Forderungen und Erwartungen an einen optimalen Volumenersatz

[Circulation therapy for severe burn injuries]

Patients with burn injuries to more than 10% of the body surface area (BSA) are in potential danger of traumatic hypovolemic shock and from 20% BSA a generalized burn edema can occur. In the preclinical setting an increased infusion therapy is generally unnecessary. Clinical circulation therapy is goal-directed taking hemoglobin concentration, hematocrit, MAP, diuresis, CVP and central venous sO(2 )into consideration. For initial volume replacement, balanced crystalloids with the addition of acetate and possibly malate are infused. Colloids should be given with great caution. Additional gelatine solution is only to be used in patients with impending hypotension and catecholamines should also be avoided if possible. If necessary, dobutamine is used to increase cardiac inotropy and cardiac output. Norepinephrine is only indicated in patients with significantly reduced SVR. Extended hemodynamic monitoring is necessary in all patients with prolonged catecholamine therapy.

[The design of the VISEP trial. Critical appraisal]

The survey transcript of the VISEP interventional trial "Prospective randomized multicenter study on the influence of colloid vs crystalloid volume resuscitation and of intensive vs conventional insulin therapy on outcome in patients with severe sepsis and septic shock" [Clinical trials.gov. identifier: NCT00135473; study start April 2003] comprises, according to the data of the year 2003, methodological shortcomings which challenge a priori the study design and thus the resolution of the purpose of the study, i.e., "determination of the influence of the studied volume and insulin interventions on morbidity and mortality of patients with severe sepsis and septic shock". The most important points of criticism are: 1. A volume therapy with exclusively crystalloids or colloids with the chosen colloid hyperoncotic, hyperchloremic HES solution (10% hydroxyethyl starch: 10% Hemohes) or the crystalloid solution with high lactate content (Sterofundin) is neither acceptable nor practicable, even if only due to exceeding the maximum dosage as recommended by the manufacturer. 2. The fact known since the year 2001 that high molecular weight, poorly biodegradable HES preparations can present an independent risk-factor for acute kidney failure in patients with sepsis or septic shock was ignored: the exclusion criterion of a serum-creatinine value of >320 micromol/l (>3.6 mg/dl) was doubled in relation to the manufacturer's specification. 3. The hyperoncotic colloid solution used (10% Hemohes) may only be employed for a brief period: it is highly hyperchloremic and causes extravascular hypohydration with consecutive reduction of renal excretion, which together with HES is a fatal combination. 4. The crystalloid solution used, i.e., Sterofundin, which contains 45 mmol/l lactate, is contraindicated with septic shock as it increases the patient's O2 consumption, hinders lactate diagnostics as a hypoxia marker by simultaneous lactate infusion, and through increased gluconeogenesis leads to hyperglycemia, at least with diabetics. 5. It is doubtful whether an intensified insulin therapy (Actrapid) can be successful if insulin is administered simultaneously with iatrogenic hyperglycemia as a result of lactate influx. Due to these flaws in the design of the VISEP trial, the only consequence can be that the results of the survey are unusable, especially with regard to the point "HES and kidney function". Thus, any further advance presentations and interpretations should be shelved in expectation of the authors' publication of all the data, in order to begin further discussions including the flaws in study design listed here.

Determinanten des insensiblen Flüssigkeitsverlustes

Accurate perioperative fluid balance is the basis of a targeted infusion regimen. However, neither the initial status nor perioperative changes of the fluid compartments can be reliably measured in daily routine. In particular, insensible losses are not consistently assessed, so that substitution therapy is generally empirical. The object of this paper is to communicate the scientific data on this topic. Preoperative fasting (10 h) does not per se cause intravascular hypovolemia. In adults, total basal evaporation by way of the skin and airways and of any wounds during major abdominal interventions is usually less than 1 ml/kg/h. An inconstant fluid and protein shift towards the interstitial space perioperatively seems to be associated with hypervolemia, which suggests it should be preventable. The decisive factor in this context seems to be deterioration of the endothelial glycocalyx, whose further patho-physiological impact is currently only partially known. Clinical studies have revealed a link between fluid restriction and improved outcome after major abdominal surgery.

„Base excess“

The base excess of blood (BE) plays an important role in the description of the acid-base status of a patient and is gaining in clinical interest. Apart from the Quick test, the age, the injury severity score and the Glasgow coma scale, the BE is becoming more and more important to identify, e. g. the risk of mortality for patients with multiple injuries. According to Zander the BE is calculated using the pH, pCO(2), haemoglobin concentration and the oxygen saturation of haemoglobin (sO(2)). The use of sO(2 )allows the blood gas analyser to determine only one value of BE, independent of the type of blood sample analyzed: arterial, mixed venous or venous. The BE and measurement of the lactate concentration (cLac) play an important role in diagnosing critically ill patients. In general, the change in BE corresponds to the change in cLac. If DeltaBE is smaller than DeltacLac the reason could be therapy with HCO(3)(-) but also with infusion solutions containing lactate. Physician are very familiar with the term BE, therefore, knowledge about an alkalizing or acidifying effect of an infusion solution would be very helpful in the treatment of patients, especially critically ill patients. Unfortunately, at present the description of an infusion solution with respect to BE has not yet been accepted by the manufacturers.

[Hemodilution and infusion therapy for hypovolemic shock. Clinical physiological and pharmacological aspects]

Hypovolemic shock is not a form of disease and can be subdivided into four special types with varying therapeutic demands. The decisive approach in the therapy of hypovolemic shock is to initially attain normovolemia by rapid administration of volume replacement agents in the sense of controlled hemodilution. This allows an adequate increase in the cardiac output resulting in delivery of sufficient oxygen to tissues. In the following article the limits of intervention will be described and the advantages and disadvantages of these measures for patients suffering from hypovolemic shock will be critically considered.