Blood gas analysis, also called ABG analysis is a procedure to measure the partial pressure of oxygen and carbon dioxide gases and the pH (hydrogen ion concentration) in arterial blood.
Purposes
- To diagnose and evaluate respiratory diseases and conditions.
- To evaluate metabolic conditions that cause abnormal blood pH, for example, diabetic ketoacidosis.
- To monitor children on 02 therapy, for example, premature infants.
- To monitor the levels of arterial CO, and 02 in children with artificial ventilation.
Sites
- Radial artery
- Brachial artery
- Dorsalis pedis artery
- Femoral artery (only in emergency)
- In neonate’s capillary blood samples may be used
- Arterial line after flushing the line to remove excess anticoagulant and fluid
Preparation
- Psychological preparation should be appropriate to the child’s age.
- A parent may be encouraged to restrain the child during sample collection.
- For children receiving 02 therapy, the 02 concentration must remain constant for 20 minutes before sample collection.
- If the test is specifically ordered without 02, the gas may be turned off for 20 minutes before the blood sample is taken to guarantee accurate test results.
Equipment
- Anticoagulate sterile syringe with needle
- Waste syringe (for 3 mL of waste) if arterial line draw
- Patient label and laboratory collection slip
- Antiseptic solution
- Gauze pieces
- Pair of sterile gloves
- Protective eye wear and gown in the anticipation of splashing
- Container with ice deep enough to immerse syringe beyond the level of specimen
Procedure
- Perform hand hygiene and don gloves and gown.
- Perform Allens test (both the radial and ulnar arteries should be compressed at a level approximately 1cm proximal to the wrist joint while the patient hand is squeezed for approximately 5 seconds then released. The palmar surface of the hand should be blanched. Release the compression on the ulnar artery.it is normal for the palmar surface to flush within 5 seconds). prolonged delay before flushing indicates decreased ulnar artery flow.
- The skin over the puncture site is cleaned with an antiseptic solution.
- Palpate the site to stabilize the artery. Slight hyperextension of the joint can be achieved by placing a rolled-up towel under the joint, this can aid the palpation and stabilization of the artery.
- Hold the syringe with the bevel of the needle upward, keeping the needle at a 25-45° angle to the artery.
- Insert the needle through the skin into the artery taking care not to puncture the posterior wall of the artery. If the artery is not entered immediately, the needle may be slightly pulled then redirected into the artery.
- Arterial pressure should cause the blood to flow into syringe.
- Withdraw the needle when an adequate sample has been obtained.
- Immediately place dry gauze or cotton over the puncture site and apply pressure.
- Single handedly cap the needle then remove from syringe.
- Expel any air bubble from the sample and cap the syringe.
- Mix the sample by rolling and tilting syringe.
- Place a sterile bandage over the puncture site to keep it clean.
Technique for Obtaining Sample from Arterial Line
- Turn the stopcock off to patient.
- Remove the sterile cap from stopcock.
- Attach sterile syringe to stopcock.
- Open stopcock to syringe and intra-arteria catheter and obtain ABG sample.
- Activate flush device to clear arterial line.
- Turn stopcock off to the patient and flush side port of the stopcock into sterile syringe until all blood is cleaned from stopcock.
- Close stopcock and replace sterile protective
сар. - Prepare arterial sample by holding syringe upright and remove air bubbles.
- Immediately seal syringe with cap. Roll and tilt syringe gently to ensure heparin mixing.
Aftercare
- Timely and appropriately transport the sample for analysis.
- After the blood sample has been taken, apply pressure to the site for about 10 minutes or until bleeding has stopped after which a dressing is applied.
- Make the child to be calm and quiet.
- Observe for signs of bleeding or impaired circulation at the puncture site.
General Instructions
- Follow standard precautions for prevention of exposure to blood-borne pathogens when performing arterial blood collection.
- The syringe used to collect the sample for a blood gas analysis must contain a small amount of heparin to prevent clotting of the blood.
- The air must be excluded from the syringe both before and after the sample is collected.
- If radial artery is lacking collateral ulnar circulation, it should be avoided as puncture site.
- For transportation, the syringe should be capped with a blind hub, placed on ice, and immediately sent to the laboratory for analysis to guarantee the accuracy of the results.
- If not analyzed immediately, store the sample in ice (2-4°C).
- Never attempt femoral artery puncture in neonates.
REFERENCES
- Annamma Jacob, Rekha, Jhadav Sonali Tarachand: Clinical Nursing Procedures: The Art of Nursing Practice, 5th Edition, March 2023, Jaypee Publishers, ISBN-13: 978-9356961845 ISBN-10: 9356961840
- Omayalachi CON, Manual of Nursing Procedures and Practice, Vol 1, 3 Edition 2023, Published by Wolters Kluwer’s, ISBN: 978-9393553294
- Sandra Nettina, Lippincott Manual of Nursing Practice, 11th Edition, January 2019, Published by Wolters Kluwer’s, ISBN-13:978-9388313285
- Marcia London, Ruth Bindler, Principles of Paediatric Nursing: Caring for Children, 8th Edition, 2023, Pearson Publications, ISBN-13: 9780136859840.
- Ernstmeyer K, Christman E, editors. Nursing Fundamentals [Internet]. 2nd edition. Eau Claire (WI): Chippewa Valley Technical College; 2024. PART IV, NURSING PROCESS. Available from: https://www.ncbi.nlm.nih.gov/books/NBK610818/
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