This is a retrospective observational study concerning patients suffering from brain damage.~All the patients suffering from brain damage are monitored in order to examine their resting energy needs (REE). For the measurement of REE the metabolic computer (Medical Graphics, Ultima CCM, Minneapolis, USA) is used.~The main purpose of this study is to reveal the (REE) changing in patients with brain death semiology and examine if the REE changes could be related to the outcome of a patient with intracranial pathology. Moreover the study will examine if the changes in REE measurement are related to changes in flow velocities in the midbrain.~Any measurement shall be preceded by calibration of the metabolic computer pneumotachograph with a 3-liter syringe with an acceptable error of less than 9 ml / lit. The metabolic unit is calibrated for VO2 measurements with two calibration cylinders containing 21% and 12% O2 and for VCO2 measurements with calibration gases containing 5% and 0% CO2 respectively.~The measurement of flow velocities in the middle cerebral artery will be done with the transcranial Doppler using a low frequency (2 MHz) ultrasound head After their final diagnosis (brain death or not) the patients' characteristics will be compared according to the categorization as brain dead or not.
The study will examine the resting energy need (REE) in patients suffering from brain damage. For the measurement of REE will be used a metabolic computer (which with continuous recording of breath-to-breath volume (Vt), respiratory rate (RR) of ventilation per minute volume (MV) ), of inhaled and exhaled gases (O2 and CO2) has the ability to calculate the values of VO2, VCO2 and with the help of equations the values of REE and RQ.