ABG DEFINITIONS

While in the PH and rotary wing transport environments, it is rare to obtain an ABG – knowing the normal values is important to check a patient prior to Role 2 to Role 3 RW transport. The ABG is extremely useful in trauma resuscitations because the pH, lactate and base deficit will give an overall picture of perfusion.

1. pH: Measure of hydrogen ion concentration (i.e. acid-base status). Acidosis (low pH) leads to coagulopathic states in trauma patients as well as development of potentially fatal cardiac arrhythmias.
2. PaO2: Measurement of dissolved oxygen in blood, also a measurement of adequacy of gas exchange at the cellular level.
3. PaCO2: Measurement of dissolved carbon dioxide in blood, also a measurement of adequacy of gas exchange at the cellular level.
4. HCO3: Measurement of bicarbonate in the blood, serves as a buffer against acid.
5. Base excess: Gives indication of metabolic component of blood gas results, most likely will not change field ventilator management but can provide information for telemedicine consultation regarding adequacy of resuscitation.
6. SaO2: Percentage of oxygen bound to hemoglobin in arterial blood, correlates closely with SpO2 values.