Nutrient Pattern Analysis in Critically Ill Patients (NAChO)

Inclusion Criteria: * Age ≥18 years * Written informed consent obtained from the patient's legal representative and later from the patients (as soon as possible) * Individuals diagnosed with severe head trauma or intracerebral hemorrhage ("central nervous system group") or with severe sepsis/ septic shock ("Sepsis group") at any time from ICU admission until day 5 (i.e. day of screening) * Patient on the ICU for ≥ 5 days ("ICU long stayer") Exclusion Criteria: * Language other than German or French * Institutionalized Individuals (e.g. prisoners, severe pre-existing mental incapacity) * Patients with known pre-existing neurological or psychiatric disease that will make informed consent likely impossible * Patients with known pregnancy or known to be lactating will not be included to the investigation. Due to the observational/ diagnostical nature of the study, a pregnancy test will not be performed. * Patients on extracorporeal membrane oxygenation (ECMO) * Clinical signs of pre-existing malnutrition (Body mass index \<18) * Pre-existing evidence for history of anorexia or bulimia * Parenteral nutrition received within last 5 days (for more than 12 hours) or evidence for parental nutrition needed within next 7 days * Terminal disease (i.e. life expectancy \<14 days) * Patients with active malignancy * Patients on biologicals interfering with metabolism (e.g. infliximab) * Patients on chronic steroid medication (i.e. prednisone equivalent dose \>10mg/day) * Patients on neuromuscular blocking agents on a regular basis (i.e. on a repetitive basis within last 48 hours or evidence for need within next 7 days) * At screening (day 5): prescribed caloric intake substantially higher (i.e. \> 150% of caloric need of indirect calorimetry) than indirect calorimetric results (in intubated patients) or i.e. standard-of-care (25 Kcal/kg body weight/day) * Severe adipositas defined as BMI \>40 * Known pre-existing allergy to standard enteral formulae * Subject previously enrolled to an interventional trial that is not considered standard-of-care (e.g. investigation of new medication/drug or medical devices)