The following is a summary of “Definitions, rates and associated mortality of ICU-acquired pneumonia: A multicenter cohort study,” published in the April 2023 issue of Critical Care by Johnstone et al.
Researchers aimed to analyze pneumonia acquired in the intensive care unit (ICU) using seven definitions while estimating the hospital mortality rate. This particular cohort study was nested within an international randomized trial to assess probiotics’ impact on ICU-acquired pneumonia in a sample of 2,650 mechanically ventilated adults. Two physicians who were unaware of the allocation and center evaluated every instance of pneumonia that was suspected clinically. The principal measure of success was the occurrence of ventilator-associated pneumonia (VAP), which was determined by the use of a ventilator for at least two days, the appearance of a new, worsening, or persistent infiltrates on imaging, and the presence of two or more of the following: a temperature above 38 °C or below 36 °C, a low white blood cell count (less than 3 × 10 (Fernando et al., 20206)/L) or a high white blood cell count (greater than 10 × 10 (Fernando et al., 20206)/L), and the production of purulent sputum. In addition, the researcher employed six alternative criteria to assess the likelihood of inpatient fatality.
The incidence of pneumonia acquired in the intensive care unit (ICU) demonstrated variability based on the definition utilized. The primary outcome of the trial, ventilator-associated pneumonia (VAP), was observed in 21.6% of cases, while the Clinical Pulmonary Infection Score (CPIS) yielded a rate of 24.9%. The American College Chest Physicians (ACCP) definition resulted in a rate of 25.0%, while the International Sepsis Forum (ISF) definition yielded 24.4%. The Reducing Oxidative Stress Study (REDOXS) definition resulted in a lower rate of 17.6%. The Centers for Disease Control (CDC) definition yielded a rate of 7.8%, and the invasively microbiologically confirmed definition resulted in the lowest rate of 1.9%. The primary outcome of the trial, which includes VAP, ISF, CPIS, and ACCP definitions, showed a significant association with hospital mortality, as indicated by the HR values of 1.31 [1.08, 1.60], 1.32 [1.09,1.60], 1.30 [1.08,1.58], and 1.22 [1.00,1.47], respectively. The incidence of pneumonia acquired in the intensive care unit (ICU) may vary depending on the criteria used to define it and is linked to varying degrees of heightened mortality risk.