RxPG - the perfect Rx for medical Post Graduate entrance blues!
Mobile Edition | Help/Newbie? | 24/7 Support
HOT | PrePG | MCQ | DNB | Careers | Books | Colleges | Dental | DocIndia | PLAB |  USMLE  | Australia | Canada | GLOBAL | OffBeat!
Articles | Forums | MCQ Crammer | Downloads | Mnemonics | Revision Tools | Recent Shouts | All Features


Interpretation of Pulmonary Function Tests

Author: RespiXP, Posted on Saturday, January 24 @ 17:35:20 IST by RxPG  

 FRIEND Add to My Pages   PRINTER Printer Friendly   FRIEND Email Story  FRIEND Download Story  Medicine alerts 

Medicine

In general, this is my approach to interpreting a pulmonary function test: First, I look at the FEV1/FVC ratio. If this is below 75%, an obstructive ventilatory defect is present. If the ratio is above 75%, are the FVC and FEV1 low? If so, a restrictive ventilatory defect is likely and I next look at the lung volume section.

A low Vital Capacity confirms a restrictive ventilatory defect. Some regard the Total Lung Capacity as confirmatory, so I consider both. In general, in a restrictive ventilatory defect, the majority of lung volumes will be decreased. In an obstructive ventilatory defect is present, the Residual Volume will be high.

I also look at the shape of the flow volume loop to differentiate an obstructive ventilatory defect from a restrictive ventilatory defect. An obstructive ventilatory defect gives a distinctive pattern. A restrictive ventilatory defect looks like a normal flow volume loop, except that it is smaller.

As far as diffusion studies, a low DLCO can be seen in both emphysema and interstitial fibrosis. The DLCO can help differentiate the cause of a restrictive or obstructive ventilatory defect. In a restrictive ventilatory defect, interstitial fibrosis may cause a decrease in DLCO but chest wall deformities and obesity would not. In an obstructive ventilatory defect, emphysema may cause a decrease in DLCO but asthma would not. The DLCO/VA is an attempt to correct the diffusion for the actual lung volume being tested. A normal value should imply that the cause of the restriction is extrinsic to the lungs (such as a chest wall deformity or obesity) instead of intrinsic to the lungs (emphysema and interstitial fibrosis). However, a normal value can occur in any of these conditions.




4 (Excellent) 3(Good) 2(Good) 1(Bad)   


Recommended Books for Medicine
• Books to read for Medicine by RxPG

Related Medicine articles
• 'CAT' RELATED POINTS IN MEDICINE
• Types of Tongues in Various Medical Conditions
• Signs in Meningitis
• How To Read Harrison And Make The Most Of It?
• Examination of nails in medicine
• Triads in Medicine: A Quick Revision List
• Medical Conditions affecting Nails
• Diagnosis of diffuse lung disease
• Common simple emergencies
• Wilson's disease
• medicine updates!
• Abnormal colours of urine
• ACANTHOSIS NIGRICANS
• Noonan's syndrome
• Medicine; Online Mock Test (PGI Pattern)
• Characteristic Feature of Hypocalcaemia
• diagnosis of pulmonary microembolism.
• CHAPTER WISE CHANGES IN HARRISON’S PRINCIPLES OF INTERNAL MEDICINE
• CHANGES IN HARRISON’S PRINCIPLES OF INTERNAL MEDICINE CATEGORISED.
• Differentiating features of Leukemias (Leukaemias)

Related Medicine Discussions

Other articles by RespiXP
• Interpretation of Pulmonary Function Tests
 

 Medicine FAQ
  Browse all FAQs


Write an Article on Medicine
You can share your exam experiences, preparation strategies, books you have read or just any information about Medicine on RxPG website and we will publish it under your name.

Article Rating
Average Score: 3.58
Votes: 12




Most Read Article
How To Read Harrison And Make The Most Of It?

Related Links
· MRCP books at Amazon.com
· Clinical Skills
· Medicine Books at Amazon.com
· Medicine Forum
· Discuss Past Papers
· Harrison's Free Trial






ARTICLE TOOLS

· Medicine section
· Articles by RespiXP
· Add to my pages
· Printer friendly version
· PDF version
· Email article
· Feedback on this article
· Medical tutorials
· Related forum posts
· Related articles
· Related downloads
· Submit article
· Medicine alerts
· Medicine books
· Medicine past papers


Most read story about Medicine:
How To Read Harrison And Make The Most Of It?



Server Status: 142 pages served in last minute. Page generation time: 0.156 seconds

Site Maps: [Books] [News] [Forums] [Reviews] [Mnemonics]

sitemap - top30 - centuries - testimonials


About Us :: Disclaimer :: Contact Us :: Reporting abuse :: Terms of Services :: Privacy Policy

Advertise with RxPG!
Made in India by RxPG Medical Solutions Private Limited

"RxPG" is a Registered Trademark

Chrome Web Store YouTube Twitter LinkedIn Wikipedia Facebook