Apex- Respiratory Monitors & Equipment Flashcards
-Bronchospasm
-Kinked ETT
& Aspiration of foreign body
The pressure-time waveform in this question shows an elevated peak pressure with a normal plateau pressure
>suggests a reduction in dynamic compliance, which is usually casued by increased airway resistance
What is compliance?
The ability of the lungs to stretch and expand
two types of pulmonary compliance:
1. static - assesses the pressure required to keep the lung inflated to give a volume when there is no air movement
2. dynamic- assesses the pressure required to inflate the lung to a given volume when there’s airflow.
> dynamic compliance is impacted by airway resistance and the tendency of hte lung/chest to collapse
Static vs dynamic compliance
static measures pressure required to inflate the lung when theres no air movement
dynamic mesausres it while their is air movement
static compliance measures lung compliance when there is no air flow
dynamic compliance measures compliance of the lung/chest wall during air movement
PIP vs Plateau
PIP is the maximum pressure in the pt’s AIRWAY **during inspiration **
Plateau is the** pressure** in the SMALL AIRWAYS and ALVEOLI after the target tidal volume is achieved
What can we evaulate to determine if alterations in pulmonary mechanics are due to changes in resistance vs compliance?
PIP vs Plat
increased resistance = increased PIP with normal PP
>kinked ett and bronchospasm
decreased compliance = increased PIP and PP
>endobronchial intubation and pulm edema
How would increased resistance manifest when compairng PIPs and PLATs
2 examples
increased PIP
normal PLAT
kinked ETT & bronchospasm
Decreased pulmonary compliance would manifest how in regard to PIP and PP
2 examples
increased PIP & PP
ednopronchial intubation and pulmonary edema
Peak pressure - max pressure in pts airway during inspiration (Dynamic compliance)
PP - pressure in the small airways and alvolei after target tidal volume is reached (static compliance)
T/F- there is controversy about whether an increased PIP in isolation increases risk of barotrauma
Tru
but barotrauma risk increaes when plat pressure exceeds 35cm/H20
Does airway resistance affect plateau pressure?
no since there there is no airflow at that time
-measured at the inspiratory pause
what measurement relfects the elastic recoil of the lungs and thorax during the inspiratory pause
plateu pressure
barotrauma risk increases with what parameter and measurement
when plateau pressure > 35cm H20
What are you noticing with each
- Normal → PIP and plat close together
- Increased PIP with no change in Plat → increased resistance Or insp. flow has increased
- High PIP AND PLAT → complance has decreased or tidal volume has increased
What to think about when your trying to figure out whether increased resistance or decreased compliance
increased resistance will be anything that increases airway pressure
decreased complinace will be anything that prevents the lungs from fully expanding
so in my head i wanna say inadequate muscle relaxation would be due to increased resistance but no
-increased resistance has to do with the airway
-it would be decreased compliance bc they resistance of the chest wall is prohibiting the lungs from expanding
What type of pulmonary compliance is a function of both airway resistance and elasticity of the chest wall?
dynamic compliance
PIP
What type of pulmnary compliance is a function of the elasticity of the chest wall only?
static compliance
d. Exhalation of anatomic dead space AND alveolar gas
just remember - exhaling anatomic dead space alone would have no etco2 (bc no exchange happens in the anatomic dead space)
What 3 things can capnography assess?
- metabolism
- circulation
- ventilation
it also provides insight into equipment related problems like airway obstruction and rebreathing
what does an increased alpha angle vs increased beta angle suggest on capnograph?
increased alpha angle → expiratory obstruction
increased beta angle → rebreathing due to a faulty insp. valve
what are the 2 methods of carbo ndioxide analysis?
which one is normall yused?
mainstream → in-line
sidestream → diverting
sidestream/diverting
mainstream/inline adds extra weight to the ETT and increases apparatus dead space
explain whats happening in each phase/point
Phase 1 (A-B) → exhalation of anatomic dead space (mouth-nose/y-piece to terminal bronchioles : no gas exchange happening here - air no blood)
Phse 2 (B-C) → exhalation of anatomic dead space AND alveolar gas
Phase 3 (C-D) → exhalation of alveolar gas
Phase 4 (D-E) → inspiration of fresh gas that doesnt contain CO2
What point is the alpha angle measured?
