4- resp/vents

Question 1

indications for intubation

Answer 1

VOPS – 
ventilation problems (not breathing, respiratory distress and fatigue),

oxygenation problems (PNA, atelectasis, etc),

airway protection,

secretions


Question 2

Besides its use in acute on chronic respiratory failure (i.e., COPD exacerbations), what are the clinical settings in which CPAP and/or BiPAP have been studied and shown to be potentially advantageous? 


Answer 2

COPD exacerbation,
pulmonary edema (PEEP pushes fluid out of interstitial space),
PNA in bone marrow unit (try to avoid intubation at any cost, 99% mortality),
neuromuscular problems

Question 3

what do you set for AC/SIMV vs Pressure support

Answer 3

AC/SIMV: RR, TV

PS: PEEP

Question 4

what do you set for pressure control

Answer 4

set RR, Peak Inspiratory Pressure (PIP) and Inspiratory Time (IT).

Question 5

Patient-ventilator dyssynchrony can be a sign that you should switch over to

Answer 5

PS

Question 6

values for TV, PEEP, RR, FiO2

Answer 6

a. TV: 7cc/kg IBD (500 ml)
b. PEEP: 5 cmH2O
c. Rate: 12
d. FIO2: 100%. Non-toxic is <60% FiO2.

Question 7

what do you set for volume control

Answer 7

TV and RR

Question 8

benefit of volume control

Answer 8

used to allow patient to rest their respiratory muscles 


Question 9

benefits of pressure control

Answer 9

minimizes risk of barotrauma; increases length of time alveoli are open; used in refractory hypoxemia and patient comfort;

Question 10

caution of pressure control in which population

Answer 10

don’t use in asthmatics; risk is no guaranteed volume and may create auto PEEP from gas trapping if there is not enough time for exhalation

Question 11

benefits of PS

Answer 11

minimizes barotauma, more comfortable;

Question 12

caution of PS in

Answer 12

don’t use if heavily sedated or brain injured because there is no backup rate

Question 13

How would you assess the appropriateness of your ventilator settings in addition to (and while waiting for) the results of an ABG?

Answer 13

If pressure is too high, the machine will be beeping. If too little, pt will be showing signs of not getting enough air.

Question 14

What would be your explanation if immediately after intubation the patient’s BP were high

Answer 14

inadequate sedation; increase sedation

Question 15

What would be your explanation if immediately after intubation the patient’s BP were low

Answer 15

too much sedation, ventilator causes an increase positive thoracic pressure, causing decreased venous return which is opposite that of spontaneously breathing; give fluids


Question 16

What type of respiratory failure is a patient with COPD most likely to develop and why?


Answer 16

ventilation; narrowed airways and poor mechanical ventilation

Question 17

resistance equation

Answer 17

Resistance = (Peak Pressure – Plateau pressure) / Flow Rate (usually 60L/min) =

Question 18

normal resistance value

Answer 18

<10

Question 19

compliance equation

Answer 19

Compliance = delta V / Delta P

= TVcc / (Pplataeu – PEEP)

Question 20

nl compliance

Answer 20

> 60

Question 21

Is the peak to plateau pressure gradient most consistent with increased airways resistance or diminished lung compliance?

Answer 21

resistance

Question 22

What are the clinical criteria for ARDS?

Answer 22

PaO2/FiO2 < 200,

CXR with diffuse infiltrates,

pulmonary edema is not fluid overload or CHF (Pcwp is not elevated if SGC is in place).

Question 23

The three most common causes of ARDS are

Answer 23

sepsis, pneumonia and aspiration.

Question 24

treat ARDS

Answer 24

fix cause and increase FiO2.

diuresis until hypotensive and either back off diuresis or add pressors

Increase the PEEP to force O2 through the fluid. 15-25 of PEEP

prone position -> inc PaO2 via blood to the less damaged sides of the lungs

optimize mixed venous O2

consider ECMO

Question 25

mechanism of ARDS

Answer 25

shunting- holes in the capillaries, causing the alveoli to fill in with fluid, leading to no O2 getting through.

Question 26

What general type of respiratory failure do patients with ARDS suffer from?

Answer 26

oxygenation

Question 27

how to optimize mixed venous O2

Answer 27

by increasing O2 delivery (DB to increase forward flow, transfuse to increase Hgb at the risk of fluid overload)

decreasing O2 consumption (first sedate or maybe paralyze the patient, treat fever).

Question 28

Weaning parameters

Answer 28

RSBI (rapid shallow breathing index, Tobin index) = freq / TV (in L)

NIF (negative inspiratory force) encouraging patient to inspire as much as possible

Question 29

weaning trials : SIMV

Answer 29

watch on less than full support; often SIMV, gradually turning down the rate. If they do fine, then extubate. If they start looking poor, then don’t d/c

5 days

Question 30

weaning trials: PS

Answer 30

PS trial: enough PIP so that they have the right volume and a reasonable RR), if you turn down and they become tachypnic, turn it back up and try tomorrow. You can extubate them if they get down to PEEP of 5;

4 days

Question 31

weaning trials: T-piece trial

Answer 31

T-Piece trial (SBT), like having a facemask with supplemental O2, but no extra pressure support, keep them like that for 30 min, if still okay, extubate. This is just turn off the vent. T-shaped so you can have extra O2 flowing by the ET tube.

3 days

Question 32

good RSBI to wean

Answer 32

RSBI < 104 is good (normal is around 20);

Question 33

good NIF to wean

Answer 33

normal is -60, bad is -20 to 0.