Pilot Study of Measuring Energy Expenditure in ECMO Patients Under Consideration of Type of Ventilation and to Approximate Cardiac Output

With the perception that lung protective ventilation with regard to low tidal volume ventilation and limiting airway pressures improves outcome in ARDS (acute respiratory distress syndrome) and that the development of new technical devices of extracorporeal lung assist systems with lower complication rates support establishment of lung protective ventilation strategies these systems are more and more frequently used. All critically ill patients with and without ECLA (extracorporeal lung assist)/ECMO (extracorporeal membrane oxygenation) treatment are on high risk for muscle wasting, leading to more comorbidity and higher mortality risk. Besides inflammation malnutrition is known as one of the main risk factors. Over and underfeeding should be prevented. However nutritional aspects of patients on extracorporeal lung assist are hardly investigated. Up to now changes in metabolic rates induced by ECLA/ECMO are poorly described. Factors like work of breathing, changes in cardiac output and septic state are influencing energy metabolism but until now there is no tool for measuring energy expenditure in clinical routine for patients on ECLA/ECMO. Indirect calorimetry is a simple device only for patients without ECLA/ECMO system. Oxygenation and CO2 (carbon dioxide) elimination by the lung assist system can be calculated but is not implemented to clinical routine. The combination of indirect calorimetry and calculation of lung assist function at the same time would give us the chance to adapt nutrition rates to energy expenditure. This may prevent muscle wasting and weakness. This pilot study will include 40 participating patients during 8 month investigating nutritional therapy adapted to energy expenditure calculated by O2 and CO2 turnover rates in patients on ECLA or ECMO systems. The investigators aim is to describe a calculation to set nutrition targets in ECMO patients. Second the investigators will describe level of nutritional needs under consideration of different mechanical ventilation states. Third O2 consumption and CO2 elimination will be used to estimate cardiac output.