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
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
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
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
