Monitoring cerebral dynamics using sweeping non-linear coherent hemodynamics spectroscopy model

We investigated cerebral physiological dynamics during cardiac arrest and resuscitation in pigs using a dynamic sweeping implementation of the nonlinear Coherent Hemodynamics Spectroscopy (CHS) model. By fitting the model to overlapping 30 second windows, we obtained time-resolved estimates of cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), and hemoglobin signals. Among 12 model parameters, arterial oxygen saturation (𝑆(α)), oxygen diffusion rate (α), and arterial volume fraction (𝜑(α)) showed consistent dynamic changes. While the average tissue oxygen saturation (StO2) dropped to about 50%, CMRO2, the venule and capillary saturations dropped to almost zero values, showing extremely severe impact of CA on the brain oxygen metabolism. The sweeping approach enabled near real-time estimation of cerebral dynamics with reduced computational load.