Assessment of ventricular contractility and ventricular-arterial coupling with a model-based sensor.

in Computer Methods & Programs in Biomedicine (2012)

Estimation of ventricular contractility and ventricular arterial coupling is clinically important in diagnosing and treating cardiac dysfunction in the critically ill. However, experimental assessment of ... [more ▼]

Estimation of ventricular contractility and ventricular arterial coupling is clinically important in diagnosing and treating cardiac dysfunction in the critically ill. However, experimental assessment of indexes of ventricular contractility, such as the end-systolic pressure-volume relationship, requires a highly invasive maneuver and measurements that are not typical in an intensive care unit (ICU). This research describes the use of a previously validated cardiovascular system model and parameter identification process to evaluate the right ventricular arterial coupling in septic shock. Model-based ventricular arterial coupling is defined by the ratio of the end systolic right ventricular elastance (E(esrvf)) over the pulmonary artery elastance (E(pa)) or the mean pulmonary inflow resistance (R(pulin)). Results are compared to the clinical gold-standard assessment (conductance catheter method). Six anesthetized healthy pigs weighing 20-30kg received a 0.5mgkg(-1) endotoxin infusion over a period of 30min from T0 to T30, to induce septic shock and veno-venous hemofiltration was used from T60 onward. The results show good agreement with the gold-standard experimental assessment. In particular, the model-based right ventricular elastance (E(esrvf)) correlates well with the clinical gold standard (R(2)=0.69) and the model-based non-invasive coupling (E(esrvf)/R(pulin)) follow the same trends and dynamics (R(2)=0.37). The overall results show the potential to develop a model-based sensor to monitor ventricular-arterial coupling in clinical real-time. [less ▲]

Patient-specific modelling of the cardiovascular system – application to septic shock with a minimal data set,

in World Congress on Medical Physics and Biomedical Engineering, September 7 - 12, 2009, Munich, Germany (2010)

Model-based Cardiovascular Therapeutics: Capturing the patient-specific impact of inotrope therapy

in Proceedings of the 3rd International Meeting of the French Society of Hypertension (2009)

Model-based diagnosis of acute pulmonary embolism - results from a porcine model

in Intensive Care Medicine (2008), 34(suppl. 1), 78

Cardiovascular Modelling and Identification in Septic Shock - Experimental validation

in IFAC 2008 (2008)

Mathematical modelling and parameter identification methods in systems

in Proceedings of the 7th joint Australia-New Zealand Mathematics Convention (ANZMC2008) (2008)

Making sense of the Chaos: Model-based CVS monitoring and decision support in critical care

in Proceedings of the NZ Physiological Society 2008 Medical Science Congress (MedSci 2008) (2008)

Model-based assessment of right ventricular arterial coupling during septic shock - Results with a procine model

in Intensive Care Medicine (2008), 34(suppl. 1), 24

Model-Based Assessment of Right Ventricular Arterial Coupling During Septic Shock – Results With a Porcine Model

in Proceedings of the 21st European Society of Intensive Care Medicine (ESICM) Annual Congress, September 21-24, 2008, Lisbon, Portugal (2008)

Study of ventricular interaction during pulmonary embolism using clinical identification in a minimum cardiovascular system model.

in Proceedings of the IEEE (2007)

Cardiovascular disturbances are difficult to diagnose and treat because of the large range of possible underlying dysfunctions combined with regulatory reflex mechanisms that can result in conflicting ... [more ▼]

Cardiovascular disturbances are difficult to diagnose and treat because of the large range of possible underlying dysfunctions combined with regulatory reflex mechanisms that can result in conflicting clinical data. Thus, medical professionals often rely on experience and intuition to optimize hemodynamics in the critically ill. This paper combines an existing minimal cardiovascular system model with an extended integral based parameter identification method to track the evolution of induced pulmonary embolism in porcine data. The model accounts for ventricular interaction dynamics and is shown to predict an increase in the right ventricle expansion index and a decrease in septum volume consistent with known physiological response to pulmonary embolism. The full range of hemodynamic responses was captured with mean prediction errors of 4.1% in the pressures and 3.1% in the volumes for 6 sets of clinical data. Pulmonary resistance increased significantly with the onset of embolism in all cases, as expected, with the percentage increase ranging from 89.98% to 261.44% of the initial state. These results are an important first step towards model-based cardiac diagnosis in the Intensive Care Unit. [less ▲]