Intraoperative data acquisition for the study of cerebral dysfunction following cardiopulmonary bypass

As a first step in our study to document postoperative cerebral dysfunction, and to determine whether global cerebral blood flow can be implicated in the etiology of this postoperative change, we have assembled a flexible data acquisition system to acquire and record data from four independent sources, three in digital form and one analog. Each of the monitors that we use has a different requirement: One has eight channels of analog output; the other three have RS-232 digital outputs, each with a data stream with different characteristics. The central element of our data collection is a personal computer running the data acquisition and analysis program, LabVIEW for Windows (National Instruments, Austin, TX). All data are processed through separate LabVIEW global variables; the data strings are concatenated and stored on the hard disk in a spreadsheet format for further analysis. We illustrate an intraoperative recording made during cardiopulmonary bypass (CPB) by showing a graph of the mean arterial pressure (MAP), mixed venous oxyhemoglobin saturation recorded from the jugular bulb (JVO2Sat), and temperature measured from the nasopharynx. A decrease in the MAP after unclamping the aorta is accompanied by a decrease in JVO2Sat.