High Hemoglobin Saturation yet low Oxygen content! - 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 1 Forum

USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 07-10-2010
USMLE Forums Veteran
 
Steps History: 1 + CS
Posts: 209
Threads: 34
Thanked 92 Times in 30 Posts
Reputation: 122
RBC High Hemoglobin Saturation yet low Oxygen content!

An adult Hb is 98% saturated with oxygen but his arterial oxygen content is decreased . The most likely cause of this condition is

A) anemia
B) an AV shunt
c) hemoglobinopathy
D) high altitude hypoxia
E) pulmonary diffusion defect
Reply With Quote Quick reply to this message
The above post was thanked by:
sm3356 (06-16-2015)



  #2  
Old 07-10-2010
USMLE Forums Scout
 
Steps History: Step 1 Only
Posts: 82
Threads: 8
Thanked 114 Times in 49 Posts
Default

i think its option A. Anemia
__________________
Will you look back on life and say, "I wish I had," or "I'm glad I did
Reply With Quote Quick reply to this message
  #3  
Old 07-10-2010
USMLE Forums Veteran
 
Steps History: 1 + CS
Posts: 209
Threads: 34
Thanked 92 Times in 30 Posts
Reputation: 122
Default

can u explain /???
Reply With Quote Quick reply to this message
 
  #4  
Old 07-10-2010
ath.pantelis's Avatar
USMLE Forums Addict
 
Steps History: 1+CK+CS
Posts: 187
Threads: 4
Thanked 372 Times in 122 Posts
Reputation: 402
Default

The formula for oxygen content is as follows:

1.34 x Hb x SaO2 / 100 + 0.0031 x PaO2.

The two most important determinants of this equation are Hb and SaO2, because PaO2 has a minor coefficient and affects the equation only when referring to high depths (where the high atmospheric pressure results to a coefficient much larger than 0.0031).

Given that SaO2 is high (by the question stem), the only variable that may affect the equation is Hb.

Hb levels fall in blood loss and hemoglobinopathy. But in hemoglobinopathy, SaO2 would also be affected (contrary to what the question stem gives), because mutated hemoglobins don't have the same affinity for O2 as HbA does. Furthermore, one wouldn't expect to diagnose a hemoglobinopathy in an adult for the first time.

So, the most probable cause of low Hb levels, that in turn lead to low O2 content, is anemia indeed.
Reply With Quote Quick reply to this message
The above post was thanked by:
abeeraltaf (11-03-2010), drHubaishi (12-07-2013), Sabio (07-10-2010), sm3356 (06-16-2015)
  #5  
Old 07-10-2010
USMLE Forums Newbie
 
Steps History: Not yet
Posts: 2
Threads: 0
Thanked 0 Times in 0 Posts
Reputation: 10
Default

An adult Hb is 98% saturated with oxygen but his arterial oxygen content is decreased . The most likely cause of this condition is

A) anemia
Reply With Quote Quick reply to this message



Reply

Tags
Hematology-, Physiology-, Step-1-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
high yield doc sam01 USMLE Step 1 Forum 4 08-15-2012 03:35 AM
Mixed Venous Oxygen content DrSeddik USMLE Step 1 Forum 5 11-20-2011 01:19 AM
Hemoglobin Dissociation Curve Sabio USMLE Step 1 Mnemonics 4 07-26-2010 08:25 AM
Content of indirect inguinal henia! nano USMLE Step 1 Forum 10 05-03-2010 07:23 AM
Obese with HF and high glucose? Rafiq2010 USMLE Step 2 CK Forum 2 03-16-2010 10:44 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)