FACTORS AFFECTING THE POST-DIALYSIS LEVELS OF VANCOMYCIN AND GENTAMICIN IN HAEMODIALYSIS PATIENTS. Acute-Haemodialysis Team St.

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1 FACTORS AFFECTING THE POST-DIALYSIS LEVELS OF VANCOMYCIN AND GENTAMICIN IN HAEMODIALYSIS PATIENTS. Acute-Haemodialysis Team St. Helier s Hospital

2 Vancomycin and Gentamicin Audit Renal Unit St Helier Hospital Presenter: Albert Acheamfour Acute Haemodialysis Manger St. Helier s Hospital UK MSc. Advancing Healthcare Practice BSc. (Hons) Healthcare Practice Undergraduate Diploma(critical care) U.K (V300) N.M.C Independent and Supplementary Nurse Prescriber

3 INTRODUCTION Infections are not an uncommon occurrence in patients undergoing dialysis and is partly attributed to the usage of the HD CVC s. Increased morbidity and mortality in dialysis patients. Targeted antibiotic after culture is the gold standard of care, Treatment in most cases often starts prior to the results of microbiological cultures taken. Vancomycin and Gentamicin commonly used by most units

4 OLDER STRATGIES OBSERVED The administration of higher doses of vancomycin (30 mg/kg) in the last two hours of haemodialysis achieved mean pre-haemodialysis plasma vancomycin concentrations of 11.7 ± 1.5 μg/ml in anuric patients on day 8 Fix therapeutic dose of 20mg/kg after a loading leads substantially to sub therapeutic levels Drawbacks to this approach: unnecessarily high peak plasma drug concentrations High risk of patients receiving sub-therapeutic dose, especially patients with residual renal function

5 BACKGROUND Vancomycin Glycopeptide antibiotic Gram-positive bacterial infections (MRSA) Gentamicin Aminoglycoside antibiotic Gram-negative bacteria infections Both are Renally excreted Narrow therapeutic window Can cause Nephrotoxic /ototoxic Effective in pathogens associated with vascular-access related infections

6 BACKGROUND Principles of monitoring: Reduces risk of damage auditory and renal Ensures therapeutic levels of the drug are circulating aids recovery Daily levels further doses if required to correct sub-therapeutic serum levels

7 RETROSPECTIVE AUDIT IN 2014 Six main key audited: 1. daily monitoring 2. dosage omission 3. dosage administration 4. dose administration without drug serum levels? 5. micro approval (?within 48-72hrs) 6. Prescription of correct dose of Vancomycin and Gentamicin

8 METHODOLOGY Data collection: Retrospective Cohort of 55 6 excluded due to lack of information available Inclusion criteria: All inpatients on renal unit prescribed Vancomycin and/or Gentamicin between July and November Data collected by analysing case notes, drug charts and discharge summaries All data anonymised to maintain confidentiality

9 DATA ANALYSIS Results Sex of patient Average age of patient 64% male 62.7 years Patients on RRT 93% Positive blood cultures 38% Immunosuppressed 18% Co-prescription of both antibiotics 78%

10 RESULT 100 Graph to show adequacy of antibiotic monitoring and prescribing Micro approval (pre) 24 Micro approval (post) Stat dose given of correct dose (pre) Stat dose given of correct dose (post) 17 Daily levels performed(pre) 10 Daily levels performed (post)

11 RESULT 100 Graph to show adequacy of antibiotic monitoring and prescribing Dosing without level (pre) Dosing without level (post) Dosed with high levels (pre) Dosed with high levels (post) Missed dosing (pre) Missed dosing (post)

12 DISCUSSION Results show poor performance in prescribing and monitoring of Vancomycin and Gentamicin in our Renal Unit: 27%patients missed antibiotic doses risk of ineffective treatment A significant proportion (29%) of patients had doses of antibiotic prescribed when their levels were high or without a level increases the risk of the patient suffering nephrotoxicity/ototoxicity

13 DISCUSSION Only 13% of patients had daily levels Of all vancomycin levels taken 16% were subtherapeutic (i.e. <15) Of all gentamycin levels taken 31% were subtherapeutic (i.e. <1)

