing long-chain (LCT; Intralipid) or long- and medium-chain triglycerides (MCT; Lipofundin MCT) were compared in seven patients with acute renal failure (ARF) and six healthy control subjects. In control subjects, clearance of MCT was slightly higher than that of LCT (1.93 +/- 0.34 vs 1.55 +/- 0.3 mL.kg body wt-1.min-1, P less than 0.05). The rise in plasma triglycerides was similar and the release of free fatty acids was higher during MCT (P less than 0.02). In ARF, clearance of both LCT and MCT was equally reduced (0.53 +/- 0.12 vs 0.59 +/- 0.14 mL.kg body wt-1.min-1, P less than 0.01 vs control subjects). Again, the rise in triglycerides was comparable. Free fatty acid release was higher during MCT but lower than in control subjects. Plasma concentrations of glucose and lactate were not affected in control subjects but increased during both LCT and MCT in ARF. Thus elimination of both LCT and MCT is profoundly decreased in ARF. The impaired lipolysis in ARF cannot be circumvented by the use of MCT.

Energy metabolism in acute and chronic renal failure.

Energy metabolism was measured by indirect calorimetry in 86 patients with various forms of renal failure and in 24 control subjects. In patients with acute renal failure with sepsis, oxygen consumption, carbon dioxide production, and resting energy expenditure were increased (P less than 0.05). In other groups with renal failure (acute renal failure without sepsis, chronic renal failure with conservative treatment or hemodialysis, and severe untreated azotemia) these indices were not different from those of control subjects. Urea nitrogen appearance was decreased in patients with chronic renal failure undergoing conservative treatment, in those with severe untreated azotemia, and in hemodialysis patients (P less than 0.05). We conclude that renal failure has no influence on energy expenditure as long as septicemia is absent. Reduced urea nitrogen appearance rates in chronic renal failure are due to a reduced energy and protein intake. Wasting is a consequence of decreased food intake but not of hypermetabolism in chronic renal failure.

Prevention of upper gastrointestinal bleeding in long-term ventilated patients. Sucralfate versus ranitidine.

Thirty-two long-term ventilated patients were randomly selected for a study of the efficacy of sucralfate (1 g six times per day via gastric tube) versus ranitidine (six 50-mg to six 100-mg doses per day intravenously) for the prevention of upper gastrointestinal bleeding. The patients of the two treatment groups (each 16) were comparable with respect to diseases precipitating acute respiratory failure and risk factors of bleeding, e.g., renal failure, thrombopenia, coagulopathy, and anticoagulant treatment. Mean duration of mechanical ventilation was 7.4 in sucralfate- and 7.7 days in ranitidine-treated patients. During mechanical ventilation, macroscopically visible bleeding developed in three of the sucralfate-treated (18.7 percent) and seven of the ranitidine-treated (43.7 percent) patients. Until the end of the study, only three of the sucralfate-treated but nine of the ranitidine-treated (56.2 percent) patients bled; the difference between the two treatment groups was at all times significant (p less than 0.05). Packed red blood cells had to be administered to the three bleeding patients in the sucralfate group and to seven bleeding in the ranitidine group. Therefore it seems that sucralfate prevented mostly minor bleeding. The high bleeding rate during ranitidine treatment was presumably due to the high number of pH-nonresponders, as almost 30 percent of the gastric aspirates of this group had a pH less than 5. During treatment no difference was found in positive blood culture specimens and bronchial secretions between the two groups. However, nosocomial pneumonia developed in two ranitidine-treated patients, whereas that complication developed in none of the sucralfate-treated patients. In long-term ventilated patients, sucralfate prevented minor upper gastrointestinal bleeding significantly better than ranitidine. However, this does not imply that major upper gastrointestinal bleeding can be prevented by either sucralfate or ranitidine in these patients.

Nutritional management of acute renal failure.

The principles of nutritional therapy (ie, maintain lean body mass, stimulate immunocompetence, and repair functions, such as wound healing) are similar for patients with acute renal failure (ARF) and with other catabolic clinical conditions. However, if a patient with ARF requires nutritional support, the multiple metabolic consequences of acute uremia must be taken into account. These do not only affect fluid, electrolyte, and acid-base balance but also the metabolism of amino acids, proteins, carbohydrates, and lipids. In addition, these metabolic alterations are modified by the acute disease process per se, by associated complications (such as severe infections), and last but not least, by the type and intensity of renal replacement therapy. Whenever possible, enteral nutrition should be provided in patients with ARF because even small amounts of luminal nutrients will help to maintain intestinal functions. Nevertheless, in many patients a parenteral nutrition, at least supplementary and/or temporarily, will become necessary. Metabolic complications of nutritional support frequently occur in patients with ARF because tolerance to volume load and electrolytes is limited and the use of various nutrients is impaired. Despite the notorious difficulty to demonstrate clear-cut benefits of nutritional interventions and especially, of parenteral nutrition on prognosis in critically ill patients, there can be no doubt that nutritional therapy presents a cornerstone in the treatment of patients with ARF. Preexisting and/or hospital-acquired malnutrition have been identified as important factors contributing to the persisting high mortality in acutely ill patients with ARF.