Risk Stratification and Goal-directed Volume Therapy

It is difficult in the majority of cases to estimate the correct intra-operative mass of fluid therapy for each patient und needs a high degree of clinical experience. Among circumstances and problems of surgery (kind of surgery, length of time, bleeding, loss of liquid via wound) and kind of anesthesia, are also the concomitant diseases of patients relevant for the action of all anesthetists. These concomitant diseases correct to detect and to deduce corresponding consequences calls likewise for high clinical experience. Furthermore, the pre-operative fasting is an important fact.

Considering all these influencing factors the anesthetist tends rather to apply to much volume during surgery, followed by much more problems in PACU and / or intensive care unit.

However, how much volume is correct for which patient during which kind of surgery? How could the investigators estimate the really intra vessel volume deficit? Which available parameters are helpful, which monitoring is useful? These questions confront daily every anesthetist.

Monitoring of clinical "traditional" factors such as diuresis, blood pressure und heart rate are from experience to inexactly. Actually exist in the experts no uniform opinion about the kind and amount of fluid administration, which to apply, as well as the adequate monitoring. The central venous pressure, a commonly used parameter, is falling more and more behind.

Cardiac filling pressures correlate bad with filling volume and are unsuitable parameters for fluid therapy. It seems that dynamic parameters such as stroke volume (SV) and stroke volume variation (SVV) are better markers. SV and SVV could be measured by usual invasive blood pressure via LiDCO- or FloTrac-Monitoring.

In the study the investigators would show, that it is necessary to optimize processes already in the anesthetic ambulance, to evaluate patients with theirs concomitant diseases correctly followed by an improvement of intra-operative processes.

With the help of questionnaire is to be better structured and classified the cardiac risk of patients in accordance with the actually ACC / AHA guidelines (8). Depending surgery risk, the development of intra-operative monitoring happens standardized preoperatively (NIBP vs. IBP vs. SVV via FlowTrac or LiDCO). The intra-operative fluid regime will be performing in the group of NIBP and IBP on the basis of standard operating procedures (SOP) as well as in the group of SVV on the basis of a targeted-volume protocol.

There are a lot of surgeries with an increased fluid turnover and increased risk for cardiac complication. This demonstrated study limits the kind of surgeries on orthopedic operations with different requirement of intra-operative volume.

Hypothesis The daily challenge of each anesthetic is the correctly estimate of volume status during surgery. Multiple factors such as concomitant diseases, pre-operative fluid fasting, anesthesia as well as circumstances of surgery inclusive bleeding risk have an important influence followed by difficult peri-operative management.

The aim of this study is the improvement of peri-operative fluid management due to process optimisation already in the anesthetic ambulance included cardiac risk factors of patients followed by intra-operative fluid protocol. Primary outcome parameters are administered fluid volume (including blood transfusion), and secondary measured by amount of blood loss, postoperatively frequency of PONV, delir as well as PACU and ICU stay.

The investigator believes that the investigators could reduce the intra-operative fluid volume as well as blood loss due to these process optimization followed by increase patient satisfaction. Furthermore, the investigators could possibly reduce the PACU and ICU stay.