PURPOSE: Severe community-acquired pneumonia (CAP) is a disease with a high mortality. Treatment is usually empiric until cultures are available. There is a paucity of published data describing microbiological causes of severe CAP in Singapore. Thus the aim of this study was to outline our hospital's experience of with patients diagnosed to have severe CAP requiring intensive care unit (ICU) admission, to determine the microbiological aetiologies and parameters influencing outcome.
METHODS: Retrospective review of the medical records of consecutive non-immuncompromised patients admitted to the Singapore General Hospital's ICU for severe CAP over a 2-year period.
RESULTS: There were a total of 103 patients (68 male, 35 female). Microbiologic cause was established in 43 patients (41.7%). The commonest organisms were Streptococcus pneumoniae (N=11, 10.7%), Staphylococcus aureus (N=9, 8.7%), Klebsiella pneumonia (N=8, 7.8%) and Burkholderia pseudomallei (N=7, 6.8%). Legionella pneumonia was uncommon (N=2, 1.9%). The mean age of patients was 63.0±17 years. Mean ICU length of stay (LOS) was 7.6±5.4 days and mean hospital LOS was 18.1±16.6 days. ICU mortality rate was 35.9%. Ninety patients (87.4%) required mechanical ventilation for acute respiratory failure, with 53 patients (51.5%) requiring inotropic support for septic shock. Factors associated with a poor ICU outcome was septic shock requiring 2 or more inotropic agents (p<0.04) and a history of prior maligancy (p<0.047). Age, history of current or previous smoking, diabetes mellitus, development of acute renal failure requiring renal replacement therapy were not associated with mortality in the ICU.
CONCLUSION: Severe CAP requiring ICU admission is associated with a mortality of 35.9%. Microbiologic cause could be established in only 41.7% of patients.
CLINICAL IMPLICATIONS: A large percentage of patients with severe CAP have no positive aetiology. Streptococcus pneumoniae is the commonest organism cultured. Factors associated with poor outcome are use of 2 or more inotropic agents for septic shock and a history of prior malignancy. Low rates of legionella pneumonia are seen, likely due to lack of systemic testing.
DISCLOSURE: Steve Yang, No Financial Disclosure Information; No Product/Research Disclosure Information