[Assessment of extracellular fluid in cardiac surgery using cardiopulmonary bypass]

Extracellular fluid (ECF) was assessed before and after the cardiac surgery using cardiopulmonary bypass (CPB), by means of a bioimpedance spectrum analyzer to see volumes of the fluid based on changes of the impedance to various frequencies. Difference between the levels before and after the operation was divided by body weight to study about a % BW. Simultaneously its relation to the lung compliance [tidal volume/(peak inspiratory pressure-end expiratory pressure)] was studied. Mean age of the 18 patients was 59.1 +/- 19 years old. ECF was assessed before to 24 hours after the operation continuously and once more after 48 hours. Mean CPB time was 165 +/- 52 minutes, and aortic cross clamp time was 121 +/- 4 minutes. A remarkable increase of ECF was noted immediately after the operation, which further increased gradually till arriving at the peak 4 hours after the operation (4.52 +/- 1.8% BW). Then it gradually decreased to 0.641 +/- 2.7% BW 48 hours later. Lung compliance measured at the same time showed the lowest level 6 hours after the operation. It was known that the bioimpedance spectrum analysis is a simple and non-invasive method, which enables to monitor the vital stable before and after the operation.