Vancomycin Nomogram Guidelines in a CPOE System
Vancomycin Nomogram Guidelines in a CPOE System
Purpose. The implementation and evaluation of vancomycin nomogram guidelines in a computerized prescriber-order-entry (CPOE) system are described.
Methods. Initial vancomycin orders for patients over age 18 years who received vancomycin between August 1 and September 30, 2006 (preimplementation), and between March 1 and April 30, 2007 (postimplementation), were compared with vancomycin nomogram recommendations to determine if the vancomycin regimen ordered coincided with the nomogram recommendation. The numbers of regimen changes and vancomycin serum concentrations measured during the first five days of therapy were also assessed. A multivariate logistic regression model assessed independent predictors of an initial vancomycin order that met the nomogram recommendation
Results. A total of 522 vancomycin orders were included in the analysis (279 in the preimplementation group and 243 in the postimplementation group). A significant difference was observed in the percentage of initial vancomycin orders that met nomogram recommendations in the postimplementation group compared with the preimplementation group (36% versus 24%, p = 0.0028). No difference was noted between the two groups in the number of regimen changes or serum vancomycin concentrations measured during the first five days of therapy. In a multivariate analysis, age (p = 0.02) and weight (p < 0.0001) were negatively associated with a vancomycin order that met nomogram recommendations, while the postimplementation group was positively associated with an order that met nomogram recommendations (p = 0.001).
Conclusion. A vancomycin nomogram implemented into a CPOE system increased the likelihood of patients receiving an initial vancomycin regimen that coincided with the nomogram's recommendations.
Vancomycin was first introduced into clinical practice in 1958, but its utility was overshadowed by the development of antistaphylococcal β-lactams. With the emergence of methicillin-resistant Staphylococcus aureus, vancomycin resurfaced as the main treatment option for this infection. Because vancomycin is a glycopeptide bactericidal antibiotic that exhibits time-dependent killing, it is imperative that the trough serum vancomycin levels remain above four to five times the minimal inhibitory concentration (MIC) of the bacteria. For this to occur, it is recommended that vancomycin be dosed based on total body weight and creatinine clearance (CLcr).
Previously at our institution, i.v. vancomycin was often initiated at a dosage of 1000 mg every 12 hours in adults, regardless of the patient's weight or renal function. This dosing regimen is not optimal for all patients, especially for those who are not of average weight or those with impaired renal function. Furthermore, with new recommendations to reach higher trough serum vancomycin concentrations of 15–20 µg/mL for complicated infections (e.g., endocarditis, meningitis, hospital-acquired pneumonia caused by S. aureus), initiation of vancomycin 1000 mg every 12 hours may lead to many suboptimal dosage regimens.
Previous research suggests that the use of a vancomycin nomogram increases the percentage of patients whose serum drug concentrations will be in the target range. Also, the use of a vancomycin nomogram has been shown to decrease the number of dosage changes and serum concentration measurements.
One concern associated with vancomycin dosing is the increase in the MIC of S. aureus strains with vancomycin. With increasing MICs also come the risks of resistance and treatment failure. To date, vancomycin-intermediate S. aureus and vancomycin-resistant S. aureus remain rare, but heterogeneous vancomycin-intermediate S. aureus (hVISA) is becoming a growing concern. The overall MIC for hVISA strains indicates vancomycin susceptibility, but sub-populations with higher MICs that are vancomycin intermediate exist within the strain. One hypothesis for the increase in hVISA strains is vancomycin dosing below target trough concentrations, which increases selective resistance among subpopulations of the strain.
With these previous studies and information emphasizing the importance of appropriate dosing regimens early in treatment, we conducted this study to determine if implementation of a vancomycin-dosing nomogram into a computerized prescriber-order-entry (CPOE) system leads to an increased number of initial optimal vancomycin orders.
Abstract and Introduction
Abstract
Purpose. The implementation and evaluation of vancomycin nomogram guidelines in a computerized prescriber-order-entry (CPOE) system are described.
Methods. Initial vancomycin orders for patients over age 18 years who received vancomycin between August 1 and September 30, 2006 (preimplementation), and between March 1 and April 30, 2007 (postimplementation), were compared with vancomycin nomogram recommendations to determine if the vancomycin regimen ordered coincided with the nomogram recommendation. The numbers of regimen changes and vancomycin serum concentrations measured during the first five days of therapy were also assessed. A multivariate logistic regression model assessed independent predictors of an initial vancomycin order that met the nomogram recommendation
Results. A total of 522 vancomycin orders were included in the analysis (279 in the preimplementation group and 243 in the postimplementation group). A significant difference was observed in the percentage of initial vancomycin orders that met nomogram recommendations in the postimplementation group compared with the preimplementation group (36% versus 24%, p = 0.0028). No difference was noted between the two groups in the number of regimen changes or serum vancomycin concentrations measured during the first five days of therapy. In a multivariate analysis, age (p = 0.02) and weight (p < 0.0001) were negatively associated with a vancomycin order that met nomogram recommendations, while the postimplementation group was positively associated with an order that met nomogram recommendations (p = 0.001).
Conclusion. A vancomycin nomogram implemented into a CPOE system increased the likelihood of patients receiving an initial vancomycin regimen that coincided with the nomogram's recommendations.
Introduction
Vancomycin was first introduced into clinical practice in 1958, but its utility was overshadowed by the development of antistaphylococcal β-lactams. With the emergence of methicillin-resistant Staphylococcus aureus, vancomycin resurfaced as the main treatment option for this infection. Because vancomycin is a glycopeptide bactericidal antibiotic that exhibits time-dependent killing, it is imperative that the trough serum vancomycin levels remain above four to five times the minimal inhibitory concentration (MIC) of the bacteria. For this to occur, it is recommended that vancomycin be dosed based on total body weight and creatinine clearance (CLcr).
Previously at our institution, i.v. vancomycin was often initiated at a dosage of 1000 mg every 12 hours in adults, regardless of the patient's weight or renal function. This dosing regimen is not optimal for all patients, especially for those who are not of average weight or those with impaired renal function. Furthermore, with new recommendations to reach higher trough serum vancomycin concentrations of 15–20 µg/mL for complicated infections (e.g., endocarditis, meningitis, hospital-acquired pneumonia caused by S. aureus), initiation of vancomycin 1000 mg every 12 hours may lead to many suboptimal dosage regimens.
Previous research suggests that the use of a vancomycin nomogram increases the percentage of patients whose serum drug concentrations will be in the target range. Also, the use of a vancomycin nomogram has been shown to decrease the number of dosage changes and serum concentration measurements.
One concern associated with vancomycin dosing is the increase in the MIC of S. aureus strains with vancomycin. With increasing MICs also come the risks of resistance and treatment failure. To date, vancomycin-intermediate S. aureus and vancomycin-resistant S. aureus remain rare, but heterogeneous vancomycin-intermediate S. aureus (hVISA) is becoming a growing concern. The overall MIC for hVISA strains indicates vancomycin susceptibility, but sub-populations with higher MICs that are vancomycin intermediate exist within the strain. One hypothesis for the increase in hVISA strains is vancomycin dosing below target trough concentrations, which increases selective resistance among subpopulations of the strain.
With these previous studies and information emphasizing the importance of appropriate dosing regimens early in treatment, we conducted this study to determine if implementation of a vancomycin-dosing nomogram into a computerized prescriber-order-entry (CPOE) system leads to an increased number of initial optimal vancomycin orders.
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