Part 2

Question 1

Minute ventilation

Answer 1

• Respiratory Rate x Tidal Volume
• Normal range 5-6 L/min

Question 2

Plateau pressure

Answer 2

• Positive pressure applied to small airways & alveoli
• Goal is to keep under 30 cmH2O because excessive alveoli stretch is thought to be a cause of ventilator-induced lung injury

Question 3

Peak flow

Answer 3

• Determines rate of tidal volume delivery to the patient during mandatory volume control breaths
• Affects I:E ratio & peak pressure

Question 4

Volume control ventilation

Answer 4

• Tidal volume is preset & the resultant airway pressure is a function of lung compliance & other factors

Question 5

Volume control ventilation advantages

Answer 5

• Advantages
• Guaranteed minute ventilation
• May help lung compliance in certain surgeries (abdominal or chest surgery

Question 6

Volume control disadvantages

Answer 6

• Patient does not trigger breath, but can see patient effort in capnogram
• May need to reduce tidal volumes if you get high PIP/PAP

Question 7

Pressure control ventilation

Answer 7

Peak airway pressure is preset & the delivered tidal volume is a product of lung compliance & other factors

Question 8

Pressure control ventilation advantages/disadvantages

Answer 8

• Reduced ventilator-induced lung injury because able to limit peak inspiratory pressure which will also limit transalveolar pressure
• Improved gas distribution because uses decelerating flow
• More rapid improvement in lung compliance & oxygenation compared to VCV

Disadvantages
Does not guarantee minute ventilation

Question 9

Volume Controlled Ventilation

Dependent variables

Answer 9

Dependent variables

• PIP is determined from tidal volume set
• Plateau Pressure is determined by applying an inspiratory hold (0.5-1 sec). Hold represents no flow, which gives pressure the alveoli are seeing

Question 10

Pressure control ventilation

Answer 10

• PIP usually same as Plateau Pressure because of how breath is delivered
• There is an inherent inspiratory pause

Question 11

Pressure support ventilation

Answer 11

Spontaneous ventilation mode that provides constant pressure once patient inspiratory effort is sensed.

Question 12

Pressure support ventilation independent variables

Answer 12

Independent Variables (What you set)

• Support Pressure
• Inspiratory Time
• Flow Trigger
• FIO2

Question 13

PSV dependent variables

Answer 13

Tidal volume
Respiratory Rate

Question 14

PSV advantages

Answer 14

• Able to have patient breath spontaneously & not “fight” the ventilator
• Able to augment tidal volume
• Able to adjust ETCO2 with support pressure

Question 15

PSV disadvantages

Answer 15

Requires patient to be breathing spontaneously

Question 15

SIMV

Answer 15

• Breaths are given at preset time intervals
• Patient can breathe spontanously between the ventilator breaths
• Ventilator will not give a breath if the patient inspires at that same instant

Question 16

SIMV independent variables

Answer 16

• Tidal Volume
• Respiratory Rate
• I:E Ratio
• FIO2
• Pressure Support Level

Question 17

SIMV dependent variables

Answer 17

Peak Inspiratory Pressure
Plateau Pressure

Question 18

SIMV advantages

Answer 18

Can be used as way to start building up CO2
Back-up mode for PSV

Question 19

SIMV disadvantages

Answer 19

May confuse patient’s brain because not physiological

Question 20

Set TV to adults? children?

Answer 20

10-15 mL/kg (adults)
6-10 mL/kg (infants, children, & COPD)

Question 21

minute ventilation formula

Answer 21

VT x RR
4 x BSA for Men
3.5 x BSA for Women

Question 22

Ventilator fresh gas flow coupling

Answer 22

Fresh gas flow adds to tidal volume delivered by ventilator

Question 23

inspiratory pause

Answer 23

• Holds breath at end of inspiration (before exhalation starts)
• Allows breath to diffuse better
• Only available with VCV
• Usually 25% of inspiratory time
• Takes time from inspiration & adds it as a hold (expiration remains same)

Question 24

PEEP

Answer 24

Constant positive pressure applied at end of exhalation Causes airway pressure to not return to 0 cmH2O

Question 25

PEEP benefits

Answer 25

* Helps keep more alveoli open to participate in gas exchange * Helps prevent atelectasis by recruiting collapsed alveoli & improving V/Q mismatching * Increases functional residual capacity (FRC) & improves oxygenation

Question 26

PEEP problems

Answer 26

* May cause high alveolar pressures resulting in * Increased dead space * Unnecessary increase in work of breathing * Increased intrathoracic pressure * Reduces pressure gradient of blood returning to the heart * Reduces right ventricular preload & output (cardiac output)

Question 27

Using PEEP

Answer 27

* Set between 2-20 cmH2O * 5-10 cmH2O usually has little effect on patient hemodynamics In circuit * On Excel: need to phyisically place PEEP valve in line on the expiratory limb * On Aestiva/Aisys/Avance: Set using a button

Question 28

Auto PEEP

Answer 28

* Air trapping in the lungs because of insufficient exhalation time Signs * Non-zero end expiratory pressure * Increasing PIP/PAP

Question 30

Peak inspiratory pressure (PIP) / Peak airway pressure (PAP)

Answer 30

The pressure measured by the ventilator in the major airways