Ventilator Modes

Question 1

What are the 2 types of Volume Cycled Modes?

Answer 1

AC
SIMV

Question 2

What is Volume Cycled Ventitilation?

Answer 2

Consistent Vt maintained with changing pressure

Question 3

What is AC (assisted/controlled)?

Answer 3

A set RR, with volume being delivered when the patient takes a breath in (when negative pressure is sensed)

Question 4

What is an advantage of SIMV over A/C?

Answer 4

SIMV requires the patient’s respiratory muscles to keep working, as a lot of the breaths are their own.

Question 4

What does SIMV stand for?

Answer 4

Synchronized
Intermittent
Mandatory
Ventilation

Question 5

What is SIMV?

Answer 5

Allows spontaneous ventilation but provides for a set minute ventilation through synchronous mandatory breaths that line up with the patient’s inspiratory efforts.

Question 6

When is a good time to do pressure-cycled ventilation?

Answer 6

An obese patient in trendelenburg postion. This will push more against then extra adipose tissue that is compressing their lungs in this position.

Question 7

What is Pressure-Cycled Ventilation?

Answer 7

The ventilator delivers Vt until a pre-set pressure is reached, meaning the Vt varies depending on the pressure set.

Question 8

What is the normal dead space/ tidal volume ratio? (VD:Vt)

Answer 8

< 0.3
an increase in this number means an increase in dead space, such as in ARF, decreased CO, and PE

Question 8

What are complications of Mechanical Ventilation?

Answer 8

Infection- main factor in nosocomial pneumonia
Barotrauma- ruptured alveoli
Atelectasis- Hypoxia duet ot atelectasis is not responsive to FiO2

Question 9

3 main causes of hypoxemia:

Answer 9

1. V/Q mismatch
2. right-to-left pulmonary shunting
3. Hypoventilation

Question 10

Does FiO2 improve a right-to-left pulmonary shunt?

Answer 10

NO!

Question 11

T/F: Chronic hypoxemia leads to larger RBCs

Answer 11

True, their mass is increased to improve O2 carrying capacity

Question 12

What is permissive hypercapnia?

Answer 12

Allowing PaCO2 to go >55 mmHg to delay the need for intubation and ventilation

Question 13

What level of hypercapnia does CNS depression result?

Answer 13

> 80 mmHg

Question 14

Vent Weaning: what are the guidelines?

Answer 14

VC of >15 mL/kg
PaO2 of >60 mmHg
>-20 cmH2O negative inspiratory pressure
Normal pH
RR <20
VD:Vt <0.6
Patient should be alert
PEEP < 5 cmH2O

Question 15

When a trial of extubation is happening, what are the 3 options?

Answer 15

1. SIMV- allows progressively fewer mandatory breaths as the patient starts improvement of breathing
2. Intermittent total removal of mechanical support
3. Lessening levels of pressure support little by little

Question 16

After removal from ventilator, what should be done?

Answer 16

Supplemental O2 to improve V/Q mismatching
Incentive Spirometry