Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Intro To Anesthesia > Ventilators > Flashcards

Ventilators Flashcards

1
Q

What are we manipulating w/ pre-oxygenation?

A

Functional Residual Capacity (FRC)

  • Expiratory Reserve Volume (ERV) + Residual Volume (RV)
  • Increasing this allows more time for intubation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the differences between an ICU vent and an Anesthesia vent

A

Anesthesia

  1. Bellows or piston driven
  2. Semi-closed circuit
  3. Exhaled gases to scavenger
  4. Need reservoir for exhaled gases
  5. Flowmeters plus vaporizers

ICU

  1. Usually piston
  2. Open circuit
  3. Exhaled gases to atmosphere
  4. No reservoir for exhaled gases
  5. Oxygen blenders
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are 3 Advantages of the Ventilator

A
  1. Provider free for other tasks
  2. Decrease fatigue
  3. Produce more regular rate, rhythm, and TV (creates more hemodynamic stability)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Disadvantages of the Ventilator

A
  1. Loss of feel (#1 reason)
    - Cannot physically push the breath into the patient and therefore cannot feel the compliance
  2. Older versions have less features
  3. Components are hard to clean and fix
  4. Not user friendly
  5. May be too noisy or too quiet
  6. May require high driving gas flows which is $$$
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is Barotrauma

A

Injury resulting from high airway pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is Compliance

A

Ratio of a change in volume to a change in pressure

  • Expressed in ml/ cmH2O
  • Lungs, chest wall, breathing tubes, and reservoir bags have compliance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is Continuous Positive Airway Pressure (CPAP)

A

Airway pressure maintained above ambient during spontaneous respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Label the contents of one breath cycle

A
  1. Expiratory Flow Time: time from beginning to end of expiration
  2. Expiratory Pause Time: time from end of expiration until inspiration begins
  3. Expiratory Phase Time: add the two time above
  4. Inspirations Flow Time: time from beginning to end of inspiration
  5. Inspiration Pause Time: time during which lungs are held inflated at a fixed volume/ pressure (zero flow)
    • Also called inspiration hold, inspiratory plateau
  6. Inspiratory Phase Time: add the two times above
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is I:E ratio

And what patients would you use it for?

A

Ratio of inspiratory phase time to Expiratory phase time

  • Typically exp. phase longer but if done in reverse then it is called
    • Inverse ratio ventilation
  • Normal = 1:2 — 1 sec to inspire, 2 sec to expire
  • Reverse = 2:1

Patient’s with disease states: emphysema, asthma, COPD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is minute volume?

A

Sum of all tidal volumes in one minute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is Peek Pressure?

A

Maximum pressure during inspiratory phase time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does PEEP stand for and what is it?

A

Positive End Expiratory Pressure (PEEP)

  • Airway pressure above ambient at end of Expiratory phase in controlled ventilation
  • APL valve in spontaneous breathing patients
  • Patients under anesthesia can’t sigh or produce surfactant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is Resistance?

A

Driving pressure to change in flow rate

  • cmH2O/L/sec
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a Sigh?

A

Deliberate increase in TV for 1+ breaths

  • Patients who are spontaneously breathing do this as a form of PEEP
  • Patients on the ventilator can’t do this

If a patient is desating d/t no ventilation give a sigh to re-expand alveoli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is Work of Breathing?

What are 3 signs ?

A

Energy expended by patient/ventilator to move gases in and out of lungs

  • Joules/L
  • WOB = grunting, accessory muscle use, retractions, belly breathing, nasal flaring, increased respiratory rate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are 3 factors that affect Tidal Volumes?

A
  1. Fresh Gas Flow
    - in older machines: increased flow - increased RR - increased I:E = increased TV
    - New machines divert extra FGF during inspiration
  2. Compliance
    - decrease compliance = decrease TV
    - Stiff chest harder to get Vol. in
    - New machines compensate for compliance in the machine checkout procedure but changes in circuit configuration (i.e. adding length) will result in inaccuracy of compensation
  3. Leak
    - ETT/LMA leak can not be compensated for by ventilator
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Optimal vent setting provide what?

