Respiratory failure and intubation

Question 1

Assist control settings:

Answer 1

RR: 14-18 breaths per minute

Tidal Volume 8-10 ml/kg IBW

FiO2: 100

PEEP: 5

Get portable CXR

ABG in 30 minutes

Question 2

If pO2 is high

Answer 2

decrease FiO2

to prevent long term oxygen poisoning. Usually happens when FIO2>50.

Question 3

If pO2 is low

Answer 3

increase PEEP we don’t like too high of PEEP at first because of high risk for barotrauma.

Question 4

If pCO2 is high

Answer 4

increase RR or increase TV

Question 5

If pCO2 low

Answer 5

decrease RR decrease TV increase sedation

Question 6

mechanical ventilation indications

Answer 6

severe rspiratory failure

impaired sensorium GCS score of

hemodynamic instability

difficulty clearing secretions

Question 7

Pulmonary weaning from ventilator includes

Answer 7

SBT for 2 hrs RSBI (rapid shallow breathing index) <105 Good mental status strong cough absent upper airway lesions (cuff leak and can lift head)

Question 8

When to consider tracheostomy

Answer 8

after 10-14 days of being ventilator

Question 9

ET tube should be inserted to average depth of:

Answer 9

20-21 cm in women and 22-23 cm in men.

Question 10

after intubation should see:

Answer 10

symmetrical rise and both lungs should have bilateral breath sounds.

Question 11

what happens if you see asymmetrical rise of chest after intubation

Answer 11

may have endobronchial intubation or right mainstem bronchus because of its more vertical orientation. will lead to eventual collapse of left lung. Tx is to pull back ET tube by 3 cm.

Question 12

Don’t be fooled! Esophageal intubuation can have normal waveform at first in end tidal CO2 capnography so what do next

Answer 12

the normal waveform will occur in first few ventilations with esophageal intubation and then flatline. Will need to reintubate the patient.

Question 13

non invasive positive pressure ventilation indications (strongest evidence)

Answer 13

COPD (severe exacerbation or prevent extubation failure)

cardiogenic pulmonary edema

acute respiratory failure

• post operative hypoxemic respiratory failure

immunosuppressed pts

• facilitate early extubation

Question 14

Contraindications to non invasive positive pressure ventilation

Answer 14

Medical instability (cardiac or respiratory distress, severe acidosis ph<7.1, non respiratory organ failure (unstable cardiac arrhythmia/hemodynamic instablility, GCS<10 or GI bleed. Also contraindicated in inability to protect airway (uncooperative or agitated, inability to clear secretions or aspiration risk mechanical issues - recent esophageal anastomosis, facial or neurological surgery, deformity or trauma upper airway obstruction

Question 15

ARDS ventilator set up

Answer 15

mode: volume assist control tidal volume:

initially 8ml/kg IBW

Reduce to 4-6 ml/kg over 1-3 hrs

PEEP is 5-15 cm and use high

PEEP for moderate to severe ARDS

Resp Rate: <35/min

goal pH >7.2

PaO2/SaO2 55-80mg / 88-95%

Question 16

ARDS plateau pressure goal

Answer 16

<30 cm H20

Question 17

what works better low or high PEEP in ARDS

Answer 17

greater improvements in oxygenation with higher levels of PEEP without no difference in mortality between the two groups. the greater PEEP opens collapsed alveoli and spreads out tidal volume over more alveoli which decreases overall alveoli distension, and this allows for less barotrauma to alveoli since there’s cyclical atelectasis.

Question 18

ideal position of ET tube is

Answer 18

2-6 cm from carina to allow for migration of head movement when neck is flexed the end of ET tube migrates towards carina.

Question 19

treatment for moderate to severe COPD exacerbation with hypercapnic acidosis

Answer 19

NPPV or non invasive positive pressure ventilation can help decrease resp acidosis, tx failure, mortality and length of hospital stay

Question 20

how long should someone be on NPPV and when should you escalate to intubation?

Answer 20

2 hrs. if doesn’t improve or worsens needs intubation and mechanical ventilation.