14 RECOMMENDATION Look critically and implement measures to ensure adequate dosing of Vancomycin and Gentamicin. We needed to know 1) What the Pre levels are 2) The percentage reduction on HDF treatment Decision was made to take Pre and post levels of all patients on Vancomycin and Gentamicin To investigate whether there were any parameters which could help predict the percentage reduction of the drugs levels on HDF treatment. Information on Vancomycin and Gentamicin prescription added to patient list. Possibly adding an alert regarding the level in previous 24 hours if this

15 SECOND AUDIT METHOD: Inpatients on RRT for AKI or CKD who required antibiotic therapy for various indications were included in this study. All the patients were on (HDF) using Fresenius 5008 machines and FX60 high-flux dialysers. Anticoagulation was varied depending on the dialysis duration and co-morbid conditions, with some patients receiving no anticoagulation and others receiving unfractionated heparin. Data on weight, dialysis access type, blood pump speed, duration of dialysis, litres processed per session and ultrafiltration volume.

16 ANALYSIS 88 samples were collected from 21 patients, 62% of whom were male. The mean age was 70.2 years (range 37-91). The average duration of dialysis was 3.3 hours (198 minutes) The median blood pump speed was 275mls/minute Ultrafiltration volumes per session ranged between 0 to 2.6L per session

17 Percentage reduction of pre-dialysis antibiotic level (y) against ultrafiltration volume in litres (x)

18 Percentage reduction of pre-dialysis antibiotic level (y) against litres of blood processed (x)

19 Percentage reduction of pre-dialysis antibiotic level (y) against litres of blood processed per kilogram body weight (x)

20 RESULTS: There was no correlation between blood pump speed, duration of dialysis, litres processed per session, ultrafiltration volume and time on dialysis with the percentage reduction of the pre-dialysis drug level following dialysis. When the litres processed per session was adjusted for body weight pre-dialysis however, we found a close correlation (R 2 = 0.23).

21 Predicting percentage reduction in 40 kg and 90kg with the same Litres process (80)using results from Pre HDF serum levels

22 LIMITATIONS TO CONSIDER IN THE NEW AUDIT Glomerular Filtration rate of the patient Blood Albumen levels of the patients

23 MODEL SCALE OF EXPECTED REDUCTION 22.5% Reduction 80 Blood Litres Processed Weight of 90kg

24 CONCLUTION From the evidence above it is possible to come up with a nomogram, based on a few of these parameters (litres processed per body weight) to guide antibiotic dosing. it would be of great benefit, especially in the management of patients on these antibiotics in the outpatient setting, where it may not always be possible to get the results of drug levels in a timely fashion.

25 ACKNOWLEDGEMENT Dabu-Tungu, E, Dorin G, Nsubuga M, Lutwama H, Padojino S, Seko P, Oumarou G, Bodneck C, Miranda G, Hoyte J, Steele M, Mallinder S, Hurley A, Giannopoulous M, Sood B, Makanjuola D of the Renal Unit, St. Helier Hospital, Carshalton, Surrey. U.K

26 REFERENCES Vandecasteele, S.J., De Bacquer, D., De Vriesse, A.S, Implementation of a dose calculator for vancomycin to achieve target trough levels of micro/ml in persons undergoing haemodialysis. clinical infectious disease, 53(2), p.124 Gomes, D.M., Smotherman, C., Birch, A, et al Comparison of acute kidney injury during treatment with vancomycin in combination with piperacillintazobactam or cefepime. Pharmacotherapy, (34), p 662 Brown, M,. Polisettv, R., Gracely, E.J., et al Weight-based loading of vancomycin in patients on haemodialysis. clinical infection disease (53), p 164 Bray, B.D., Boyd, J., Daly, C et al Vascular access type and risk of mortality in a national prospective cohort of haemodialysis patients. Q.J Medical. (105), p 1099 Rayner, H.C., Pisoni, R.L., The increasing use of haemodialysis catheter: evidence from DOPPS on its significance and ways to reverse it. Semin Dialysis. (23) p 6