Respiratory Monitoring Flashcards
What two things does airway management include?
the ability to oxygenate AND ventilate a patient
How is CO2 made in the body?
cellular respiration
What vital sign is the indicator of the CO2 response curve?
respiratory rate
tidal volume x respiratory rate
minute ventilation
-Heavy weight chest piece placed on skin or
esophageal temperature probe used
-Custom fitted ear piece connects the tubing to
either the chest piece or esophageal probe
esophageal stethoscope
What things can an esophageal stethoscope detect?
Confirms ventilation by breath sounds Can detect abnormal breath sounds -stridor -wheezing Detects abnormal heart sounds
esophageal stethoscope contraindicated with?
esophageal varices
What can esophageal stethoscope NOT detect?
diffusion abnormalities
esophageal stethoscope placement?
Place at 4th intercostal space and left sternal border
clinical condition: apnea, vent or circuit disconnect, accidental extubation
stethoscope finding?
absence of breath sounds
clinical condition: air embolism
stethoscope finding?
sudden appearance of new murmur (mill wheel murmur)
clinical condition: bronchospasm/aspiration
stethoscope finding?
wheezing
clinical condition: CHF
stethoscope finding?
S3 gallop rhythm, rales
clinical condition: arrhythmias/cardiac arrest
stethoscope finding?
irregular heart sounds
absence of heart sounds
what tidal volumes do you want to achieve?
tidal volumes between 6-8 ml/kg (ideal body weight)
5 ways to monitor Tidal Volume
- adequate amount tidal volume 6-8
- do not exceed PiP> 35-40
- bilateral chest rise and fall
- control of ETCO2
- bellows moving
[PiP = peak inspiratory pressure]
The weight of the bellows gives about how much intrinsic PEEP?
2-3 cmH2O
6 things on an abg
PaO2 PaCO2 pH oxyhgb sat base excess bicarb
what two numbers on abg are for oxygenation assessment?
PaO2
oxyhgb sat
what number on abg is for the assessment of ventilation?
PaCO2
What numbers are for acid-base?
pH
bicarb
base excess
Decreased blood oxygen levels
resulting from decreased delivery of oxygen from
atmosphere to the blood
Hypoxemia [PaCO2]
Decreased delivery of oxygen to the
tissues.
Hypoxia
5 reasons we have hypoxia
- hypoxemia 90%
- anemic hypoxia 10%
- circulatory hypoxia 5%
- affinity hypoxia
- histiocystic hypoxia
5 things that cause hypoxemia?
- ↓ blood oxygen tension ↓ PaO2
- Low inspired oxygen (FiO2)
- Hypoventilation
- V/Q mismatch – shunt
- Diffusion limitations
not enough Hgb
Anemic hypoxia
not enough cardiac output
Circulatory hypoxia
decrease release of O2 ( ↓temp, increased pH, carbon monoxide poisoning
Affinity hypoxia:
cell won’t accept the
delivery of the O2, (cyanide poisoning)
Histiocystic hypoxia
what is cyanosis?
- -Skin is blue, ashy or dark purple
- -PaO2 is low causing deoxygenated hgb
what results in greater cyanosis?
higher hgb levels
[testosterone supplementation]
these pts have little to no cyanosis
Anemic patients
PO2 of 40, 50, 60 equals:
sat of 70, 80, 90
PO2 of 50 =
paO2 of 26
Average oxygen consumption at rest is
2-4 ml O2/kg/minute
Fi02-Fe02 x Vm /weight in kg
VO2
FiO2 x Vm /weight in kg
DO2 (lungs)
will increasing FiO2 have any affect on DO2 if sat is 100%?
No, you need more hgb to increase O2 at that point
what 2 factors have greatest effect on 02 consumption and delivery?
hgb level and CO
what is the limiting factor in delivery of O2 to tissues?
cardiovascular system
what does the alveolar gas equation calculate?
alveolar partial pressure of O2 (PAO2)
fio2 x 6
PaO2 can be determined by
fio2 x 5
Pa-AO2 gradient is ≤ 10 mmHg with
FiO2 .21
Pa-AO2 gradient is ≤ 50 mmHg with
FiO2 1.0
CaO2 (mls/dL) x CO(mls/min)/kg/100
DO2
what will you see with hypoventilation?
decreases 02 and increased CO2
5 things that result from hypoxia?
- Hypoventilation
- Low partial pressure of oxygen in lung(PAO2)
- Low partial pressure of oxygen in arterial blood
(PaO2) - Low arterial oxygen saturation (SaO2)
- Low oxygen content (CaO2)
what is cpr intended for?
to keep delivering oxygen to brain
pulse ox is measured by Dual wavelengths of light by
660nm and 940 nm pass
through tissue and vascular beds via LED
this results in SpO2 that is falsely high
COHgb
MetHgb is similar to Hgb, how does the pulse ox differ?
