Objective To evaluate the effect of autologous plateletpheresis and back⁃transfusion on P⁃selectin and inflamma⁃ tory cytokines in patients with acute type A aortic dissection (ATAAD) to explore its lung protection. Methods Forty⁃eight consecu⁃ tive type⁃A aortic dissections patients undergoing aortic arch replacement and elephant trunk stent implantation under cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest, aged from 24 to 68 years old, were divided into two groups (n=24): control group (group C) and plateletpheresis group (group P), according to the random number table method. In group P, autologous plateletpheresis was performed after general anesthesia, and autologous platelet⁃rich plasma (aPRP) was back⁃transfused after CPB. In group C, the pa⁃ tients were infused with normovolemic 6% hydroxyethyl starch(130/0.4). In all patients, the arterial blood was drawn for blood gas anal⁃ ysis, arterial partial pressure of oxygen (PaO2)/fraction of inspiratory oxygen (FiO2) and alveolar⁃arterial oxygen partial pressure differ⁃ ence (P(A⁃a)O2 ) were calculated, and the venous blood was drawn for measuring the concentration of P⁃selectin and inflammatory cyto⁃ kines [interleukin (IL)⁃6, IL⁃8, tumor necrosis factor⁃α (TNF⁃α)], platelet counts and white blood cell counts before anesthesia induc⁃ tion (T1), before CPB (T2), at 30 min after the end of CPB (T3) and at 6 h after operation (T4). Results Compared with those values at T1: P⁃selectin, platelet count, and white blood cell count decreased, while P(A⁃a)O2 increased at T2 in group P (P<0.05). Compared with those at T1, PaO2/FiO2, platelet count and white blood cell count decreased, while P(A⁃a)O2, P⁃selectin, IL⁃6, IL⁃8, and TNF⁃α increased at T3 in group P (P<0.05). Compared with those at T1, PaO2/FiO2 and platelet count decreased, while P(A⁃a)O2, P⁃selectin, IL⁃6, IL⁃8 and TNF⁃α increased at T4 in group P (P<0.05). Compared with those values at T1, PaO2/FiO2, platelet count, P(A⁃a)O2, P⁃selectin, IL⁃6, IL⁃8 and TNF⁃α expression decreased from T2 to T4 time point , while white blood cell count increased at T4 in group C(P<0.05). Compared with group C, PaO2/FiO2 value increased, while P(A⁃a)O2, P⁃selectin, IL⁃6, IL⁃8, TNF⁃α values and white blood cell count decreased from T2 to T4, and platelet count decreased at T2 and T3 in group P (P<0.05) Conclusions Autologous plateletpheresis and back⁃transfu⁃ sion can reduce the concentrations of intraoperative and postoperative P⁃selectin and inflammatory cytokines (IL⁃6, IL⁃8, TNF⁃α) in pa⁃ tients with ATAAD. Thus, it has lung protection effect by reducing the inflammatory reaction.