Effects of normothermia versus hypothermia on extravascular lung water andserum cytokines during cardiopulmonary bypass: A randomized, controlled trial

Objective: To evaluate the influence of perfusion temperature on the system ic effects of cardiopulmonary bypass (CPB), including extravascular lung wa ter index (EVLWI), and serum cytokines. Design: Prospective, randomized, controlled study. Setting. Cardiothoracic intensive care unit of a university hospital. Patients. Patients undergoing elective coronary artery bypass grafting. Interventions. Twenty-one patients undergoing elective coronary artery bypa ss grafting were randomly assigned to receive either normothermic bypass (3 6 degreesC, n = 8) with intermittent antegrade warm blood cardioplegia (IAW BC), or hypothermic (32 degreesC, n = 13) CPB with cold crystalloid cardiop legia. Measurements and Main Results., Mean arterial pressure, heart rate, cardiac output, systemic vascular resistance, mean pulmonary arterial pressure, an d pulmonary vascular resistance were determined at baseline, i.e., after in duction of anesthesia but before sternal opening (T-1), at arrival in the i ntensive care unit (TO), and 4 hrs (M), 8 hrs (T8), and 24 hrs (T24) after surgery. EVLWI, intrathoracic blood volume index (ITBVI), and EVLW/ITBV rat io were obtained by using thermal dye dilution utilizing an arterial thermi stor-tipped fiberoptic catheter and were recorded at T-1, T0, T4, T8, and T 24. Serial blood samples for cytokine measurements were obtained at each he modynamic measurement time point. Before, during, and after CPB, there were no differences in the conventional hemodynamic measurements between the gr oups. There were no changes in EVLWI up to T8 in either group. Furthermore, no change in the ratio EVLW/ITBW was observed between the groups at any ti me, further indicating the absence of a change in pulmonary permeability. P lasma levels of interleukin-6, tumor necrosis factor-alpha, and interleukin -10 increased during and after CPB, independently of the perfusion temperat ure. Conclusion., Normothermic CPB is not associated with additional inflammator y and related systemic adverse effects regarding cytokine production and EV LWI as compared with mild hypothermia. The potential temperature-dependent release of cytokines and subsequent inflammation has not been observed and normothermic CPB may be seen as a safe technique regarding this issue.