Chapter 19 study guide Flashcards
what is the difference between invasive& noninvasive analyzing monitoring?
Invasive requires inerstion of sensor or collection device into body - more accuracy but greater risk
Noninvasive monitering is means of gathering data externally
what are the sites for arterial puncture and the preferred site?
Brachial artery
Radial Artery
Femoral Artery
Dorsalis Pedis
radial artery is preferred
indications for blood gas sampling
Evaluate ventilation, acid base balance, oxygenation status & oxygen carrying capacity of blood
Assess the patient’s response to therapy or diagnostic test
To monitor the severity & progression of a documented disease process
Complications of ABG puncture
Arteriospasm
Hemorrhage
Air or clotted blood emboli
Trauma to the vessel
Anaphylaxis from location anesthetic
Patient or sampler contamination
Vasovagal response
Hematoma
Pain
what are the supplies needed for percutaneous arterial blood sampling of an adult?
barrier protection (gloves/safety goggles)
Preheparinzied blood gas kit syringe (1-3mL)
Short bevel 20- to 22-gauge needle with a clear hub (23- to 25- gauge for children/infants)
Isopropyl alcohol (70%), povidone-iodine(Betadine)
Sterilize gauze squares, tape, bandages
puncture resistant container
ice slush, depending upon the analyzer
towels, sharp container, local anesthetic, & needle capping device
What do you check in a chat/medical record prior to an arterial puncture and invasive procedure involving blood sampling? (safety precautions for clinician&patient)
past medical history, medications, age, medications
Describe Modified Allen’s test meaning
Done before an arterial puncture to ensure collateral circulation of the hand
Describe safe handling of a used needle
never recap a used needle without a safety device
Never handle a used needle using both hands
Never point a used needle toward any part of the body
Never bend, break, or remove a used needle from syringes by hand
Always dispose of used syringes, needles, & other sharp items in appropriate puncture resistant sharps containers
Levels for Oxygen?
95%
Levels for pH (hydrogen levels in blood)
7.35-7.45 mmHg
Levels for partial pressure of carbon dioxide (PaCO2 associate to lung)
35 - 45 mmHg
Levels for Bicarbonate (HCO3 - associate to kidneys)
22 - 26 mEq/L
Acid-Base Status
pH , CO2, HCO3-
Levels for mild hypoxemia
60 - 79 mmHg
Levels for Moderate hypoxemia
40 - 59 mmHg
Levels for severe hypoxemia
<40mmHg
Oxygenation Status
PaO2
Low Oxygen Level is termed as?
hypoxemia
Can hyperventilation (unsteady breathing) cause changes in ABG results while doing the procedure?
What is the time to return to steady states for healthy lungs & lung disease?
Pre-analytic errors associated with arterial blood
occurs before sample analysis
obtaining samples anaerobically (with immediate expulsion of air bubbles) using proper anticoagulated syringes made of low diffusibility material, & prompt sample analysis using properly function equipment
Pre-analytic error associated with air in sample
pH increases
PCO2 decreases
PO2 increase or decrease towards 150 mmHg (room air)
recognize : visible bubbles or froth
avoid : fully expel bubbles, cap sample quickly then mix sample
Pre-analytic error associated with excess anticoagulant
pH decreases
PCO2 decreases towards 0 mmHg
PO2 increases or decreases towards 150 mmHg
recognize : visible heparin remains in syringe before sampling
avoid: use premade lyophilized(dry) heparin blood gas kits
Pre-analytic error associated with venous admixture
pH decreases
PCO2 increases
PO2 decreases
recognize: failure of syringe to fill by pulsations (veins do not pulsate)
avoid: avoid brachial & femoral sites, do not aspirate & used a short bevel needle
do not “overshoot” crosscheck with SpO2%
Pre-analytic error associated with metabolic effects
pH decreases
PCO2 increases
PO2 decreases
recognize : time lag since sample was collected
avoid: analyze within 15 minutes & place sample in slush (iced to prevent metabolizing)
what is the recommended time for analysis of arterial blood?
within 10-15 minutes no later than 30 minutes
what is the amount of blood required for arterial sampling?
