Clinical Monitoring 6/5

Question 1

Monitoring standards for CRNAs are set by _______ (2)

Answer 1

AANA
ASA

Question 2

What are the monitoring standards?

Answer 2

1. Oxygenation
   -clinical observation
   -pulse ox
   -ABGs (as indicated)
2. Ventilation
   -auscultation
   -chest excursion
   -ETCO2
   -pressure monitors/flow volume loops (as indicated)
3. Cardiovascular
   -ECG
   -auscultation (as needed)
   -BP/HR q5min (at minimum)
4. Thermal regulation
   -when clinically significant changes in body temp are anticipated or suspected
5. Neuromuscular
   -as indicated –> when administered a NMB
6. Positioning/protective measures
   -nerve damage can be caused dt positioning
7. Additional means depend depending on needs
   -Ex) blood loss – giving blood; biz monitoring

Any omission of the above must be charted with a valid reason

Question 3

Pulse ox mechanics is based on the ________ law, which is the “law of _______”. Describe it.

Answer 3

Beer-Lambert Law

Absorption

Visible light passing thru a chemical solution of fixed geometry experiences absorption proportional to the concentration of the solute

(More solute = more absorption you see, less solute = less absorption you see)

Question 4

What happens to light when it goes thru matter?

Answer 4

it is transmitted, absorb, or reflected

Question 5

What are the different types of Hb that are normally bound? (4)

Answer 5

Oxyhemoglobin (HbO2)
Reduced Hb
Methemoglobin (metHb)
Carboxyhemoglobin (COHb)

Question 6

The most accurate type of oximetry & gold standard is ______. It operates off _____ wavelengths. When do we use this?

Answer 6

Co-oximetry

4

If there are 2 types of Hb showing the same dt only using 2 wavelengths w/ pulse oximetry

Question 7

Normal pulse oximetry works off ____ wavelengths. What are the value of those?

Answer 7

2

660 & 940 nanometers

Question 8

Pulse ox measure oxygenation from ____ blood. Why?

Answer 8

Arterial

Pulsatile expansion of the artery increases length of light path –> increases absorbency

Question 9

From a pulse ox, light is transmitted through…. (give order)

Answer 9

Skin –> soft tissue –> venous blood –> arterial blood –> capillary blood

Question 10

Equation: Pulse oximetry

Answer 10

Flucating component (pulsatile) / Nonflucating component for each wavelength

Ex) (AC 660/DC 660) / (AC 940/DC 940)

Question 11

Whats the difference between SaO2 & SpO2?

Answer 11

SaO2 – ARTERIAL SATURATION

SpO2 – THIS IS THE PULSE OX READING

2-3% difference

Question 12

What can cause artifact w/ pulse oximetry? (5)

Answer 12

1. Ambient light
   -solved by altering red/infrared –> machine set to do this
2. Low perfusion
   -decreased BP; hypovolemia
   -signal & artifact amplified
3. Venus blood pulsations
   -slower to report changes
4. Additional light absorbers
   -intravenous dyes & pulseox that uses 8 wavelengths
5. Additional forms of Hb

Question 13

What are the monitoring standards that aren’t required with every case– Only as indicated? (4)

Answer 13

ABG’s
Pressure monitors/flow volume loops
Thermoregulation (still have to take temps)
Neuromuscular monitoring

Question 14

We have to document vital signs every ____ minutes, this is the minimum

Answer 14

5

Question 15

What happens when O2 is taken up into the lungs?

Answer 15

Blood is nearly 100% saturated

Question 16

As blood passes through systemic capillaries, _______ amounts of O2 is released & there is a small _______ in PaO2 (tension)

Answer 16

large

Decrease

Question 17

What happens to the Oxyhemoglobin-dissociation curve if the blood is poorly saturated?

Answer 17

Curve goes to the L

Small amounts of O2 released (increased affinity) & LARGE drop in PaO2 (tension)

Question 18

Why is it important to keep O2 sats above 90%?

Answer 18

Below that we see large drops in PaO2 (tension)

Question 19

PaO2 =

Answer 19

PP of O2 in the ARTERY

Question 20

At 90% saturation, the PaO2 is about _____. What is the revelance of this point?

Answer 20

60 mmHg

Above this point: slow rise of PaO2 tension/PP of O2 in artery
-Small change in PaO2 = small change in SpO2
-Hb is near fully saturated
-Slope more horizontal

Below this point: rapid decreased in PaO2 tension/PP of O2 in artery when saturation decreases
-Small changes in PaO2 = LARGE drops in SpO2
-Slope very steep/more vertical

Question 21

What is the x & y axis of the Oxyhemoglobin-dissociation curve?

