Continuous Infusion Versus Intermittent Bolus of Beta-Lactams in Critically Ill Patients with Respiratory Infections: A Systematic Review and Meta-analysis.

Background: Critically ill patients display altered pharmacokinetics and pharmacodynamics and are more likely to be infected with more resistant pathogens. Beta-lactam antibiotics exhibit time-dependent pharmacodynamics; therefore, it is postulated that continuous infusion (CI) may optimize these parameters.

Objective: To perform a systematic review and meta-analysis of the available literature comparing CI versus intermittent bolus (IB) of beta-lactam antibiotics in critically ill adult patients with respiratory infections to determine if clinical benefits exist.

Methods: PubMed, EMBASE, and Web of Science were searched. Thirteen randomized controlled trials were included in the meta-analyses of clinical cure and/or mortality. Four retrospective studies reporting clinical cure and/or mortality, and 11 studies that reported pharmacokinetic/pharmacodynamic parameters were included in the systematic review.

Results: The majority of patients in both groups maintained the percentage of time the free drug concentration exceeded the minimum inhibitory concentration (%fT > MIC) targets throughout the treatment, with differences favoring CI being more prevalent when the MIC of the offending pathogen increased. CI of beta-lactam antibiotics in critically ill adult patients with respiratory infections significantly improved clinical cure rates when compared to IB (risk ratio [RR] 1.177; 95% CI 1.065-1.300). No significant differences in mortality rates were seen when patients were treated with either dosing modality (RR 0.845; 95% CI 0.644-1.108).

Conclusions: CI of beta-lactam antibiotics is associated with better cure rates and higher %fT > MIC when administered to critically ill patients with respiratory infections, but may be most beneficial in severely ill patients with more resistant Gram-negative bacterial infections.