Patent ID: 7886739

Claim:
A circuit compliance compensated volume control system in a patient respiratory ventilation system, the volume control system comprising: a circuit compliance estimator, to provide a relationship between a circuit volume V CC and a differential pressure ΔP Y between a circuit pressure P Y and a positive end-expiratory pressure PEEP of the respiratory circuit; a circuit volume estimator, operative to provide an estimated circuit volume VOL CKT — EST based on the relationship between V CC and ΔP Y ; a patient volume observer, operative to provide an estimated patient volume VOL TID — EST by subtracting the estimated circuit volume VOL CKT — EST from a measured machine delivered net volume VOL NET ; and a volume delivery controller, operative to update the machine delivered net volume VOL NET based on the estimated patient volume VOL TID — EST and a set tidal volume VOL TID — SET , wherein the volume delivery controller further comprises: an error percentage converter for providing a volume error percentage VOL PCT — ERR defined by a ratio of an absolute value of the volume error VOL TID — ERR to the set tidal volume VOL TID — SET ; a gain scheduler for determining a gain K VTID of the volume error as a function of the volume error percentage VOL TID — ERR ; and a volume integrator for updating a circuit compliance volume compensation factor VOL TID — CTL by adding a product of the gain VOL VTID and the volume error VOL TID — ERR thereto, wherein the circuit compliance volume compensation factor VOL TID — CTL is updated at the beginning of every inspiratory phase, and wherein the volume error VOL TID — ERR is defined as the volume differential between the set tidal volume VOL TID — SET and the estimated patient volume VOL TID — EST .