Normal alpha angle?
causes of increased alpha angle (3)
Point C
100-110
expiratory airflow obstruction → COPD/bronchospasm/kinked ETT
At what point in the capnograph is the beta angle measured
normal value
main cause of it being increased
Point D
90 degrees - should go straight down
rebreathing caused by a faulty inspiratory valve
*WILL BE NORMAL with exhausted co2
If you notice your capnogram isn’t returning to baseline, how would you differentiate it being from a faulty inspiratory valve vs exhausted co2?
if it’s a faulty inspiratory valve - there will be an increased beta angle
exhausted co2 absorbant = beta angle will be normal (go straight down 90 degrees)
what do the others signify ?
A
B- increased ETCO2
C. Curare cleft
D. Cardiac oscillations
What does this signify?
3 examples
Things you could do to improve it
Airflow obstruction
COPD - monitor
Bronchospasm - try to manually ventilate, should be able to get air in, but bag wont readily fill back- albuterol
Kinked ett- look for it
What does this signify?
Cause?
What would you do about it?
Cardiac oscillations
casued by the heart beating agaisnt the lungs
nothing as long as all else is well
*more common in kids (close proximity of heart to lungs
redo
What is this?
What does it signify?
What can you do about it?
Curare Cleft
spontaneous breaths during mechanical ventilation
1. assess where yoru at in the case:
→ re-dose paralytic if appropriate
→ overbreathe for them
→ switch tehm to an SIMV mode
→ increase gas
What does this signify?
3 different potential causes with examples of each
Low EtCO2
look for a scale or reference wave
- Hyperventilation → light anesthesia, metabolic acidosis
- ↓CO2 production → hypothermia
- ↑ Alveolar dead space: (air, no blood) → hypotension, PE
What does this signify?
2 main things that can cause this and examples of each
Hypercarbia
look at baseine - it returns to zero so it’s not regreathing
- ↑ CO2 production → MH, thyroid storm, fever, sepsis
- ↓ alveolar ventilation → hypoventilation, narcotics
Whats happening here
potential causes
High inspired CO2
the beta angle - normal –> rebreathing
Exhausted CO2 absorbent
Incompetent EXPIRATORY valve
hole in inner tube of bain system
inadequate FGF with mapelson circuit
rebreathing under drapes in a pt who is not intubated
Cause of this
Incompetent INSPIRATORY valve
decreased slope during inspiratory phase (widened beta angle)
part of the exhaled breath re-enters the inspiratory limb, so the patient rebreaths some of the previously exhaled CO2 on the next breath
increase FGF > pts minute ventilation
Which inspired CO2 capnogram has an increased beta angle (decreased slope during the inspiratory phase) - an incompetent inspiratory or expiratory valve
incompetent INSPIRATORY valve
-decreased slope during the INSPIRATORY phase
-part of the exhaled breath re-enters the inspiratory limb, so the pt rebreaths some of the previously exhaled CO2 on the next breath
-incopetent expiratory valve would have a normal beta angle
What would it mean if you see a curare cleft during spontaneous ventilation?
Inadequate muscle relaant reversal (lack of synchronization b/t intercostal muscles and diaphragm)
What does this indicate and why
A leak in the sample line during PPV
obesity and pregnancy
-the beginning of the plateau is low bc alveolar gas is diluted with air from the atmosphere
-positive pressure during inspiration pushes the co2 rich gas through the sample line (peak)
*not seen with spontaneous ventilation bc there is no positive pressure
When might you see this?
explain
After a single lung gransplant
severe kyphoscoliosis
-Alveolar gas from the tranplanted lung has a normal time constant (initial peak)
-Alveolar gas from the diseased lung is trapped in the sick lung and has a longer time constant
which conditions are MOST likely to cause this ETCO2 waveform? ( select 3)
Metabolic acidosis (CAUSES this bc of hyperventilating)
PE (air no blood to dump off co2)
inadequate seal with LMA
What 3 causes should be considered with a change in etco2?
