When should you ice an ABG sample?
>15 minutes
Know how to basically tx abnormal ABG
must tx according to pt's normal.
Interpret Fully compensated Respiratory Acidosis
Chronic Ventilatory failure
Interpret Partially compensated
Acute on Chronic Ventilatory failure
Interpret No compensation
Acute Ventilatory failure (We have to fix this!!)
Compensated Respiratory Acidosis Exception to the rule
PACO2 >50 Check Cl ion=is probably low
All ways on arterial blood gas sample can be drawn?
Percutaneous puncture of a peripheral artery, from a catherter, (Arterial line), or capillary sampling
Equipment needed to properly perform an ABG?
Gloves, heparinized syringe with 20-22 gauge needle (23-25 for infants and children), Pt label, alcohol pad, sterile gauze, band-aid, puncture resistant container, sharps container, ice, needle capping device
Purpose of an ABG?
Dx/Management of Oxygenation and acid-base disturbances
What parameters should capillary gases (in infants) be used to check?
Estimates of PCO2 and pH, Cannot use for PO2
Clinical findings would you expect with Compensated respiratory acidosis?
Normal pH, increased PaCo2, increased HCO3
Complications associated with ABG puncture?
Ateriospasm, Embolus, Anaphylaxis, Hematoma, Trauma to vessel, Arterial occlusion, Vasovagal response, Pain
What are non-invasive techniques to assess gas exchange?
Capnometry, Transcutaneous monitoring, Oximetry
ABG indications?
Sudden unexplained dyspnea, cyanosis, abnormal BS, severe unexplained tachypnea, heavy use of accessory muscles, changes in ventilator settings, cardio resuscitation, diffuse infiltrates in CXR.
Know differenty types of O2 analyzers and the electrochemical principles they use?
Polarographic (Clark) mostly found in ABG analyzers, Galvanic Fuel cell (Teledyne, Biomarine) mostly foumd in handheld O2 analyzers
Preventative Maintenance
Scheduling routine part replacement and routine function (reduces machine failure and faulty analysis).
Performance validation
Proscess of testing a new instrument to ensure accuracy and precision of testing samples of known values.
Proficiency testing
Federal mandated testing for external quality control with unknown values, performed 3 times/yr with 5 samples/test.
Quick and easy way to ensure adequate circulation (Collateral)?
Positive Modified Allen's test.
What steps should you take to ensure adequate results from an analyzer?
You must first calibrate it, calibrate to 100% FiO2, calibrate to 21% (room air), analyze the FiO2.
Compensated?
Co2,HCO3 same direction with Normal pH
Uncompensated?
CO2 or HCO3 is normal with Abnormal pH
Partially Compensated?
CO2, HCO3 in same direction with Abnormal pH
pH electrode?
Sanz
PCO2 electrode?
Severinghaus
PO2 electrode?
Clark
Know what occurs with ventilation when Capnograph waveform is increasing?
PaCO2 is increasing with exhalation, Pt is Hypo-ventilating.
What occurs with PaCO2 when pt is Hypoventilating?
CO2 increases and pH decreases
What occurs with PaCO2 when pt is Hyperventilating?
CO2 decreases and pH increases
Estimate Normal PaO2 based on Pt age?
105-(0.5 x age)
ex. 105-(0.5x30)
=105-15
= 80
Mainstream?
In-line analysis between pt airway and vent circuit
Sidestream?
Continually pumps small volume of gas from circuit into a "SIDE"chamber within the device for analysis
Understand how to use and end-tidal CO2 detection devices to verify ET tube placement?
Turns yellow when we are in the trachea (YES=Yellow). Detects that the CO2 present.
How long should you hold pressure on a site after arterial stick?
Until bleeding stops @ 2-5 minutes under normal circumstances
ph normal value?
7.40
PCO2 normal value?
40
HCO3 normal value?
24
B.E. normal value?
0
Capillary Gas Values?
Provides estimates of PCO2 and pH. Cannot use for correlating PO2 levels
Arterial Gas Values?
Rapid flow of IV fluids (mainly heparin) can dilute the blood sample and affect O2 content of the blood
Pre-analytical error--Air in sample?
Increases PO2, decreases PCO2...increases pH
Pre-analytical error--Venous admixture?
Decreases PO2 significantly, increases PCO2....decreases pH
Pre-analytical error--Excess Coagulant?
Increases PO2, decreases PCO2 which increases pH because of heparin
Pre-analytical error--Metabolic affects (Fever)?
Decreases PO2, increases PCO2...decrease pH
What should be tested when a Pt has been suspected to have smoke inhalation?
COHb (Carboxyhemoglobin)
Refractory Hypoxemia
Abnormal deficiency of O2 in the arterial blood that is resistant to Tx.
Time it takes for Pts to achieve a "Steady State"?
Healthy= 5 minutes COPD pt= 20-30 minutes
Trouble-shoot a Galvanic Fuel Cell O2 analyzer?
Replace fuel cell first --if still not working-then replace sensor
Collateral circulation?
Ensures that if there is damage to the radial artery, there will be effective blood flow from the ulnar artery to supply the hand with adequate blood flow
Site of choice for ABG?
Radial artery, newborn umbilical artery line
What is the time frame on ABG will remain accurate after puncture?
1 hr
What procedures for drawing blood gases require arterialization before draw?
Capillary sampling and Transcutaneous monitoring.
Transcutaneous monitoring sites?
Abdomen, chest, and lower back (avoid burns by rotating regularly q 2-6hrs.
Modified Allen's Test
Make fist and pressure is applied to the unlnar and radial arteries, open hand exposing blanched palm and fingers, removing pressure on the ulnar artery should result in flushing of the hand.