Aminoglycoside volume of distribution and illness severity in critically ill septic patients.

The volume of distribution of amikacin and the APACHE II score were determined in 42 critically ill patients being treated for a gram-negative infection. The mean volume of distribution (Vdt) was 0.41 +/- 0.12 l/kg with a wide range (normal of 0.25 l/kg). There was a good relationship between the Vdt and illness severity as measured by the APACHE II score (r = 0.70; P < 0.001). Critically ill patients should receive larger loading doses of aminoglycosides in order to achieve therapeutic blood levels. The aminoglycoside Vdt may be useful in determining the degree of capillary leak and tissue oedema that accompanies sepsis.