Question 21

criteria for ARDS

Answer 21

1 new or worsening respiratory symptoms during past week or within 1 week of known clinical insult

2 bilateral lung opacities - fluffy infiltrates that look like pulm edema

3 no signs of cardiac failure or fluid overload

4 Severity of hypoxemia defined by P/F ratio <300 with a PEEP >5

Question 22

ARDS severity of hypoxemia as defined by

PaO2/FiO2 ratio <300 mmHG with PEEP>5 cm H20

Answer 22

mild ARDS: 200-300 mmHG

moderate: PF 100-200 mmHG
severe: PF< 100 mmHG

Question 23

goal PaO2 for ARDS

Answer 23

55-80 mm Hg

Question 24

why do we like low tidal volumes

Answer 24

6 ml/kg of IBW. Preferred compared to high tidal volume because it can cause over distension, alveolar rupture and gross barotrauma decreases mortality and number of ventilator days.

Question 25

what helps to improve mortality in ARDS

Answer 25

early administration of neuromuscular blockers and prone positioning.

Question 26

goal plateau pressure in ARDS

Answer 26

<30 cm H20

Question 27

which pts should not have low tidal volumes or hypercapnia or respiratory acidosis?

Answer 27

those with increased ICP, cerebral edema, or seizure disorder.

Question 28

Do we allow for permissive hypercapnia in ARDS?

Answer 28

yes as long as pH >7.20 because this means we can have less barotrauma as there’s lower tidal volume ventilation (aim for 4-6 ml/Kg of idea body weight) and so this allows for lower plateau pressure.

Question 29

how to reduce risk for oxygen toxicity?

Answer 29

try to lower FIO2 when able to <60%.

Question 30

PEEP is divided into

Answer 30

extrinsic and intrinsic components

extrinsic is provided by ventilator

intrinsic is component of air that remains in lungs due to incomplete expiration (auto peep)

Question 31

who is at greater risk for autoPEEP?

Answer 31

those are those who are unable to complete exhalation before the start of next inspiratory cycle. This occurs over repeated breaths and end expiratory alveolar pressure rises above the extrinsic PEEP and results in auto PEEP

Question 32

how to correct for auto PEEP?

Answer 32

reduce minute ventilation (reduction in tidal volume or respiratory rate) increasing expiratory time (using bronchodilators and inhaled corticosteroids to relieve airway obstruction)

Question 33

visualization of PEEP and autoPEEP on pressure and flow

Answer 33

Paw= airway pressure Palv = alveolar pressure PEEP= positive end expiratory pressure

Question 34

criteria for extubation failure

Answer 34

extubation failure is about 12-15% normally and if you have lower extubation rates you may need to try to extubate more people.

Question 35

extubation failure is associated with

Answer 35

increased hospital mortality, increased risk of nosocomial pneumonia, and longer ICU stays and total hospital stays.

Question 36

Fluid management in ARDs:

aim for a target of CVP<4mm and pulmonary artery occlusion pressure <8 mmHg

Answer 36

Pulmonary edema can develop easily in ARDs at any given hydrostatic pressure because the quality of intravascular hydrostatic pressure as oncotic pressure is unable to retain fluid in the capillaries.

Fluid restriction therefore can decrease risk fo developing pulmonary edema

Conservative management improves oxygenation index and lung injury score (PaO1/FiO2) ratio and resulted in fewer days on the ventilator or ICU.

Question 37

how to treat a patient is in pain while ventilated?

Answer 37

see them over breathing, see grimacing, agitation, writhing or signs of sympathetic activation with tachycardia, hypertension, and tachypnea - see overbreathing the vent with resp alkalosis.

Give adequate pain control with IV opioids like fentanyl, hydromorphone, or morhpine to decrease physiological responses to pain (hypermetabolism, increased catabolism, and oxygen demand)

Question 38

while intubated and on ventilator, causes of

Increased peak pressure and NORMAL plateau pressure:

Increased peak pressure and INCREASED plateau pressure:

Answer 38

Question 39

peak airway pressure definition:

Answer 39

maximum pressure measured in tidal volume that is being delivered. Try to keep peak pressure <35 cm H2O prevent risk of barotrauma.

Equals the sum of resistive pressure (flow X resistance) and plateau pressure

Peak airway pressure = resistive pressure + plateau pressure

Peak pressures are dynamic pressures that measure resistance of flow of air delivered from ventilator and the amount of pressure to needed to inflate lung.

