Arterial Blood Gas Sampling
Posted: Friday, August 27th, 2021 | Updated: Sunday, January 15th, 2023
Posted: Friday, August 27th, 2021 | Updated: Sunday, January 15th, 2023
The Process For Sampling Arterial Blood
1. Prepare your blood analyzer machine for processing the arterial blood
2. Using a syringe, 1 ml or 3 ml, attach a 25 gauge needle to the end. Coat the syringe with a small amount of sodium heparin only leaving a small amount remaining in the hub of the needle. Alternatively, you may use an arterial blood gas syringe. These syringes are vented and contain anticoagulant. Therefore, you must pull the plunger back to the desired volume of blood prior to sampling. The blood will automatically fill in this type of syringe
3. The dorsal pedal arteries are often used for drawing a blood gas sample, however, the femoral and lingual arteries may be used as well. Palpate the pulse generated from the desired artery using two fingers
4. Clip and clean the location where you’ll be taking the sample. You may infuse a small amount of local anesthetic such as lidocaine around the site of puncture to decrease any pain associated with sampling
5. With gloves, locate the pulse again. Once you are sure on where you’ll be sticking, insert the needle at a 45 or 90 degree angle to where you feel the pulse
6. Once you enter into the artery, a flash of blood will enter into the hub of the needle. If you are using a vented syringe, the blood will automatically fill to the desired volume
7. After obtaining your sample, withdraw the needle and apply pressure to the site for about five minutes. It’s easiest to use a pressure wrap for this purpose
8. Monitor the site for any bleeding or hematoma formation. Pressure may be needed longer on the site if this occurs
9. Any air must quickly be removed from the syringe and the needle must be capped with a rubber stopper or in a way that no air is let in
10. Run the sample as soon as possible. Samples run after 20 minutes are likely to show increases in pCO2 and decreases in pH. Alternatively, the sample may be placed in an ice water bath for up to 2 hours, but this is not ideal
1. Prepare your blood analyzer machine for processing the arterial blood
2. Using a syringe, 1 ml or 3 ml, attach a 25 gauge needle to the end. Coat the syringe with a small amount of sodium heparin only leaving a small amount remaining in the hub of the needle. Alternatively, you may use an arterial blood gas syringe. These syringes are vented and contain anticoagulant. Therefore, you must pull the plunger back to the desired volume of blood prior to sampling. The blood will automatically fill in this type of syringe
3. The dorsal pedal arteries are often used for drawing a blood gas sample, however, the femoral and lingual arteries may be used as well. Palpate the pulse generated from the desired artery using two fingers
4. Clip and clean the location where you’ll be taking the sample. You may infuse a small amount of local anesthetic such as lidocaine around the site of puncture to decrease any pain associated with sampling
5. With gloves, locate the pulse again. Once you are sure on where you’ll be sticking, insert the needle at a 45 or 90 degree angle to where you feel the pulse
6. Once you enter into the artery, a flash of blood will enter into the hub of the needle. If you are using a vented syringe, the blood will automatically fill to the desired volume
7. After obtaining your sample, withdraw the needle and apply pressure to the site for about five minutes. It’s easiest to use a pressure wrap for this purpose
8. Monitor the site for any bleeding or hematoma formation. Pressure may be needed longer on the site if this occurs
9. Any air must quickly be removed from the syringe and the needle must be capped with a rubber stopper or in a way that no air is let in
10. Run the sample as soon as possible. Samples run after 20 minutes are likely to show increases in pCO2 and decreases in pH. Alternatively, the sample may be placed in an ice water bath for up to 2 hours, but this is not ideal
Blood Gases
When obtaining an arterial blood sample, the SaO2 or oxygen saturation of arterial blood samples should be greater than 90% in most patients. This correlates to having a PaO2 of greater than 60 mmHg. Some patients who are severely hypoxemic may have values as low as 80%. Arterial blood gases are used to monitor the patient's oxygenation and ventilation. See Blood Gas Evaluation for more information
When obtaining an arterial blood sample, the SaO2 or oxygen saturation of arterial blood samples should be greater than 90% in most patients. This correlates to having a PaO2 of greater than 60 mmHg. Some patients who are severely hypoxemic may have values as low as 80%. Arterial blood gases are used to monitor the patient's oxygenation and ventilation. See Blood Gas Evaluation for more information
Sources:
Ford, Richard B., and Elisa M. Mazzaferro. Kirk and Bistner's Handbook of Veterinary Procedures and Emergency Treatment. 8th ed., Saunders Elsevier, 2006.
Sidari, Heather Ann. "The Veterinary Nurse's Role in Reading Blood Gases." Today's Veterinary Nurse. Summer 2021.
Snyder, Katherine. "How to Obtain Arterial Samples for Blood Gas Analysis." DVM 360, 1 Nov. 2009, www.dvm360.com/view/how-obtain-arterial-samples-blood-gas-analysis.
Ford, Richard B., and Elisa M. Mazzaferro. Kirk and Bistner's Handbook of Veterinary Procedures and Emergency Treatment. 8th ed., Saunders Elsevier, 2006.
Sidari, Heather Ann. "The Veterinary Nurse's Role in Reading Blood Gases." Today's Veterinary Nurse. Summer 2021.
Snyder, Katherine. "How to Obtain Arterial Samples for Blood Gas Analysis." DVM 360, 1 Nov. 2009, www.dvm360.com/view/how-obtain-arterial-samples-blood-gas-analysis.