Impact of Fluid Management Within a Goal-directed Hemodynamic Protocol on Acid-base Balance in Elective Trauma Surgery

Inclusion Criteria: * Patients at the age of 60 and above who want to undergo an elective hip replacement surgery in the center of musculoskeletal surgery * Offered patient information and written informed consent Exclusion Criteria: * Participation in another trial according to the German Drug Law 30 days to and during the study * Lacking willingness to save and hand out data within the study * Accommodation in an institution due to an official or judicial order * (Unclear) history of alcohol or substances disabuse * Absent knowledge of german language * Analphabetism * Allergy to hydroxyethyl starch or other ingredients of the intravenous solutions * For women: Pregnancy or positive pregnancy test within the preoperative screening * Operation due to case of emergency, polytrauma or pathologic fracture * Only use of regional anaesthesia * American Society of Anaesthesiologists (ASA) classification greater than III * Peripheral or central edema * AIDS (according to the CDC-classification of HIV-infection: category C) * Rheumatoid disease under treatment with Anti-TNF-alpha-Ab and/or high-dose-corticoid-treatment * Immunosuppression therapy * History of bleeding tendency (e.g. von-Willebrand-disease, thrombocytopenia) * Derailed metabolic disorder (e.g. Diabetes mellitus (Glucose \> 300 mg/dl) during the preoperative screening) * Known history of electrolyte disturbance (e.g. Hyperkalemia \> 5.8 mmol/l, Hypernatraemia \> 155 mmol/l) * Known history of acid-base-dysbalances * History of intracranial hemorrhage within one year of participation in the study * Neurological or psychiatric disease with limited contractual capability * Advanced disease of the oesophagus or upper respiratory tract * Operation in the area of the oesophagus or nasopharynx within the last two months * CHF (congestive heart failure) according to (New York Heart Association) classification - NYHA class IV * Liver disease (CHILD B or C cirrhosis, end-stage liver disease (MELD-score greater than 10)) * Conditions after acute or chronic pancreatitis * Renal insufficiency (serum creatinine greater than 2.0 mg/dl or greater than 150 µmol/l or dependency of haemodialysis)