SESSION TITLE: Disorders of the Pleura
SESSION TYPE: Original Investigation Slide
PRESENTED ON: Wednesday, October 28, 2015 at 02:45 PM - 04:15 PM
PURPOSE: Pleural infections are associated with pleural fluid and blood neutrophilia. Our aim was to investigate the association of pleural and blood neutrophil percentages with age and prognosis.
METHODS: Observational study of adults admitted to our hospital for parapneumonic effusion (including empyema) between June 2009 and January 2014. Pleural fluid and blood were analysed using manual and automated cell-counting respectively. Locally weighted scatterplot (lowess) smoothing and linear regression was performed to examine the relationship between neutrophil percentage and age. Using logistic regression with backward selection (P-for-removal=0.2), pleural neutrophil percentage was studied in relation to the need for surgery (minimally-invasive or open thoracotomy) and hospital mortality, controlled for age, gender and comorbidity. Blood neutrophil percentage was similarly studied.
RESULTS: One hundred and forty-one patients were studied (101 parapneumonic effusion and 40 empyema). Mean age was 57.9 years (standard deviation 18.1), 110 (78.0%) were males, 29 (27.7%) needed surgery and 17 (12.1%) died in-hospital. Only two patients received streptokinase. The comorbidities in the cohort were as follows: 13 (9.2%) congestive cardiac failure, 14 (9.9%) cancers, 29 (20.6%) diabetes mellitus; 17 (12.1%) chronic renal failure; 14 (9.9%) chronic obstructive lung disease and 4 (2.8%) liver cirrhosis. Thirty-two (22.7%) patients had pleural neutrophil percentage<50%. Lowess smoothing revealed a negative linear association between pleural neutrophil percentage and age (regression coefficient -0.45%/year, 95% CI -0.71%/year to -0.19%/year, P=0.001), and no association between blood neutrophil percentage and age. Pleural neutrophil percentage was also associated with need for surgery (odds ratio 1.03, 95% CI 1.01-1.05, P=0.004). Pleural neutrophils >90% identified the need for surgery with 44% sensitivity and 90% specificity. Other associations between pleural/blood neutrophil percentage and surgery/mortality were not significant.
CONCLUSIONS: Pleural neutrophilia is negatively correlated with age, and is positively associated with the need for surgical treatment. In contrast, no such associations exist for blood neutrophilia.
CLINICAL IMPLICATIONS: Lower levels of pleural neutrophilia should not exclude pleural infection in older patients. Additionally, pleural neutrophil percentage may be useful for determining therapy.
DISCLOSURE: The following authors have nothing to disclose: Kay See, Sok Boon Tay, Venetia Ong, Tow Keang Lim
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