Clin Med - Vent basics

Question 1

why intubate?

Answer 1

1. airway protection
2. difficulty oxygenating
3. difficulty w/ respirations

Question 2

what is a ventilator

Answer 2

• a simple machines: it delivers a volume of air at a specified pressure for a determined length of time at a prescribed rate
• it’s a bellows; you can squeeze faster, harder, deeper

Question 3

Vt (or Tv)

Answer 3

tidal volume

Question 4

MV

Answer 4

minute ventilation

Question 5

FiO2

Answer 5

fraction of inspired oxygen

Question 6

PEEP

Answer 6

positive end expiratory pressure

Question 7

BPAP

Answer 7

bi-level positive airway pressure

Question 8

CPAP

Answer 8

continuous positive airway pressure

Question 9

SaO2/So2

Answer 9

a derived value of the arterial oxygen saturation; measures the percentage of hgb which is fully combine w/ oxygen

Question 10

PO2

Answer 10

partial pressure of oxygen

Question 11

PCO2

Answer 11

partial pressure of CO2

Question 12

What to consider in ventilation?

Answer 12

The “Ts”

• trigger
• target

Question 13

who triggers the vent?

Answer 13

• vent provider takes complete control

- if patient is able to breath on their own, they take control

Question 14

modes of ventilation (3)

Answer 14

• AC (assist control)
• SIMV (synchronized intermittent mandatory ventilation)
• pressure support/pressure control

Question 15

AC Ventilation

Answer 15

• provider/vent determines the rate for the patient
• does not sense pts efforts at all
• can lead to breath stacking
• can lead to respiratory alkalosis/acidosis
• can lead to lung injury/PTX

Question 16

SIMV Ventilation

Answer 16

• control is shared by vent and pt
• provider/vent set the rate and minute ventilation and any pressure support
• vent sense pt by negative pressure or interruption of flow loop
• if pt breathes on their own b/w scheduled breaths, vent does nothing
• if pt breathes near an upcoming scheduled breath the vent applies continued pressure to reach a specified Tv

Question 17

pressure controlled/ pressure support ventilation

Answer 17

• completely patient dependent
• provider/vent specify pressure
• vent triggers at beginning of breath and measures negative pressure
• if insufficient, vent provides background pressure to increase breath
• must set an apnea time

Question 18

targets for ventilation

Answer 18

• for most pts, volume is best target
• A/C has volume control
• A/C and SIMV have pressure control

Question 19

what is traditional volume set on ventilation?

Answer 19

• 8-12 cc/kg of IBW
• ARDSnet volume 4-8cc/kg
• measure plateau pressure goal is <30

Question 20

peak pressure

Answer 20

• sum of lung stiffness, chest wall compliance and airway resistance
• goal is < 35

Question 21

plateau pressure

Answer 21

• measured by holding during inspiratory phase

- reflects the pressure at the alveoli

Question 22

What could high pressure alarms mean?

Answer 22

• machine (inappropriate settings, dysynchrony)
• circuit (kinking, mucus, wet filter)
• man (bronchospasm, decreased compliance, PTX, effusion, obesity, coughing)

Question 23

What is the first thing to do if high pressure alarms go off?

Answer 23

-disconnect the pt from vent and resume bagging

Question 24

How do you tell what the problem is?

Answer 24

-measure peak AND plateau pressures

Question 25

if peak pressure is high, but plateau pressure is normal what should be considered?

Answer 25

-problem with resistance

Question 26

if peak AND plateau pressure are high what should be considered?

Answer 26

-problem with compliance and lung restriction

Question 27

volume mode

Answer 27

• a flow of air over a unit of time

- breath is terminated once the entire volume is inhaled

Question 28

pressure mode

Answer 28

-breath terminates after a certain amount of time

Question 29

review cases

Answer 29

start at slide 18