[Dialysis patients in intensive care units]. / Der Dialysepatient auf der Intensivstation.

The number of dialysis patients needing intensive medical care is steadily increasing, mostly due to cardiovascular diseases. Of the patients 50% are admitted due to myocardial infarction, malignant arrhythmia or acute cardiac failure and many also due to hyperkalemia and acute volume overload against the background of anuria or oligouria associated with arterial hypertension and hypervolemic hypertensive pulmonary edema. The treatment of an acute cardiac syndrome is comparable to the treatment of patients with healthy kidneys and despite the significantly higher cardiovascular mortality of these patients the acute prognosis is not significantly different to non-dialysis patients. In association with hypervolemic hypertensive pulmonary edema and all forms of hyperkalemia, dialysis treatment is always necessary. In the case of complications due to infections, in particular septicemia, dialysis patients seem to profit from the general therapy guidelines for septic patients, such as early goal-directed therapy. Underdosing of antibiotics for dialysis patients with sepsis represents a substantial problem in the clinical practice and can additionally endanger these patients.

A Regional health care network: eHealth.Braunschweig. Domain fields and architectural challenges.

BACKGROUND: Health care network eHealth.Braunschweig has been started in the South-East region of Lower Saxony in Germany in 2009. It composes major health care players, participants from research institutions and important local industry partners. OBJECTIVES: The objective of this paper is firstly to describe the relevant regional characteristics and distinctions of the eHealth.Braunschweig health care network and to inform about the goals and structure of eHealth.Braunschweig; secondly to picture and discuss the main concepts and domain fields which are addressed in the health care network; and finally to discuss the architectural challenges of eHealth.Braunschweig regarding the addressed domain fields and defined requirements. METHODS: Based on respective literature and former conducted projects we discuss the project structure and goals of eHealth.Braunschweig, depict major domain fields and requirements gained in workshops with participants and discuss the architectural challenges as well as the architectural approach of eHealth.Braunschweig network. RESULTS: The regional healthcare network eHealth.Braunschweig has been established in April 2009. Since then the network has grown constantly and a sufficient progress in network activities has been achieved. The main domain fields have been specified in different workshops with network participants and an architectural realization approach for the transinstitutional information system architecture in the healthcare network has been developed. However, the effects on quality of information processing and quality of patient care have not been proved yet. Systematic evaluation studies have to be done in future in order to investigate the impact of information and communication technology on the quality of information processing and the quality of patient care. CONCLUSIONS: In general, the aspects described in this paper are expected to contribute to a systematic approach for the establishment of regional health care networks with lasting and sustainable effects on patient-centered health care in a regional context.

[Renal replacement therapy in acute renal failure]. / Nierenersatztherapie beim akuten Nierenversagen.

Acute kidney injury (AKI) is characterized by a sudden breakdown of the incretoric and excretoric functions of the kidneys. In intensive care it is always part of a multiple organ failure (MOF). It has a high incidence in intensive care (5 - 20 %), increasing up to 50 % in patients with septic shock. Its prognosis is variable (mortality 20 - 80 %) due to the fact, that up to the establishing of RIFLE and AKIN no consistent classification existed. Early start of extracorporeal treatment may lead to a reduced mortality in critically ill with AKI and MOF as the negative influence of AKI on other vital function disturbances may be reduced. Independent of the treatment form, all critically ill need a dosage of dialysis enabling negative effects of the hypercatabolic situation for these patients. An increase of the dosage over these demands did not lead to a better survival in the inhomogeneous group of all patients with AKI and MOF. In continuous forms of treatment an exchange amount of 20 ml/kg/h should be reached, as in intermittent hemodialysis a Kt/V lower 4 - 4.5/week should be avoided. According to the survival of the patients there is no evidence that either continuous forms of treatment or intermittent dialysis is superior over the other, comparing always these heterogeneous groups of medical and surgical AKI patients. There seems to be a small group of patients (mortality > 80 %) never included in any prospective randomized trial which can only be treated continuously.

Parenteral nutrition in patients with renal failure - Guidelines on Parenteral Nutrition, Chapter 17.

Partial EN (enteral nutrition) should always be aimed for in patients with renal failure that require nutritional support. Nevertheless PN (parenteral nutrition) may be necessary in renal failure in patient groups with acute or chronic renal failure (ARF or CRF) and additional acute diseases but without extracorporeal renal replacement therapy, or in patients with ARF or CRF with additional acute diseases on extracorporeal renal replacement therapy, haemodialysis therapy (HD), peritoneal dialysis (PD) or continuous renal replacement therapy (CRRT), or in patients on HD therapy with intradialytic PN. Patients with renal failure who show marked metabolic derangements and changes in nutritional requirements require the use of specifically adapted nutrient solutions. The substrate requirements of acutely ill, non-hypercatabolic patients with CRF correspond to those of patients with ARF who are not receiving any renal replacement patients therapy (utilisation of the administered nutrients has to be monitored carefully). In ARF patients and acutely ill CRF patients on renal replacement therapy, substrate requirements depend on disease severity, type and extent/frequency of extracorporeal renal replacement therapy, nutritional status, underlying disease and complications occurring during the course of the disease. Patients under HD have a higher risk of developing malnutrition. Intradialytic PN (IDPN) should be used if causes of malnutrition cannot be eliminated and other interventions fail. IDPN should only be carried out when modifiable causes of malnutrition are excluded and enhanced oral (like i.e. additional energy drinks) or enteral supply is unsuccessful or cannot be carried out.

