[Monitoring of intraperitoneal administration of vancomycin in patients on continuous ambulatory peritoneal dialysis]

To validate a pharmacokinetic model of the treatments with intraperitoneal vancomycin applied to patients on continuous ambulatory peritoneal dialysis with bacterial peritonitis.

To carry out a prospective study divided in 2 cohorts: the first one including ten patients of 56±14 years and 65±5 kg, and the second one with 10 patients (12 episodes of peritonitis) aged 52±13 years and 64±8 kg. The treatment consists of administering and retaining for 6 h in the peritoneal cavity a solution containing 2 g of vancomycin and 1 g of ceftazidime into 2 l of "dialysis solution". After the antibiotic administration, blood samples were obtained at 4, 6, 8, 10, 24, 48 and 168 h in the first cohort and at 6 and 120 h (C(VAN)(120)) in the second. The pharmacokinetic model was developed from the parameters obtained from the first cohort and was validated by the second cohort, calculating the mean error (ME) and the mean squared prediction error (MSPE) of the C(VAN)(120).

Vancomycin serum concentrations fell from 39.63±7.62 mcg/ml at 4h to 8.55±2.87 mcg/ml at 168 h for the first cohort, and from 37.65±6.84 mcg/ml at 6h to 10.82±2.66 mcg/ml at 120 h (C(VAN)(120)) for the second cohort. The pharmacokinetics parameters were: C1=0.006 1/h/kg and Vd:=0.52 1/kg for the first cohort, and C1=0.006 1/h/kg and Vd:=0.53 1/kg for the second. The predictive ME and MSPE of the C(VAN)(120). were 0.59 mcg/ml ([EM*100/C(VAN)(120)=5.5%) and 10.38 mcg(2)/ml(2) ([MES*100/(C(VAN)(120))(2)]) respectively.

The presented model shows an adequate exactitude and precision for the monitoring of intraperitoneal vancomycin in patients submitted to continuous ambulatory peritoneal dialysis with peritonitis.