Mod 3 ABGs and CBGs Flashcards
Indications for ABG
- Evaluate CO2 or O2 needs
- Alterations to pH status
- Check Pt. conditions and response to therapy
- Get a gas q24h if Pt. is well at the min.
What Assessments help determine if a ABG is needed?
- initiation, change, or discontinuation of therapy
- abnormalities from other tests (like x-rays)
- history and physical indicators (onset of SOB or smoking)
Main contraindications for ABG
- Arterial graft located @ puncture site
- failing a bilateral negative modified allen’s test (check to see if there is collateral circulation)
- Pt. on any anti coagulation/thrombolytic disorder or medication
- Pt. refuses to coop
What are some relative conditions where ABGs shouldn’t be performed?
Pt with Raymond’s disease, fibroses arteries, or a large hematoma site
how do you mitigate a hematoma when performing a ABG?
What are 6 hazards of ABGs to Pts?
- hematoma/hemmorhage
- infection
- thrombosis
- arterial spasm
- laceration of blood vessels/nerves
- pain
hazards to staff when performing a ABG?
blood borne infections
Normal value for platelets?
Normal platelet count = 150 - 400 x 10E9/L
INR value ranges?
Normal value 0.9 - 1.1
- Critical values > 5
- High INR = blood is clotting slow
what is activated partial thromboplastin time (aPTT)
time for blood to clot/blood to return?
edit need to confirm
What are 3 lab values we assess from ABGs?
- Primary and secondary hemostasis (platelet count and INR)
- aPTT
- Fibrinogen (factor I in coagulation cascade)
What is the difference between a Primary and secondary hemostasis lab assessment ?
Primary observes platelet count
Secondary observes INR
What is thrombocytopenia
Decreased platelet counts
- Low platelet count causes bleeding into the tissues, bruising, and slow blood clotting after injury.
Causes of thrombocytopenia?
- Aplastic anemia (when the body stops making blood cells)
- some immune diseases, blood clotting disorders, inherited disorders or bleeding disorders.
- pregnancy.
- medications (warfarin)
- cancers, such as leukaemia, or cancer treatments including chemotherapy.
- Infection in the bone marrow.
what platelet count range is a high risk of spontaneous bleeding?
platelet count < 10 x10E9/L
key elements of a ABG
- pre assessment
- informers consent
- perform ABG
- Label and analysis
what things should you think about when performing an ABG
is the Pt. on O2? is it @ RA?
- It could affect outcome if testing home o2 viability
- PaO2 <55 on room air test
- SpO2 <88% on room air (alt if not poking)
What does INR assess vs APTT?
- INR assess extrinsic and common coagulation pathways (Tissue factor to initiate clotting)
- aPTT is used to assess the function of intrinsic or contact pathway of coagulation (artificial surface to trigger clot formation)
Causes of high INR?
- Warfarin
- Liver disease
- cephalosporin antibiotics
what are some causes of prolonged partial thromboplastin time (PTT)?
Heparin and clotting factor deficiencies
Fibrinogen normal value
Norm: 1.6 - 4.1 g/L
critical low value for fibronogin?
less than or equal to 1 g/L
what size syringes are used for ABG?
23 or 25 gauge needles for radial pokes
- they’re vented and heparnized
- heparinized prevents the blood from clotting
what is the procedure for a radial puncture?
- Verify order & Pt. Check lab results
- Examine site perform SpO2, check therapy
- Perform Allens test
- Clean site, allow to dry
- palpate site and notify Pt. prior to puncture
- puncture @ 30-45 degree angle
- Apply pressure as needle withdrawn
- vent air, make sharp safe, agitate sample
- Hold pressure until no bleeding (5 mins or longer)
need to know radial muscle
- add images from from RSV14 or look in d2l
Indications for CBG
Used as an alt access in infants and small children.
Tests for:
- pH
- PaCO2
- PO2 (SpO2 is more useful) why?*
What is a CBG?
capillary blood gas
what drugs would affect hemoptysis?
- Anticoagulants (heparin, vitamin K)
- Thrombolytics (streptase, retavase, activate)
- Platelet Inhibitors (aggrexnox, plavix, intergrilin, ASA)
What are the 4 normal lab values needed for a ABG?
- Platelet count of 150-400x10E9
- INR of 0.9-1.1
- aPTT of 27-37 seconds
- Fibrinogen of 1.6-4.1 g/L
Advantages of a radial artery
- collateral circulation
- easily accessible
- easy to palpate, stabilize, and puncture
- Not close to any major nerves
Disadvantages of radial arteries
- More likely to spasm than the fermoal
- Radial vein is located on each side of the radial artery, makes it possible to draw a venous sample
The radial artery will not likely spasm if what condition is present?
The ulnar flow is present
What is a modified allen’s test?
A test before drawing a ABG, it tests for collateral circulation (if the ulnar and radial are present)
What is the minimum length of time to hold pressure on puncture site after ABG is drawn?
5 minutes
What are calgary lab services standards for cleaning a site?
- use 70% isopropyl alcohol to pre-cleanse site for 30 seconds
- Use 2% chlorhexidine w/70% isopropyl alcohol. to cleanse site for 30 seconds prior to puncturing skin
- Allow to dry, min 1 minute. (ideally -> 2 mins)
what are the advantages of Brachial Artery Sampling?
- Less subjective to low pressure/flow problems (bc its close to heart)
- Brachial artery is large and easy to palpate
- Distal aspect of the humerus is easily accessible
Disadvantages of Brachial Arterial Sampling
- No real collateral circulation
- Deeply located under the bicep brachii muscle
- is close to the artery, meaning a miss can be painful.
what is the recommended needle size for a brachial sample?
23G x 1 inch, 25G x 5/8 inch
What angle should you insert a needle for the brachial artery?
60-90
When would you perform a femoral arterial sample?
A last resort when BP is too low for a more peripheral sample to be obtained.
Needle choice for a Femoral artery sample?
22G X 1 ¼”, 21G X 1½”, 18G X 1½’
Textbook is 21 and 18 tho
What angle should be used for a Femoral artery sample?
90
Need to add info on this, from slide 37
For Femoral arterial samples, what are the preferred needle choices?
- [22G x 1 ¼”]
- [21G X 1½”]
- [18G X 1½’]
- Longer as needed to go deeper, larger as artery is larger.
After gathering a arterial sampling, how long should you apply pressure?
A min of 5 mins, longer if needed.
Which demographic would a CBG used for?
Infants and small children
Why would you use CBGs?
- ABG analysis is needed but no access to arterial site
- non invasive monitor readings are abnormal (SpO2)
- Access initiation or change to therapy
List the structures of the following figure:
- Wrist anatomy
Tip:
- yellow = nerves
- grey = tendons
- Red = arteries
List the structures of the following figure:
- Forearm Anatomy
List the structures of the following:
- Upper arm
List the structures of the following figure:
- Forearm Anatomy
List the structures of the following figure:
- Forearm Anatomy
List the structures of the following figure:
- Forearm Anatomy
When would you monitor aptt vs INR?
- Monitor aPTT for pts on heparin, detecting lupus/liver diseases/DIC, and/or inherited bleeding disorders
- Monitor INR for pts on warfarin, detecting liver dysfunction, and assessing vitamin K deficiency or DIC
When would you monitor aptt vs INR?
- Monitor aPTT for pts on heparin, detecting lupus/liver diseases/DIC, and/or inherited bleeding disorders
- Monitor INR for pts on warfarin, detecting liver dysfunction, and assessing vitamin K deficiency or DIC
