Arterial blood gas (APACHE)
This article is about collecting the value for APACHE, see Arterial blood gas (labs) for labs collection.
This article is about ABGs (Arterial Blood Gas) for APACHE.
Collection Instructions
Enter available blood gases following usual APACHE physiological variable collection instructions (worst ones only if you are sure) into the #ABG Helper in CCMDB.accdb's APACHE tab. Pick the ABG that has the highest score.
All arterial blood gas results (FiO2, PO2, CO2 & PH) must be from the same specimen.
An ABG result is preferred, but if no ABG available during the first 24 hours in ICU then select the worst Serum CO2. Do not use venous gases.
IF FiO2 ≤ 49% - Base the selection of the worst ABG on the worst PO2.
IF FiO2 ≥ 50% - Base the selection of the worst ABG on the worst AaDO2 (you can use the #ABG Helper to help determine this.
ABG Helper
There is an ABG helper in the CCMDB.accdb, opened with the ABG Helper button. You can enter two or more blood gas values and the program will show the number of APACHE points each value generates, whether it is the PO2, AaDO2 or the pH. Choose the individual blood gas that gives the most APACHE points. Only one complete blood gas can be used; do not pick a pH from one blood gas and other values from another blood gas.
ABGs as part of apnea tests
There was confusion whether ABGs done as part of apnea tests should be included since they are as part of an intervention, and we should not use iatrogenically changed values. We will include these because any poor/high scoring results are a reflection of the patient's neurological status when we take away the support of the ventilator. It is a more accurate reflection of the patient's status than the ABG's we take when we are controlling the patient's minute ventilation.
ABG Scoring for APACHE
- If no ABG
- apply score only for the SerCO2
- ignore pH component
- else (ie. ABG present)
- apply pH score
- if FIO2 >= 50
- apply worst AaDO2 score
- else (ie FIO2 < 50)
- apply worst PO2 score