USMLE World Ventilator Question! - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
Home
USMLE Articles
USMLE News
USMLE Polls
USMLE Books
USMLE Apps
Go Back   USMLE Forums > USMLE Step 2 CK Forum

USMLE Step 2 CK Forum USMLE Step 2 CK Discussion Forum: Let's talk about anything related to USMLE Step 2 CK exam


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 07-10-2012
tyagee's Avatar
USMLE Forums Master
 
Steps History: ---
Posts: 1,365
Threads: 648
Thanked 584 Times in 354 Posts
Reputation: 594
Question USMLE World Ventilator Question!

Quote:
Several values related to pulmonary mechanics can be calculated in mechanically ventilated patients. Lung
compliance is calculated by performing the end-inspiratory hold maneuver. Airway resistance is calculated
by examining the peak airway pressures. Positive end-expiratory pressure (PEEP) is calculated with the end-
expiratory hold maneuver.
please any one who understands this...please explain...it all sounds gibberish to me
Reply With Quote Quick reply to this message
The above post was thanked by:
mayursn39 (07-11-2012)



  #2  
Old 07-10-2012
tyagee's Avatar
USMLE Forums Master
 
Steps History: ---
Posts: 1,365
Threads: 648
Thanked 584 Times in 354 Posts
Reputation: 594
Default

question in regard to the above fact from uworld...

A 32-year-old man is intubated and mechanically ventilated after an opioid drug overdose. The ventilator
triggers 12 breaths per minute, each delivering 500 ml of tidal volume at a flow rate of 60 Umin. You perform
an inspiratory hold for 2 seconds following delivery of the tidal volume, and the airway pressure is measured
to be 30 em H20.
The measured pressure reflects which of the following?
A. Upper airway resistance
B. Total airway resistance
C. Pulmonary compliance
D. Expiratory muscle strength
E. End-expiratory pressure
Reply With Quote Quick reply to this message
  #3  
Old 07-10-2012
USMLE Forums Scout
 
Steps History: Not yet
Posts: 61
Threads: 7
Thanked 81 Times in 32 Posts
Reputation: 91
Default

okay I got this answer right on UWorld and my logic (although not good enough) is as follows:
When the patient is asked to perform an inspiratory hold it is essentially similar to Positive Pressure Ventilation. The air is trapped in the alveoli and the alveoli is prevented from collapsing. (Thats why we use PPV in atelectasis). Now the only parameter thats related to alveoli not collapsing is 'compliance'. It is the ability of the lung/alveoli to expand (and not collapse..collapse is 'recoil of the lung').
Its crude but thats the best I could come up with :/
Reply With Quote Quick reply to this message
The above post was thanked by:
mayursn39 (07-11-2012)
  #4  
Old 07-11-2012
tyagee's Avatar
USMLE Forums Master
 
Steps History: ---
Posts: 1,365
Threads: 648
Thanked 584 Times in 354 Posts
Reputation: 594
Default

thanks for reply.

can we get more explanation.this seems to be high yeild topic .

lets discuss it more...
Reply With Quote Quick reply to this message
The above post was thanked by:
legendkiller (09-01-2015)
  #5  
Old 07-11-2012
USMLE Forums Master
 
Steps History: 1+CK+CS
Posts: 1,867
Threads: 149
Thanked 2,085 Times in 1,046 Posts
Reputation: 2105
Default

Think of the lung as a balloon.
Inspiration is an active phenomenon and compliance is the capacity of the lung,
Expiration is passive and depends on recoil of the lung.

Now, in a mechanically ventilated lung the ventilator is practically substituting for diaphragm.
To test for compliance you have to measure once the lung is inflated with the tidal volume and the pressure at the end of the delivery of TV is a reflection of the compliance of the lung.

To test for PEEP, you have to know how PEEP works. It provides resistance at the end of expiration to prevent alveoli from collapsing. So, it makes sense to check it at the end of expiration when no pressure is being exerted by the air in the alveoli delivered as TV.
Reply With Quote Quick reply to this message
The above post was thanked by:
excellence (03-04-2015), K06100 (10-05-2012), pkul85 (07-06-2013), Remee (08-02-2013), shaan.medico (06-03-2013), Thrax_usmle (08-03-2014), tyagee (07-12-2012), usmledr (07-12-2012), vikyeergreen (02-05-2014)
  #6  
Old 06-29-2014
USMLE Forums Scout
 
Steps History: Not yet
Posts: 10
Threads: 1
Thanked 0 Times in 0 Posts
Reputation: 10
Send a message via Skype™ to Jorabim
Default

In ICUs they do it to measure a Static Compliance
Reply With Quote Quick reply to this message



Reply

Tags
Pulmonology-, Step-2-Questions

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

Favorite USMLE Books
What USMLE books you really think are useful. Leave blank if you don't want to tell.
Location
Where you live. Leave blank if you don't want to tell.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Difference between Offline Usmle World and Online Usmle World noone_123i USMLE Step 1 Forum 15 06-01-2016 10:00 AM
Patient wants to remove the ventilator? Hope2Pass USMLE Step 1 Forum 14 04-27-2012 10:20 AM
How would manage this arterial blood gas on ventilator! achistikbenny USMLE Step 2 CK Forum 6 03-16-2012 01:34 PM
Effective Way to do the USMLE World question bank donofitaly USMLE Step 1 Forum 4 02-05-2011 09:13 AM
RA treatment, question from u-world gargabhi2 USMLE Step 1 Forum 8 10-25-2010 07:08 PM

RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2014)