Exam 1 Clinical Monitoring Part 1 [6/6/24] Flashcards
AANA Monitoring Standards for Oxygenation
- Clinical Observation (watch your patient for chest rise and fall)
- Continuous Pulse Oximetry
- ABG’s as indicated
S2
AANA Monitoring Standards for Ventilation
- Auscultation
- Chest excursion (rise/fall of chest)
- ETCO2 documentation
- Pressure monitors as indicated
- Monitor RR q 5 mins [in practice q3min]
CEAP’M Ventilated
S2
AANA Monitoring Standards for Cardiovascular System
- Electrocardiogram [its okay to have just the pulse OX as long as its showing the HR continuously]
- Auscultation as needed
- BP and HR documentation q 5 mins
S2
AANA Monitoring Standards for Thermoregulation
- When clinically significant changes in body temp are anticipated or suspected
- Continuous monitor of temperature in cases longer than 20 minutes, pediatric cases, or elderly patients.
- in children, we set the OR to be warm bc they lose body heat very rapidly compared to adults
S2
AANA Monitoring Standards for Neuromuscular System
- When neuromuscular blocking agents are administered.
- TOF are charted q 15 mins
S2
Additional means of monitoring depends on the needs of ?
- patient, surgical technique, or procedure
S3
If not charting monitoring standards, what must be done?
- Omission with reason must be charted
S3
Name factors that will cause the Hb dissociation curve to shift left
Left:
* Alkalosis
* Hypocarbia
* Hypothermia
* Decreased 2,3 DPG
* COHb
* Fetal Hb
Right shift = ↓ Hb affinity to O2.
Left shift = ↑ Hb affinity to O2*
S5
Name factors that will cause the Hb dissociation curve to shift right.
Right
* acidosis
* hypercarbia
* hyperthermia
* Increased 2,3 DPG
Right shift = ↓ Hb affinity to O2.
Left shift = ↑ Hb affinity to O2
S5
How low can a healthy normal adult patient’s PaO2 decrease before:
* their O2 saturation drops below 90%?
* their O2 saturation drops below 75%?
* their O2 saturation drops below 50%?
- PaO2 can decrease to 60 mmHg before O2 saturation drops below 90%.
- PaO2 can decrease to 40 mmHg before O2 saturation drops below 75%
- PaO2 can decrease to 27 mmHg before O2 saturation drops below 50%
S5
Light through matter
is ______, ______, or _____.
Transmitted, absorbed, or reflected
S6
Upon what law of physics is pulse oximetry based?
- Beer-Lambert Law
S6
What is the beer-lambert law?
- Law of absorption
- Relates the transmission of light through a solution to the concentration of the solute in the solution
- Light absorption must be measured at wavelengths that are proportional to the number of solutes
S6
Explain how concentration of a solute affects light absorption in pulse oximetry.
- Amount of light absorbed is proportional to the concentration of the light absorbing substance (Beer’s Law)
- Higher Hb concentration, more light absorption
S7
Explain how distance affect light absorption in pulse oximetry.
- Amount of light absorbed is proportional to the length of the path that the light has to travel in the absorbing substance (Lambert’s Law)
- Wider arteries, more light absorption
S7
What were the four species of Hb in adult blood discussed in lecture?
- Oxyhemoglobin (O2Hb)
- Deoxyhemoglobin (deO2Hb)
- Methemoglobin (metHb)
- Carboxyhemoglobin (COHb)
S8
What is sulfahemoglobin?
- Sulfahemoglobin is not normally present in the body.
- Made from oxidation of iron in the body usually from drugs.
S8
Most common etiology of sulfhemoglobinemia is the use/misuse of sulfur-containing medications such as AZO
What is considered the gold standard for SaO2 measurements and is relied on when pulse oximetry readings are inaccurate or unobtainable?
- CO-oximetry
- instead of looking at 2 wavelengths like a pulse ox it looks at 4 wave lengths.
S8
pulse ox is inaccurate with COhb [will show higher than normaly] so this is the gold standard.
All types of hemoglobin are read at 940 nm except?
- Carboxyhemglobin
S8
The wavelength of red light
- 660 nm
S9
The wavelength of infrared light
- 940 nm
S9
__________ absorbs more infrared light.
___________ absorbs more red light.
- Oxyhemoglobin (O2Hb) absorbs more infrared light than deoxyhemoglobin
- Deoxyhemoglobin (deO2Hb) absorbs more red light than oxyhemoglobin
- SeXy DARLing:
SiX hundred wavelength, DeoxyHb Absorbs Red Light.