List 5

A
  1. Distending pressures
  2. Alveolar recruitment
  3. V/Q matching
  4. Homogeneity
  5. Prevention of Ventilator Induced Lung Injury (VILI)
  • Research says w/ better hemodynamics there is decreased mortality & MODs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the 4 main components of a Bellows Ventilator?

A
  1. Driving Gas Supply
    • Pneumatically powered but electronically controlled
    • Needs driving gas, air or O2 ($), do not use during power failure d/t cylinder use being short lived
  2. Controls
    • Regulates flow, Volume, Timing, & Pressure
  3. Alarms
    • REGULATION: must have both high and low pressure alarm
  4. Pressure limiting mechanism
    • REGULATION: adjustable mechanism to limit inspiratory pressure
      • potential for operator error
    • Prevents barotrauma
    • Set inspiratory pressure 10 cmH2O above peek pressure with desired TV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why would the alarm for high Peek Inspiratory Pressure be going off?

A
  1. Decrease compliance in the chest (Broncospasm)
  2. Surgeons open retractors more & add more padding in the chest cavity
  3. Could be someone leaning on the patient
  4. Adding air into the belly (laproscopic cholecystectomy)
  5. Coming off paralytic or anesthesia is light
  6. Breath stacking
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the 3 safety valves in the Bellows assembly and what do they do?

A
  1. Exhaust Valve
    - opens to allow gases from the housing chamber into the environment on beginning of exhalation (does not contain volatile)
  2. Spill Valve
    - allows excess FGF inside Bellow (accordion) to be sent to scavenging system during end of exhalation (contains volatile)
    - this prevents extra pressure/ volatile to go to the patient
  3. Safety Relief Valve
    - expels excess gas from housing if driving pressure too high, will see in Mid-inspiration
21
Q

How are Piston Driven Ventilators different that Bellows?

A
  1. Electronically driven
  2. Reservoir bag not isolated on exhalation but is on inhalation
  3. Reservoir bag used to modulate pressures in the system = prevent negative inspiratory pressure (safety feature)
  4. Inspiration pushes gases into breathing system and excess into reservoir bag
22
Q

What are 2 Advantages of the Piston Ventilator?

A
  1. Decrease cost due to no driving gas

2. More accurate TV at constant velocity

23
Q

What is the main disadvantage of the Piston Ventilator?

A

Air entrainment from disconnect may not generate alarm

  • The disconnect could come from either the circuit at the point of the CO2 line or a flutter valve stuck open
  • If this occurs we worry about awareness d/t dilution
24
Q

What are some considerations when taking a patient to MRI and they are on a ventilator?

A
  1. MRI compatible machine - Cannot use a standard machine b/c of ferromagnetic substances
  2. If you have to use an anesthesia machine have to keep it in the hallway — have to have extension tubing
  3. Use pipeline supply - cannot take cylinders in or have to have nonferrous cylinders
25
Q

What are 4 main things that can go wrong with ventilators?

A
  1. Ventilation Failure
    • no power supply, too high FGF, fluid in electronic circuitry, leaking bellows, left on for periods long than 24 hrs
  2. Loss of Breathing System Gas
    • Failure to occlude spill valve (bellows) (all flow sent to scavenger(?), system leak (less apparent in descending bellows, that’s why they are obsolete)
  3. Incorrect Settings
    • not adjusted for new case, not adjusted for new position/pressure changes, vent turned off for x-ray
  4. Pressure Problems
    • O2 flush on inspiration w/ APL valve closed (use) = Barotrauma (high pressure O2 flush = 35 - 75 L/min)
    • Insufficient Expiratory time = auto Peep - breath stacking, barotrauma
26
Q

What are the most common Vent Modes?

7

A
  1. Volume Control
  2. Pressure Control
  3. Assist Control
  4. Spontaneous Intermittent Mandatory Ventilation (SIMV)
  5. Pressure Support Ventilation (PSV)
  6. Constant Positive Airway Pressure (CPAP) & Bi-level Positive Airway Pressure (BiPAP)
  7. Airway Pressure Release Ventilation (APRV)
27
Q

What 2 Factors do ventilator settings depend on ?

