Tissue antibiotic levels with tourniquet use in orthopedic surgery

Ten adult mongrel dogs were given 500 mg of cefazolin intravenously, before and after tourniquet cuff inflation. Muscle tissue antibiotic levels were comparable to the control side when the antibiotic was administered prior to tourniquet inflation. Muscle tissue antibiotic levels were markedly diminished compared to the control limb when the antibiotic was given after the tourniquet was inflated. The low level of antibiotic appeared slowly and peaked at 60 minutes as a reflection of minimal limb blood flow. It was questionable whether the small antibiotic concentration in the latter situation served adequate protective cover.