Disorders of Ventilation

8 vq ratio 08 vq pulmonaryartery lightred 5 lmin

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: fectiveness of gas exchange – “How well gases are swapped” • Ventilation – alveoli receives air at a normal rate of 4 L per minute • Perfusion – Capillaries supply blood to the alveoli at a rate of 5 L per minute Normal Ventilation and Normal Perfusion • Ventilation = 4L inspired air • Perfusion = 5L circulating blood • VQ ratio = 4:5 (0.8) V/Q ratio = 0.8 V/Q Pulmonary artery Light red 5 L/min blood flow in I ns p i r ed A i r V/Q – 4:5 4 L/min air in = 21% oxygen Pulmonary vein Dark red Inadequate Perfusion – Dead space • Ventilation is normal = 4L air • Perfusion is reduced or absent ­ 3L blood • Cause: embolism • VQ ratio HIGH 4:3 (1.33) 5 l/min Pulmonary artery I ns p i r ed A i r DEAD SPACE VENTILATION VENTILATION 4 l/min air in = 21% oxygen 3 l/min Pulmonary vein V/Q ratio = 4:3 = 1.33 HIGH Chief Complaint: compromised O2 Inadequate Ventilation (Shunt) • Ventilation is LOW = 2L air • Perfusion is normal 5L blood • VQ ratio 2:5 (0.4) LOW by ½ norm Inspir ed A ir SHUNT SHUNT 2 l/min air in Un­inflated alveoli. Cause of narrowing: asthma, allergic rxn, smokers (mucous), COPD 5 l/min Pulmonary artery V/Q ratio = 2:5 = 0.4 Pulmonary vein Inadequate Ventilation & Perfusion (Silent Unit) ”nothing going in or out” • Absence of Ventilation & • Absence of Perfusion They gon’ die Pulmonary artery Inspir ed A ir SILENT UNI...
View Full Document

Ask a homework question - tutors are online