# Intensive Care Nursing/Arterial Blood Sampling

Arterial Blood Gas Sampling Process
The collection of blood from an arterial cannula closed system.
Clinical Noteː Arterial lines are for sampling only, no medications are to be administered (ensure arterial line labelled to prevent incorrect use).
Indications For Sampling:
* Determine acid/base balance, electrolytes, Haemoglobin, glucose levels
* Blood test analysis
* Measurement of respiratory gases on analysis of respiratory or ventilator changes
* Assess the response of therapeutic interventions (such as electrolyte replacement, glucose or insulin administration)
Contraindications:
* Rationale for sampling needs to be determined to prevent unnecessary levels of sampling and loss of blood.
* If checking respiratory gases after ventilation change, ensure an appropriate time period has elapsed (15-20 minutes or follow your unit policy).
* Legal and professional issues, such as consent or when practice limitations are in place.
Arterial Blood Gas Sample Process:
| Equipment | Gloves & Apron Eye protection Sterile dressing pack Chlorhexidine/Alcohol swabs × 4 Syringes 5mL syringe for clearing line Pre-heparinised arterial blood gas syringe for analysis Appropriate blood sample bottles and request forms (see below for order of draw) Leur-lock cap x 2 |
| Procedure | Check patient identification and obtain consent if appropriate. Perform hand hygiene. Prepare equipment. Silence arterial alarm, other monitoring to continue. Perform hand hygiene. Apply gloves, apron and eye protection. Check three way tap is closed to port. Remove cap from transducer three way tap and clean with chlorhexidine/Alcohol swab. Attach 5ml syringe. Turn three way tap to artery and port. Depending on closed system port. Clean sample port, or remove cap from sample three way tap and clean with chlorhexidine/alcohol swab. Connect blood gas syringe to the port. Turn three way tap on to artery and port. Slowly remove the recommended amount for sample. Remove blood gas syringe and expel air bubbles (into gauze if required). Mix the sample to dissolve the heparin (gentle inversion process). If required other blood sampling can be taken at this point (see below for order of draw). Turn three way tap to open to port (flush side) by squeezing the transducer actuator. Clean with chlorhexidine/alcohol swab and apply sterile leur-lock cap. Turn three way tap to open to artery, flush line gently by squeezing the transducer actuator. Ensure arterial line monitor is on. Analyse or send to blood gas analyser. |
| Order of Draw | Always follow local policy and guidance on order of drawː Blood cultures Coagulation Serum samples (serology and chemistry tests) Other sampling, such as ammonia levels Haematology and blood typing, cross-matching and antibody screen |
References:
* AAGBI Safety Guideline: Arterial line blood sampling: preventing hyoglycaemic brain injury
* Dougherty, L., & Lister, Sara. (2015). The Royal Marsden Manual of Clinical Nursing Procedures (9th ed.). Hoboken: Wiley
* Order of Draw for Multiple Tube Collections – Quest Laboratories
Note:this is not a formal guide or competency checklist for performing an arterial blood sample from a closed system
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