Production of reactive oxygen species by central venous and arterial neutrophils in severe pneumonia and cardiac lung edema

Abstract

Objective: In pneumonia the influx of neutrophils to the lungs is thought to be of primary importance with regard to host defence and to complications like the adult respiratory distress syndrome. We wanted to evaluate the neutrophil function in patients in acute respiratory failure who required admission to the intensive care unit.

Design: We determined the luminol-enhanced chemiluminescence (CL) of neutrophils isolated both from central venous and arterial blood. In addition, the plasma-concentrations of α₁-proteinase inhibitor, (α₁PI), α₂-macroglobulin (α₂PI) and elastase-α₁PI-complex (elastase) were determined by chemiluminescence immunoassay, and the intracellular elastase content of blood neutrophils was determined using immuno activation assay.

Patients: 28 Patients, 18 with acute pneumonia (group 1) and 10 with cardiac pulmonary edema (group 2).

Measurements and results: In group 1, luminol enhanced CL was significantly higher than in group 2 (mean 87.7 vs 30.4×10⁶ counts per minute, p<0.01). The production of reactive oxygen species was significantly higher in central venous than in arterial neutrophils in the patients with pneumonia (p<0.03). In patients with pulmonary edema there was no such difference. The plasma concentration of elastase in group 1 was significantly higher than in group 2, that of α₂PI were significantly lower. The intracellular elastase content of neutrophils was lower in group 1 than in group 2. In group 1, there was a trend for a correlation between lower intracellular elastase content and a higher elastase plasma concentration. There were no central venous – arterial differences with regard to leukocyte count, cell differential or protein concentration in either group.

Conclusion: The central venous – arterial differences in neutrophil production of reactive oxygen species support the concept of compartmentalization of activated neutrophils from the systemic to the pulmonary compartment.