MODEL BASED MONITORING OF HYPOTHERMIC PATIENTS

In open heart surgery the patient is connected to a heart-lung machine which pumps and oxygenizes the blood. The body core temperature is reduced by cooling the blood in a heat exchanger to reduce oxygen consumption of the tissues and so protect organs from hypoxia. Monitoring of vital parameters is crucial for safety of the patient. However, only little information is available from direct measurement. Models of haemodynamics and heat exchange in the human body are presented in this paper which provide the perfusionist with detailed data on blood flow and temperature in regions of the body which cannot be accessed by measurement devices. Simulation is performed on a real-time hardware platform which receives measured signals from the heart-lung machine via a serial interface.

[1]  D. Sessler,et al.  Thermoregulatory Vasoconstriction Impairs Active Core Cooling , 1995, Anesthesiology.

[2]  K. Lomas,et al.  Computer prediction of human thermoregulatory and temperature responses to a wide range of environmental conditions , 2001, International journal of biometeorology.

[3]  T. David,et al.  Numerical Models of Auto-regulation and Blood Flow in the Cerebral Circulation , 2002, Computer methods in biomechanics and biomedical engineering.

[4]  A. Guyton,et al.  Textbook of Medical Physiology , 1961 .

[5]  B. Hillen,et al.  Effects of anterior communicating artery diameter on cerebral hemodynamics in internal carotid artery disease. A model study. , 1995, Circulation.

[6]  Robert B. Roemer,et al.  A Mathematical Model of the Human Temperature Regulatory System - Transient Cold Exposure Response , 1976, IEEE Transactions on Biomedical Engineering.

[7]  H. H. Penns.  Analysis of tissue and arterial blood temperatures in the resting human forearm , 1948 .

[8]  Uwe Kiencke,et al.  Beobachtung des Patientenzustands bei Herzoperationen (Observing Patient Status during Cardiac Surgery) , 2002 .

[9]  Frank B. Sachse,et al.  Segmentation and Tissue-Classification of the Visible Man Dataset Using the Computertomographic Scan , 1996 .

[10]  T David,et al.  One-dimensional and three-dimensional models of cerebrovascular flow. , 2005, Journal of biomechanical engineering.

[11]  J. A. J. Stolwijk,et al.  Temperature regulation in man — A theoretical study , 1966, Pflüger's Archiv für die gesamte Physiologie des Menschen und der Tiere.

[12]  S. Sherwin,et al.  Modelling the circle of Willis to assess the effects of anatomical variations and occlusions on cerebral flows. , 2007, Journal of biomechanics.

[13]  J. Chase,et al.  Metabolic model of autoregulation in the Circle of Willis. , 2006, Journal of biomechanical engineering.

[14]  Rune Aaslid,et al.  Comparison of Flow and Velocity During Dynamic Autoregulation Testing in Humans , 1994, Stroke.

[15]  Frank B. Sachse,et al.  Preprocessing of the Visible Man Dataset for the Generation of Macroscopic Anatomical Models , 1996 .

[16]  A. P. Avó.  Multi-branched model of the human arterial system , 2006 .

[17]  J. Werner,et al.  A dynamic model of the human/clothing/environment-system. , 1997, Applied human science : journal of physiological anthropology.

[18]  B. Hillen,et al.  A mathematical model of the flow in the circle of Willis. , 1986, Journal of biomechanics.

[19]  T David,et al.  3D models of blood flow in the cerebral vasculature. , 2006, Journal of biomechanics.

[20]  N Westerhof,et al.  Models of the arterial tree. , 2000, Studies in health technology and informatics.

[21]  Uwe Kiencke,et al.  Integration of the Circle of Willis into Avolio's model of the arterial haemodynamics , 2008 .

[22]  T David,et al.  Lumped Parameter and Feedback Control Models of the Auto-regulatory Response in the Circle of Willis , 2004, Computer methods in biomechanics and biomedical engineering.

[23]  K. Lomas,et al.  A computer model of human thermoregulation for a wide range of environmental conditions: the passive system. , 1999, Journal of applied physiology.

[24]  A P Avolio,et al.  Functional origin of reflected pressure waves in a multibranched model of the human arterial system. , 1994, The American journal of physiology.