- increase/decreased co2 production
- increased/decreased alvolar ventilation
- equipment malfunction
Pulseox emits 2 wavelengths of light: infrared and near-infrared
oxygenated blood absorbs which @ what nm
deoxygenated blood better absorbs which light @ what nm
oxygenated blood better absorbs near-infrared light (940nm)
deoxygenated blood better absorbs red light (660)
think deoxygenated blood is blue and wants to be red- absorbs the red light
red light = prostitution, prostitution = devil, devil = 660nm
6+4 = 10 and thats how ill remember its 660 & 940
Apex has a more normal way to remember this lol:
lower wavelength and lower amount of bound o2 (venous blood)
higher wavelenght and higher amount of bound o2 (arterial blood)
You want to use ear pox on everyone, what can be your arguement other than you have easier access to it ?
it has a faster response to desaturation
it’s also more resistant to vasoconstrivitve effects of SNS timulation and hypothermia
What can happen if your pts in trendelenburg and your pox is on the head or esophagus?
it can result in a falsely low SpO2 measurement due to venous engorgement with tberg
Your pulseox reads 80%; you estimate your PaO2 is approximately what?
50
SpO2 90 = 60
SpO2 80 = 50
SpO2 70 = 40
T/F: SpO2 monitoring is most useful when the patient’s PaO2 aligns with the STEEP portion of the oxyhemoglobin dissociation curve
True
You can rougly estimate PaO2 based on the SaO2/SpO2
SpO2 90% = PaO2 of
SpO2 80% = PaO2 of
spO2 70% = PaO2 of
SpO2 90% = PaO2 of 60mmhg
SpO2 80% = PaO2 of 50mmhg
spO2 70% = PaO2 of 40mmhg
90-60 (69)
then decrease by 10
T/F: once SpO2 hits 100% you have no way of knowing if the PaO2 is 100 or 500mmHg
True
would need to measured with ABG
Will chronic anemia shift the curve left or right
right
less hgb, so will ahve to release more
Does hypocapnia shift the curve left or right
left
decreaed metabolic byproducts , less need to release o2
The pulseox is a useful monitor of:
A. ventilation
B. bronchial intubation
C. anemia
D. vascular compression
D. vascualr compression
T/F: the pulseox is NOT a good monitor of anemia
True
SpO2 monitors the % of hemoglobin bound with o2
- it does not quantify the amount of hemoglobin
- the amount of hemoglobin is reduced with anemia, but it can still be fully saturated with o2
-the pox can overestimate spo2 with severe anemia
T/F: th pulseox is NOT a good monitor of bronchial intubation
True
3 things the pulseox can assess
hgb saturation (oxygenation)
heart rate
fluid responsiveness (pulse pressure variation)
Where is the scope placed during mediastinoscopy
where should you place the pox
behind the thoracic aorta and infront of the trachea
im confused, let me find a picture
pox on right to detect compression of the inominate artery
>supplies blood to right arm, head , and neck
T/F- the innominate artery is the third branch off the aorta
True
the first 2 are the right and left coronary arteries
The pox may (over/underestimate) the SpO2 with severe anemia
overestimate
will be lower than whats projected
Which condition is LEAST likely to affect the reliability of the pox?
