Mechincal ventilation Basics Flashcards by Derrick Chuong

3 methods to deliver O2

Face mask - non invasive

Face mask via CPAP/BiPAP - non invasive

EDT mech. ventilation - invasive

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Benefits of CPAP and PEEP?

keeps intra alveolar pressure positive airways open at a PEEP at least of 5

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CPAP is the same thing what mode, and what is their main difference?

CPAP has the same mode as PEEP.

The difference:

->CPAP = non-invasive

->PEEP = invasive

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When would you consider endotracheal intubation and mechanical ventilation?

Think ABCs or when patients cannot breath:
-A: can the airway be maintinaed
-B: can breathing be maintained
-C: Circulation

-causes of hypoventilation

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What is the purpose of mech. ventilation during surgery?

deliver anesthetic drugs

prevents aspiration syndrome (gastric-content aspiration)

controls PaO2 and PaCO2
-i.e oxygenation and pH

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Generally describe CMV

Vent mode that does not allow for spontaneous breathing; the machine does all the work or gives assisted breaths.

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Cons to CMV

Asynchronous breathing; the machine and pt do not match
-aka they fight

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Generally describe IMV

Allows for spontaneous breathing; pt can’t trigger it whenever

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Give an example of IMV

Patient can breath between set breaths; used wen pt is conscious and is able to breath regularly.

mode would hopefully be switched to pressure support.

i.e we set 12 breaths as a minimum but allow for a RR of 13. They can take an extra breath but will not fall bellow 12.

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Describe the modes you may see on a old system

Assist control (AC) = CMV

Pressure control

Pressure support

CPAP/BiPAP

Synchronized interment mandatory ventilation (SIMV)

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Flow rate describes what?

how FAST would you like to push volume in

Flow = volume/time

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What is volume?

volume = tidal volume

aka

How much air would you like to give into the patient and out

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Describe the relationship in lung compliance

i.e Compliance

Compliance = delta V/ delta P

If the volume is constant, the relation between C and P is inverse
-(one increases, other decreases)
If pressure is constant, relationship between C and V is direct.
-(both increase or decrease)

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Lung compliance what happens when compliance decreases?

pressure increases to fill the airways

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What does it mean when a lung is compliant

A lung is compliant when it expands a big deal (volume increases) with only a slight pressure (low pressure)

C = delta v/ delta P

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What is volume control

you control (set) the volume, and keep an eye on the pressure.

If pressure increases, compliance is decreasing

when pressure increases too much -> alarms

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What is pressure control

you control (set) the pressure, and keep an eye on the volume.

If volume decreases -> Compliance is decreasing

when volume decreases too much —> alarm

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What vent. settings affect PCO2

RR and Vt

They both change alveolar ventilation

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Which vent. settings determine PO2?

FiO2 and PEEP

manipulation of oxygenation

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If a patient is hypoventilation; what is happening to his vitals; what is the appropriate response?

PCO2 increasing -> pH deceasing = resp. acidosis

Response:
Increase RR and tidal volume

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What should you do if a patient with high hypoxemia? what is happening to his vitals?

PaO2 = 50 = low

response:
increase FiO2 and PEEP

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When is a lung is considered compliant?

Study These Flashcards

when giving a small amount of pressure, it increases its volume drastically

if P is constant; lungs compliance decreases and volume decreases as a result

What factor determines peak pressure?

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Airway resistance

The greater the resistance the lower the pressure

change in peak pressure = what change?

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change in airway resistance

What is plateau pressure? *edit* needs a check for accuracy

when the air stops moving in (end of inspiration), the factor that determines the pressure in *compliance*

what increases inspiratory pause or plateau pressures?

Compliance

What does it mean when peak pressure (PIP) increases? *edit* needs a check for accuracy

Airway resistance, such as secretions

What does it mean when Pplat increases?

Lung compliance is decorticating

Review: low vs high lung compliance?

low = stiff lungs high = floppy wanna be somewhere in the middle.

If there is a problem with the peak pressure; where can you usually assume the problem lies?

airway issue

if there is a problem with the Pplat; what can you assume (usually) is the problem?

Lung compliance issue

*edit* add factors from a screen on shot on phone

Pulmonary MV and Alveolar MV

Pulmonary MV = RR x Vt Alveolar MV = RR x (Vt - dead space)

If RR is increased and FiO2 is maxed out, what could be the reason as to a patient who is not improving in condition?

Alveolar ventilation is not necessarily increased because of Deadspace (or Shunting?) where there is no gas -i.e hyperventilating; you’re only ventilating dead space

How do you increase alveolar ventilation

Deep, slow breathing or adding pressure (forces air into airways)

*continune watching medicos is perfctinalis vid on mech. vent* *edit*

left off at RR

What is a normal Vt range?

*5-8 ml/Kg of patients IBW* so somwhere between 350-700mL

What should you set PEEP at?

4-6, but rule of thumb stick w/5 on the initial vent setting

What happens when you increase inspiratory time?

Increase oxygenation, but may have diminishing returns because it affects the I:E ratio

Why are is too much Ti bad? *edit*

Stresses the body too much; normally you want a higher expiration ratio to inspiratory ratio

Normal Ti range?

0.9 - 1.10

How do you calculate MV?

Vt x RR

Normally you count RR according to the patient; how do you determine the RR for a vent? *insert image from SMS*

IBW x 6 (OR choose something between 5-8) = X [x] take that value * 100 = Y y/x = RR

Normal MV range?

5-6 L/min

Normal Vd/Vt ratio? aka deadspace?

2.2

Why would deadspace be increased?

◦Increased due to ventilation of areas of lung with poor perfusion ◦Altered V/Q (increased ventilation) Result = increased MV with PPV required to control PaCO2.

What is the Trigger, Limit, cycle, and Baseline for: VC-CMV

Trigger: Time OR Patient Limit: Flow Cycle: Volume Baseline: PEEP

What is PEEP also known as?

Base airway pressure

What is the Trigger, Limit, cycle, and Baseline for: PC-CMV

Trigger: Time or Patient Limit: Pressure Cycle: Time Baseline: PEEP or BAP

What is the Trigger, Limit, cycle, and Baseline for: PC-CMV Adaptative

Trigger: Time or Patient Limit: Pressure Cycle: Time Baseline: PEEP or BAP

On the PB980; what mode is PRVC?

AC-VC+

What is driving pressure?

Pplat - PEEP

How do you calculate resistance from a vent? - What is a bad range?

Ppeak - Pplat > 10 Implies too much resistance (or artifact)

What does a Ppeak - Pplat < 10 imply?

Compliance problem

Mechincal ventilation Basics Flashcards

(54 cards)