Ventilation Modes

Question 1

Peak Inspiratory Pressure

Answer 1

PIP
Total pressure required to distend the lungs & airway
Pressure used to calculate dynamic compliance

Question 2

Plateau Pressure

Answer 2

Pplat
Distending pressure to expand only the lungs
Measures air redistribution flow through lungs
Used to calculate static compliance (reflects intrinsic lungs)

Question 3

Mechanical Ventilation Variables

Answer 3

RR - respiratory rate
Vt - tidal volume
Pressure - PIP/Pplat/PAW
I:E ratio - inspiration to expiration

Question 4

Trigger Variable

Answer 4

Represents inspiration start

*Pressure, volume, flow, time

Question 5

Limit Variable

Answer 5

Target variable
Controls how inspiratory breath maintained
Once threshold reached will not exceed set limit

*Pressure, volume, flow

Question 6

Cycling Variable

Answer 6

Transition from inspiration to expiration
Once achieved set cycling variable → start expiration

*Volume, pressure, flow, time

Question 7

Baseline Variable

Answer 7

Pressure maintained at end expiration

Peak end expiratory pressure

Question 8

PEEP

Answer 8

Alveolar pressure above atmosphere
Individualized to patient
Prevents atelectasis
Intrinsic - 2nd to incomplete expiration (auto-PEEP)
Extrinsic - applied PEEP via mechanical ventilator

Question 9

Volume Control Ventilation

Answer 9

Time = trigger
Volume = limit
Time = cycling

Airway pressure (upside down V) changes breath-by-breath based on changing respiratory compliance
Flow remains constant (flat box)

Set appropriate PIP/pressure alarms

Question 10

Pressure Control Ventilation

Answer 10

Time = trigger
Pressure = limit
Time = cycling

Airway pressure controlled (flat box)
Vt changes breath-by-breath based on changing respiratory compliance
Decelerating wave flow - homogenous gas flow through lungs (improves ventilation pattern ↓WOB)

Avoid barotrauma d/t excessive pressure
Set appropriate Vt alarms

Question 11

Pressure Control Volume Guarantee

Answer 11

PCV-VG
Time = trigger
Pressure = limit
Time = cycling

Ventilator adjusts pressure delivered when current volume not at set #

• Adjustments take 3-5 breaths to complete
• Atelectasis development when ↓compliance & ventilator delayed in providing adequate pressure to distend lungs

Question 12

Synchronized Intermittent Mandatory Ventilation

Answer 12

SIMV
Delivers set Vt at set RR w/ patient initiated breaths
Time OR patient = trigger
Flow L/min = limit
Volume = cycling

Patient breaths are not supported (unless SIMV-PSV)
Appropriate mode when weaning from ventilator - less desynchrony w/ patient initiated breaths
Hypoventilation when inadequate Vt & RR w/ patient ↓respiratory effort
Hyperventilation when ↑PS level

Question 13

Pressure Support Ventilation

Answer 13

PSV
Supported ventilation mode for spontaneously breathing patient
Patient = trigger
Pressure = limit
Flow = cycling

Set Psupport & PEEP
Back-up mode Pinsp & RR

Question 14

Oxygen Delivery Formula

Answer 14

DO2 = CO x CaO2 (arterial)

Question 15

Oxygen Use Formula

Answer 15

VO2 = CO x O2a - O2v

Question 16

Hypoxemia

Answer 16

O2 deficiency in the blood

Question 17

Hypoxia

Answer 17

O2 delivery to the tissues not sufficient to meet metabolic demand

Question 18

Anesthesia Goal

Answer 18

Maintain oxygenation & ventilation

Question 19

Oxygen Therapy Goal

Answer 19

Prevent & correct hypoxemia & tissue hypoxia

Question 20

Hypoxia S/S

Answer 20

Vasodilation
Tachycardia
Tachypnea
Cyanosis
Confusion
Lactic acidosis

Question 21

Nasal Cannula

Answer 21

Flow rates 1-6L/min

FiO2 ↑4% per L/min

Question 22

Simple Face Masks

Answer 22

FiO2 40-60%

Minimum 6L flow required to prevent rebreathing

Question 23

Face Masks w/ Reservoir

Answer 23

FiO2 60-100%

Question 24

Venturi Masks

Answer 24

FiO2 24-50%
Set flow rate to ensure exact oxygen delivery
Bernouilli’s principle application

Question 25

Oxygen Toxicity

Answer 25

↑FiO2 over long periods → harmful to lung tissue ↓ciliary movement (unable to expel mucus) Alveolar epithelial damage Interstitial fibrosis Safe 100% O2 up to 10-20hr Toxic 50-60% O2 >24-72hr

Question 26

Absorption Atelectasis

Answer 26

Nitrogen replaced by oxygen Under-ventilated alveoli ↓volume ↑pulmonary shunting

Question 27

COPD

Answer 27

Chronic CO2 retention Hypoxic drive - do not administer oxygen Induced hypoventilation d/t ↑O2 *Theoretical only

Question 28

What triggers peripheral chemoreceptors?

