Pat Jamerson, PhD, RN; Karen Wilson, MSN, RN; Kelly Schlechte, RN; Beth Witzig, RN; Jonica Huntman, PharmD
Washington University School of Medicine and St. Louis Children’s Hospital, St. Louis, Missouri
Cystic fibrosis (CF) is a chronic illness of genetic origin currently affecting about 30,000 children and adults in this country. Unfortunately, CF patients frequently experience pulmonary infections requiring systemic antibiotic therapy with high potential for toxicity. Current practice in the care of children with CF is to obtain blood for drug concentration analysis from peripheral sites even though access can be difficult and many of the CF children have indwelling central venous catheters. Empirical data regarding the validity of antibiotic concentration of blood samples obtained from central venous catheters in children is scant and the findings are inconsistent. A study was designed to compare the accuracy of vancomycin and tobramycin blood concentrations obtained from peripheral sites as compared to levels obtained from indwelling central venous catheters in CF children.
Methods: A sample of 50 children between the ages of 2 and 18 who are admitted to St. Louis Children’s Hospital pediatric ward with CF, have a functional indwelling central catheter, and have tobramycin or vancomycin drug concentration analysis (peak and trough) ordered, are invited to participate in the study. When ordered, blood antibiotic levels are obtained by both central and peripheral routes according to hospital policy and analyzed in a CLIA-approved laboratory.
Results: There were no statistically significant differences between the fourteen central line and peripheral specimens (T9 = 0.217 ; p = 0.83); but in fact, the specimens are highly correlated R = 0.947; p = 0.001).
Conclusions: These preliminary results suggest blood antibiotic levels may be obtained from either route. Continuation of the study is needed before a final decision about best clinical practice can be made.