A Multi-segment Mathematical Model with Variable Compliance for Pressure Controlled Ventilation

Konvika Kongkul,^a,c Sahattaya Rattanamongkonkula,^c,d,* and Philip S Crooke^b

ABSTRACT: A mathematical model with multi-segment variable compliance which describes the volume of a single compartment lung for pressure controlled ventilation has been proposed and compared against a constant compliance model. The compliance in the constant compliance model is the average of those in the variable compliance model. In our model, on the other hand, a variable compliance is approximated by piecewise linear function of the lung volume. The model was then used to compute the outcome variables of clinical interest; tidal volume, average volume, end-expiratory pressure, and mean alveolar pressure. Using data obtained from healthy and injured pigs, the variable compliance model was used to study effects of recruitment maneuvers on the key outcome variables. Furthermore, the limiting value for each outcome variable was derived as a function of the physiologic and ventilatory parameters.

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a Department of Mathematics, Mahidol University, Bangkok 10400, Thailand.
b Department of Mathematics, Vanderbilt University, Nashville, TN 37240, USA.
c Supported by a scholarship under the Ministry Staff Development Project of Ministry of University Affairs, Thailand.
d Supported by the Thailand Research Fund and the National Research Council of Thailand.

* Corresponding author, E-mail: g4336633@student.mahidol.ac.th

Received 15 Nov 2003, Accepted 8 Mar 2004