Antibiotic concentrations in blood and tissue. Intraoperative ischemia as a model for the determination of tissue concentrations using mezlocillin and oxacillin as examples.

Blood present in the tissue distorts the results obtained during measurement of antibiotic tissue levels. The greater the blood supply to the tissue, the bigger the error when tissue levels are measured. The examination of tissue removed during temporary intraoperative ischemia is an alternative to the indirect mathematical method of correcting errors of blood level measurement. This technique was tested by determining tissue concentrations after i.v. injection of 4 g mezlocillin and 2 g oxacillin. The tissue was removed during operations on limbs after the application of an Esmarch's bandage. Determination of hemoglobin in ischemic tissue confirmed exsanguination so that the 6-((R)-2-[3-methylsulfonyl-2-oxo-imidazolidine-1-carboxamido]-2-phenylacetamido )-penicillanic acid-Na (mezlocillin) and 5-methyl-3-phenyl-4-isoxazolylpenicillin (oxacillin) concentrations determined corresponded to the actual tissue levels. The concentrations of mezlocillin and oxacillin in fat, skin, tendon, muscle, ganglion, aponeurosis, tumour, ligament, subcutis, synovial fluid, epineurium and serum are given in the text.