Vancomycin Serum Concentration after 48 h of Administration: A 3-Years Survey in an Intensive Care Unit

Risk factors for acute kidney injury associated with intravenous vancomycin in neurosurgical inpatients: a retrospective study

PURPOSE

Vancomycin (VAN) is widely used in neurosurgical patients for intracranial infections. We aimed to assess the incidence and risk factors for VAN-associated acute kidney injury (VA-AKI) in this population.

METHODS

A case-control study of patients who treated with vancomycin in neurosurgery from January 2020 to December 2022 was conducted. Demographics and potential risk factors were collected. Multivariate logistic regression analyses were performed to identify risk factors for VA-AKI. AKI was defined according to the Kidney Disease Improving Global Outcomes Guidelines (KDIGO).

RESULTS

A total of 345 patients participated with a VA-AKI incidence of 17.1% (59 cases). Among them, 15 patients had renal impairment (Stage 2 or higher), and 2 required dialysis. With univariate analysis and binary logistic regression analysis, we found that the use of mannitol (OR: 4.164; 95% CI: 1.606-10.792; P = 0.003), loop diuretics (OR: 3.371; 95% CI: 1.633-6.958; P = 0.001), three or more antimicrobial applications (OR: 3.623; 95% CI: 1.600-8.206; P = 0.002), diastolic blood pressure 80-89 mm Hg (OR: 5.532; 95% CI: 1.677-18.250; P = 0.005) and diastolic blood pressure ≥ 90 mm Hg (OR: 6.845; 95% CI: 1.518-30.866; P = 0.012) were independent risk factors for VA-AKI. In addition, according to the Youden Index, the trough concentration of vancomycin should not exceed 15.845 mg/L.

CONCLUSION

The incidence of VA-AKI in neurosurgical patients was 17.1%. The concomitant use of mannitol and loop diuretics, along with higher diastolic blood pressure and the combined use of more than three antimicrobial agents, were associated with an increased risk of neurosurgical VA-AKI.

Serum concentration of continuously administered vancomycin influences efficacy and safety in critically ill adults: a systematic review

OBJECTIVES

Vancomycin is used to treat Gram-positive infections in critically ill adults. For vancomycin administered by continuous infusion (CI), various target ranges have been used, ranging from 15-20 mg/L to 30-40 mg/L. This systematic literature review was conducted to investigate the impact of steady-state serum concentration (Css) of CI on safety and efficacy of therapy in critically ill adults.

METHODS

Relevant literature was identified by searching two electronic databases (PubMed, Cochrane Library) and Google Scholar from inception until July 2023, focusing on studies reporting measured Css and treatment outcomes (e.g. mortality, nephrotoxicity) with CI. Due to study heterogeneity, a narrative synthesis of the evidence was performed.

RESULTS

Twenty-one publications were included with a total of 2949 patients. Mortality was higher (two studies, n = 388 patients) and clinical cure was lower (one study, n = 40 patients) with Css < 15 mg/L measured 24 h after initiation of CI (C24). An adequate loading dose appeared most important for maintaining higher C24. Generally, higher Css was associated with higher rates of acute kidney injury (AKI) (15 studies, n = 2331 patients). It was calculated that Css < 25 mg/L (versus ≥25 mg/L) was preferable for reducing nephrotoxicity (three studies, n = 515 patients).

CONCLUSIONS

Despite sparse data availability, the target range of 15-25 mg/L in CI may increase clinical cure and reduce mortality and AKI. In future research, vancomycin Css cohorts should be formed to allow evaluation of the impact of Css of CI on treatment outcomes.

P14 Improving adherence to and effectiveness of an adult critical care vancomycin continuous infusion protocol: a pilot quality improvement and administration data accuracy project

Background

Vancomycin treats serious Gram-positive infections. In St George's Hospital (SGH) intensive care unit (ICU) settings, vancomycin is administered intravenously by continuous infusion. Steady-state serum concentrations are monitored daily with a 20–25 mg/L therapeutic target. Non-therapeutic concentrations are associated with patient harm and prolonged stay.1 A service evaluation revealed variable adherence to/effectiveness of the vancomycin prescribing/administration/monitoring protocol. Electronic prescribing and medicine administration (ePMA) system interface issues may have contributed.2 Consequently, multifaceted interventions were devised and piloted on General ICU.

Objectives

To (i) improve combined protocol prescribing/administration/monitoring adherence; (ii) enhance therapeutic protocol dosing; and (iii) ascertain accuracy of patients’ paper drug administration (PDA) charts compared with the ePMA system.

Methods

The quality improvement project (QIP) was approved by SGH clinical governance/audit teams. Over a 9 month period (September 2021 to May 2022) system/person-focused interventions were implemented. Protocol dosing2 was revised; introducing a &gt;90 kg patient 2 g loading dose, new renal-function categories and an increased maintenance dose for creatinine clearance (CLCR) &gt;90 mL/min. Protocol accessibility was increased via ePMA and CliniBee/Microguide app integration. Educational protocol presentations were incorporated into medical/nursing induction training. Vancomycin prescribing/administration/monitoring data for non-renal replacement patients during the intervention period, was extracted retrospectively from the ePMA system. This was compared with baseline informing ICU data collected July 2020 to July 2021.2 Patient's drug administration accuracy data (PDA charts/ePMA system) was extracted retrospectively from January to May 2022 and analysed.

