Patent ID: 7794230

Claim:
A method of modeling a circulatory system using a programmed computer, the method comprising: providing a circulatory system model in the computer, the model including one or more time-dependent pressure functions, each of said one or more time-dependent pressure functions representing a pressure in a portion of the circulatory system; using a logistic function in the computer to represent a regulatory mechanism parameter, said regulatory mechanism parameter representing a regulatory mechanism having an impact on circulatory system function; dividing the circulatory system into a plurality of compartments and a heart pump, said plurality of compartments representing a portion of the circulatory system, said heart pump interacting with at least one of said plurality of compartments; assigning, using the computer, one of said one or more time-dependent pressure functions to each of said plurality of compartments; using a smooth muscle contraction parameter, said smooth muscle contraction parameter representing an autonomic nervous system effect on smooth muscle contraction in a wall of one of said plurality of compartments, wherein said smooth muscle contraction parameter is represented according to the following equation: {dot over (V)}=C ·( {dot over (P)} −({dot over (φ)}+{dot over ( P )}*)) wherein {dot over (V)} is a time derivative of a volume of said one of said plurality of compartments, {dot over (P)} is a time derivative of the pressure inside said one of said plurality of compartments, {dot over (φ)} is a time derivative of said smooth muscle contraction parameter, {dot over (P)}* is a time derivative of the pressure outside of said one of said plurality of compartments, and C is an active compliance defined according to the following equation: C = rV Max ⁢ ⅇ - r ⁡ ( P - ( ϕ + P * ) ) ( 1 + ⅇ - r ⁡ ( P - ( ϕ + P * ) ) ) 2 wherein r>0, V Max is a maximum volume of said one of said plurality of compartments, P is the pressure inside said one of said plurality of compartments, P* is the pressure outside said one of said plurality of compartments, and φ is said smooth muscle contraction parameter; and solving, using the computer, one or more equations for said one or more time-dependent pressure functions and said logistic function to determine a circulatory system dynamic.