title: Reliability of stroke volume to pulse pressure ratio for estimating and detecting changes in arterial compliance.
abstract: Total arterial compliance is an important haemodynamic variable which is difficult to measure in vivo. Using a Windkessel model, it can be determined from the ratio of the diastolic-decay time constant (tau) of the arterial system and the peripheral resistance. Using this technique, paired estimates of arterial compliance were determined in control and in mechanically produced low-compliance steady states. Since determination of compliance based on the three-element Windkessel model is tedious the same data were retrospectively analysed to evaluate the reliability of the stroke volume to pulse pressure ratio (SV:PP) for estimating and predicting changes in compliance. The linear correlation coefficient for 148 paired values of compliance determined by the two methods was r = 0.85, P less than 0.001. Both methods indicated similar values (mean +/- s.e.m.) for compliance in the control steady state: 0.35 +/- 0.01 ml/mmHg (using tau/R) versus 0.36 +/- 0.01 ml/mmHg (using SV:PP), P was NS, and both methods detected a significant decrease in compliance, P less than 0.001, in the low-compliance steady state: 0.18 +/- 0.01 ml/mmHg (using tau/R) and 0.21 +/- 0.01 ml/mmHg (using SV:PP). Thus, SV:PP compared with (tau/R) was a good index of compliance and changes in compliance and may prove to be a useful index for estimating compliance clinically.
authors.forename: O S
authors.initials: OS
authors.lastname: Randall
authors.forename: N
authors.initials: N
authors.lastname: Westerhof
authors.forename: G C
authors.initials: GC
authors.lastname: van den Bos
authors.forename: B
authors.initials: B
authors.lastname: Alexander
mesh_terms: D000818:Animals; D001158:Arteries / Q000502:physiology*; D003187:Compliance; D004285:Dogs; D011674:Pulse; D013318:Stroke Volume