Volume of 0.5 - 1ml of blood
actual depends on anticoagulant used
requirements of specific analyzer used
whether or not other test will be performed on obtained sample
what should be charted/recorded once an arterial puncture has been completed?
Date, time & site of sampling
Results of the modified Allen test
Patient’s body temp, position, activity level, & respiratory rate
Type & level of O2 supplementation & all applicable ventilatory support settings
what is the advantage of point of care testing?
bedside non invasive
define the purpose of transcutaneous monitoring & gases monitored ; is it invasive or noninvasive?
Noninvasive
The need to monitor continuously the adequacy of arterial oxygenation or ventilation
The need to quantify the real time responses to disgnostic & therapeutic interventions, as evidenced by PtcO2 or PtcCO2 values
define capillary blood gases (CBG)
Reflect & provide clinically useful estimates of arterial pH & PCO2 levels
Indications for CBGs
ABG analysis is indicated, but arterial access is unavailable
Noninvasive monitor readings are abnormal
assessment of initiation, administration, or change in therapy is indicated
A change in patient status is detected by history or physical assessment
Monitoring the severity & progression of a documented disease process is desirable
Common sites for transcutaneous monitoring
Infants/Children - abdomen, chest, & lower back
Indications for transcutaneous monitoring
The need to monitor continuously the adequacy of arterial oxygenation or ventilation
Need to quanify the real time responses to diagnostic & therapeutic interventions, as evidenced by PtcO2 or PtcCo2 values
Define pulse oximetry & its use in monitoring (invasive or noninvasive)
Noninvasive monitoring technique performed at bedside
SpO2 normal > 95% on room air
Noninvasive portable monitoring device providing estimates of SaO2
What is carboxyhemoglobin (HbCO)
when carbon monoxide binds to hemoglobin preventing it from carrying oxygen
Problems when monitoring with pulse oximetry, can the reading be accurate?
Device limitations causing false-negative results for hypoxemia or false positive results for normoxemia or hypoxemia may lead to inappropriate treatment of patients
Factors affecting SpO2, accuracy include motion artifact, abnormal hemoglobins, intravascular dyes, low perfusion states, skin pigmentation, & nail polish
Unreliable during carbon monoxide poisoning
What other oximetry analysis should we recommend if carbon monoxide is suspected?
Hemoximety (cooximetry)
Precautions/complications of capillary blood gas
Contamination & infection of the patient
Burns
Hematoma
Bruising
Scarring
Bleeding
What is capnometry?
Mainstream sampling (common)
Sidestream sampling
The measurement of CO2 in respiratory gases. A device that measures CO2.
Mainstream - places an analysis chamber in patient’s breathing circuit
Sidestream - pumps small volume of gas from circuit into nearby analyzer
Understand etCO2 range
35-mmHg or 5% co2
Understand waveform
Waveforms
Understand gradient
measures the difference between oxygen concentration in the alveoli and arterial system
Why is the Radial Artery preferred/common?
Near the surface/easy to stabilize
Collateral circulation usually exists
No large veins are near
Relatively pain free
Describe Modified Allen Test procedure
Hand is clenched into a tight fist
Hand is opened (not fully); palm & fingers are blanched
Removal of pressure on the ulnar artery should cause flushing of the entire hand (5-10 sec) which indicate adequate collateral circulation (positive)
What is PaCo2
partial pressure of carbon dioxide in arterial blood
What is pH & PaCO2
ph measure the acidity or alkalinity of the blood
PaCO2 measures the partial pressure of carbon dioxide in arterial blood
What is SaO2
arterial oxygen saturation
Clinical signs & needs for Blood Gas Sampling
Sudden, unexplained dyspnea
Cyanosis
Abnormal breath sounds
severe, unexplained tachypnea
Changes in ventilator settings
Cardiopulmonary resuscitation
Acute hypotension
Acute deterioration in neurologic function
Sudden appearance or progression of cardiac arrythmias
Contraindictaions for Transcutaneous Monitoring
There are no absolute contraindications. In patients with poor skin integrity or adhesive allergy, alternative devices should be considered
Hazards of Transcutaneous Monitoring
False negative or false positive results may lead to inappropriate treatment
Tissue injury (erythema, blisters, burns, skin tears) may occur at the measuring site
