Risk factors and pathogens involved in early ventilator-acquired pneumonia in patients with severe subarachnoid hemorrhage

Abstract

Ventilator-acquired pneumonia (VAP) is a common burden in intensive care unit (ICU) patients, but, to date, specific data are not available in patients with severe aneurysmal subarachnoid hemorrhage (SAH). A single neuro-ICU retrospective analysis of 193 patients with SAH requiring mechanical ventilation (MV) ≥48 h admitted from January 2005 to May 2010 was undertaken. The diagnosis of early VAP was prospectively upheld during a multidisciplinary staff meeting, according to the American Thoracic Society (ATS) 2005 guidelines with a threshold of 7 days after the onset of MV. Patients had a median age of 53 (44-62) years and 70 (36 %) were male. The median Glasgow coma scale (GCS) score before MV was 9 (5-14). 142 (74 %) patients had a World Federation of Neurosurgeons (WFNS) score ≥III. Aneurysm was secured with an endovascular coiling procedure in 162 (84 %) patients. 81 (48.7 %) patients declared an early VAP. On multivariate analysis, male sex (odds ratio [OR] 2.26, 95 % confidence interval [CI] [1.14-4.46]), use of mannitol before day 7 (OR 3.03, 95 % CI [1.54-5.95]), and achieving enteral nutrition ≥20 kcal kg(-1) day(-1) after day 7 (OR 2.91, 95 % CI [1.27-6.67]) remained independent risk factors of VAP. The main pathogens involved were methicillin-susceptible Staphylococcus aureus (MSSA) (34.9 %), Haemophilus influenzae (28.1 %), Streptococcus pneumoniae (15.5 %), and Enterobacteriaceae (10.7 %). Early VAP was associated with a longer duration of MV and ICU stay, but not with an excess of mortality. Early VAP bears significant morbidity in patients with severe SAH. Pathogens involved in early VAP are susceptible to antibiotics. Among modifiable risk factors of VAP, early enteral nutrition could be an easy and effective target.