UMEM Educational Pearls

 

Background:

· Empiric broad spectrum antibiotic therapy is a mainstay of the management of critically ill patients with septic shock.

· Vancomycin is widely used for the coverage of potential MRSA infection

• PROS: cheap, widely available, relatively widespread tissue penetration when given IV, and is generally well-tolerated

• CONS: has a complicated dosing regimen requiring specifically-timed serum concentration sampling and subsequent dose changes, frequently subtherapeutic, carries a risk of AKI especially when used concomitantly with piperacillin/tazobactam,¹ as it commonly is during empiric therapy for septic shock.         

· Continuous infusion of vancomycin has been repeatedly demonstrated to reach target serum concentrations faster, maintain consistent serum vancomycin levels better, with fewer serum concentration sampling required, and less overall vancomycin required to do so, in both adult and pediatric populations.^2-5

 

Current Article: 

Flannery AH, Bissell BD, Bastin MT, et al. Continuous Versus Intermittent Infusion of Vancomycin and the Risk of Acute Kidney Injury in Critically Ill Adults: a Systematic Review and Meta-Analysis. Crit Care Med. 2020;48(6):912-8.

· Systematic review and meta-analysis of 11 studies for a total of 2123 patients

· Comparing continuous versus intermittent vancomycin infusion.

· Primary outcome of AKI, secondary outcome of mortality

· Found a reduction in the incidence of AKI in the continuous infusion cohort:

• OR 0.47 (95% CI 0.34-0.65) even when taking into account trough levels /area under the curve concentrations and the severity of AKI examined by the individual studies.

· No association between infusion strategy and mortality

 

Considerations:

· Initial loading dose used in most of the studies (15 mk/kg) probably underdosed, current recommendation for 25mg/kg initial loading dose⁷ (which is not even always effective by itself)⁸ (Reardon)

· Continuous infusion may be difficult with limited IV access

· AKI associated with increased hospital stay, costs, mortality (although didn’t pan out in study) – worth preventing if possible.

 

Take Home:

· Give a 25-30mk/kg loading dose of vancomycin in critically ill patients with suspicion of MRSA to achieve target serum concentrations sooner.

· Continuous vancomycin is a viable option and could be considered in ED boarders, especially if there is concern for impending renal injury.

 

References