Plasma neutrophil elastase correlates with pulmonary vascular permeability: a prospective observational study in patients with pneumonia.

BACKGROUND AND

OBJECTIVE

Little is known about plasma neutrophil elastase (PNE) levels in patients with community-acquired pneumonia (CAP) requiring treatment in the intensive care unit (ICU) or high care unit (HCU). In addition, the influence of PNE on pulmonary vascular permeability in a clinical setting has not been investigated. The aims of this study were (i) to investigate PNE levels in patients with CAP and (ii) to explore the relationship between PNE and pulmonary vascular permeability.

METHODS

Fourteen consecutive CAP patients who were admitted to the HCU (n = 8) or ICU (n = 6) were prospectively investigated over a 6-month period. A group of eight patients with hydrostatic pulmonary oedema without CAP served as a control group (CG). PNE levels were measured at regular intervals. The pulmonary vascular permeability index (PVPI) was monitored in all ICU and CG patients, using the PiCCO system.

RESULTS

PNE levels were higher in the CAP patients (132 (84-261) ng/mL) than in the CG patients (77 (64-107) ng/mL) (P = 0.04), and were highest in the ICU patients (186 (75-466) ng/mL). The PVPI was higher in the ICU patients (2.85 (1.90-4.00)) than in the CG patients (1.15 (0.75-2.35)) (P = 0.02). PNE levels correlated with PVPI in the ICU patients (r = 0.81, P < 0.001) but there was no correlation among the CG patients (r = 0.14, P = 0.73).

CONCLUSIONS

Patients with severe CAP had high levels of PNE, which was closely correlated with PVPI. PNE may be involved in the pathogenesis of severe pneumonia.