A dynamic empirical model of the human response to sodium nitroprusside during cardiac surgery

A description is given of a partially successful attempt at using real operating room data to generate a dynamic model of the human response to sodium nitroprusside (SNP) during cardiac surgery. The principal goal of the model is to understand the problems associated with adaptive closed loop control of blood pressure during such surgeries. If successful, such a model would be valuable for simulating patients while designing controllers and would also be useful in the construction of estimation algorithms for use in adaptive controllers. The model presented dynamically relates mean arterial pressure (MAP) as a function of SNP infusion and unmeasured disturbances. It uses data (0.5-Hz sampling rate) on MAP and SNP taken over a complete cardiac surgery. Special attention is given to modeling the noise characteristics of the MAP signal.<>