2. Venous Blood Gas Sampling Flashcards
Who are Venous Blood Gas Samples taken from?
- Critically Ill Patients
2. Deteriorating Patients
How often are Venous Blood Gas Samples taken?
On a Daily Basis
Why are Venous Blood Gas Sample Taken?
- To Assess Levels of
a) Carbon Dioxide
b) pH
c) Bicarbonate - To Screen for Systemic Acidosis
What is Venous Blood Gas Samples not taken for?
Assessing Patient’s Oxygenation
What is the name of the Machine which Analyses the Venous Blood Gas Samples?
Blood Gas Analyser
What can Blood Gas Analysers also measure?
- Electrolytes
- Glucose Levels
- Serum Lactate
Where is the Sample Obtained from? (Site)
- A Peripheral Catheter (IV Cannula)
2. PICC
When can Venous Blood Gas Samples be Obtained from a Peripheral Catheter ((IV Cannula)?
Immediately After Placement is Complete
What are the Indications for Obtaining a Venous Blood Sample in a Critically Ill / deteriorating Patient?
- Determine the Acid - Base Balance (e.g. Pericardiac / Respiratory Arrest, Diabetic Ketoacidosis)
- Determine the Electrolyte Levels
- Are there special “Arterial Blood Sampling Kits” available?
- What is special about them?
- Yes
- The syringe is pre-filled with the required amount of Heparin - to prevent clotting
Note - The Heparin is not normally seen but is there
If an “Arterial Blood Sampling Kit” is not available, what is the procedure?
- 1mL of 1000 micrograms/mL of Heparin is Drawn into a Syringe
- The Heparin is completely expelled, leaving a very small amount of Heparin in the Hub
- The Needle is Changed to a fresh 25 Gauge Needle
How much Heparin is required for the 2-3mL Blood Sample taken?
0.2mL - This is what will remain in the Hub of the Syringe
Are Tourniquets used in the Venous Blood Sampling procedure?
No
What needs to happen if the Venous Blood Gas Sample will not be Analysed, by the Blood Gas Analyser, for 30 minutes or more?
- The Cap is Securely Fitted
- The Sample is Labelled with:
a) Patient’s Details
b) Time and Date of the Sample
c) FiO2 at the time of Sampling - The Syringe is placed in a Biohazard Bag and sealed
- The Biohazard Bag is placed in Ice
In Clinical Practice, are Venous Blood Samples always taken from an IV Cannula, which has just been Inserted?
No, Veins from Phlebotomy may be Accessed
What are the Site Specific Contraindications?
- Presence of an A-V Fistula
- Cellulitis, Broken Skin, or Other Signs of Infection
- No Palpable Vein
- Fractured Limb
How is the Risk of Discomfort / Pain Reduced?
Careful Consideration of Drawing in an Emergency from an IV Cannula just Inserted
What do you need to know in order to interpret results?
- Inspired Oxygen Concentration at the time of Sampling
2. Pulse Oximetry Values
What must not be present in the Syringe, with the sample?
- Air Bubbles
2. They will Potentially Change Sample Results - Falsely increase PaO2
What needs to happen to the Heparin in the Sample, to Prevent Clotting?
It Needs to be Mixed through
What should the Procedure Documentation Contain?
- Indication for the Procedure
- Type of Equipment used
- The Location of the IV Cannula used
- Patient’s Response to Procedure
- Informed Valid Consent Was Obtained (if possible)
- Date and Time of Procedure
- Patient’s FiO2 at time of Sampling
- Pulse Oximetry Values
- Results of the Investigation
- Any Complications or Problems
How is the Risk of Infection Reduced?
Strict Aseptic Non-Touch Technique with Equipment and IV Cannula Access is used
How is the Risk of Fear / Anxiety Reduced?
- Explaining the Procedure to the Patient
2. Reassuring the Patient througout
How is the Risk of an Air Embolus Reduced?
By Removing the Air from the Syringe Prior to a Puncture
What Equipment is Required for Venepuncture and an IV Cannula Insertion?
- Clean Tray with A Sharps Container
- Orange Clinical Waste Bag
- Alcohol Based Hand Gel
- Gloves and Apron
- Several Alcohol Swabs or Alternative Agent
- Heparinised Arterial Blood Gas Syringe
- Primed Add-On Device if not Replacing White Cap
- Appropriate Speciment Request Form / Bag (if the sample is being sent to the Lab)
- Sticker with the Patients Details
- 5mLs 0.9% Sodium Chloride in Water
- What is the First Step of Obtaining a Venous Blood Gas Sample from an IV Cannula?
- Why?
- Identifying the Patient (First / Surname, DoB against the Patient I.D. Badge)
- To Ensure that you are performing the procedure on the correct patient - Patient Saftey
- Once you have Identified the right patient, What must you do?
- Why?
- Understand and Explain Indications for the Procedure:
a) What Will Happen
b) Positive Outcomes / Expected Outcomes
c) Possible Unexpected Outcomes / Possible Complications - a) To inform the patient and reduce stress / anxiety
- b) Must have valid informed consent to do an invasive procedure
Once the patient has had the procedure explained to them, what must you do next?
Obtain and Document Informed Valid Consent
