chapter  1
22 Pages

Biomechanics in Medical Diagnosis in the Form of Nondimensional Physiological Indices

WithDhanjoo N. Ghista

CONTENTS 1.1 Scope ............................................................................................................... 2 1.2 Introduction ................................................................................................... 2 1.3 Formulation of NDPI(s) for Some Physiological Systems ..................... 3

1.3.1 Index for Efficiency of Left-Ventricular Pumping ...................... 3 1.3.2 Assessing Cardiac Fitness and Conditioning

by Means of a Treadmill Test ......................................................... 4 1.3.2.1 Monitored and Computed Results for a Typical

Normal Subject ................................................................... 5 1.3.3 Nondimensional Lung Ventilatory Performance Index ............ 7 1.3.4 Nondimensional Diabetes Index with Respect to Oral

Glucose Tolerance Testing .............................................................. 9 1.3.5 Characterization of Aortic Stiffness or Arteriosclerosis ........... 11 1.3.6 Noninvasive Determination of Aortic Elasticity (m),

Peripheral Resistance (R), and the Aortic NDI ......................... 12 1.3.7 Mitral Valve Property Characterization (to Provide

Interventional Guidelines) ............................................................ 14 1.3.8 Noninvasive Determination of Osteoporosis Index

for Osteoporosis Detection ............................................................ 16 1.4 Conclusion ................................................................................................... 17

1.4.1 Performance Index ......................................................................... 17 1.4.2 Cost-Effective Index ....................................................................... 18 1.4.3 Strategy of Operation ..................................................................... 19

References ............................................................................................................. 19

This introductory chapter delineates the theme and scope of the book. Herein, we are providing a novel concept of physiological systems analysis, in terms of nondimensional physiological indices (NDPIs), for quantifying patient health and disease status as well as patient improvement. We have developed NDPIs for several physiological phenomena and systems, and indicated as to how they can be employed diagnostically. NDPIs have been formulated and evaluated for (1) left-ventricular pumping performance, (2) cardiac fitness and conditioning, (3) lung ventilatory function, (4) oral glucose tolerance test, (5) arteriosclerosis, (6) atherosclerosis and peripheral resistance, (7) mitral valve property, and (8) osteoporosis. This chapter is based on my paper, Ref. [1].*

The concept of nondimensional physiological number index is quite new, and has been adopted from engineering, where nondimensional numbers (made up of several parameters) are employed to characterize a regime or strata disturbance phenomena. For example, in a cardiovascular fluid-flow regime, the Reynold’s number

Nre ¼ rVD=m (1:1)

is employed to characterize the conditions when Nre exceeds a certain critical value, at which laminar flow changes to turbulent flow, which can occur in the ascending aorta when either the aortic valve is stenotic (giving rise to murmurs) or in the case of anemia (decreased blood viscosity). Similarly, we can construct other such physiological numbers to charac-

terize disturbance from physiological homeostasis. In physiological medicine, the use of nondimensional indices or numbers can provide a generalized approach by which unification or integration of a number of isolated but related events into one NDPI can help to characterize an abnormal state associated with a particular physiological system. The evaluation of the distribution of the values of such NDPI(s), in a big patient population, can then enable us to designate normal and disordered ranges of NDPI, with a critical value of NDPI separating these two ranges, as illustrated in Figure 1.1. In this way, NDPI(s) can help us to formulate physiological health indices (PHIs), not only to facilitate differential diagnosis of patients but also to assess the severity of the disease or disorder. Herein, we have formulated several such new NDPIs [1].