A. Jaundice
B. LVAD
C. Carboxyhemoglobin
D. Blue nail polish
A. Jaundice
LVAD = nonpulsatile flow
Carboxy absorbs same wavelenth as oxyhemoglobin and will overestimate spo2
blue nail polish= underestimates
The pulseox’s margin of error when SpO2 is:
70-100%-
50-70%-
70-100% = +/- 2-3%
50-70% = 3%
Methemoglobin or Carboxyhemoglobin:
Absorbs 660nm and 940nm equally
Methemoglobin
Carboxyhemoglobin absorb 660 equally (cars, prostitutes, devil, red light special)
Methemoglobin or Carboxyhemoglobin:
overestimates SpO2 always
Carboxyhemoglobin
carboxy and oxyhemoglobin look the same to the pulseox
Methemoglobin or Carboxyhemoglobin:
Falsely underestimates SpO2 if O2 sat is what
Falsely overestimates SpO2 if O2 sat is what
Methemoglbin
Falsely underestimates SpO2 if O2 sat > 85% [spo2 will be greater than value]
Falsely overestimates SpO2 if O2 sat <85% [spo2 will be lower than value]
What color nail polishes most greatly affect POX
which are okay?
Blue, black, green
red and purple are fine
how would TR affect SpO2?
falsely decrease it due to venous pulsations
sure
Do acrylic fingernails affect pox?
no
T/F: Fluorescein interfers with pulseox
False
dont know wtf that even is but ok
contrast dye used in eye procedures . wonderful
Does fetal hemoglobin affect reliablity of the pulseox?
No
Does polycythemia affect reliability of the pulseox?
no
What is the most common method of measuring exhaled gases inside the breathing circuit?
A. Mass spectrometry
B. raman scattering
C. piezoelectric cystals
D. infrared absorption
D. Infrared absorption
Does O2 absorb infrared light
no- thats why o2 concentration has to be measured by elecctgrochemical analysis (galvanic cell or clark electrode) or paramagnetic analysis
where as co2 can be measured by infrared light
Match: Mass Spectrometry, Ramand Scatter Spectrometry, and Piezoelectric cyrstals with:
-bombards gas sample with electrons creating ion fragments that become charged
-uses a high power argon laser to produce photons
-uses a lipid layer to respond to individual gases
Mass Spectrometry- bombards gas sample with electrons creating ion fragments that become charged
Raman Scatter Spectrometry- uses a high power argon laser to produce photons
Piezoelectric Crystals-uses a lipid layer to respond to individual gases
T/F: Mass spectrometry system is large and can only be utilized for one patient at a time
False - it is large but CAN be utilized for more than one patient at a time
Which condition can cause a falsely increased POX value?
A. TR
B. Red nail polish
C. carboxyhemoglobin
D. Fluorescein
C. Carboxyhemoglobin
shivering and venous pulsation (TR) can falsey REDUCe SpO2
red nail polish and flurescein dont interfere with it
Which monitor is unable to measure the o2 concnetration in the breathing circuit?
A. Clark electrode
B. Infrared absorption spectrophotometry
C. Raman scatter spectrometry
D. Paramagnetic analysis
B. Infrared absorption spectopohometry
Which conditions are assoicated with a decreased PaCO2 to EtCO2 gradient?
A. Venous air embolism
B. Dysfunctional inspiratory unidirectional valve
C. CO2 absorption during laparoscopic surgery
D. Seizures
B. Dysfunctional inspiratory unidirectional valve
A unidirectional valve that’s stuck in the open position leads to rebreathing of exhaled CO2 and increases the PaCO2 and EtCO2 bu the gradient becomes smaller.
VAE increaes dead space, increasing the PaCO2 to EtCO2 gradient (air no blood)
Seizures and co2 absoprtion during lap surgery increase the PaCO2 but the gradient is normal
Most reliable idnicator of endobronchial intubation
auscultation of breath sounds
Infrared analysis is able to measure (select 3):
-helium
-o2
-n20
-xenon
-volatiles
-co2
-co2
-volatiles
-n20
IR analysis cannot measure oxygen, helium , nitrogen, or xenon bc these species only contain one type of atom
Match each condition with its MOST likely effect on pulmony pressure monitoring :
PE, endobronchial intubation, mucous plug
PE- no change in dynamic or static compliance
endobronch- decrease static compliance
mucous plug- decreased dynamic compliance
