Cefazolin prophylaxis in neurosurgery monitored by capillary electrophoresis

Prophylactic use of antibiotics to prevent postoperative infections is a routine method in neurosurgery. Little is known about the period of effectiveness of antibiotics applied only for the purposes of operation. The actual concentration of cefazolin was determined in the serum, in the contents of wound drains, and in the cerebrospinal fluid in a 24-hour postoperative period after the administration of 1 g of cefazolin just prior to skin incision in 8 patients undergoing lumbar discectomy and 11 patients undergoing craniectomy. The concentration of the antibiotic was then compared with the minimal inhibitory concentration values of cefazolin for 10 different bacterial species. For evaluating the concentration of cefazolin, capillary electrophoresis was used, which is a new clinical application of this separation technique. Results showed that the antibiotic was effective against bacterial breeding in the serum and in the drainage up to 12 hours. The drug concentration in the cerebrospinal fluid remained less than the value of the serum, and it exceeded the minimal inhibitory concentration values only for approximately 5 hours.