CCMDB Wiki

AaDO2: Difference between revisions

← Older edit
TOstryzniuk (talk | contribs)
CCMDB_legit, approved, Bureaucrats, Administrators
27,522 edits
mNo edit summary
m Text replacement - "[[Category: " to "[[Category:"
 
(33 intermediate revisions by 6 users not shown)
Line 1: Line 1:
AaDO2 - Alveolar-arterial oxygen tension difference
{{Data element
 
|field_name=AaDO2
|CCMDB_label=<not in CCMDB>
|CCMDB_tab=Apache
|data_type=number
|datafield_length=N/A
|program_collecting=CC
|created_raw=Created
|data_element_sort_index=34
|element_description=The patient's  {{#show: AaDO2 | ?AP phys name}} level in {{#show: AaDO2 | ?AP phys unit}}.
}}
'''AaDO2 - Alveolar-arterial oxygen tension difference
'''
*See [[APACHE Scoring table]]
*See [[APACHE Scoring table]]
*See [[FiO2 |APACHE FIO2 Table]]
*See [[FiO2 |APACHE FIO2 Table]]
Line 9: Line 20:


*To calculate the AaDO2:  
*To calculate the AaDO2:  
**'''AaDO2 =(([[FiO2 | FIO2]] X 713) - [[PaO2]]) - [[PaCO2]]'''
**'''AaDO2 =(([[FiO2 | FIO2]] X 713) - [[PAO2]]) - [[PACO2]]'''
 
 
**Example with FIO2 50%, PO2 85 and CO2 40:
**Example with FIO2 50%, PO2 85 and CO2 40:
**231.5 = ((0.5 X 713)- 85) - 40))
**((0.5 X 713)- 85) - 40)) = 231.5


{{APACHE physiological variable
|AP phys name= Alveolar-arterial oxygen tension difference
|AP phys unit=
|AP H4= >500
|AP H3= >=350 and <500
|AP H2= >=200 and <350
|AP 0= <200
}}


*if FIO2 being administered to a patient is <=49%, select the ABG with the WORST PO2.
==Background ==
*if FIO2 being administered to a patient is >=50%, select the ABG result with the WORST [[AaDO2]].
=== Why the constant 713? ===
*For APACHE II, select the ABG (arterial blood gas) with the WORST AaDO2 or the WORST PO2, which ever one gives you the highest[[APACHE Scoring table | APACHE II points]] in the first 24 hrs of ICU admission.  
The value 713 mmHg is the barometric pressure (Pb) used in the AaDO2 formula.  


Normal Sea level Pb is 760 mmHg. (Winnipeg is close to sea level. We don't adjust for different elevations around the city nor do we adjust this value for the constant changes in Pb).


The barometric pressure is corrected for water vapor pressure (Pbc).
*(vapor pressure is 47 mmHg @ a temperature of 37C).
*(760-47)= Pbc of 713 mmHg.


=== can be less than 0 ===
=== *4 AaDO2 can be 0 or negative===
Unlike other physiological variables AaDO2 can be 0 or negative, so unlike the others the score for a 0 AaDO2 is 0 if AaDO2 < 200, which includes AaDO2<=0.


NOTE: I put this detail here because I get asked this time an again.
Note for programming only: The score is still null if the AaDO2 is null. <!-- Julie and Tina discussed 2021-09-29 - there really should never be a null because [[cross check]]s would catch this, but if there every is, this is as good as any solution. -->
*the value 713 mmHg is the barometric pressure (Pb) used in the AaDO2 formula.
*Normal Sea level Pb is 760 mmHg. (Winnipeg is close to sea level.  We don't adjust for different elevations around the city nor do we adjust this value for the constant changes in Pb).
*The barometric pressure is corrected for water vapor pressure (Pbc).
*(vapor pressure is 47 mmHg @ a temperature of 37C).
*(760-47)= Pbc of 713 mmHg.
 
*[[User:TOstryzniuk|TOstryzniuk]] 20:25, 8 January 2009 (CST)


== Data Integrity Checks ==
{{Data Integrity Check List}}


[[Category: APACHE II]]
[[Category:ABG]]
[[Category:APACHE II]]
Retrieved from "https://ccmdb.kuality.ca/index.php?title=AaDO2"