Initiating and managing ventilator support

Question 1

What is the purpose of mechanical ventilation

Answer 1

1. maintain homeostasis.
2. Mechanical ventilation is indicated when a person cannot achieve an appropriate level of ventilation to maintain adequate gas exchange and acid–base balance

Question 2

What is the indication of mechanical ventilation

Answer 2

1. respiratory failure
   - oxygenation failure
   - ventilatory failure
   - ->acute
   - ->impending
2. Apnea

Question 3

What are the phsyiological goals of ventilatory support ?

Answer 3

1. support gas exchange
   2.lung recruitment
   3.reduce WOB
   minimizes cardiovascular effects

Question 4

What are the disadvantages of Volume or flow control breaths?

Answer 4

• patient with high drive to breath can result in alveolar hyperinflation
• pressure changes due to changes in C and R can result in high pressure
• can lead to patient-ventilator dyssycnhrony if patient can breath on their own and increase WOB`

Question 5

When is volume of flow control breath used?

Answer 5

• when patient isn’t triggering

- high pressure isn’t a concern

Question 6

When is pressure control breath use

Answer 6

for a spontaneous breathing patient because flow pattern can vary with demand

Question 7

What are the advantages of pressure ventilation?

Answer 7

1. variable flow capability for patient
2. rapid filing of the alveoli
3. easier to control airway pressure
4. improved gas distribution and better V/Q matching

Question 8

What are 2 ways to get desired Vt in pressure ventilation

Answer 8

1. start in VC, measure plateau pressure. Then switch to pressure ventilation and set inspiratory pressure equal to plateau pressure
2. start in pressure ventilation, and set Pinsp at 10cmh2o above peep
   - move pressure by 1 - 2 cmh20 until Vt is met

Question 9

What are 2 factors to be considered when setting tidal volume?

Answer 9

• tubing comlpiance loss

- mechanical deadspace

Question 10

What is the typical I time?

Answer 10

0.8 - 1.2 sec

Question 11

What flow waveform should be used if patient has high drive to breath?

Answer 11

descending ramp

- higher initial flow is better to meet their demand

Question 12

what flow waveform should be used for COPD(emphseyma ) patient

Answer 12

descending ramp

• higher initial flow gives shorter I time
• gives longer E time for patient to fully exhale

Question 13

What flow wavefirm should be used for ARDS

Answer 13

• lower flow from lower pressure setting
• ->helps with lung protection
• -> better distribution of ventilation

Question 14

How is the assessment of ventilator settings perfomred?

Answer 14

1. vent round done:
   - -> q4h
   - ->after parameter is changed
   - ->after ABG is done
   - ->after changes in patient condition

2.monitor patient variable