Evaluating and Mitigating Risk of Acute Kidney Injury with the Combination of Vancomycin and Piperacillin-Tazobactam in Children

Piperacillin pharmacokinetics and pharmacodynamics in paediatric patients who received high frequency intra-operative piperacillin/tazobactam dosing

Piperacillin/tazobactam (PTZ) is a broad-spectrum antibiotic, typically dosed every six hours (q6h). Guidelines recommend dosing PTZ every 2 hours (q2h) intra-operatively for complex abdominal surgery, including liver transplant. The data supporting the guidelines for intra-operative dosing are sparse and the pharmacokinetics/pharmacodynamics (PK/PD) of q2h dosing has not been studied by simulation or in humans. In this study, PK/PD parameters of high-frequency intra-operative dosing and q6h post-operative dosing were compared in critically ill children. Paediatric patients who received PTZ during complex abdominal surgery or transplant and who had intra-operative and post-operative opportunistic samples were included. Using a published PK model and observed concentrations, individual piperacillin PK/PD parameters were estimated using Bayesian estimation. Alternative post-operative dosing strategies were simulated using the patients with the highest and lowest estimated piperacillin clearance. Thirteen patients were included (median age: 3.1 years, 85% liver transplant recipients). PK parameters in the intra-operative and post-operative phases were not significantly different (clearance: 15.8 ± 7.2 vs. 12.6 ± 6.3 L/h/70 kg, P=0.070; central volume: 13.4 [13.1, 13.8] vs. 15.2 [12.2, 16.0] L/70 kg, P=0.22). At an individual level, intra-operative clearance values were -35% to 139% of the post-operative values, whereas central volume intra-operative values were -40% to 77% of the post-operative values. Intra-operative piperacillin exposure was higher during high-frequency dosing compared with the post-operative period (AUC/h: 109 [93.4, 127] vs. 62.8 [41.6, 78.3] mg/L, P=0.002). Simulations showed great variation in optimal dosing strategies that would minimise toxicity and maximise efficacy, indicating a role for individualised dosing in paediatric surgical populations.

Evaluation of Strategies for Reducing Vancomycin-Piperacillin/Tazobactam Incompatibility

BACKGROUND

Drug incompatibility is defined as a physical-chemical reaction between two or more injectable drugs and that results mainly in precipitation or insolubility. Several strategies for reducing incompatibilities have been implemented empirically in intensive care units. However, these strategies have never been compared directly (and particularly in terms of the particulate load and drug mass flow rate) under standardized conditions. The objective of the present in vitro study was to evaluate the impact of various strategies for preventing incompatibility between simultaneously infused vancomycin and piperacillin/tazobactam.

METHODS

An in-line filter, a dilute vancomycin solution (5 mg/mL), and an alternative saline administration line were evaluated separately. The infusion line outlet was connected to a dynamic particle counter. The antibiotic concentration was measured in an HPLC-UV assay.

RESULT

The use of an in-line filter and an alternative saline administration route did not significantly reduce the particulate load caused by vancomycin-piperacillin/tazobactam incompatibility. Dilution of the vancomycin solution was associated with a significantly lower particulate load and maintenance of the vancomycin mass flow rate.

DISCUSSION

It is important to systematically compare the efficacy of strategies for preventing drug incompatibility. The use of diluted vancomycin solution gave the best results in the case of vancomycin-piperacillin/tazobactam incompatibility.

Relationship between piperacillin concentrations, clinical factors and piperacillin/tazobactam-associated acute kidney injury

BACKGROUND

Piperacillin/tazobactam, a commonly used antibiotic, is associated with acute kidney injury (AKI). The relationship between piperacillin concentrations and AKI remains unknown.

OBJECTIVE

Estimate piperacillin exposures in critically ill children and young adults administered piperacillin/tazobactam to identify concentrations and clinical factors associated with piperacillin-associated AKI.

PATIENTS AND METHODS

We assessed piperacillin pharmacokinetics in 107 patients admitted to the paediatric ICU who received at least one dose of piperacillin/tazobactam. Piperacillin AUC, highest peak (Cmax) and highest trough (Cmin) in the first 24 hours of therapy were estimated. Piperacillin-associated AKI was defined as Kidney Disease: Improving Global Outcomes (KDIGO) Stage 2/3 AKI present >24 hours after initial piperacillin/tazobactam dose. Likelihood of piperacillin-associated AKI was rated using the Naranjo Adverse Drug Reaction Probability Scale. Multivariable logistic regression was performed to identify patient and clinical predictors of piperacillin-associated AKI.

RESULTS

Out of 107 patients, 16 (15%) were rated as possibly or probably having piperacillin-associated AKI. Estimated AUC and highest Cmin in the first 24 hours were higher in patients with piperacillin-associated AKI (2042 versus 1445 mg*h/L, P = 0.03; 50.1 versus 10.7 mg/L, P < 0.001). Logistic regression showed predictors of piperacillin-associated AKI included higher Cmin (OR: 5.4, 95% CI: 1.7-23) and age (OR: 1.13, 95% CI: 1.05-1.25).

CONCLUSIONS

We show a relationship between estimated piperacillin AUC and highest Cmin in the first 24 hours of piperacillin/tazobactam therapy and piperacillin-associated AKI, suggesting total piperacillin exposure early in the course is associated with AKI development. These data could serve as the foundation for implementation of model-informed precision dosing to reduce AKI incidence in patients given piperacillin/tazobactam.