Ventilators Flashcards
Basic starting vent settings for asthma patient
Vt, FiO2, f, I:E, control type, PPlat, PIP
Vt-6-8 ml/kg
Fio2- 100% (1.0)
f- 8-10
I:E- 1:4 or 1:5
Pressure control preferred
PPlat- <30 cm/H20
PIP < 50 cm/H20
permissive hypercapnia
What is the starting peak inspiratory flow volume? (L/min)
50-60 L/min
What is CMV (AC) and what characteristics are involved.
- no spon. resp.
- sets min # of bpm with SET Vt
- can deliver an assisted breath to augment a spon one at a SET Vt
SIMV
- patient must have some spon. breaths
- get a min. # of bpm at SET Vt
- Spon breaths at the patients Vt
What is PSV and how does it affect the patient?
Assist inhalation by giving additional pressure to “blow the breath in”. Decreased WOB.
What is Volume controlled ventilation?
MD sets Vt for each breath
the pressure required to achieve that Vt can vary
Describe Pressure controlled ventilation? (what it is, wave form and effect on the patient).
MD sets insp. pressure and I:E ratio
creates a decelerating wave form pattern
less WOB than VCV
What may unprogrammed auto-PEEP indicate?
breath stacking/CO2 retention
What components determine the Ve?
minute volume
usually 100ml/kg
comprised of f and Vt
smaller Vt require faster f
slower f requires higher Vt to achieve the same Ve
What is Vt ? How much is the volume generally? How is this volume distributed in the lungs?
Tidal volume, 500ml or 5-8ml/kg in men. represents the volume in inhaled air that reached the alveoli of about 350ml plus another 150ml in the anatomic dead space.
What is the IRV?
inspiratory reserve volume- how much more air can you breath in after a normal breath
What is the RV?
residual volume- the amount of air remaining in the lungs after MAXIMAL expiration
What is the IC?
inspiratory capacity- the maximal volume of air that can be inspired after maximal exhalation.
What is the VC?
vital capacity- the volume of air that can be exhaled after the deepest possible inspiration
What is the FRC?
functional residual capacity- the volume of air remaining in the lungs at the end of a normal expiration
Two main types of resp failure
Hypoxic and hypercapnic/failure to oxygenate or failure to ventilate
What is the Flow rate? What is the measurement?
the SPEED at which a prescribed Vt is given. Usually 40-60L/min.
Pros & Cons of high flow rates
- decrease inspiratory time (allowing for longer exp time, allowing for less air trapping and CO2 exhalation PRO
- Increases PIP 2nd more turbulent flow CON
- may lead to maldistribution of gases in alveoli CON
- required to achieve high MV CON
Pros & Cons of low flow rates
- increased inspiratory time
- decreased PIP 2nd more laminar flow
- may improve as distribution in alveoli
What are the Pores of Kohn?
holes between alveoli allowing for collateral airflow between alveoli
Four main types of flow wave patterns
- square
- sinusoidal
- accelerating
- decelrating
Four Benefits of decelerating flow wave?
- may improve gas distribution in alveoli
- decreases dead space
- increases PaO2 tension
- reduces PIP
PxO2/PxCO2, what are the four x components?
a- arterial
A-alveolar
v - venous
c- capillary
PxO2/PxCO2, what are the x components
a- arterial
A-alveolar
v - venous
c- capillary
What is the PaO2 and it’s range?
75-100 mmHg Partial pressure of O2 in the arterial blood
What is the PvO2 and it’s range?
30-40 mmHg (remember it is similar to pH) Partial pressure of O2 in the venous blood
What is the PaCO2 and its range?
35-45 mmHg Partial pressure of CO2 in the artery
What is the PvCO2 and it range?
40-50 mmHg (remember it will be higher than arterial because venous blood carries CO2 back to lungs for exhalation) Partial pressure of CO2 in the vein