Obtaining Arterial Blood

1. Obtaining Arterial Blood First Year Respiratory Care RsCr 224

2. Prior to Obtaining Sample Check patients chart for The order Is the patient receiving anti-coagulants or thrombolytics? What is the current oxygen order? If a recent FIO2 change has occurred, you must wait 5-10 minutes before performing the puncture. With COPD patients wait 20-30 minutes!

3. Ways to Obtain Arterial Blood Radial Puncture Brachial Puncture Femoral Puncture Arterial Line Draws

4. Radial Site Near the surface Best chance of collateral circulation No large veins nearby Not too painful

5. Perform the Allen’s Test Prior to Radial Puncture Tests for adequate collateral circulation Results can assist in determining which radial artery to use - left versus right Have patient make a fist while you tightly squeeze both the radial and ulnar arteries; Let go of the ulnar and watch to see if hand is uniformly re-perfused (pinks up). If large areas remain pale - check the other hand.

6. Have Patient Make a Fist While You Occlude Both Arteries

7. Have Patient Open Hand While Pressure Is Maintained

8. Let Pressure Off of Ulnar Artery Only While Observing Hand

9. Steps in Performing Arterial Puncture Choose site - Radial is first site of choice Don gloves & clean site using Betadine &/or alcohol pad Prepare syringe - position gauze for holding the site after puncture is completed Palpate site; make sure bevel of needle is pointing up & needle is parallel to artery. Insert needle slowly at a 45 degree until blood enters the hub of the needle

10. Issues in Arterial Puncture Blood will enter syringe automatically because it is under pressure Arterial blood is generally brighter red than venous blood It is best to obtain a 1 - 2 ml of arterial blood. (Most blood gas machines can give accurate blood gas values with a sample of low as 0.2 ml of arterial blood.)

11. Handling Syringe after Puncture Expel any air present using care not to splatter blood Insert exposed needle into “rubber block” or “wax cap”. DANGER! Do NOT re-cap needle! Mix blood by rolling syringe between fingers and turning it upside down

12. Post-puncture Issues Upon needle removal, immediately hold site with pressure using gauze for 5 - 10 minutes. Inspect site to assure bleeding has stopped. Band-aid is optional Ice sample unless it is to be run immediately Note patient’s FIO2 and temperature

13. Complications of Arterial Puncture Arteriospasm Air or clotted blood emboli Hematoma at site Hemorrhage Pain Inadvertent needle stick Trauma to artery or nerve Loss of feeling below puncture site

14. Characteristics of Arterial Blood Gas Values A standard blood gas machine actually measures only the following values PO2; PCO2; pH The following values are calculated by the machine; SO2% (saturation); HCO3; Base Excess A special blood gas machine called a CO-oximeter actually measures oxygen saturation; carbon monoxide saturation and hemoglobin levels

15. ABG Analyzation Errors Air in Sample – See bubble in syringe Increases PO2, decreases CO2 Venous Blood – See dark, slow filling Much lower oxygen levels Lower pH and higher carbon dioxide levels Sample sits too long – 30 min without ice Higher carbon dioxide Lower pH and oxygen levels

16. Indwellling Arterial Catheters Used to measure blood pressure and to obtain blood samples Peripheral catheters used to measure systolic blood pressure and to obtain arterial blood samples Central catheters used to measure heart pressures & to obtain “mixed venous blood”

17. Example of Peripheral Catheter

18. Hazards of Indwelling Catheters Infection Thrombus formation on catheter Damage to artery on insertion

19. The End! Now go for it