Influence of initial resistance on gain of short-term systemic autoregulation

The relationship between strength of short-term whole body autoregulation and peripheral resistance in the reference state (initial resistance) was investigated in dogs (n=9) and cats (n=18) after abolishing baroreflex activity. Aortic and venous pressure and aortic flow the authors remeasured in the reference state and one to three minutes after partial vena cava occlusions. After cardiac output and peripheral resistance were normalised for body weight, autoregulation resistance gain (G_ra) was estimated from the experimental data. The relationship between values of G_ra and the corresponding values of initial resistance was approximated by a straight line (r=0.9) with positive slope. This result indicates that the higher the resistance in the reference state, the stronger autoregulation will be