Year in review 2013: Critical Care--respiratory infections

Abstract

Infectious complications, particularly in the respiratory tract of critically ill patients, are related to increased mortality. Severe infection is part of a multiple system illness and female patients with severe sepsis have a worse prognosis compared to males. Kallistatin is a protective hormokine released during monocyte activation and low levels in the setting of septic shock can predict adverse outcomes. Presepsin is another biomarker that was recently evaluated and is elevated in patients with severe sepsis patients at risk of dying. The Centers for Disease Control and Prevention has introduced new definitions for identifying patients at risk of ventilator-associated complications (VACs), but several other conditions, such as pulmonary edema and acute respiratory distress syndrome, may cause VACs, and not all patients with VACs may have ventilator-associated pneumonia. New studies have suggested strategies to identify patients at risk for resistant pathogen infection and therapies that optimize efficacy, without the overuse of broad-spectrum therapy in patients with healthcare-associated pneumonia. Innovative strategies using optimized dosing of antimicrobials, maximizing the pharmacokinetic and pharmacodynamic properties of drugs in critically ill patients, and newer routes of drug delivery are being explored to combat drug-resistant pathogens. We summarize the major clinical studies on respiratory infections in critically ill patients published in 2013.

Figure 1

Plasma kallistatin levels on day 1 of ICU admission and likelihood of 60-day survival. (A) Receiver operating characteristic curves determining the cutoff value of day 1 kallistatin (6.5 μg/ml) to discriminate between survivors and nonsurvivors. (B) Kaplan-Meier curves of 60-day survival with patients grouped according to day 1 kallistatin levels >6.5 μg/ml or <6.5 μg/ml at ICU admission. Log-rank test was performed for comparisons between the groups. AUC, area under the curve. Adapted from Lin and colleagues [10].

Figure 2

Differential expression of procalcitonin in different populations. Boxes represent interquartile range, and whiskers the 5th and 95th percentiles in each category. HF, heart failure; PCT, procalcitonin. Adapted from Wang and colleagues [12].