Answer 21

y (vertical): arterial saturation

x (horizontal): arterial O2 tension which is the PP of O2 in the arteries

Question 22

A R shift in the Oxyhemoglobin-dissociation curve causes ______ O2 affinity. What does this mean? What causes this? (3)

Answer 22

Reduced

Releases O2 easier from Hb

Increased:
Temp
2-3 DPG
Hydrogen ions –> acidosis/decreased pH

Question 23

________ (2) are sensitive to vasoconstriction. What can this cause?

Answer 23

Fingers & Toes

inaccurate readings w/o enough pulsatile flow

Question 23

A L shift in the Oxyhemoglobin-dissociation curve causes ______ O2 affinity. What does this mean? What causes this? (3)

Answer 23

Increased

Hb doesnt want to release O2

Decreased:
Temp
2-3 DPG
Hydrogen ions –> alkalosis/increased pH

Increased carbon monoxide (CO)

Question 24

T/F: dark polish/synthetic nails inhibit transmission for pulse ox symmetry

Answer 24

T

Question 25

Detection of desaturation/saturation is slower ________. What does this mean? What consideration should we have?

Answer 25

peripherally With unstable/fluctuating conditions like unstable HR & BP --> pulse ox may be slower to detect changes With unstable conditions --> use central location: Nose Earlobe Forehead (anything closer to the trunk)

Question 26

Pulse ox should not be placed on _______. Why?

Answer 26

Index finger When waking up patient has a tendency to scratch --> **increase risk for corneal abrasion**

Question 27

_______ are more reliable with pulse ox for epidural blocks. Why?

Answer 27

Toes dt increase vasodilation below the block

Question 28

___________ (3) are less affected by vasoconstriction. Why is it relevant?

Answer 28

Tongue Cheek Forehead Reflects desaturation/saturation quicker --> prevents treating inaccuracies

Question 29

What are the advantages of pulse ox? (10)

Answer 29

1. Accuracy +/-2% when compared to ABG's when sats >70% 2. Not affected by anesthetic vapors 3. Non-Invasive 4. Continuous 5. May indicate decreased CO 6. Convenient 7. Tone modulation --> hear changes when sats drop 8. Probe variety -- clamp vs stickers 9. Battery operated --> portable 10. Economical -- can get basically anywhere & not expensive

Question 30

What are limitations to pulse ox? (10)

Answer 30

1. Failure to determine saturation if very vasoconstricted or sats very low 2. Poor function with poor perfusion 3. Difficulty in detecting high PP 4. Delayed hypoxic event detection -- esp in peripheries 5. Erratic performance with dysrhythmia --> Afib/Aflutter may not be able to pick up 6. Inaccuracies w/ different Hb -- Ex CO 7. Inaccuracies with dyes 8. Optical interference 9. Nail polish & coverings 10. Motion artifacts

Question 31

What are the 3 most common dyes that we use? Which absorbs the worst with pulse ox & gives the most inaccurate readings?

Answer 31

Methylene blue Indocyanine green Indigo carmine Methylene blue

Question 32

Carboxyhemoglobin (COHb) absorbs as much light in the ______ nanometer range as _______ does. What consideration should we have with this?

Answer 32

660 Oxyhemoglobin Falsely elevate SpO2 readings

Question 33

Each 1% increase in COHb will falsely increase SpO2 by ___%

Answer 33

1%

Question 34

smokers have _______% COHb. What consideration should we have with this?

Answer 34

>6% (Remember Schmidty said 1% was normal) SpO2 falsely elevated by 6% or more Ex) SpO2 read 94% = actual PaO2 is 88 or less

Question 35

____% of NCE boards is equipment related

Answer 35

15%

Question 36

History: Knowledge of pulse

Answer 36

China & India

Question 37

History: Circulatory system understanding & correlation between heartbeat & pulse

Answer 37

Dr. William Harvey 1600

Question 38

History: 1st recorded blood pressure

Answer 38

Reverend Hales 1733 **Was recorded on a horse**

Question 39

History: 1st Sphygmomanometer

Answer 39

Samuel Von Basch 1881

Question 40

History: BP measured w/ systolic and diastolic pressures/sounds --> Kororkoff sounds

Answer 40

1905

Question 41

The different sounds used to measure SBP & DBP are called _____. What is the definition of this?