A
  1. Compliance: ability to stretch/expand the chest
  2. Gas exchange: oxygen delivery at alveoli
    - Can assess these via blood gases
28
Q

If your patient’s blood gas read:

  • pH 7.4, PCO2 45, PaO2 50

What would you change on your vent setting?

Mode, Vt, Peep, RR, FiO2, I:E

A

Add Peep

- If you just increase FiO2 & they have collapsed alveoli you are not going to get the full benefit of O2

29
Q

How do you calculate a normal PaO2?

A

Take the FiO2 x 5 and it gives you what the PaO2 should be according to the FiO2 setting

  • Normal PaO2 = 80 - 100
    • this is a range where all systems work the best
30
Q

What 2 ventilator settings would you use if your patient was not spontaneously breathing?

A

Positive Pressure Ventilation:

  1. Volume Control
  2. Pressure Control
31
Q

Volume Control Ventilation

A
  • Preset tidal volume on a timer
    • Pushes vol. into patient no matter what
  • Vt does not depend on patient effort, resistance, or compliance changes
  • Volume does not change — Pressure varies
  • Good for paralyzed patients
  • Inspiratory phase can be limited if excessive airway pressures are reached
  • Inspiratory flow too high = High PIP (Peek Inspiratory Pressure)
    • giving them a breath too quick
  • Change in compliance = change in PIP
32
Q

Consideration for exhalation on Volume Control Ventilation

A
  • Exhalation is passive
    • requires appropriate time (I:E= 1:2 or 1:3)
    • Dependent on patient’s resistance & elastance (pressure required to inflate lungs) or compliance
    • Pts w/ an increase need longer time to exhale
  • At the end of expiration airway pressure returns to atmospheric pressure or to what PEEP is set at
  • If not allowed enough time to exhale = high intrathoracic pressure
    = decreased venous return & cardiac output
    = increased risk of barotrauma
    = displacement of the diaphragm & inspiratory muscles from their optimal functional position
33
Q

Pressure Control Ventilation

A
  • Vent will deliver the breath at a preset pressure in a given time
  • Delivers breath no matter the patient’s effort
  • Pressure is set - Volume varies

Good for:

  • Lung injury
  • Single lung ventilation
  • SUPRAGLOTTIC AIRWAYS (if you give a set vol. the extra could go into belly = aspiration)
    • good to have a set pressure for LMAs (20 cmH2O)
  • Partial airway obstructions
    • b/c the decelerating flow patterns provide the best delivery of gas to the alveoli
34
Q

Which vent mode in the sedated patient is better for alveolar recruitment?

A

Pressure control

  • it is a more consistent & uniform way to give breaths
  • maximizes oxygenation for the patient
  • homogeneity (all the same)
35
Q

Which vent mode is preferred if you have to have a set MV (minute ventilation)?

A

Volume control

  • Minute ventilation = RR x Vt
    • normal is 4-6 L/min
  • RR and Vt are present in VC vs. PCV when Vt fluctuates
36
Q

In a spontaneously breathing patient what ventilator modes are used?

And which ones are for Sedated & Non-sedated pts.

A

Negative Pressure Ventilation:

Sedated patients:

  1. Intermittent mandatory ventilation (IMV)
  2. Assist Control (AC)
  3. Synchronized intermittent mandatory ventilation (SIMV)
  4. Pressure support ventilation (PSV)
  5. Airway pressure release ventilation (APRV)

Non-sedated patients:

  1. CPAP
  2. BiPAP
  3. APRV
37
Q

Benefits of using synchronized breathing ventilator modes:

A
  1. restoring gas exchange
  2. Unloads the WOB/ resp muscle use
  3. Relieving dyspnea - assist the patient if they are weak but still allow them to use their diaphragm

In the critically ill patient’s:

  1. Reduces sedation and paralysis
  2. Minimize cardiovascular side effects of mechanical vent.
  3. Decreases disuse diaphragm atrophy
  4. Improves V/Q mismatch (uniform O2 delivery
38
Q

