Cardiopulmonary model to study interaction hemodynamics in Muller maneuver

Abstract

SUMMARYThe Muller maneuver (MM) is a frequently used physiological test in evaluating the cardiopulmonary (CP) interactions along with baroreflex functions in human. In spite of extensive experimental efforts, there is still ambiguity, controversy and disagreement in explaining different aspects of underlying mechanisms during MM. So far a complete comprehension of these mechanisms and the interactions among them is unavailable. In the present study, a CP model with detailed representation of cardiovascular, respiratory and baroreflex system is developed for the purpose of complete, continuous and simultaneous monitoring of all above three systems in MM to explain the underlying mechanisms. Our model incorporates the advantages of various models of all three systems reported separately in literature. Effective coupling is realized by intrapleural pressure between cardiovascular system and respiratory system Baroreflex regulation on cardiovascular system is achieved through vital cardiac parameters such as cardiac duration, contractility and peripheral resistance. Initially, the CP dynamics are tested qualitatively by simulating quiet breathing. Quiet breathing is simulated by perturbing intrapleural pressure in an exponential way from −3.7 to −5.5 mmHg. The quantitative analysis of CP interaction is studied by simulating MM in which strong intrapleural pressure variation is realized. The developed model can predict significant physiological events in individual system dynamics along with their interactions in quiet breathing condition as in literature data. In MM, simulated arterial pressure shows typical characteristic pattern. The quantitative analysis carried out with five different MM simulations shows an increase in LV afterload and decrease in RV preload, which lead to decrease in LV stroke volume. Mean arterial pressure is not significantly changing, however, the pulse pressure reduces significantly that stimulates baroreflex activation in MM. This suggests that arterial baroreflex responds mainly to pulsatile pressure changes compared to mean pressure changes. The right heart hemodynamics are more affected than left heart dynamics in MM. The model results are well supported by the experimental data reported in literature. Therefore, the model can be used as a tool to investigate the CP system dynamics to various normal and abnormal conditions.

Ballistocardiography and seismocardiography detection of hemodynamic changes during simulated obstructive apnea

“…MIP was used as a surrogate for pleural pressure in order to indirectly estimate LV wall stress. Even if they do not represent the same measures, variations of oral pressure correctly describe corresponding variations in the alveolar pressure that, in turn, reflects pleural pressure swings (Hemalatha 2011).…”

Human circulatory system response to changes in alveolar pressure and lung volume

“…The Valsalva maneuver is used to diagnose many human diseases, using the peculiarities of the circulatory reaction in the known four phases of the reaction [Nishimura and Tajik, 1986; Pstras et al, 2016]. The dynamics of the circulatory response to the Müller maneuver is described, for example, in [Hemalatha and Manivannan, 2011].…”

In silico study of airway/lung mechanics in normal human breathing

“…In particular, it could be used to evaluate the effects induced by mechanical ventilatory assistance on the hemodynamic and energetic variables of the cardiovascular system. Many models are available from current literature describing lung/airway mechanics alone [2,3,13,16,23,25,30,33] or the combination of lung/airway mechanics and gas exchange, along with the interaction between the respiratory and the circulatory system [1,15,[20][21][22]26,27,32,38]. These models are all based on the same schematization of the respiratory system and known constitutive functions of the main components such as upper airway and collapsible airway resistances, lung elastic recoil or the transmural pressure.…”