An audit of the adherence to dosing and therapeutic monitoring of intravenous vancomycin in accordance with the trust’s antimicrobial guidelines
Authors: Adams O 
Published: November 2024

Abstract

Introduction
Inappropriate vancomycin dosing and monitoring have compromised patient safety, causing acute kidney injury and prolonged hospital stays. Misuse of antibiotics, like vancomycin, accelerates resistance, a global health threat. Following guidelines can prevent harm and curb the emergence of vancomycin-resistant enterococci and resistant Staphylococcus aureus1.

Aim
To assess the level of adherence to trust guidelines for the dosing and monitoring of intravenous vancomycin.

Audit Standards
Standard 1: Patients prescribed intravenous vancomycin should have documented indication
Standard 2: Patients prescribed intravenous vancomycin should have correct loading dose
Standard 3: Patients prescribed intravenous vancomycin should have correct maintenance dose
Standard 4: Patients prescribed intravenous vancomycin should have trough levels taken at the right time
Standard 5: Patients prescribed intravenous vancomycin should have doses accurately adjusted against trough level Results: Standard 6: Patients prescribed intravenous vancomycin should have all prescribed doses administered (i.e. no missed doses).
Standard 7: Vancomycin prescriptions should be screened by a pharmacist.

Methods
This audit was approved by both the Trust Clinical Audit Committee and the Antimicrobial Stewardship Group. A retrospective audit using data extracted from EPMA. The data collected included: indication documented (Yes/No), correct loading dose? (Yes/No), missed doses? (Yes/No), correct maintenance dose? (Yes/No), correct first sampling? (Yes/No), correct subsequent sampling? (Yes/No), correct dose adjustments based on levels? (Yes/No) and prescription screened by a pharmacist? (Yes/No). Data was input into Microsoft Excel for analysis.
The period covered was 01/12/2022 to 31/05/2023. Ethics approval was not required, as clinical audits do not require ethical review.
The inclusion criterion was adult patients prescribed intravenous vancomycin. The exclusion criteria were patients in maternity, labour, and renal wards, due to different guidelines and ITU due to no EPMA. The population size was 243; sample size (n) =150 ensuring a 95% confidence level.

Results
In total, 150 patient drug charts were analysed, of which 96 % had their vancomycin indication documented. 65.3% of patients had the correct loading dose, 64.7% had the correct maintenance dose. 32.23% had the initial trough level done at the right time and 35% had correct subsequent trough levels measured. 44% had correct dose adjustments based on their trough levels and 57.33% had their prescriptions screened by a pharmacist.

Discussion and conclusion
None of the target compliance rates were met, highlighting significant issues with vancomycin dosing and therapeutic monitoring within the trust. Therapeutic drug monitoring (TDM) is crucial to ensure optimal patient outcomes2.
Audit findings have been shared with the wider multidisciplinary team, education on TDM has taken place with junior pharmacists and digital prompts on EPMA have been included to help improve adherence.
A limitation of this audit is its retrospective nature, useful for trend analysis but not for identifying causes. A prospective audit was not feasible due to staffing pressures. Conducting clinical audits are an important tool for assessing and ensuring safe clinical practice.

References
1. Joint Formulary Committee (2023). British National Formulary [Online]. London: British Medical Association and Royal Pharmaceutical Society of Great Britain. Available from: https://bnf.nice.org.uk/drugs/vancomycin/#drug-action.
2. ‌ASHP Statement on the Pharmacist’s Role in Antimicrobial Stewardship and Infection Prevention and Control. (2010). American Journal of Health-System Pharmacy, [online] 67(7), pp.575–577. doi:https://doi.org/10.2146/sp100001.