Answer 41

Kororkoff sounds Series of audible frequencies produced by turbulent flow beyond the partially occluding cuff dt the artery being partially occluded --> produces **Turbulent flow (Non-laminar flow)**

Question 42

What are the 3 phases of Korotkoff sounds?

Answer 42

Phase 1: most turbulent/audible (SBP) Phase 2-3: sound changes Phase 4-5: muffled/absent (DBP)

Question 43

Equation: Mean BP (MAP)

Answer 43

((2 x DP) + SP) / 3

Question 44

What are limitations to auscultation (Old fashioned BP)?

Answer 44

1. Decrease peripheral flow -shock -intense vasoconstriction 2. Changes in vessel compliance (stiff diastolic) -severe edema -calcific arteriosclerosis -normal aging (these increase DBP #) 3. Shivering 4. Incorrect cuff size

Question 45

If the BP cuff size is too small it will show a false ______ in BP & if too large it will show a false _______ in BP

Answer 45

Increase (HTN) Decrease (hypotension)

Question 46

In BP cuffs, you want the maximum cuff pressure to be ______ in adult adults & ______ for neonates

Answer 46

300 mmHg 150 mmHg

Question 47

Why is it important that the BP cuff has a means to prevent extended inflation?

Answer 47

Machine needs to know its been inflated for a few mins & deflate on its own --> help prevent nerve damage

Question 48

The BP cuff bladder needs to be ____ of arm circumference & ____ of length of upper arm.

Answer 48

40% 80%

Question 49

How does automatic non-invasive BP work? How is SBP calculated? How do you identify MAP?

Answer 49

Based on oscillometry SBP & DBP calculated from algorithm SBP = 25-50% of MAP amplitude MAP = highest amplitude

Question 50

With automatic non-invasive BP which value is the lease accurate?

Answer 50

DBP

Question 51

Automatic non-invasive BP is almost equal to A-line pressures under what condition?

Answer 51

When MAP 75mmHg or lower

Question 52

According to the book, non-invasive BP has a ______ difference when compared to A-line. What is the reality tho? What is the most important thing for us to do w/ BP?

Answer 52

+/- 5 mmHg Reality: large variances -underestimates MAP during HTN -overestimates MAP during hypotension -Ankle, thigh, calf cuffs never validated Averaging, trending necessary for measurements to be reliable -never go off 1 number

Question 53

What are the advantages of non-invasive BP?

Answer 53

-automaticity (can set to automatically take) -simplicity -non-invasive -reliable(ish) -monitor integration --> pulse ox won't alarm if BP monitor inflates

Question 54

What are the disadvantages of non-invasive BP? (4)

Answer 54

1. unsuitable for rapidly changing situations --> won't trend fast enough 2. Patient discomfort w/ increased freq 3. Clinical limitations -- w/ extreme HR & pressures 4. Trauma -- dt increased freq -coagulopathy -peripheral neuropathy -arterial/Venous insufficiency -compartment syndrome

Question 55

What are indications for an A-line? (5)

Answer 55

1. Continuous, real time monitoring (beat to beat) 2. Planned pharmacologic manipulation 3. Repeated blood sampling 4. Determination of volume responsiveness 5. IABP -- timing of counterpulsation

Question 56

The most common site for an A-line is ______. What other benefits are there to this area? (3)

Answer 56

Radial Easy to access Clean compared to fem Complications are uncommon

Question 57

What 2 arteries does Allen's test involve? What is the purpose of this test? Describe the entire test

Answer 57

Radial & Ulnar artery Purpose: to see if we put A-line in radial artery & it occludes -- **is there enough flow from Ulnar artery** to prevent ischemia in hand Test: 1. Compress both radial & ulnar arteries 2. Pt make tight fist --> Exsanguinating venous blood out of hand 3. Pt open hand 4. Release ulnar artery only 5. Color of palm should return in less than 10 secs if ulnar artery flow is sufficient

Question 58

Slogoff studies identified what regarding the allen's test, occlusion & ischemia?

Answer 58

25% evidence of radial artery occlusion after decannulation --> no evidence of ischemia Allen's test is predictive of occlusion but **not so much of ischemia**

Question 59

_______ is the gold standard for determining **occlusion** w A-line placement in the radial artery but not _____. How accurate is it?

