Clinical characteristics of critical patients with pandemic influenza A (H1N1) virus infection in Chengdu, China

Objective: The critical illness of pandemic influenza A (H1N1) virus infection may be associated with relatively poor outcomes. The objective of this study is to describe clinical features and factors associated with the deaths of critical patients. Methods: Medical records of 26 critical patients with H1N1 infection admitted from Sept. 1 to Dec. 31, 2009, were retrospectively reviewed. Diagnosis was established by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay. Results: The mean age of the patients was (40.4 +/- 18.4) years and 73.1% of them were male. Clinical manifestations included fever, cough, and sputum production. The laboratory findings included leukocytosis, lymphopenia, C-reaction protein, and lactic dehydrogenase elevation. In this series, 17 subjects survived and 9 died. The parameters between the deaths and survivors were compared, which included acute physiology and chronic health evaluation II (APACHE II) scores (23.8 +/- 10.1 vs. 14.3 +/- 6.6, P<0.05), sequential organ failure assessment (SOFA) scores (13.3 +/- 3.0 vs. 6.6 +/- 3.3, P<0.05), and multiple organ dysfunction syndrome (MODS) scores (7.4 +/- 2.5 vs. 3.3 +/- 1.7, P<0.05). The cases of deaths had higher incidences of cardiovascular failure (100% vs. 41.2%, P<0.05), renal failure (55.6% vs. 11.7%, P<0.05), encephalopathy (44.4% vs. 5.9%, P<0.05), hepatic failure (33.3% vs. 5.9%, P<0.05), and septic shock (33.3% vs. 17.6%, P<0.05). Conclusions: The critical patients with H1N1 infection have high APACHE II, SOFA, and MODS scores, which may be associated with an increased risk of death and complex clinical courses.