Settings based on Pathophysiology- CH1

Question 1

Restrictive lung diseases are associated with a reduction in respiratory system compliance. What does the lung wants to do?

Answer 1

The lungs want to collapse. In other words, it’s hard to get air in and easy to get air out.

Question 2

Restrictive Lung disease goals of ventilation :

Alveoli, oxygenation, distention of lungs

Answer 2

• recruit vulnerable alveoli
• prevent cyclical alveolar closure
• provide adequate oxygenation
• minimize volutrauma from overdistension.

Question 3

What should be the initial mode of ventilation for the patient with restrictive lung disease?

Answer 3

The initial mode should be one that takes over the work of breathing for the patient. VC or PCV

Question 4

Assist control include 2 kind of settings?

Answer 4

Assist-control, using either volume-controlled or pressure-controlled ventilation

Question 5

Mode of choice for patients with restrictive lung diseases such as ARDS, pneumonia, aspiration , pulmonary edema

Answer 5

Assist control using VCV or PCV

Question 6

Explain the settings for Volume ventilation
Set TV at _______of what body weight?
Rate of ____bpm with what kind of flow pattern?
FiO2 start at _______reduce to _______if SPO2>__%
reduce intrapulmonary shunting

Answer 6

1. Tidal volume of 6 mL/kg PBW
2. Rate of 14-18 breaths per minute, with a decelerating flow pattern
3. FiO2 100% at first; reduce to 60% if SpO2 ≥ 88%

Question 7

If hypoxemia persists, increase the_____ until the SpO2 is 88% or better. Don’t exceed the number___

Answer 7

PEEP ; 20

Question 8

After adjusting the PEEP, you should check what pressure?

Answer 8

plateau pressure. If the PPLAT is more than 30 cm

H2O, decrease the tidal volume until the PPLAT is less than 30. Don’t go below 4 mL/kg PBW.

Question 9

Don’t go below ____ mL/kg PBW.

Answer 9

4

Question 10

Remember, the more opacification in the lungs on the chest X-ray, the more PEEP will be needed to

Answer 10

Remove the intrapulmonary shunting

Question 11

After initiating ventilation, check an arterial blood gas. ____is enough time for gas exchange to equilibrate.

Answer 11

15-20 _minutes

Question 12

When on volume-control? monitor the____And keep it _______

Answer 12

PPLAT (volume-control) at 30 cm H2 O or less.

Question 13

On pressure control keep Peak Insp Pressre at_______

Answer 13

PINSP (pressure control) at 30 cm H2 O or less.

Question 14

Static compliance (Cstat) formula

Answer 14

Cstat = TV/ Pplat - PEEP

Question 15

Keep SPO2 between 88% and 94%. There’s nothing to gain from keeping the PaO2 above this range, with few exceptions:

Answer 15

Patients with traumatic brain injury sometimes require a higher PaO2 ,usually in conjunction with brain tissue oxygen monitoring. Victims of carbon monoxide
poisoning also benefit from breathing 100% oxygen.

Question 16

Goal for patient with COPD:

Answer 16

reduce hyperinflation.

Question 17

COPD patient best (ideal) setting?A

Answer 17

Assist-control ventilation is usually the mode of choice, and volume-control is preferable to pressure-control. SIMV with PS can also be used.

Question 18

High airway resistance and high peak inspiratory pressures characterize exacerbations of _____and ____

Answer 18

COPD and asthma,

Question 19

COPD TV setting and why? Rate?

Answer 19

Tidal volume of 8 mL/kg PBW.Lower tidal volumes can lead to air trapping and worsening hyperinflation. Rate of 10-14 breaths per minute

Question 20

Inspiratory time for COPD? and why?

Answer 20

Inspiratory time adjusted to keep an I:E ratio of 1:3 or higher. In obstructive airways disease, air gets in easily but has a hard time getting out due to narrow, inflamed
bronchioles and bronchi. Give the air some time to escape.

Question 21

COPD and FiO2 settings

Answer 21

5. FiO2 of 100% to start; lower this to 60% as long as the SpO2 remains 88% or better.

Question 22

Severe Metabolic Acidosis and vent settings? What happens with metabolic acidosis?

Answer 22

It is very difficult to set the ventilator to provide a high minute ventilation, even if you set the rate to be 30-35 and the tidal volume to be 800-1000 mL.

Patients with severe metabolic acidosis will often breathe in when the vent is trying to breathe out, and vice versa—this leads to significant patient-ventilator dyssynchrony and alarming of the machine. More consequentially, the volume and pressure alarms that are normally helpful will ACTUALLY WORK AGAINST the patient by limiting the minute ventilation that can occur.

Question 23

Examples of the wrong setting hurting the patient?

Answer 23

For example—a patient who has a pH of 6.88 and a HCO3 of 4 needs a PaCO2 of 14-15. If he’s intubated and sedated, and the vent settings are put in the
“usual” range, his PaCO2 may rise to 25-30. In the setting of severe acidemia, this increase in CO2 will cause his pH to fall to 6.6 or so, which will most likely lead to a
CARDIAC ARREST

Question 24

The best way to deal with this situation with a patient with Severe metabolic acidosis is to let the

Answer 24

patient’s naturally high respiratory drive work in his favor.

Question 25

Sedation and NMBA in the patient with severe metabolic acidosis? Comment on vent mode, CPAP aka PEEP
5. Allow the patient to have a minute ventilation of 18-25 L/min. Don’t be alarmed to see him pull spontaneous volumes of 1000-2000 mL. The high minute ventilation will keep the pH up while the cause of the metabolic acidosis is being treated.

Answer 25

Use the bare minimum of sedation to intubate and avoid neuromuscular blockers entirely.

2. Set the vent mode to be Pressure Support Ventilation.
3. CPAP (a.k.a. PEEP) 5-10 cm H2 O, depending on the degree of hypoxemia
4. Pressure Support (PS) of 10-15 cm H2 O. Adjust if needed to allow the patient to breathe comfortably; most of the time, 10 cm is enough PS.

Question 26

The patient with severe metabolic acidosis and MV : what should you allow and why?

Answer 26

Allow the patient to have a minute ventilation of 18-25 L/min. Don’t be alarmed to see him pull spontaneous volumes of 1000-2000 mL. The high minute ventilation will keep the pH up while the cause of the metabolic acidosis is being treated.

Question 27

What parameters is helpful to helpout the Left ventricle in patients with either systolic and diastolic failure

Answer 27

The left ventricle likes PEEP—increasing the intrathoracic pressure lowers preload and afterload, which is beneficial in acute cardiac failure due to left ventricular dysfunction (either systolic or diastolic).

Question 28

Compare the LV and the RV response to increase PEEP

Answer 28

The right ventricle, doesn’t care for PEEP very much. Increased intrathoracic pressure can increase pulmonary vascular pressures and stress the thin-walled RV.

Question 29

In situations where RV failure is present (massive pulmonary embolism, worsening pulmonary hypertension), use more of ____and less of ______to maintain oxygenation

Answer 29

use more FiO2 and less PEEP

(ideally 10 cm or less) to maintain oxygenation

Question 30

PEEP may increase the intracranial pressure, but it seems to be significant only when the PEEP is

Answer 30

15 cm or higher

Question 31

Hyperventilation (PaCO2 < 32) ______intracranial pressure, but it works by causing cerebral vaso_____.

Answer 31

lowers; constriction

Question 32

Prolonged hyperventilation on the brain _____; For patient with brain injury aim for a _____PacO2 range of _____

Answer 32

worsens brain ischemia and has no lasting effect on intracranial hypertension. Aim for a normal (35-40) PaCO2 .