Arterial Blood Gas Review Flashcards
What should be the first choice for ABG draws?
Other arteries? 2
- The radial artery is superficial, has collaterals and is easily compressed
It should be the first choice - Other arteries:
- femoral,
- brachial
What test should you do to make sure the pt has collateral cicrulation before doing ABGs?
Allen test
ABGs: Performing the Procedure
12
- Put on gloves
- Prepare the site (Drape the bed and cleanse the radial area with alcohol)
- Position the wrist (hyper-extended, using a rolled up towel if necessary)
- Palpate the arterial pulse and visualize the course of the artery
- Open the ABG kit
- Line the needle up with the artery, bevel side up
- Enter the artery and allow the syringe to fill spontaneously
- Withdraw the needle and hold pressure on the site
- Protect needle
- Remove any air bubbles
- Gently mix the specimen by rolling it between your palms
- Place the specimen on ice and transport to lab immediately
What an ABG measures and the normal range? 5
- pH (7.35-7.45)
- CO2 (35-45 mmHg)
- O2 (83-102 mmHg)
- HCO3 (22-28 mmol/L)
- Anion gap (10-16 mmol/L)
Acidosis can cause what?
- Decreased force of cardiac contraction
- Decreased vascular response to catecholamines
- Decreased response to the effects and action of certain medications
Alkalosis can interfere with
what body functions? 3
- Tissue oxygenation
- Neurological and
- muscle function
Oxygen-Hgb Dissociation
- Hemoglobin transports what?
- Alterations in homeostasis will affect the rate of what?
- oxygen
2. unloading of the oxygen from the hemoglobin
- PO2 of the aterial end of the capillary?
2. PO2 of the venous end of the capillary?
- 95 mm/Hg
2. 40 mm/Hg
What controls pH?
5
- Diet
- Metabolic production of CO2
- Regulation through the GI tract
- Influence of other electrolytes
- BUFFERS
Acid/Base Balance
1. pH describes what?
- pH is inversely proportional to the what?
- Normal range?
- = how acidic or alkaline the blood is
- H+ concentration
- 7.35-7.45
3 systems maintain body pH
- Chemical buffering
- The respiratory center
- The kidneys
What substances are involved in chemical buffering? 3
- Carbonic acid
- Phosphate
- Plasma proteins
The carbonic acid buffering system is the main buffer
- Whats the equation?
- CO2 is a byproduct of what?
- CO2 is best trabsported as?
- As the CO2 increased so does the what?
- The higher the H+ (or CO2) the ______ the pH?
- H2O + CO2 ↔ H2CO3 ↔ HCO3- + H+
- CO2 is a by product of cellular metabolism
- CO2 is best transported as HCO3-
- As the CO2 increases so does the H+ concentration
- lower
The respiratory buffer
1. Concentrations of what will trigger the respiratory center?
- What will be altered to either increase or decrease ventilation? 2
- This response occurs in what amount of time?
- CO2,
- carbonic acid
- HCO3
- Respiratory rate
- tidal volume
- 1-3 minutes
THE RENAL BUFFER
1. The kidneys can excrete either acid or alkaline urine, thereby adjusting what?
- How do they do this?
- This response takes place over what timeline, but represents a more powerful regulatory system?
- the pH of the blood
- Excrete or retain HCO3- and H+
- hours or even days
Physiological Buffer Systems
- Chemical buffer systems occur how quickly?
- Respiratory and renal systems: Describe the rate and capacity of these compared to the chemical buffer system?
- almost immediately
- Act more slowly than chemical buffer systems
- Have more capacity than chemical buffer systems