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Acute respiratory distress syndrome (ARDS) is a serious disorder of intensive care unit patients. We evaluated the safety of continuous prone position ventilation (PRONE) and its effects on oxygenation and plasma cytokine concentrations in patients with ARDS caused by severe community-acquired pneumonia (CAP). Methods: This was a prospective observational clinical study conducted in a respiratory intensive care unit of a 1200-bed medical center in central Taiwan. Twenty-two patients with severe CAP and ARDS were included. They were treated by traditional supine ventilation (SUPINE, n = 11) or PRONE (n = 11) if they met the criteria for ARDS. Patients in the PRONE group were ventilated in prone position continuously for at least 72 hours. Plasma cytokines were collected and analyzed at baseline, 24 hours and 72 hours after enrolment. Serial PaO2/FiO2 and complications were evaluated. Results: Complications associated with PRONE were minor and self-limited. PRONE had higher PaO2/FiO2 ratio than SUPINE did at 48 hours after enrolment. The levels of plasma IL-6 concentration declined significantly with time in the PRONE group (p = 0.011). The levels of plasma IL-6 concentration at enrolment, 24 hours and 72 hours after enrolment also predicted the 14th day mortality of all patients. Conclusion: PRONE was a safe and effective maneuver for improving oxygenation in patients with severe CAP and ARDS. PRONE also influenced IL-6 expression in patients with severe CAP.

The relationship between bacterial etiology and serum cytokine levels in patients with severe community-acquired pneumonia (CAP) without response to initial empiric treatment remains unclear. This study investigated the bacterial etiology, outcomes, and bronchoalveolar and systemic cytokines (interleukin [IL]-1β, IL-8, IL-10) in these patients. Methods: This hospital-based study enrolled 47 consecutive patients without response to initial empiric treatment and requiring mechanical ventilation due to severe CAP between July 1, 2000 and October 31, 2001, in a respiratory intensive care unit of a 1200-bed teaching hospital in central Taiwan. Bronchoalveolar lavage (BAL) was performed within 3 days after hospitalization. BAL fluid was processed for quantitative bacterial cultures. Blood samples were taken just before BAL, and the levels of both BAL and serum cytokines were measured. Results: The most common pathogens isolated were Pseudomonas aeruginosa (22.5%) and Klebsiella pneumoniae (25%). Patients with a K. pneumoniae isolate (w = 10) had significantly higher levels of IL-1β in BAL fluid and significantly higher levels of IL-10 in serum and BAL fluid than patients with other etiologies. Non-survivors had higher levels of serum IL-8 (p = 0.001), serum IL-10 (p < 0.001) and BAL IL-10 (p = 0.039) than survivors. Marked increases in local and systemic cytokine expression (IL-8 and IL-10) were noted in rapidly fatal cases. Conclusion: P. aeruginosa and K. pneumoniae are the most common causes of CAP requiring mechanical ventilation in Taiwan. Cytokine patterns in the BAL fluid and serum of patients with severe CAP due to K. pneumoniae showed significant elevations compared to other pathogens. Bronchoalveolar and systemic cytokine levels (especially IL-10) predicted mortality. These findings suggest the need for a clinical trial to determine how immunomodulating therapy might affect cytokine profiles and clinical outcome.