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Mechanism study of pulsus paradoxus using mechanical models.

Xing CY, Cao TS, Yuan LJ, Wang Z, Wang K, Ren HR, Yang Y, Duan YY - PLoS ONE (2013)

Bottom Line: Model 1 demonstrated that the simulated RIPC had different influence on the simulated SVR and PVR.It increased the volume of the simulated right ventricle (SRV) when the internal pressure was kept constant (8.16 cmH2O), while it had the opposite effect on PVR.Our models demonstrate that the different anatomical arrangement of the two venous return systems leads to a different effect of RIPC on right and left ventricles, and thus a pressure gradient across IVS that tends to shift IVS left- and rightwards.

View Article: PubMed Central - PubMed

Affiliation: Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi'an, China.

ABSTRACT
Pulsus paradoxus is an exaggeration of the normal inspiratory decrease in systolic blood pressure. Despite a century of attempts to explain this sign consensus is still lacking. To solve the controversy and reveal the exact mechanism, we reexamined the characteristic anatomic arrangement of the circulation system in the chest and designed these mechanical models based on related hydromechanic principles. Model 1 was designed to observe the primary influence of respiratory intrathoracic pressure change (RIPC) on systemic and pulmonary venous return systems (SVR and PVR) respectively. Model 2, as an equivalent mechanical model of septal swing, was to study the secondary influence of RIPC on the motion of the interventriclar septum (IVS), which might be the direct cause for pulsus paradoxus. Model 1 demonstrated that the simulated RIPC had different influence on the simulated SVR and PVR. It increased the volume of the simulated right ventricle (SRV) when the internal pressure was kept constant (8.16 cmH2O), while it had the opposite effect on PVR. Model 2 revealed the three major factors determining the respiratory displacement of IVS in normal and different pathophysiological conditions: the magnitude of RIPC, the pressure difference between the two ventricles and the intrapericardial pressure. Our models demonstrate that the different anatomical arrangement of the two venous return systems leads to a different effect of RIPC on right and left ventricles, and thus a pressure gradient across IVS that tends to shift IVS left- and rightwards. When the leftward displacement of IVS reaches a considerable amplitude in some pathologic condition such as cardiac tamponade, the pulsus paradoxus occurs.

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Hemodynamic analysis of the circulation system.The circulation system may hydromechanically be divided into two enclosed fluids, the WITS and PITS (the white and the dark parts of the circulation system in the figure). They are operating at a very different pressure level and kept separated by either the atrio-ventricular valves in systole (top panel) or the semilunar valves in diastole (bottom panel), though they are connected in series. The systemic venous return (SVR) system consists of systemic vasculature and right heart, and the pulmonary venous return (PVR) system consists of pulmonary vasculature and left heart. Their location relative to WITS and PITS changes in diastole and systole. Modified from Wang et al. PLoS ONE.[10].
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pone-0057512-g001: Hemodynamic analysis of the circulation system.The circulation system may hydromechanically be divided into two enclosed fluids, the WITS and PITS (the white and the dark parts of the circulation system in the figure). They are operating at a very different pressure level and kept separated by either the atrio-ventricular valves in systole (top panel) or the semilunar valves in diastole (bottom panel), though they are connected in series. The systemic venous return (SVR) system consists of systemic vasculature and right heart, and the pulmonary venous return (PVR) system consists of pulmonary vasculature and left heart. Their location relative to WITS and PITS changes in diastole and systole. Modified from Wang et al. PLoS ONE.[10].

Mentions: Functionally, the circulation is divided into systemic and pulmonary circulation systems. While from the hemodynamic point of view, we propose to divide the whole circulation system into two closed portions which are separated by the semilunar valves in diastole and by the atrio-ventricular valves in systole (Figure 1).


Mechanism study of pulsus paradoxus using mechanical models.

Xing CY, Cao TS, Yuan LJ, Wang Z, Wang K, Ren HR, Yang Y, Duan YY - PLoS ONE (2013)

Hemodynamic analysis of the circulation system.The circulation system may hydromechanically be divided into two enclosed fluids, the WITS and PITS (the white and the dark parts of the circulation system in the figure). They are operating at a very different pressure level and kept separated by either the atrio-ventricular valves in systole (top panel) or the semilunar valves in diastole (bottom panel), though they are connected in series. The systemic venous return (SVR) system consists of systemic vasculature and right heart, and the pulmonary venous return (PVR) system consists of pulmonary vasculature and left heart. Their location relative to WITS and PITS changes in diastole and systole. Modified from Wang et al. PLoS ONE.[10].
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585346&req=5

pone-0057512-g001: Hemodynamic analysis of the circulation system.The circulation system may hydromechanically be divided into two enclosed fluids, the WITS and PITS (the white and the dark parts of the circulation system in the figure). They are operating at a very different pressure level and kept separated by either the atrio-ventricular valves in systole (top panel) or the semilunar valves in diastole (bottom panel), though they are connected in series. The systemic venous return (SVR) system consists of systemic vasculature and right heart, and the pulmonary venous return (PVR) system consists of pulmonary vasculature and left heart. Their location relative to WITS and PITS changes in diastole and systole. Modified from Wang et al. PLoS ONE.[10].
Mentions: Functionally, the circulation is divided into systemic and pulmonary circulation systems. While from the hemodynamic point of view, we propose to divide the whole circulation system into two closed portions which are separated by the semilunar valves in diastole and by the atrio-ventricular valves in systole (Figure 1).

Bottom Line: Model 1 demonstrated that the simulated RIPC had different influence on the simulated SVR and PVR.It increased the volume of the simulated right ventricle (SRV) when the internal pressure was kept constant (8.16 cmH2O), while it had the opposite effect on PVR.Our models demonstrate that the different anatomical arrangement of the two venous return systems leads to a different effect of RIPC on right and left ventricles, and thus a pressure gradient across IVS that tends to shift IVS left- and rightwards.

View Article: PubMed Central - PubMed

Affiliation: Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi'an, China.

ABSTRACT
Pulsus paradoxus is an exaggeration of the normal inspiratory decrease in systolic blood pressure. Despite a century of attempts to explain this sign consensus is still lacking. To solve the controversy and reveal the exact mechanism, we reexamined the characteristic anatomic arrangement of the circulation system in the chest and designed these mechanical models based on related hydromechanic principles. Model 1 was designed to observe the primary influence of respiratory intrathoracic pressure change (RIPC) on systemic and pulmonary venous return systems (SVR and PVR) respectively. Model 2, as an equivalent mechanical model of septal swing, was to study the secondary influence of RIPC on the motion of the interventriclar septum (IVS), which might be the direct cause for pulsus paradoxus. Model 1 demonstrated that the simulated RIPC had different influence on the simulated SVR and PVR. It increased the volume of the simulated right ventricle (SRV) when the internal pressure was kept constant (8.16 cmH2O), while it had the opposite effect on PVR. Model 2 revealed the three major factors determining the respiratory displacement of IVS in normal and different pathophysiological conditions: the magnitude of RIPC, the pressure difference between the two ventricles and the intrapericardial pressure. Our models demonstrate that the different anatomical arrangement of the two venous return systems leads to a different effect of RIPC on right and left ventricles, and thus a pressure gradient across IVS that tends to shift IVS left- and rightwards. When the leftward displacement of IVS reaches a considerable amplitude in some pathologic condition such as cardiac tamponade, the pulsus paradoxus occurs.

Show MeSH
Related in: MedlinePlus