Whitten C W, Hill G E, Ivy R, Greilich P E, Lipton J M
Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center at Dallas 75235-9068, USA.
Anesth Analg. 1998 Jan;86(1):28-33. doi: 10.1097/00000539-199801000-00006.
Cardiopulmonary bypass (CPB) induces a systemic inflammatory response characterized by release of proinflammatory cytokines, including interleukin 6 (IL-6). Recent reports suggest that plasma IL-6 is increased after CPB. Previous studies evaluating the influence of duration of CPB and/or aortic cross-clamp time on the release of IL-6 are conflicting. Infusion of blood and blood products during these studies may have influenced plasma concentrations of proinflammatory cytokines by inducing host cell (monocyte) activation and IL-6 release. The purpose of our investigation was to determine, in an environment free from blood and/or blood product administration, the influence of duration of CPB and/or aortic cross-clamp on the magnitude of the IL-6 response in patients undergoing cardiac surgery. We prospectively evaluated plasma IL-6 levels preinduction (T0) and at sternal closure in 16 patients undergoing CPB (coronary artery bypass grafting, n = 9; valvular cardiac surgery, n = 7) to determine whether there is a correlation between the absolute increase in IL-6 and the duration of CPB or aortic cross-clamp time. None of the patients received blood and/or blood products during the study to control for the introduction of additional activated cells and soluble mediators, including IL-6. The results demonstrate that the magnitude of the IL-6 response to CPB is positively correlated with the duration of CPB but not with duration of aortic cross-clamp. It seems that induction of IL-6 release is part of a normal response to CPB and does not depend on activation of host cells during prolonged aortic cross-clamp. The activation or presence of inflammatory cytokines associated with administration of blood and/or blood products could have influenced previously published investigations relating the influence of duration of CPB and/or aortic cross-clamp time to the magnitude of the IL-6 response.
This study found a positive correlation between the magnitude of the interleukin 6 response to cardiopulmonary bypass and duration of cardiopulmonary bypass (but not duration of aortic cross-clamp) when measurements were made in the absence of blood/blood product transfusion. Future studies evaluating strategies to reduce cytokine responses to cardiopulmonary bypass should therefore control for cardiopulmonary bypass duration.
体外循环（CPB）可引发全身炎症反应，其特征为促炎细胞因子的释放，包括白细胞介素6（IL-6）。近期报告显示CPB后血浆IL-6水平升高。此前评估CPB持续时间和/或主动脉阻断时间对IL-6释放影响的研究结果相互矛盾。在这些研究中，输注血液及血液制品可能通过诱导宿主细胞（单核细胞）活化和IL-6释放，从而影响促炎细胞因子的血浆浓度。我们研究的目的是在不进行血液和/或血液制品输注的环境下，确定CPB持续时间和/或主动脉阻断对心脏手术患者IL-6反应强度的影响。我们前瞻性地评估了16例接受CPB（冠状动脉搭桥术，n = 9；心脏瓣膜手术，n = 7）患者诱导前（T0）和胸骨关闭时的血浆IL-6水平，以确定IL-6的绝对升高与CPB持续时间或主动脉阻断时间之间是否存在相关性。在研究期间，所有患者均未接受血液和/或血液制品，以控制额外活化细胞和可溶性介质（包括IL-6）的引入。结果表明，对CPB的IL-6反应强度与CPB持续时间呈正相关，但与主动脉阻断时间无关。似乎IL-6释放的诱导是对CPB的正常反应的一部分，并不依赖于长时间主动脉阻断期间宿主细胞的活化。与血液和/或血液制品输注相关的炎性细胞因子的活化或存在可能影响了先前发表的关于CPB持续时间和/或主动脉阻断时间对IL-6反应强度影响的研究。
本研究发现，在未进行血液/血液制品输血的情况下进行测量时，白细胞介素6对体外循环的反应强度与体外循环持续时间（而非主动脉阻断持续时间）呈正相关。因此，未来评估降低对体外循环细胞因子反应策略的研究应控制体外循环持续时间。
