Application of electrical impedance tomography and aquaporin 4 for cerebral edema in patients who underwent surgery for aortic coarctation at age < 3 years

Abstract:

Objective：To compare cerebral edema of antegrade cerebral perfusion（ACP） among different temperatures in patients who underwent surgery for aortic coarctation at age < 3 years，and to evaluate the feasibility of electrical impedance tomographic assessment of cerebral edema. Methods：We retrospectively analyzed the basic data（sex，age，and weight） of 60 patients who underwent aortic coarctation and intracardiac deformity within 3 years of age，between January 2012 and January 2017，in our hospital. According to the nasopharyngeal temperature at the time of stopping circulation，the patients were divided into the deep hypothermia（17.0 ℃-20.0 ℃），medium-low temperature（20.1 ℃-25.0 ℃），and shallow hypothermia groups（25.1 ℃-30.0 ℃）. In addition，serum aquaporin 4 expression level and brain electrical impedance coefficients（CEICs） were measured at seven time points（including the time after anesthesia induction，before ACP，at the end of ACP，at the end of cardiopulmonary bypass，and 3，12，24 hours after sur-gery）. Twenty patients with subarterial ventricular septal defect in our hospital during the same period were included as the control group. Results：Analysis of variance was used to analyze the whole set of data，and the Sidak test of simple effect analysis was used to analyze the difference between groups at the same time point. The serum AQP4 level was significantly higher in the deep hypothermic group than in the moderate hypothermic，mild hypothermic，and control groups at the end of ACP，the end of CPB，3 hours after surgery，12 hours after surgery，and 24 hours after surgery（Famong groups=160.755，Pamong groups=0.000；Ftimes=283.208，Ptimes=0.000；Finteractions=19.859，Pinteractions=0.000）. The CEIC level was significantly higher in the deep hypothermic group than in the moderate hypothermic，mild hypothermic，and control groups at the end of CPB，and 3，12，and 24 hours after surgery（Famong groups=55.243，Pamong groups=0.000；Ftimes=90.805，Ptimes=0.000；Finteractions=10.743，Pinteractions=0.000）. Conclusion：The cerebral injury in the deep hypothermia group during the antegrade cerebral perfusion of the aortic coarctation at age < 3 years may be higher than that in the moderate hypothermic，mild hypothermic，and control groups. Electrical impedance tomography can be used for assessing cerebral edema.