Synchronized Intermittent Mandatory Ventilation (SIMV)

A
  • The vent is synched with the patients own breathing
  • It detects patient driven inspiration to deliver:
    • Vt or pressure
    • Rate
    • minimum mandatory ventilation rate
  • Does not require I:E ratio
  • Good for facilitating emergence from anesthesia
    • allows for titration of medication so we don’t snow them
  • If settings too high = can knock out the patients spontaneous drive to breathe
39
Q

Assist Control

A
  • Vent delivers a preset Vt whether the patient initiates it or not
  • VC/PCV on steroids - accentuates every breath
  • Ideal for muscle recovery b/c the vent does most of the work
  • Good for: (ICU pts)
    • Post resuscitation
    • Acute resp distress syndrome (ARDS)
  • Bad for: (OR, especially on emergence)
    • Anxious patients who frequently trigger the vent = hyperventilation
    • Needs adequate time for exhalation or it increases the risk of barotrauma or pos. Drive ETCO2 down and disrupt pH
40
Q

Pressure Support Ventilation

A
  • Provides positive pressure to patient initiated breath
  • No set R
  • Vt determined by:
    • PS level
    • lung characteristics
    • Patient effort
      • No effort = no breath

Bad for:
- Hyperventilating patient = breath stacking

Good for:
- reducing the WOB, increasing FRC, oxygenating obese pts, supraglottic airways, weaning, vent harmony

41
Q

Airway Pressure Release Ventilation (APRV)

A
  • Rarely used
  • Inverse ratio of inhalation pressure
    • Typically 10:1 (5 sec : 0.5 sec)
  • Used mainly as a rescue therapy for ARDS
    • Extra time to inhale
  • Has to be carefully monitored so you don’t have breath stacking
42
Q

Benefits of PEEP/CPAP/BiPAP (4)

A
  1. More uniform distribution of Vt
  2. Increased FRC
  3. Better arterial oxygenation
  4. Redistribution lung water
  5. Reduced V/Q mismatch
43
Q

What are 5 protective lung strategies

A
  1. Low Vt = 6- 8 mL/kg PBW)
  2. Maintaining Pplat less than 30 cmH20 (if pleural pressure is normal)
  3. Use PEEP & recruitment maneuvers (sigh)
  4. Reduce FiO2
  5. Permissive hypercapnia (controlled increase in PCO2, reduces inflammation, & relaxing smooth muscles)
44
Q

5 Reasons why you might be getting a Vent alarm

DOPES

A 
D = Dislodgment
O = Obstruction of ETT - mucus plug, bitting, kink
P = Pneumothorax
E = Equipment malfunction
S = Stacked Breaths or dis-synchrony
45
Q

Low Peak Pressure Alarm

A

Think Leak

  • Problem = can’t generate pressure needed to oxygenate patient
  • Common issue = ETT too high or dislodged, cuff leak, chest tube leak
  • Least likely issue = bronchopulmonary fistula
46
Q

High Pressure & normal Plateau Alarm

A

Think Resistance

Problem = smaller diameter for air flow

Common issues =

  • Bronchospasm
  • Mucus plug
  • Aspiration
  • Hemoptysis (blood in airway)
  • Water condensation
  • Kink
47
Q

High Peak Pressure & High Plateau Alarm

A

Think Compliance

Problem = lungs resisting ventilation

Common issues =

  • Worsening pneumonia
  • Pulmonary edema
  • Auto PEEP
  • Right Mainstem intubation
  • Tension Pneumothorax

Least likely issue =

  • Diaphragm injury
  • Compartment syndrome
  • Circumferential burn (constriction)
48
Q

Hypoxia with normal curve

A

Think Shunt

Problem = increase dead space ventilation or poor perfusion

Common issues =

  • Pulmonary embolism
  • Hypovolemia
  • Shock
  • AV fistula

Least likely issues =
- Intracardiac shunt (PFO)

49
Q

What is the first thing you should do if you have High Airway Pressure?

A

Disconnect from the circuit & manual vent while you locate the problem

  • if you leave patient connected to high pressures it will cause barotrauma

Intro To Anesthesia (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions