<prompt> Which of the following statements about VentilationPerfusion ratio is true:In a complete airway obstruction, the ventilationPerfusion ratio approaches InfinityIn complete Pulmonary Embolism, the ventilationperfusion ratio approaches ZeroVentilation Perfusion Ratio of Zero indicates Dead spaceVentilation perfusion ratio of infinity indicates no gas exchange  <response>: VQ ratio of infinity indicates Zero perfusion. This creates ;Dead space; where no Gas exchange occurs since pulmonary blood flow perfusion is blocked. Option A: In a complete airway obstruction, the ventilation is Zero hence VQ ratio approaches Zero not infinity Option B: In complete pulmonary embolism, the perfusion is zero and hence the VQ ratio approaches Infinity not Zero Option C: VQ ratio of Zero a shunt Not dead space where perfused blood is shunted without oxygenation. VQ ratio is defined as the ratio of ventilation the amount of air reaching the alveoli to perfusion the amount of bloof reaching the alveoli V- Ventilation- The air which reaches the alveoli Q- Perfusion- The blood which reaches the alveoli An area with No ventilation V0 Has a VQ ratio of zero An area with No perfusion Q0 has a VQ Ratio of infinity An area where ventilation is perfectly matched to perfusion VQ Has a VQ Ratio of 1.0 Shunt Dead space Adequate Gas exchange This is also termed as a shunt since deoxygenated blood is shunted without oxygenation due to lack of any ventilation Perfusion is Wasted This is also termed a dead space since the Ventilation is wasted This represents IdealAdequate Gas Exchange Ref: Pathophysiology: The essentials 4th edition Pgno: 22 