USING CDSS FOR APPROPRIATE DOSING OF ANTIBIOTICS WITH

REDUCED RENAL FUNCTIONPresented By:

Kwavi Agbeyegbe, Sam Ruffing, Michael Peterson

MED INF 406-DL FALL 2010

Identify the Problem Antibiotics are one of the most widely used

classes of drugs in hospitals and account for one-third of total pharmacy cost.

Suboptimal dosing decisions are the most common reason for inappropriate antibiotic prescribing in the hospital setting, with the majority of errors occurring in the prescribing phase.

It is believed 25-50% of all prescribed antibiotics are inappropriate in respect of drug choice, dose administered or duration of treatment (Ena,1998)

Identify the Problem Antibiotics which are eliminated from the

human body by renal excretion, are inappropriately dosed in an estimated 18-26% of patients (Nicholas,2009).

The estimated prevalence of impaired renal function (GFR<60 ml/min/1.73m2) is 13% for men and 36% for women over the age of 65.

Dosing of renal cleared antibiotics is very complex, it requires complicated dosing algorithms and pharmacokinetic monitoring.

Antibiotics Antibiotics are eliminated from our bodies by

basically two routes. * Renal elimination * Metabolized by the liver Antibiotics can be cleared by one route, both

routes, or any proportion of either route. Our CDSS will focus on antibiotics that

required a reduction in dosage or kinetic monitoring when renal function is diminished.

Examples: Quinolones , Aminoglycosides and Vancomycin.

Renal Function

Renal Function Decreasing as patients get older (COOK, 2007)

Different Calculation Methods: Glomular Filtration Rate (GFR), Creatinine Clearance (CrCl)

Negative Effects

Adverse Drug Events: Nephrotoxicity, Ototoxicity, Cardiotoxicity….

Economic Cost: Increased length of stay, higher cost for monitoring, increased medication costs.

Societal Cost: Increased Insurance cost, Loss of antibiotic efficacy, lower quality of care.

Antibiotic Dosing Model Our CDSS Antibiotic dosing model

requires data from multiple sources: ADT, Lab, Pharmacy, EMR, Clinics

Baseline data required: Age, sex, height, allergies, diagnosis, infection site, current drug therapy, WBC with diff, albumin.

Lab work-up: Scr, BUN, cultures Loading dose based on ideal body weight,

and dosing interval determined by renal function.

Monitoring Parameters Trough and Peak levels at steady state Measuring SrCr every two days or every

day in unstable renal function Weigh patient every two to seven days Measure and monitor urine output daily When the patient is on an aminoglycoside

baseline and weekly audiograms, and check for tinnitus or vertigo daily.

EPIC Pharmac

yEPIC

Beaker LISHMSADT

HMS EMR

HMS Nursing

DocEPIC

Radiology

TheraDocKnowledge Base

Antibiotic AssistantClinical Alerts

ADE AssistICP Assist

Interface Engine

Alerts

Physician/Pharmacist

EpicClinic

EPIC uses HL7, ANSI X 12, XML

HMS is ODBCcompliant

TheraDoc-HL7, LOINC, NHSN, PHIN, MS,

SNOMED-CT and Rx Norm

CCOW

Real time interface

1. Physician selects an Antibiotic-Initial Order

2. All known needed data elements are pulled to one screen:•Allergies•Current/Past Renal Dx•Serum Creatinine, BUN, WBC w/diff and albumin results•Demographics•Radiology results-Chest X-rays findings•Pathology findings if relevant

3. Recommendations includeAntibiotic dosage/ selectionPeak / trough levels orderedRepeat BUN/Creatinine ordered

4. Physician selects agree/change

If order selection is changed drop down box with reasons will require completion

Once order is completed:

Peak and trough dates and times will be ordered

eMAR will populate Antibiotic Selections with peak and trough draw times

To : Physician and PharmacistMicro results on culture and sensitivity with new recommendations for Antibiotic choice, if appropriate

To: Nurses/phlebotomistAlerts for peak and trough times for drawing

To: Physicians Alerts from nursing documentation/Lab that may signal signs and symptoms of toxicity

Alerts

Evaluation

To implement a knowledge-based clinical decision support system for clinical information systems, it is crucial to verify and validate the knowledge base. (Kim, Kim, Cho, Lee, & Kim, 2010).

Evaluation The requirements of the CDSS should

meet the user requirements and also satisfy all the regulatory specifications.

Methods and techniques used in the Verification and Validation should be designed carefully with verification taking place before validation.

Software validations should not be left to the closing phases of the project.

Verification and Validation

Building the system right

Building the right system

Verification Requirements Specification gathering

Functional design

Internal systems design

Code verification

Verification Walk through

Buddy Checks

Inspection

ValidationTesting Strategy

Black box testing

Equivalence partitioning testing

Validation

User Acceptance Testing/Validation

Functional Testing/Validation

Integration Testing/Validation

Code Validation

Requirement Specification gathering

Requirement Specification Verification

Coding

User Acceptance Testing (UAT)

Validation

Functional Design

Functional Design Verification

Integration Testing

Validation

Functional Testing

Validation

Internal System Design Specification

Internal System Design Specification Verification

Code Verification Code Validation

Verify

Verify

Verify

Verification levels with corresponding Validation tests.

Verify

However, the FDA is realistic enough to recognize that a developer cannot test forever. Under-testing vs. Over-testing

Under-testing vs Over-testing

Benefits of Verification and Validation

Benefits of Verification and Validation(Chojnowski, 2008)

System limitations Physician autonomy

Computer literacy

IT Support Availability

Impact on workflow

System limitations

Training

Buy-in from clinicians and administrative staff

Lack of standards for CDSS development

Future Extensions Study the prescribing behavior and

structure of errors when physicians override the default value.

Open source Standard for development of CDSS

Post-implementation review

Conclusion Stakeholders have to be informed and

involvedprior, during and after implementation.

CDSS is more effective when combined with CPOE.

CDSS System review concludes aided drug dosing provides an overall benefit.

To increase adoption, CDSS should be integrated into existing workflow.