To achieve this aim, many authors already suggested that the continuous infusion might solve the problem of too low antibiotic plasma and ELF levels. Studies about pharmacokinetics of continuous infused antibiotics, which were conducted in healthy volunteers or patients with normal organ function, cannot be assigned to critical ill patients. Rationales for this statement are that data about plasma and tissue levels of antibiotics in critical ill patients are highly influenced by modified volume of distribution, elimination half-life period and impaired tissue perfusion compared to healthy volunteers. These physiological variances implicate that the response to the antibiotic treatment remains doubtful. Under these pathophysiological conditions, data about antibiotics plasma and ELF levels may provide additional information in order to adjust the dosing regime of antibiotics.