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Impact of Clinical Decision Support Guidelines on Therapeutic Drug Monitoring of Gentamicin in Newborns

Fonzo-Christe, Caroline MSc, PhD*; Guignard, Bertrand MSc, PhD*; Zaugg, Claudia MSc*; Coehlo, Ana MSc*; Posfay-Barbe, Klara M. MD; Gervaix, Alain MD; Desmeules, Jules MD, PhD§,¶; Rollason, Victoria MSc, PhD§,¶; Combescure, Christophe PhD; Corbelli, Regula MD**; Rimensberger, Peter MD**; Pfister, Riccardo MD, PhD**; Bonnabry, Pascal MSc, PhD*,¶

doi: 10.1097/FTD.0000000000000071
Original Article

Background: Our institution's gentamicin dosing and therapeutic drug monitoring (TDM) practices for newborns were suspected to be very heterogeneous. Once-daily dosing (ODD) or extended-interval dosing (EID) and trough concentration measurement were recommended. Clinical decision support guidelines were developed and implemented as clinical decision support in the computerized prescriber order entry system. Impact on dosing, TDM practices, and blood sampling were evaluated.

Methods: A 1-year retrospective historically controlled study before (April 2008–March 2009) and after the implementation of guidelines (January 2010–December 2010) for newborns (<30 days of life) receiving gentamicin. Blood concentrations (% of peak concentrations sampled, % of patients with zero or one concentration sampled, % of trough concentrations ≤1 mg/L) and dose regimen (ODD/EID) were compared between groups. Factors potentially associated with gentamicin concentration were analyzed (multivariate analysis).

Results: One hundred thirty-two (postguidelines) versus 102 (preguidelines) patients were included (median gestational age: 34.3 versus 35.8 weeks, P > 0.05). After implementation of the guidelines, an ODD/EID regimen was almost exclusively used (97.7% versus 61.6%, P < 0.001), the percentage of peak concentrations (0.9% versus 17.2%, P < 0.001) and the number of blood samples per patient (87.1% having 0 or 1 concentration measured versus 48.0, P < 0.001) sharply reduced. A significantly higher percentage of trough concentrations were ≤1 mg/L (68.5% versus 33.0%, P < 0.001). The probability of a trough concentration ≤1 mg/L increased with an ODD/EID regimen (odds ratio, 7.23; 95% confidence interval: 3.48–15.0, P < 0.001) and in the postguidelines group (odds ratio, 2.02; 95% confidence interval: 1.01–4.02, P = 0.045).

Conclusions: Guideline implementation generated a sharp reduction in blood sampling. Clinical benefits of better gentamicin dosing and TDM practices were evident. Cost-effectiveness and clinical benefit of reduced blood sampling should be evaluated.

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*Service of Pharmacy;

Pediatric Infectious Diseases Unit;

Division of Pediatric Emergency;

§Service of Clinical Pharmacology and Toxicology, Geneva University Hospitals;

School of Pharmaceutical Sciences, University of Geneva/University of Lausanne;

Clinical Research Center and Division of Clinical Epidemiology; and

**Neonatology and Pediatric Intensive Care Unit, Geneva University Hospitals, Switzerland.

Correspondence: Caroline Fonzo-Christe, MSc, PhD, Service of Pharmacy, Geneva University Hospitals (HUG), Rue Gabrielle-Perret-Gentil 4, CH-1211 Geneva 14, Switzerland (e-mail:

C. Fonzo-Christe was involved in the conception of the study, interpretation and statistical analysis of the data, and drafted the article. B. Guignard was involved in the conception of the study, interpretation of the data, and writing of the article. C. Zaugg was involved in the conception of the study, in guidelines development, and compiled the data before guidelines implementation. A. Coehlo compiled the data after guidelines implementation. A. Gervaix, K. M. Posfay-Barbe, R. Corbelli, V. Rollason, and J. Desmeules were involved in the guidelines elaboration. C. Combescure performed the statistical analysis of the data. P. Rimensberger and R. Pfister were involved in the interpretation of the data and reviewed the article. P. Bonnabry supervised the design and execution of the study, and contributed to the writing of the article.

The authors declare no conflict of interest.

Presented in part as a poster at the 39th Congress of the European Society of Clinical Pharmacy, October 21–23, 2010, Lyon, France and at the 17th Congress of the European Association of Hospital Pharmacy, March 21–23, 2012, Milan, Italy.

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Received July 26, 2013

Accepted March 20, 2014

© 2014 by Lippincott Williams & Wilkins