Severe community- acquired pneumonia – studies on imaging, etiology, treatment, and outcome among intensive care patients

Abstract Pneumonia is a common diagnosis for intensive care unit (ICU) admission. In 2012, 51% of the ICU-treated infections in Finland were of pulmonary origin. The ICU-treated pneumonias can be classified according to acquisition of infection as community-acquired (CAP) or hospital-acquired (HAP). Ventilator-associated pneumonia (VAP) is a subtype of HAP. Patients with severe community-acquired pneumonia (SCAP) require ICU treatment due to need of mechanical ventilation or hemodynamic support. SCAP is associated with high morbidity and high ICU and hospital mortality. The aim of this observational study was to evaluate the clinical characteristics and outcome of SCAP, with special interest on imaging, viral etiology, combination antibiotic treatment and long-term outcome. The thesis comprises three retrospective studies with altogether 392 SCAP patients, median age 55 years, 55.9% of them male. The usefulness of early chest CT and β-lactam-respiratory quinolone (βQ) versus β-lactam-macrolide (βM) therapy for SCAP treatment was evaluated. The hospital and long-term outcomes of SCAP patients were compared with 66 HAP and 25 VAP cases. A prospective study included 49 mechanically ventilated SCAP patients. The frequency of viral etiology in SCAP was analyzed. In SCAP patients, the chest CT as compared to the chest radiograph yielded new imaging findings for 58.5% of the SCAP patients. This information led to procedures or treatment changes in 43% of the cases. The severity of oxygenation disorder correlated to the extent of lung involvement. In prospective SCAP series ICU- mortality was 6.1% and hospital mortality was 12.2%. Viral etiology was found to be common in SCAP and viruses were demonstrated in 49% of patients. The outcome was similar whether SCAP patients were treated with βQ or βM combination. The type of pneumonia did not have a significant association with hospital mortality in ICU-treated SCAP, HAP and VAP patients. Among the hospital survivors, the long-term mortality was substantial, SCAP patients representing the best 1-year outcome. In conclusion, early CT might be useful in SCAP diagnostics and treatment. Viral etiology is common in SCAP. Both β-lactam-respiratory quinolone and β-lactam macrolide combinations were equally good in SCAP treatment. Hospital mortality did not differ among ICU-treated pneumonia cases, but SCAP had the best long-term survival.%%%%Tiivistelma Keuhkokuume on yleinen tehohoitoon johtava tulehdussairaus. Suomessa vuonna 2012 teho-osastolla hoidetuista infektioista 51 % oli keuhkoalkuisia. Keuhkokuume luokitellaan hankintapaikan mukaan kotisyntyiseksi (CAP) tai sairaalasyntyiseksi (HAP). Hengityslaitehoitoon liittyva keuhkokuume (VAP) on sairaalasyntyisen keuhkokuumeen alatyyppi. Vakavalla kotisyntyisella keuhkokuumeella (SCAP) tarkoitetaan vaikeaa keuhkoinfektiota, joka vaatii hengityslaitehoitoa tai verenkierron tukihoitoa teho-osastolla. SCAP:iin liittyy korkea sairastuvuus seka tehohoito- ja sairaalakuolleisuus. Tassa havainnoivassa kliinisessa tutkimuksessa…