Figure 3. Block diagram of the CLAD system.

The target level of burst suppression is set by p^target and is converted into the target brain anesthetic $x_2^{\mathit{target}}$ by inverting Eq. (3). The control signal, the current state estimate x_2,k∣k computed from the BSP filter in Eq. (9), is subtracted from $x_2^{\mathit{target}}$ to compute $e_{k,k}=x_2^{\mathit{target}}-x_{2,k\mid k}$. The controller uses Eq. (21) to compute the pump’s infusion rate u_k∣k. By Eq. (1) the infusion rate changes the anesthetic level in the central compartment and in the brain compartment. Changing the brain compartment level changes the level of burst suppression on the EEG, and hence, the value of the binary time series, n_k+1 at time k + 1. The BSP filter uses n_k+1 to compute pk+1,k+1, and the update of the control signal x_2,k+1∣k+1, which is fed back to compute the next control output u_k+1∣k+1.