Is there a role for hemoperfusion/hemodialysis as a treatment option in severe tricyclic antidepressant intoxication?

OBJECTIVE: Suicidal self-poisoning with tricyclic antidepressants like doxepin is a major therapeutic problem in emergency medicine with a high fatality rate. Deaths are mainly caused by cardiotoxicity with arrhythmias, intraventricular conduction disturbances and myocardial depression. For treatment, alkalinization and hypertonic saline are recommended. The role of extracorporeal, treatment procedures is not clear. The possible benefit of hemoperfusion/hemodialysis is discussed in a case report with respect to the published literature. CASE REPORT: After ingestion of an amount of at least 5000 mg doxepin a 37-year-old man with endogenous depression developed cardiac arrest. After preclinical resuscitation with prolonged external cardiac massage, he was admitted to the intensive care unit with persistently severe hypotension and wide QRS complexes (230-260 ms). Despite fluid load, alkalinization, hypertonic saline and high-dose vasoactive substances the patient's condition did not improve. Hemoperfusion over hemoresin combined with hemodialysis led to an impressive clinical improvement with shortening of QRS duration (from 230 to 120 ms) and hemodynamic stabilization. The patient fully recovered without neurologic deficits. CONCLUSION: We report a successful treatment with hemoperfusion over hemoresin and hemodialysis in a patient with life-threatening doxepin poisoning intractable with the generally recommended treatment. In such acute TCA intoxication with severe cardiotoxicity, hemoperfusion/hemodialysis should be considered a potential treatment option, as the "toxicokinetics" of drugs may totally differ from their usual pharmacokinetic behaviour. Experimental and clinical studies are needed to clarify the toxicokinetics of TCA in order to improve the therapeutic approach.

Lactate- or bicarbonate-buffered solutions in continuous extracorporeal renal replacement therapies.

BACKGROUND: Continuous renal replacement therapies (CRRTs) are well accepted for critically ill patients with acute renal failure (ARF). Today, daily fluid exchange in CRRT reaches 30 to 40 liter and more. Therefore, the composition of the substitution/dialysate fluid, often primarily developed either for intermittent treatment or for peritoneal dialysis, becomes more relevant. Lactate (30 to 45 mmol/liter) is frequently used as the buffer because of the high stability of this substance. However, lactate is thought to have negative effects on metabolic and hemodynamic parameters. METHODS: Published data for different substitution fluids are presented with respect to acidosis and lactate concentration, uremia, and hemodynamic and metabolic alterations. RESULTS: Only a few studies compare substitution fluids with different buffers. Uremia and acidosis (pH, base excess) were sufficiently controlled during CRRT with an exchange volume of in average 30 liters using either buffer. If patients with severe liver failure and lactic acidosis were excluded, no difference in hemodynamic and metabolic parameters between the solutions occurred. The plasma lactate concentration was elevated during lactate use in some cases, but lactate levels remained within normal limits in patients without liver impairment. The bicarbonate concentration in the solutions should exceed 35 to 40 mmol/liter, as in some cases the buffer capacity of the solutions was inadequate. In patients with severe liver failure or lactic acidosis, solutions with lactate buffer were shown not to be indicated. CONCLUSION: In patients with reduced lactate metabolism, for example, concomitant severe liver failure, after liver transplantation or in lactic acidosis, bicarbonate-buffered solutions should be used. In nearly all other cases of critically ill patients with ARF, lactate-buffered solutions may be used as well as bicarbonate solutions.

Hirudin elimination by hemofiltration: a comparative in vitro study of different membranes.

BACKGROUND: Recombinant hirudin (r-hirudin) is a highly specific and selective thrombin inhibitor. Since 1997, it has been approved for the treatment of heparin-induced thrombocytopenia (HIT type II). Renal function impairment drastically prolongs the elimination half-life time. In cases of bleeding or overdosage, there is currently no antidote available. Hemofiltration has been reported to be useful in r-hirudin elimination. In this study, we determined sieving coefficients (SCs) and drug clearances for two different hemofilters currently used in clinical medicine and intensive care. METHODS: We developed an in vitro postdilution hemofiltration model using 500 ml heparinized (2 IU unfractionated heparin/ml) fresh human blood and bicarbonate substitution fluid. The investigated membranes were high-flux polysulfone F50 (1.0 m2, Fresenius) and AN69 Nephral 200 (1.05 m2, Hospal Cobe). After equilibration, a bolus of Lepirudin was injected into the postfilter port to achieve a r-hirudin blood level of approximately 15 microg/ml. Serial blood and ultrafiltrate samples were taken for the determination of hirudin levels (chromogenic assay) and control parameters. SC and clearances were calculated according to standard formulae. RESULTS: The observed SCs and clearances differed significantly between F50 and Nephral 200 (0.60+/-0.17 and 21.0+/-5.9 ml/min, respectively, vs. 0.44+/-0.09 and 15.5+/-3.0 ml/min, respectively; P = 0.001). The determination of prothrombin fragments showed no coagulation activation during the experiments. The hematocrit values remained stable. CONCLUSIONS: Our data show that r-hirudin can be eliminated by hemofiltration. The elimination obviously depends on the membrane material with high-flux polysulfone being more effective than AN69. These findings may be important in cases of overdosage and for r-hirudin dosage guidelines in continuous hemofiltration.