If SaO2 > 85% then SpO2 will be
low, if SaO2 < 85% then SpO2 high
what two things are pulse ox NOT affected by?
Fetal Hgb and Sickle Cell Anemia
These two things result in falsely low SpO2
Improper fitting probe
SpO2 < 60%
5 things that cause errors in pulse ox resulting in falsely low SpO2?
- low Hgb concentration
- Methylene blue
- blue nail polish close to 660 nm
- excessive motion
- poor perfusion
1 thing that causes falsely high SpO2?
ambient fluorescent light
Measurement of CO2 during ventilatory cycle
capnography
CO2 is measured by
infrared absorption.
Airway gas is aspirated through tubing
to a measurement chamber
Sidestream
CO2 is affected by
VO2
CO2 transport
Alveolar ventilation
8 things that cause increased CO2 readings
Fever Physical activity Seizures Sepsis Hyperthyroidism Trauma and burns High carbohydrate diet Hypoventilation
7 things that cause decreased CO2 readings
Hypotension Decreased cardiac output Right to left pulmonary shunt: Hypothyroidism Hypothermia Paralysis, motionless Hyperventilation
Cardiac status and ventilator settings affect
elimination/evacuation of CO2, not production
Patient metabolic status affects CO2 production. What does VO2 mirror?
CO2 level.
Percent change in VO2 can indicate what the EtCO2 will show.
3 things that cause increased PetCO2
increased CO2 production and delivery to lungs
decreased alveolar ventilation
equipment malfunction
3 things that cause decreased PetCO2
decreased CO2 production and delivery to lungs
increased alveolar ventilation
equipment malfunction
Inaccurate low readings and waveforms are
common as contaminated exhaled gases are
mixed with ambient air
capnography in non-intubated patients
Occurs during times without gas flow, such as
during an inspiratory pause or at the end of
inhalation.
static lung compliance
static lung compliance is measured by
using plateau pressure
end inhalation prior to exhalation
Plateau pressure:
Plateau pressure is always lower than
Peak pressure
Occurs during times of gas flow, during active inspiration, Measures lung compliance plus airway resistance
dynamic lung compliance
dynamic lung compliance is measured by
Peak pressure
what contributes to a decrease in dynamic compliance
Airway resistance
Airway resistance measured using peak pressures can ____
from breath to breath while lung compliance mostly remains
_____
changed
unchanged
highest circuit pressure
during inspiratory cycle
Indicator of dynamic compliance
when flow is occurring.
PIP
peak inspiratory pressure
pressure during inspiratory pause,
no flow
Plateau pressure (Pplat)
Normal FEV1 (Forced expiratory volume over one second)
at least 80% of vital capacity
FEV1/FVC (Forced Expiratory Volume/Forced vital capacity) ratio normal
80%, declines with age
Forced Expiratory flow (FEF 25%-75%) between 25% and 75% of exhaled breath normal is
4-5L/sec
Least affected by patient effort (effort independent)
Forced Expiratory flow
most objective measurement of airway resistance medium airways
Forced Expiratory flow
Normal results are found in restrictive disease
Forced Expiratory flow
Most sensitive indicator of small airway obstructive disease
Forced Expiratory flow
Diffusion capacity (DL test) Can identify
shunt, VQ mismatch, fibrosis, emphysema
what is diffusion capacity test?
Carbon monoxide inhaled then measured
Measures gas ability to cross alveolar-capillary membrane
how do restrictive lung volumes compare to normal values?
Reduced TLC, FRC, RV
Reduced FVC & FEV1
FEV1/FVC ratio preserved
how do obstructive lung volumes compare to normal?
Enlarged TLC, RV, FRC
Reduced ERV
Indicator of lung compliance (distensibility).
Yields information regarding leaks, lung over-inflation and obstruction
pressure volume loops
Loops move based on
positive or negative pressure
how do loops move during positive pressure vs spont respirations?
Counter-clockwise during positive pressure ventilation.
Clockwise direction during spontaneous respiration.
Higher pressure moves loop
farther right.
Slope = lung compliance. what do they indicate?
Flatter slope indicates decreased compliance
Steeper slope indicates increased compliance
Restrictive Lung Disease flow volume loop characteristics
Normal shape
Lung volumes are smaller
Flows are reduced
obstructive lung disease flow characteristics
Shape is caved in which indicates expiratory obstruction
Lung volumes are larger
Flows are reduced
Obstructed flow will always yield a
flatter, less round
shape as air flow is impeded.