Answer 28

Hypoxemia

Question 29

Fire Hazard

Answer 29

``` Extreme caution in head & neck cases Vigilance when administering O2 Notify surgeon when ↑O2 Risk w/ cautery instruments Chronic ICU patients receiving tracheostomy = high risk d/t ↑FiO2 requirements ```

Question 30

Retinopathy

Answer 30

ROP O2 therapy → vascular proliferation, fibrosis, retinal detachment, & blindness Premature neonates <36wk (up to 44wk) gestation or weigh <1500gm Safe O2 admin = PaO2 60-80mmHg

Question 31

Hypercapnia Causes

Answer 31

↑alveolar dead-space ↓alveolar perfusion Impaired pulmonary circulation Lung disease ↓alveolar ventilation (central or peripheral) Respiratory depression most common cause

Question 32

Hypercapnia Considerations

Answer 32

- Ventilatory drive regulation - Cerebral blood flow - Smooth & cardiac muscle depression - ↑catecholamine release - Vasodilation vs. vasoconstriction - ↑RR & PVR

Question 33

Hypercapnia Treatment

Answer 33

Identify cause | ↑minute ventilation

Question 34

Hypocapnia

Answer 34

Cause typically iatrogenic Clinical manifestations: ↓CBF ↓CO & coronary constriction Hypoxemia d/t hypoventilation Treatment ↓minute ventilation

Question 35

Anesthesia & Surgical Impact on Lungs

Answer 35

``` Neuromuscular blockers ↓muscle tone Abdominal contents cephalad displacement Alveolar compression ↑intra-abdominal pressure ↑BMI Trendelenburg position ↓FRC (upright → supine + paralysis + induction agents) ```

Question 36

Functional Residual Capacity

Answer 36

Decreases w/ age | ↓1.2-1.5L or 30mL/kg

Question 37

Recruitable vs. Non-Recruitable

Answer 37

Recruitable - General anesthesia - ↓FRC - Atelectasis Non-Recruitable - ARDS - Cellular debris - Edema

Question 38

Ventilation Induced Lung Injury

Answer 38

VILI | Ventilator SETTINGS cause injury

Question 39

Ventilation Associated Lung Injury

Answer 39

VALI Specific to OR setting Volutrauma - damaged epithelium, ↓surfactant, ↑capillary leak Barotrauma - damage from + pressure effects Atelectrauma - repeated collapse & re-inflation (under-utilized PEEP alveoli closed) Biotrauama - inflammatory mediator release

Question 40

Factors that Contribute to Alveolar Collapse

Answer 40

Position ↓FRC Induction loss muscle tone FiO2 reabsorption → atelectasis Maintenance ↓compliance → progressive airway closure Emergence high FiO2 promotes postop atelectasis Absence CPAP after extubation → continued lung collapse

Question 41

Lung Protective Ventilation Settings

Answer 41

``` Vt 6-8mL/kg IBW FiO2 <30% PEEP 30% BMI I:E 1:1.5 Alveolar recruitment maneuvers ```

Question 42

Induction Strategies

Answer 42

Initial FiO2 100% Elevate HOB >30% or reverse Trendelenburg Apply CPAP w/ bag-mask APL valve or vent mode Oral or nasal airway as needed

Question 43

LPV Goals

Answer 43

Restore lung volume w/ alveolar recruitment maneuver Maintain lung volume & minimize atelectasis formation (individualized PEEP) Maximize lung compliance - Use lowest possible driving pressure ΔP - Compliance = Vt / ΔP

Question 44

Alveolar Recruitment Maneuvers

Answer 44

BMI <30 → 40cmH2O 30-40 → 40-50cmH2O 40-50 → 50-55cmH2O >50 → 50-60cmH2O

Question 45

Emergence FiO2

Answer 45

<80% | Reduce atelectasis formation

Question 46

Pressure-Volume Loop

Answer 46

Assesses driving pressure Maximize volume delivered at lowest pressure *See OneNote graphs

Question 47

Flow-Volume Loop

Answer 47

Represents expiratory flow | *See OneNote graphs