Kinetics of plasma SPB and RAGE during mechanical ventilation in patients undergoing major vascular surgery

Receptor-of-Advanced-Glycation-End-products (RAGE) and Surfactant-Protein-type-B (SPB) are reported as lung injury markers. Unlike SPB, RAGE is secreted by several tissues, so that RAGE specificity as lung injury marker is questionable. We measured SPB and RAGE in 19 patients undergoing major vascular abdominal surgery. SPB and RAGE were measured before mechanical ventilation (T0), at 1st (T1), 2nd (T2) and, when present, 3rd (T3) hour of mechanical ventilation, and 1h after extubation (T(POST)). Last data during mechanical ventilation, either T2 or T3, are reported as T(END). SPB and RAGE values were normalized for total protein (SPB(N) and RAGE(N)). SPB(N) and RAGE(N) increments from T0 to T(END) were 56.2 [39.1] ng/mg (mean [75-25 percentile]) and 10.6[7.1] pg/mg, respectively. SPB values increased progressively during mechanical ventilation, whereas RAGE values increased at T(1) but not thereafter. SPB(N) increase (T(END)-T0), but not RAGE(N), was related to ΔPaO(2)/FiO2 changes during mechanical ventilation (r=0.575, p=0.01). Plasma RAGE(N) and SPB(N) kinetics in patients undergoing major vascular surgery are different.