Background: Hospital-acquired pneumonia (HAP) in intensive care patients is a frequent reason for mechanical ventilation (MV). The management of MV and ventilator weaning vary, depending on the type of lung inflammation. This retrospective, observational study screened the data from all patients admitted to the intensive care unit (ICU) of the Department of Anaesthesiology and Intensive Care Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc between 2011 and 2016. The aims were to determine the parameters of pressure-controlled ventilation, the frequencies of tracheostomy, bronchoscopy, reconnection to MV, the length of ICU and hospital stay and the mortality in subgroups with early-/late-onset HAP compared to a subgroup with community-acquired pneumonia (CAP) and patients with MV without pneumonia. The primary outcome of this study was MV length.
Results: Over the study period, a total of 2672 patients were hospitalised. Excluded were 137 organ donors, 66 patient without MV and 20 patients placed on volume-controlled ventilation. The cohort comprised 2.447 patients requiring MV. A total of 1.927 patients (78.7%) were indicated for MV without signs of pneumonia. CAP was diagnosed in 131 patients (5.4%). The criteria for HAP were met by 389 patients (16.0%). Early-onset and late-onset HAP was diagnosed in 63 (2.6%) and 326 (13.3%) patients, respectively. In the subgroups without pneumonia, with CAP, early- and late-onset HAP, the median MV times were 3, 6, 6 and 12 days, respectively, and the median peak inspiratory pressure (Pinsp) of MV was 20, 25, 25 and 27 cm H2O, respectively. The median positive end-expiratory pressure (PEEP) was 5, 8, 8 and 11 cm H2O, respectively. The median inspired oxygen concentrations (FiO2) were 0.45, 0.7, 0.7 and 0.8, respectively. The median length of hospital stays was 8, 15, 15 and 17 days. The mortality rates were 11.4%, 3.8%, 9.5% and 31.3%, respectively.
Conclusions: During MV, the late-onset HAP subgroup was shown to have the highest Pinsp, PEEP and FiO2, the longest MV time, ICU and hospital stay, the highest frequency of tracheostomy, reconnection to MV, pulmonary hygiene bronchoscopy and the highest mortality compared to the early-onset HAP and CAP subgroups. The lowest values were found in the mechanically ventilated patients without pneumonia. The differences were due to the severity of lung damage that is graduated from CAP over early-onset HAP after late-onset HAP.
Keywords: hospital-acquired pneumonia; mechanical ventilation; mortality; ventilator-associated pneumonia.