[Antibiotics in the critically ill].

Introduction: Antibiotics are one the most common therapies administered in the intensive care unit setting. This review outlines the strategy for optimal use of antimicrobial agents in the critically ill.

Indications For Empirical Antimicrobial Therapy: In severely ill patients, empirical antimicrobial therapy should be used when a suspected infection may impair the outcome.

Adjunctive Measures Before Administration Of Antimicrobial Therapy: It is necessary to collect microbiological documentation before initiating empirical antimicrobial therapy. In addition to antimicrobial therapy, it is recommended to control a focus of infection and to modify factors that promote microbial growth or impair the host's antimicrobial defence.

Choice Of Empirical Antimicrobial Therapy: A judicious choice of antimicrobial therapy should be based on the host characteristics, the site of injection, the local ecology, and the pharmacokinetics/pharmacodynamics of antibiotics. This means treating empirically with broad-spectrum antimicrobials as soon as possible and narrowing the spectrum once the organism is identified (de-escalation), and limiting duration of therapy to the minimum effective period.

Monotherapy Versus Combined Therapy: Despite theoretical advantages, a combined antibiotic therapy is nor more effective than a mono-therapy in curing infections in most clinical trials involving intensive care patients. Nevertheless, textbooks and guidelines recommend a combination for specific pathogens and for infections commonly caused by these pathogens.

Prevention Of Development Of Bacterial Resistance: Avoiding unnecessary antibiotic use and optimizing the administration of antimicrobial agents will improve patient outcomes while minimizing risks for the development of bacterial resistance. It is important to note that each intensive care unit should have a program in place which monitors antibiotic utilisation and its effectiveness. Only in this way can the impact of interventions aimed at improving antibiotic use be evaluated at the local level.