الفهرس 
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Abstract
The respiratory system mechanical properties (elastance and resistance) have a great influence on the process of mechanical ventilation. The single-compartment lung model can be utilized for the application of Newtonian laws on the respiratory system in terms of the equation of motion which divides the pressure applied on the respiratory system at any given time into elastic and resistive components. During mechanical ventilation, one or more of the variables of ventilation (pressure, flow, volume, and time) are controlled (set / input variables), and the others are dependent (output variables). The variables of ventilation are also utilized in defining the different phases of the respiratory cycle which are: triggering of inspiration, inspiration, cycling to expiration, and expiration. The modern ICU ventilators display on their screen volume, flow, and pressure versus time curves, as well as flow-volume and pressure-volume loops. These real-time curves and loops are very important in tailoring the proper mode and settings of ventilation to the specific patient, identifying and managing patient-ventilator dyssynchrony, identifying the response to adjuvant therapies, and improving the process of weaning. The respiratory system mechanics (compliance and resistance) can be accurately measured by applying rapid airway occlusion at end-inspiration utilizing the end-inspiratory pause button available in modern ventilators. Air trapping and dynamic pulmonary hyperinflation are frequently encountered in mechanically ventilated patients especially those with obstructive lung disease, where the alveoli do not expel all their contents completely resulting in intrinsic PEEP which has several patho-physiological and clinical consequences.