GCX damage and its relationship to pharmacodynamics and pharmacokinetics of beta lactam antibiotics in critically ill Hypothesis to be tested: GCX damage impairs pharmacodynamics and pharmacokinetics of beta-lactam antibiotics in critically ill patients. There is correlation between GCX damage and insufficient beta lactam levels in patients with commonly used dosing. The aim of the study: Evaluation of relationship between GCX damage and pharmacodynamics and pharmacokinetics of beta-lactam antibiotics in critically ill. Type of the study: Observational. Subjects: Adult patients admitted to ICU with beta-lactam antibiotic therapy (meropenem or piperacillin/tazobactam empirically or based on culture results). Sample size calculation: 20 patients (expected correlation coefficient 0,6, alpha error = 0,05) will lead to power study = 0,89. Intervention: none. Data to be recorded and analyzed: Demographics, type of patients (trauma, post surgical, medical, after cardiac arrest), severity score - Apache II, SOFA, fluid balance, a presence of delirium, clinical outcome, sublingual microcirculation by SDF imaging will be recorded three times during antibiotic treatment at the time points for blood samples required for pharmacodynamics and pharmacokinetic analysis, microcirculatory data and Perfused Boundary Region.

Inclusion Criteria:

• Adult patients admitted to ICU with beta-lactam antibiotic therapy (meropenem or piperacillin/tazobactam empirically or based on culture results).

Exclusion Criteria:

• None.

Adult patients admitted to ICU due to sepsis or polytrauma in need for intravenous antibiotic therapy.