caa a22 4500 465826075 CHVBK 20180323112149.0 cr unu---uuuuu 170327e19900401xx s 000 0 eng 10.1007/BF02828288 doi (NATIONALLICENCE)springer-10.1007/BF02828288 Gorback Michael Department of Anesthesiology, Duke University Medical Center, Box 3094, 27710, Durham, NC aut Problems associated with the determination of pulmonary vascular resistance [Elektronische Daten] [Michael Gorback] The presence of critical pressures in the pulmonary circulation complicates the traditional use of pulmonary vascular resistance (PVR). The recruitable nature of the pulmonary circulation violates a basic assumption of the PVR formula, that is, that the involved vessels arc rigid-walled. Flow through collapsible blood vessels is subject to the influence of critical opening pressures in addition to inflow and outflow pressures. As a result, PVR has a variable relationship to the Poiseuille resistance, approximating it better when zone 3 conditions predominate. In addition to being flow-dependent, PVR cannot easily distinguish among vasodilation, recruitment, and rheologie changes. PVR may be viewed as an index of steady-state power dissipation by the circulation, describing the relationship between power dissipation and flow, but it will still underestimate power dissipation by as much as 50%, since it cannot express oscillatory and kinetic power components. Laboratory data regarding the pulmonary circulation are predicted and explained by positing the existence of critical pressures in the pulmonary circulation and allow estimation of Poiseuille resistance. Unfortunately, clinical application of this approach is difficult owing to the necessity of generating pressure-flow plots under very stringent conditions. The clinical use of both pressure-flow and PVR-flow plots is impaired by shifting to different curves during hemodynamic manipulation. PVR must be interpreted in light of its considerable limitations. Little, Brown and Company, 1990 Monitoring: pulmonary vascular resistance nationallicence Lung: vascular resistance nationallicence Blood: flow nationallicence Journal of Clinical Monitoring Springer Netherlands 6/2(1990-04-01), 118-127 0748-1977 6:2<118 1990 6 10877 https://doi.org/10.1007/BF02828288 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02828288 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Gorback Michael Department of Anesthesiology, Duke University Medical Center, Box 3094, 27710, Durham, NC aut NATIONALLICENCE 773 0- Journal of Clinical Monitoring Springer Netherlands 6/2(1990-04-01), 118-127 0748-1977 6:2<118 1990 6 10877 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer