| Question | Answer |
| What is analysis? | Discrete measurements of fluids or tissue that must be removed from the body. |
| What is monitoring? | An ongoing process by which clinicians obtain and evaluate dynamic physiological processess in a timely manner, usually at the bedside. |
| What is a monitor? | A device that provides the important data to the clinician in real time, usually without removal of samples from the body. |
| What is a pulse oximeter? | An inexpensive and portable, noninvasive monitoring device that provides estimates of arterial blood oxyhemoglobin saturation levels. |
| Spectophotometry | detects oxygen saturation |
| What is spectophotometry? | Measurement of color in a solution by determining the amount of light absorbed in the ultraviolet, infrared, or visible spectrum, widely used in clinical chemistry to calculate the concentration of substances in a solution. |
| According to the principles of spectophotometry... | Every substance has a unique pattern of light absorption, much like a fingerprint. A substances pattern of light absorption varies predictably with the amount present. |
| Plethysmography detects | heart rate |
| What is plethysmography? | use of light waves to detect changes in the volume of an organ or tissue; pulse oximeters use the principle of photoplethysmography to measure the arterial pulse. |
| A pulse oximeter consists of a | sensor, processor, and display unit. |
| What are some causes that may cause a pulse oximeter to not read properly? | Nail Polish
Low Blood Pressure (low perfusion)
Dopamine (vasoconstrictors)
Hypothermia
Motion artifact
ethnicity |
| What is the #1 thing that causes a pulse ox not to work correctly? | Motion artifact |
| Sa02 and Sp02 should be roughly | equivalent |
| Sa02 comes from | hemoximetry |
| sp02 comes from | pulse oximetry |
| A pulse oximeter measures | the oxygen saturation of the blood |
| What are the advantages of pulse oximetry? | Non-invasive
continuous
can be used to spot check
-self calibrating |
| Pulse oximetry is based on 2 principles? | spectophotometry
plethysmography |
| THe pulse ox consists of | 2 light beams and a photodetector
(Red/Infrared) |
| The measurement sites with the pulse ox include. | Fingers/Toes
Ear Lobes
Bridge of Nose
Forehead |
| The Pulse oximeter should be left on for at least how many seconds? | 20 seconds |
| What should you always chart when using pulse oximetry? | The device and 02 liter flow.
Date, time, position, Fi02, placement site, compare with ABG results. |
| What are the pulse oximetry indications? | Monitor oxygen saturations (use value as a trend)
Evaluate response to theraputic or diagnostic procedure.
Comply with recomendations and regulations |
| What are the contraindications? | Monitoring after a house fire.
CO should be less than 1 in a normal person. |
| What are hazards/complications of pulse oximetry? | False Values
Pressure Sores
Electrical Shocks/burns |
| What are the limitations of pulse oximetry? | Motion artifact
low perfusion states
dysfunctional hgbs
intravascular dyes
lighting
skin pigmentation
nail polish/coverings |
| A pulse oximeter is within what accuracy of the hemoximitry value? | +- 3-5 % |
| The lower the Sa02 value the less reliable the | sp02 value will be |
| What are the qualifiers for home oxygen? | A Pa02 of less than 44 mm Hg
A sp02 of 87% during activity |
| Capnometry | The measurement of C02 in respiratory gases. |
| Capnometer | Device that measures C02 |
| Capnography | graphic display of c02 levels |
| dead space | portion of inhaled air that does not take place in gas exchange. |
| Capnography is used primarily | in the OR and Critical Care Unites |
| Capnography is used to assess | ventilation |
| End exhalation has the | highest level of c02 |
| Capnography mesures | carbond dioxed exhaled at the airwsay |
| PETCO2 | End Tidal C02 |
| What are the advantages of capnography? | It's non invasive
Continuous
Measures exhaled C02 and cuts down on ABG sticks |
| What is principal of capnography? | Spectrophotometry
(infrared absorption) |
| Method? | Infrared absorption and a photodetector. |
| Sampling systems | Mainstream/sidestream |
| Mainstream sampling systems | are inserted directly in line with the ventilator circuit |
| Sidestream sampling systems are | off to the side of the circuit |
| C02 absorbs | infrared light |
| Because C02 absorbs infrared radiation, the greater the concentration of C02 in the sample | the less infrared light that will arrive at the detector. |
| What are advantages of mainstream capnometers | sensor at patient airway
fast response (crisp waveform)
No short lag time (real time reading)
No sample flow to reduce tidal volume |
| What are disadvantages of mainstream capnometers? | secretions and humidity can block sensor window.
Sensor requires heating to prevent condesnation.
Requires frequent calibration.
Bulky sensor at patient airway
Does not measure N2O
Difficult to use with nonintubated patients.Cleaning |
| What are the advantages of sidestream capnometers? | No bulky sensors or heaters at airway
Ability to measure N20
Disposable sample line
Ability to use with nonintubated patients |
| What are disadvantages of sidestream capnometers? | Secretions block sample tubing
trap required to remove water from the sample.
Frequent calibration required
Slow response to C02 changes
Lag time between C02 changes and measurement.
Sample flow may decrease tidal volume. |
| Sudden changes associated with Changes in High PETC02 | sudden increase in Cardiac output
sudden release of tourniquet.
Injection of sodium bicarbonate. |
| What are gradual changes associated with High PETCo2? | Hypoventilation
Increase in C02 production. |
| What are sudden conditions associated with low PETC02 | SUdden hyperventilation
Sudden decrease in cardiac output
Massive pulmonary embolism
Air embolism
Disconnection of the ventilator
obstruction of the ET tube |
| What are gradual conditions associated with low PETCO2 | Hyperventilation
decrease in oxygen consumption
decreased pulmonary perfusion |
| You should use capnography as a | trend and corrolate with blood gas values |
| What are the indications of capnography? | Monitor exhaled C02 (use value as a trend)
Evaluate response to therapuetic or diagnostic procedure.
Monitor severity of pulmonary disease.
Determine tracheal intubation.
Monitor ventilator circuit/artificial airway integrity. |
| Name more indications of capnography. | Evaluate ventilator and patient interface.
Monitor adequacy of blood flow.
Monitor respiratory C02 when administered therapuetically. |
| What are the contraindications to capnography? | None |
| What are the hazards of capnography? | False values
Positioning
Weight
Increased deadspace. |
| What are the limitations? | Requires adequate response time.
Moisture/Secretions
Requires calibrations |
| If there is a leak you may have | false values |
| The difference of PaC02 and PETC02 increase | as dead space increases |
| Stae I of capnograph curve | Expiratory pure deadspace |
| Stage II of capnograph curve | mixture of deadspace/ventilatory CO2 |
| Stage III of capnograph curve | Pure C02 (end exhalation) |
| Stage IV of capnograph curve | Inhalation of oxygen. |
| What are other methods of capnography? | Calormetric C02 detector
Mass spectometer
Raman Spectroscopy. |
| A colormetric CO2 detector changes from purple | to yellow if C02 is detected |
| In healthy adults PETCO2 is 1-5 mm HG less than | PaC02 |
| Transcutaneous monitoring is primarily used in | neonates/small children |
| Transcutaneous monitoring is | time intensive |
| Transcutaneous monitoring measures | Pa02 and PaC02 |
| The Ptc02 is measured with a | clark electrode |
| The PtcC02 is measured with a | Severinghause electrode |
| What are the advantages of transcutaneous monitoring? | non-invasive
continuous
can monitor hyperoxygination |
| What is the principle of transcutaneous monitoring? | Diffusion through skin surface
Requires stabilization time. |
| Where are the measurement sites | abdomen
chest
lower back |
| Transcutaneous monitoring | provides estimates of PaC02 and Pa02 with sensor.
Sensor is heated up to 42 degress celsius.
this allows for diffusion. |
| What are the indications of transcutaneous monitoring? | Monitor PaO2 and PaC02 (use value as a trend)
Evaluate response to theraputic or diagnostic procedure. |
| What are the contraindications of transcutaneous monitoring? | Poor skin integrity
allergy to adhesive |
| If you have a leak the C02 will read | 0 |
| Transcutaneous monitoring must correlate with | ABG initially |
| Transcutaneous monitoring doesn't reflect | oxygen delivery or content |
| What are the hazards/complications of transcutaneous monitoring? | False values
tissue/skin erythema
blisters
burns
skin tears
must change site every 2-6 hours |
| limitations of transcutaneous monitoring include | prolonged stabilization required
low perfusion states
skin thickness
improper electrode placement
improper calibration
labor intensive |
| What are ABG indications? | To monitor ABG values.
To evaluate response to therapeutic or diagnostic procedures.
to monitor disease progression or severity. |
| What are the puncture sites? | Radial artery (requires modified allens test)
Brachial artery
Femoral artery. |
| The femoral artery | risky, huge veins and arteries, a fibrinolytic automatically rules out femoral sticks. |
| Radial artery | Collateral circulation
superficial and easy to palpate
Is the number 1 artery for sticking
Not near large veins.
Relatively pain free |
| The brachial artery is | risky, nerves and large veins.
No collateral circulation.
Increased risk for venous samle |
| Modified allens test | Occlude radial/ulnar artery.
Make fist, release fist, release ulnar artery.
Should pick up within 10-15 seconds for + allens test. |
| What are the contraindications for ABG? | negitive modified allen's test
avoid lesions or surgical shunts
avoid infection of PVD
Avoid femoral site on outpatients
High dose anticoagulation |
| What are the hazards/complications? | Thrombosis or air embolis
Hemorrhage
hamatoma
arteriospasm
loss of blood flow or circulation
infection
trauma
vasovagal response
pain
sample contamination |
| There are preset and self filling | syringes |
| Arterial blood gas supplies | gloves/safety glasses
3 CC syringe/ 22-25 Guage needle
anticoagulant-liquid sodium heparin
crystalized lithium heparin.
Needle cap/syringe plug
local anesthetic (1%xylocaine/tuberculin syringe)
Alcohol or betadine wipe
gauze pad
bandage
cup of i |
| What do you chart on your blood gas? | Date/Time, Patient Name and room number, Initials, site, Fi02, ventilator settings, temperature, 0xygen therapy device |
| Pre-analytical errors occur | before the sample is inserted into the machine |
| Post-analytical errors happen | while running the machine |
| Pre- analytical errors | bubble contamination- for 21% fi02 pa02 will increase. For 100% fi02, pa02 will go down.
Delay in sample- pa02 will decrease pac02 will increase.
Anxiety paco2 will decrease pa02 will increase.
venous sampling- lowers ph, increases pac02 and decrease p |
| What is one more pre-analytical error? | Excessive heparin- makes the sample more acidic. You'll see visable froth |
| What are some post-analytical errors? | incorrect callibration
error in sampling |
| Blood gas analyzers are calibrated at | 37 degrees celsius |
| Pa02 changes7% for each | degree celsius. |
| PaC02 changes 4% for each | degree celsius |
| What are indications for an arterial line? | continuous ABP monitoring
Repeated ABGs |
| Where are insertion sites? | radial
brachial
femoral |
| What are the component parts of the a-line? | starter sheath
pressure transducer
high pressure tubing and pressure bag
3 way stop cock
flush
tape or sutures |
| The high pressure tubing and pressure bag | prevents blood from coming out of the body |
| The pressure bag should be set at | 300 mm HG or 50 mmHG above systolic ABP |
| What are requirements for sample? | gloves and safety syringes
2 syringes (waste/ABG syringe)
syringe plug
gauze bad
cup of ice
label |
| What are the hazards and complications | same as abg
#1 complication is clotting
infection is a complication |
| The CBG is an alternative to the | abg procedure |
| The CBG gives a | rough estimate of pH and pc02.
P02 is of no value of est. oxygenation. |
| How is the procedure done? | blood is collected in a heparinized glass capillary tube and the site must be warmed before procedure. |
| The site prep and handling of the CBG is | the same as ABG sampling |
| Which population uses the CBG? | Infants and small children |
| CBGs should be avoid in | critical cases
infants less than 24 hours old |
| The sites for the CBG include the | heel of foot, fingertip and ear lobe |
| The ABG laboratory include | the operator interface
measuring chamber
calibrating gas tanks
reagent containers
waste/disposable container
transmittal system |
| The operator interface includes | controls, keypad, software, screen display |
| Measuring Chamber | incorporates a 3 electrode system
(measures 02, PC02, PH) |
| PH has 2 electrodes (halfcells) | Reference chamber and measuring chamber |
| Measured values | PaC02 severinghaus electrodce
pH: uses 2 electrodes or half cells
Pa02: Clarck (polaropgraphic) electrode (galvonic fuel cell) |
| What are the derived values? | Sa02, HC03, BE/BD
you need co-oximetry to measure true Sa02 |
| ABG analysis process? | Verify order and follow procedure
document procedure
analyze sample
follow lab documentation procedure |
| Quality assurance accreddidation | JCAHO, College of American Pathologists |
| Purpose of quality assurance | to prevent innaccuracies |
| Components of quality assurance | record keeping, performance validation, preventative maintenance, automated calibration, calibration verification, remedial action, documentation |