Influence of hematocrit on hemostasis in continuous venovenous hemofiltration during acute renal failure.

BACKGROUND: Hematocrit plays a major role in primary hemostasis by influencing blood viscosity and platelet adhesion. During continuous venovenous hemofiltration (CVVH), it is suspected that an increased hematocrit is accompanied by an activation of hemostasis and frequently leads to thromboses in the extracorporeal system. In order to examine this hypothesis, we studied the influence of hematocrit on hemostasis during CVVH. METHODS: Fourteen patients (8 men and 6 women, mean age 65+/-10 years) with acute renal failure undergoing CVVH were prospectively enrolled. Polysulfone hemofilters (AV 600; Fresenius, Oberursel, Germany) were used in all of the patients; blood flow rates were adjusted to 120 ml/min. No blood products and coagulation-related medication, except unfractionated heparin, were applied. Study exclusion criteria included a history of thromboembolism and artificial heart valves. Hemostasis activation markers (fibrinopeptide A, thrombin-antithrombin III complex, beta-thromboglobulin, platelet retention) and hematocrit values were determined before and at three-day intervals during the course of CVVH treatment. RESULTS: The mean hematocrit value (mean +/- SEM) was 29+/-1% (range, 22 to 35%). Patients with hematocrit values of less than 30% (N = 7) were compared with patients with higher hematocrit values (>30%, N = 7). The patients with a lower hematocrit (<30%) showed a stronger activation of hemostasis during CVVH when compared with those with a higher hematocrit (>30%), as indicated by a tendency toward higher values for fibrinopeptide A (25+/-8 vs. 14+/-5 ng/ml, P = 0.35), thrombin-antithrombin III complex (15+/-4 vs. 10+/-2 ng/ml, P = 0.66), and a higher beta-thromboglobulin/creatinine ratio (0.62+/-0.17 vs. 0.48+/-0.12, P = 0.8). CONCLUSION: Contrary to our hypothesis, hematocrit values of more than 30% are not accompanied by an increased hemostasis activation during CVVH. Concerning hemostasis activation, hematocrit values between 30 and 35% may be suitable for patients on CVVH.

Is cytokine removal by continuous hemofiltration feasible?

Patients who are critically ill with acute renal failure and sepsis have extremely high mortality rates. While it seems reasonable that eliminating the inflammatory mediators (such as cytokines, chemokines, tumor necrosis factor-alpha, etc.) by continuous renal replacement therapy (CRRT) would be effective, studies show that only insubstantial numbers of these mediators are removed in comparison with endogenous clearance. Mass removal seems only to be effective when highly permeable membranes (sieving coefficient of approximately 1.0) are used, there is a filtrate volume greater than 2 liters/hour, and when the half-life of the substance to be eliminated is greater than 60 minutes. Removal of cytokines by membrane adsorption is another possibility. However, because the membrane surfaces are saturated after a few hours, frequent filter changes are necessary for them to generate effective adsorption of these mediators. Despite filter changes, only a brief and transient drop in the TNF plasma level has been observed. Controlled clinical trials are needed to determine whether or not CRRT actually has a beneficial effect on the systemic inflammatory response syndrome (SIRS).

The nutritional management of acute renal failure in the intensive care unit.

The nutritional support of patients with acute renal failure (ARF) in the ICU has undergone major changes. Nutritional therapy in these patients should not depend on the impairment of renal function but on the severity of multiple organ failure (MOF). There are no differences in general rules for the nutrition of the critically ill with or without ARF. Because ARF, per se, does not affect energy expenditure, energy requirements in these patients are the same as in other MOF patients. Thirty to 35 kcal/kg/day should be administered as carbohydrate and lipid solutions, and the serum concentration of glucose and triglycerides controlled. In contrast to patients with chronic renal failure, in ARF patients nitrogen administration of approximately 1.5 to 1.7 g amino acids/kg/day is necessary to diminish protein catabolism. No clinical data exist about the best composition of the administered amino acids, but a mixture of essential and nonessential amino acids seems sensible; the exclusive administration of essential amino acids is obsolete. New dialysis techniques such as continuous renal replacement therapy offer the opportunity to adapt nutrition to each individual patient's needs. Using these techniques, there is no reason to reduce nutrition because of fluid restriction, as is often necessary in intermittent hemodialysis.