title: A mathematical model approach quantifying patients' response to changes in mechanical ventilation: evaluation in volume support.
abstract: This paper presents a mathematical model-approach to describe and quantify patient-response to changes in ventilator support. The approach accounts for changes in metabolism (V̇O2, V̇CO2) and serial dead space (VD), and integrates six physiological models of: pulmonary gas-exchange; acid-base chemistry of blood, and cerebrospinal fluid; chemoreflex respiratory-drive; ventilation; and degree of patients' respiratory muscle-response. The approach was evaluated with data from 12 patients on volume support ventilation mode. The models were tuned to baseline measurements of respiratory gases, ventilation, arterial acid-base status, and metabolism. Clinical measurements and model simulated values were compared at five ventilator support levels. The models were shown to adequately describe data in all patients (χ(2), p > 0.2) accounting for changes in V̇CO2, VD and inadequate respiratory muscle-response. F-ratio tests showed that this approach provides a significantly better (p < 0.001) description of measured data than: (a) a similar model omitting the degree of respiratory muscle-response; and (b) a model of constant alveolar ventilation. The approach may help predict patients' response to changes in ventilator support at the bedside.
authors: Respiratory and Critical Care Group (RCARE), Center for Model-based Medical Decision Support, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7, E4-213, DK-9220 Aalborg, Denmark. Electronic address: larraza@hst.aau.dk.
authors: S
authors: S
authors: Larraza
authors: Department of Anaesthesia and Intensive Care, Regions Hospital Herning, Herning, Denmark.
authors: N
authors: N
authors: Dey
authors: Respiratory and Critical Care Group (RCARE), Center for Model-based Medical Decision Support, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7, E4-213, DK-9220 Aalborg, Denmark.
authors: D S
authors: DS
authors: Karbing
authors: Mermaid Care A/S, Nr. Sundby, Denmark.
authors: J B
authors: JB
authors: Jensen
authors: Department of Anaesthesia and Intensive Care, Regions Hospital Herning, Herning, Denmark.
authors: M
authors: M
authors: Nygaard
authors: Department of Anaesthesia and Intensive Care, Regions Hospital Herning, Herning, Denmark.
authors: R
authors: R
authors: Winding
authors: Respiratory and Critical Care Group (RCARE), Center for Model-based Medical Decision Support, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7, E4-213, DK-9220 Aalborg, Denmark.
authors: S E
authors: SE
authors: Rees
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002245:Carbon Dioxide / Q000378:metabolism; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D009068:Movement / Q000502:physiology; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012121:Respiration, Artificial / Q000379:methods*; D012132:Respiratory Muscles / Q000503:physiopathology
chemical_list: D002245:Carbon Dioxide
keywords: Chemoreflex respiratory control; Computer simulation; Mechanical ventilation; Support ventilation modes; Ventilatory response to CO(2)