Results

Compared with baseline, the proportion of patients receiving per protocol prescribing/administration of vancomycin loading/maintenance doses with daily monitoring increased [39% (7/18) to 68% (15/22)]. Within 48 h 54% (7/13) of vancomycin serum concentrations in all patients were therapeutic, demonstrating a baseline increase of 21% (3/9 to 7/13). In per protocol treated patients, serum concentrations increased 16% (2/7 to 4/9) therapeutically, decreased 20% (3/7 to 2/9) supra-therapeutically and increased 4% (2/7 to 3/9) sub-therapeutically. Supra-therapeutic concentrations were associated with CLCR &lt;50 mL/min. Sub-therapeutic concentrations were associated with CLCR &gt;90 mL/min and obesity. Compared with the ePMA system, there was 38% (5/13) less PDA charts recording both loading/maintenance doses. Administration time differences &gt;60 min were recorded for 38% (3/8) of loading and 31% (4/13) maintenance doses.

Discussion

Staff turnover periods were associated with decreased protocol compliance. Further education is required around prescribing/administration of standardized vancomycin infusion bags, with associated rate changes. Integration of pharmacists into daily Microbiology ward rounds may alleviate these issues. Higher 20 mg/kg loading doses for &gt;100 kg patients and maintenance dose revisions may reduce non-therapeutic concentrations.3 Multidirectional variation in vancomycin administration timings recorded between PDA charts/ePMA system, requires further investigation. Infusion-pump data may offer the most accurate administration time for calculating pharmacokinetic variables.

Conclusions

Multifaceted interventions were successful at improving adherence to/effectiveness of the vancomycin protocol. Findings will inform QIP roll-out across all three SGH ICUs, which will incorporate infusion-pump data collection to facilitate pharmacokinetic modelling. This will inform local dosing strategies and research into patient variability.

Population Pharmacokinetics and Dosing Simulation of Vancomycin Administered by Continuous Injection in Critically Ill Patient

Background: Vancomycin is widely used for empirical antimicrobial therapy in critically ill patients with sepsis. Continuous infusion (CI) may provide more stable exposure than intermittent infusion, but optimal dosing remains challenging. The aims of this study were to perform population pharmacokinetic (PK) analysis of vancomycin administered by CI in intensive care unit (ICU) patients to identify optimal dosages. Methods: Patients who received vancomycin by CI with at least one measured concentration in our center over 16 months were included, including those under continuous renal replacement therapy (CRRT). Population PK was conducted and external validation of the final model was performed in a dataset from another center. Simulations were conducted with the final model to identify the optimal loading and maintenance doses for various stages of estimated creatinine clearance (CRCL) and in patients on CRRT. Target exposure was defined as daily AUC of 400-600 mg·h/L on the second day of therapy (AUC24-48 h). Results: A two-compartment model best described the data. Central volume of distribution was allometrically scaled to ideal body weight (IBW), whereas vancomycin clearance was influenced by CRRT and CRCL. Simulations performed with the final model suggested a loading dose of 27.5 mg/kg of IBW. The maintenance dose ranged from 17.5 to 30 mg/kg of IBW, depending on renal function. Overall, simulation showed that 55.8% (95% CI; 47-64%) of patients would achieve the target AUC with suggested dosages. Discussion: A PK model has been validated for vancomycin administered by CI in ICU patients, including patients under CRRT. Our model-informed precision dosing approach may help for early optimization of vancomycin exposure in such patients.

Impact of Antimicrobial Stewardship Program on Vancomycin Usage: Costs and Outcomes at Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam

Background

Nowadays, with the emergence of vancomycin-resistant strains, the clinical use of vancomycin has been followed closely by applying the antimicrobial stewardship program (ASP) to enhance effectiveness in treatment and reduce cost burden for patients.

Methods

A descriptive cross-sectional study at the Hospital for Tropical Diseases was conducted to assess the inpatient status assigned to intravenous vancomycin and factors associated with the cost of treatment during two periods of implementing ASP, which were i) from April 1, 2016 to March 31, 2018 (previous ASP-pASP) and ii) from June 1, 2018 to March 31, 2020 (new ASP-nASP).

Results

Among 1375 patients who met the sampling criteria, there were 601 and 774 patients in pASP and nASP, respectively. The rate of no improvement/mortality in the pASP was higher than that in nASP (37.10% vs 25.98%, p <0.05). The proportion of patients with two or more infection episodes in nASP is lower than that in pASP (9.83% vs 18.64%, p<0.05). Besides, nASP has higher length of therapy (LOT) and higher day of therapy (DOT). The average treatment cost in the pASP is higher than that in the nASP, 1891.22 (95% CI, 1713.46–2068.98) USD vs 1775.55 (95% CI, 1576.22–1974.88) USD. There are seven factors (p<0.05) that associate with the total cost of treatment (age, number of infection episodes, length of stay, discharge status, clinical department, LOT, DOT) in pASP. On the other hand, the nASP has five factors (p<0.001), in which the log(LOT) and age are not as statistically significant (p=0.5127 and 0.3852, respectively) as in the pASP model.

Conclusion

The implementation and improvement of the ASP at the Hospital for Tropical Diseases have initially shown benefits for patients using intravenous vancomycin. Specifically, the ASP helps to reduce treatment costs, improve patient outcomes, reduce length of stay and decrease the average daily dose of vancomycin.