Minimal model quantification of pulmonary gas exchange in intensive care patients

• Published in: Medical engineering & physics Vol. 33; no. 2; pp. 240 - 248
• Main Authors: Karbing, Dan S., Kjærgaard, Søren, Andreassen, Steen, Espersen, Kurt, Rees, Stephen E.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.03.2011; Elsevier
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Carbon Dioxide - metabolism; Computer Simulation; Computerized, statistical medical data processing and models in biomedicine; Critical Care - methods; Emergency and intensive respiratory care; Humans; Intensive care; Intensive care medicine; Lung - physiopathology; Medical sciences; Models and simulation; Models, Biological; Models, Statistical; Monitoring, Physiologic - instrumentation; Oxygen - metabolism; Pneumology; Pulmonary Gas Exchange - physiology; Radiology; Reproducibility of Results; Respiration; Respiration, Artificial - instrumentation; Respiratory function tests; Respiratory Function Tests - instrumentation; Respiratory insufficiency; Respiratory Insufficiency - pathology; Respiratory system : syndromes and miscellaneous diseases; Sensitivity and Specificity; Theoretical models; Ventilation-Perfusion Ratio - physiology; Ventilation–perfusion ratio; Intensive care; Theoretical models; Respiratory insufficiency; Ventilation–perfusion ratio; Respiratory function tests; Human; Ventilation perfusion relationship; Respiratory disease; Ventilation-perfusion ratio; Modeling; Lung function; Theoretical model; Respiratory failure; Gas exchange; Mathematical model; Comparative study; Biomedical engineering
• ISSN: 1350-4533; 1873-4030; 1873-4030
• DOI: 10.1016/j.medengphy.2010.10.007

Mathematical models are required to describe pulmonary gas exchange. The challenge remains to find models which are complex enough to describe physiology and simple enough for clinical practice. This study aimed at finding the necessary ‘minimal’ modeling complexity to represent the gas exchange of both oxygen and carbon dioxide. Three models of varying complexity were compared for their ability to fit measured data from intensive care patients and to provide adequate description of patients’ gas exchange abnormalities. Pairwise F-tests showed that a two parameter model provided superior fit to patient data compared to a shunt only model ( p < 0.001), and that a three parameter model provided superior fit compared to the two parameter model ( p < 0.1). The three parameter model describes larger ranges of ventilation to perfusion ratios than the two parameter model, and is identifiable from data routinely available in clinical practice.