Examination of Cardiovascular Function/ Cardio Respiratory Interaction on Spontaneous Breathing Trials in Patients in the Prolonged Weaning

Inclusion Criteria: * legal Age (≥18 years) * written informed consent Prior to study participation * patient in prolonged weaning with NYHA I-II and an actual positive Ventilator Screening test: 1. PaO2 ≥ 60 mmHg at FiO2 ≤ 0.4 2. PEEP ≤ 8 cmH2O 3. Glasgow Coma Scale \> 13 4. Temp. \< 38°C 5. Hb \> 80-100 g/L 6. less requirement on catecholamines (\<0.1µg/kg/min) * and on these patients are already performed a spontaneous breathing trial with following result: 1. abortion this spontaneous breathing trial \< 30min, but possible \> 10min 2. reason for an abortion was NOT hypercapnia Exclusion Criteria: * weaning patients are assigned on Group 1-2 * patient with heart failure (NYHA III-IV) and/ or other cardiac comorbidity * acute NSTEMI (non-ST-segment elevation myocardial infarction) * pregnancy and breast-feeding