S9
Pulsatility of arterial blood flow estimates _____
- SaO2
S10
Light is transmitted through
- Skin
- Soft tissue
- Venous blood
- Arterial blood
- Capillary blood
S10
Ratio of AC and DC light absorption
- Pulsatile expansion of the artery ____ length of light path which _____ absorbency
- Pulsatile component divided by?
- Pulsatile expansion of the artery increases length of light path which Increases absorbency
- Pulsatile component divided by non-pulsatile component for each wavelength
S10
AC= alternating current = pulsatile
DC=direct current = non-pulsatile
Schematic of the Pulse Principle.
- Light absorption through tissue is characterized by a pulsatile component (AC) and a non-pulsatile component (DC).
- The pulsatile component of absorption is due to arterial blood. The non-pulsatile component is due to venous blood and the remainder of the tissues.
____ absorbs as much light in the 660 nm range as oxyhemoglobin does. What is the clinical relevance?
- Carboxyhemoglobin
- Falsely elevates SpO2
S11
What patients are we concered about with in regards to carboxyhemoglobin?
- Pts who have been in fires
- Carbon monoxide poisoning.
S11
Each 1% increase in COHb will increase SpO2 by _____%.
- 1%
S11
Many smokers have > ______% of COHb.
- 6%
S11
What factors cause signal artifacts in pulse oximetry?
- Ambient light: Usually solved by alternating red/infrared
- Low perfusion: Signal amplitude reduced
- Venous blood pulsations: Detection of venous O2Hb sat, results in reduction of presumed arterial SpO2
- Additional light absorbers (methylene blue/IV dyes)
- Additional forms of Hb
- Nail polish
NAAALV
S12
Advantage of Pulse Ox
How accurate is pulse oximetry when measured against ABGs as long as the patient’s O2 saturation is >70%?
- Pulse oximetry’s accuracy is within 2% of an ABG.
S13
List advantages of pulse oximetry. (Long list, common sense)
- Accurate/ Convenient
- Not affected by anesthetic vapors
- Noninvasive
- Continuous
- May indicate decreased cardiac output
- Tone modulation
- Probe variety (Ear probe)
- Battery-operated
- Economical
S13
List disadvantages of pulse oximetry. (Long list, common sense)
- Poor function with poor perfusion
- Delayed hypoxic event detection
- Erratic performance with dysrhythmias
- Inaccuracy with different hemoglobin (COHb)
- Inaccuracy with dyes
- Optical interference
- Nail polish and coverings
- Motion artifact
S14
Useful Tips
Fingers are relatively sensitive to ________
- vasoconstriction
S15
Useful Tips
Useful tips to take into consideration about SPO2:
* Fingers are relatively sensitive to ____
* Dark polish or synthetic nails ____ transmission
* Detection of desaturation and resaturation is ____ peripherally
* Should not be placed on ____ _____.
* ____ may be more reliable with epidural blocks
* _____, _____, _____ less affected by vasoconstriction, reflects desaturation quicker
- Fingers are relatively sensitive to vasoconstriction
- Dark polish or synthetic nails inhibit transmission
- Detection of desaturation and resaturation is slower peripherally
- Should not be placed on index finger
- Toes may be more reliable with epidural blocks
- Tongue, Cheek, Forehead less affected by vasoconstriction, reflects desaturation quicker
S15
Useful Tips
Why shouldn’t the pulse oximeter be placed on the index finger?
- ↑ risk of corneal abrasion
Where will you place a pulse oximeter for the most accurate reading during an epidural block?
- Toes
Toes will be more dilated than fingers with an epidural block.
S15
What three parts of the body are least affected by vasoconstriction and will reflect desaturation quickly?
- Tongue
- Cheek
- Forehead
S15
Most indirect methods of blood pressure measurement utilize a sphygmomanometer.
What is the series of audible frequencies produced by turbulent flow beyond the partially occluded cuff called?
- Korotkoff sounds
S17
Describe the phases of the Korotkoff sounds.
During what phase will you hear SBP and DBP?
- Phase I: the most turbulent/audible (SBP)
- Phase II: softer and longer sounds
- Phase III: crisper and louder sounds
- Phase IV: softer and muffled sounds
- Phase V: sounds disappear (DBP)
2-cheese pull, 3 lays chip, 4 brownie
S17