Answer 59

Allen's test Ischemia 80% accurate for color change at 5 secs

Question 60

The angle for A-line placement is _____

Answer 60

30-45 degrees

Question 61

What do we need to do to help w/ A-line placement in radial art? (2)

Answer 61

Towel under wrist -- helps bring radial artery up Tape all 5 fingers down (esp thumb) -Moving thumb = radial artery moving

Question 62

The main technique used for A-line placement is _________. Describe it

Answer 62

Seldinger's Technique 1. Insert needle -- see flashback of blood 2. Pass guidewire through needle 3. Remove needle once guide wire is substantially through catheter 4. Insert catheter fully over wire

Question 63

What is the 2nd way to place an A-line called? Why is it not the best technique? Describe it.

Answer 63

Transfixion technique Studies say not associated w/ more frequent complications BUT: -Increased hematoma -increase art lines that don't hold up Procedure: 1. Same positioning/prep as Seldinger's Technique **2. Front & back walls are punctured intentionally** 3. Needle removed 4. Catheter withdrawn into pile blood flow appears --> advanced catheter further into artery

Question 64

What are the other common sites for A-line placement? (5)

Answer 64

1. Brachial 2. Posterior tibial 3. Axillary 4. Dorsalis Pedis 5. Femoral

Question 65

Why do we try and avoid the brachial artery when placing A-line?

Answer 65

If occluded --> lose significant part of arm

Question 66

The automatic flush w/ A-lines goes at _____. What does it prevent? What do we use in the flush? What do we not use anymore & why?

Answer 66

1-3 ml/hr Prevent thrombus formation We use NS now vs heparin & dextrose We dont use heparin bc risk of HIT & DM w/ dextrose

Question 67

Zeroing the A-line references pressures against ________

Answer 67

Atmospheric air

Question 68

leveling the A-line is at the _______, which is ________ visually.

Answer 68

Aortic root Mid axillary line/ mid chest

Question 69

How do we maximize the waveforms with A-lines? (3)

Answer 69

1. Limit stopcocks -just 1 as close to artery as you can get for blood draws 2. Limit tubing length 3. Use non-distensible tubing -not IV tubing or any other tubing that easily expands --> it absorbs pressure & wont see a waveform

Question 70

What are the 6 types of waveforms of an A-line in the order they appear?

Answer 70

1. Systolic upstroke 2. Systolic peak pressure 3. Systolic decline 4. Dichotic notch 5. diastolic runoff 6. end-diastolic pressure

Question 71

Why does the morphology change when arterial pressure measured at different sites? How does this affect the waveform? (5)

Answer 71

Impedence changes along vascular tree As pressure wave move to periphery: 1. Arterial upstroke steeper 2. Systolic peak higher 3. Dicrotic notch later 4. End-diastolic pressure lower 5. MAP changes very little

Question 72

How is the Aortic arch A-line waveform different from the Fem artery A-line?

Answer 72

Femoral: higher systolic peak -lower dicrotic notch

Question 73

Waveforms made from A-line are a summation of ________ waves. What are they? (2)

Answer 73

sine waves Fundamental waves + harmonic waves

Question 74

________ is an analysis of the summation of sine waves w/ A-line waveforms

Answer 74

Fourier analysis

Question 75

What is the Squared Wave Test? How is it done?

Answer 75

Way to make sure that A-line is correctly calculated -- not overdamped or underdamped Push flush button --> see square wave -w/i a few secs should return to normal

Question 76

Compare an overdamped (5) vs underdamped A-line waveform

Answer 76

Underdampened: Systolic pressure elevated Overdamped: -SQUISHED -Systolic pressure decreased -Absent dicrotic notch -narrow pulse pressure -loss of detail

Question 77

Overdamped waveforms are ______

Answer 77

squished

Question 78

All A-line systems have a partially built-in ______ capability. What does this help with? (3)

Answer 78

damping -Helps make system more accurate --> decreases system resonace -Prevents exaggerated waveforms -prevents waveforms from looking flat

Question 79

What are pathologies that cause A-line waveform changes? (8)

Answer 79

1. Age -- lack of distensibility 2. Atherosclerosis 3. Embolism 4. Arterial dissection 5. Shock/hypotension 6. Hypothermia 7. Vasopressor infusions 8. Over/underdamping

Question 80

What are complications w/ A-lines? (5)

Answer 80

1. Distal ischemia or pseudoaneurysm 2. Hemorrhage 3. Hematoma 4. Local infection 5. Peripheral neuropathy