Question 40

plateau pressure definition

Answer 40

plateau pressure is the pressure measured during an inspiratory hold maneuver, when pulmonary airflow and therefore resistive pressure are both 0. Keep plateau pressure <30 cm H2O to prevent barotrauma.

Plateau pressure equals sum of elastic pressure (elastance X tidal volume) and positive end expiratory pressure

Plateau pressure = elastic pressure + PEEP

Plateau pressures are static lung pressures that give an estimate of lung compliance

Question 41

peak pressure equation

Answer 41

Equals the sum of resistive pressure (flow X resistance) and plateau pressure

Peak airway pressure = resistive pressure + plateau pressure

Question 42

what to we try to keep peak pressures below:

Answer 42

Try to keep <35 cm H2O to prevent barotrauma

Equals the sum of resistive pressure (flow X resistance) and plateau pressure

Peak airway pressure = resistive pressure + plateau pressure

Question 43

equation for plateau pressure

Answer 43

Plateau pressure equals sum of elastic pressure (elastance X tidal volume) and positive end expiratory pressure

Plateau pressure = elastic pressure + PEEP

Question 44

ideal plateau pressure should be below

Answer 44

Keep plateau pressure <30 cm H2O to prevent barotrauma.

Question 45

how are elastance aned compliance related?

Answer 45

inversely related so decreased compliance (pulmonary fibrosis) will have stiffer lungs and higher elastic pressure

Question 46

increased peak pressure with unchanged plateau pressure means that

Answer 46

there’s increased airway resistance without change in lung compliance.

This means increased flow resistance from either: mucus plug, biting the tube, or bronchospasm

Question 47

Treatment of mucus plug

Answer 47

increased suctioning

Question 48

increased peak pressure and increased plateau pressure in a ventilated pt means:

Answer 48

this means there’s higher overal pressure in the closed system with the higher normal peak airway pressure

The higher overall plateau pressure may from increased elastic pressure or decreased compliance of the lung from either a pneumothorax, pulmonary edema, pneumonia, atelectasis or right mainstem intubation.

Question 49

benefit of non invasive positive pressure ventilation in heart failure?

Answer 49

NPPV increases intrathoracic pressure and reduces venous return and decreases right and left ventricular preload and improves cardiac output with the Frank Starling relationship.

It helps with cardiogenic pulmonary edema because of the increased preload from the reduced LV function and increased LV filling pressures and left atrial pressure (preload is increased) and these elevated pressures are eventually transmitted to the pulmonary capillaries that leads to fluid transudation.

Question 50

laryngospasm after thyroidectomy is a

What causes this?

Answer 50

is a medcial emergency

stridor after thyroidectomy plays a clue to cause

if respiratory distress or stridor is apparent after extubation then there’s bilateral recurrent laryngeal nerve injury

If stridor appears within a few hours of surgery it’s probably a wound hematoma with tracheal compression. Need to remove the bandages and look.

If stridor appears even lader and preceded by paresthesias and muscle cramps then its likely hypoglycemia from transient hypoparathroidism or inadavertent parathyroidectomy

Question 51

what is tracheomalacia?

Answer 51

diffuse or segmental tracheal weakness,

presents with dypsnea, cough, increased sputum production, wheezing, and stridor.

Question 52

what causes tracheomalacia?

Answer 52

prolonged intubation, chest wall trauma, severe emphysema, compression from a lesion

Question 53

what is the RSBI is rapid shallow breathing index

and how is it calculated and what is its role in determining if someone can be extubated?

intubated pt is breating RR 28 and tidal volume is 200 ml

Answer 53

RSBI is rapid shallow breathing index and if this ratio is <105 will be ok to extubate

it’s calculated by the Respiratory Rate / tidal volume

28/ 200 ml in LITERS or 28/0.2 = 140 which is too high. Probably will fail extubation. Needs to remain on assist control

Question 54

tracheostomy indications

Answer 54

long term mechanical ventilation -can’t remain intubated for >14 days. generally done after 11 days internationally

weaning failure

upper airway obstruction

copious secretions.

Question 55

Goals for ARDS:

Answer 55

low tidal volume 4-6 cm3

ok for permissive pCO2 as long as pH>7.2

pO2>55

Peak pressure <30

Question 56

how to determine if someone is brain dead?

Answer 56

Prior to the bedside apnea test, they are pre-oxygenated with 100% oxygen for 10 minutes using exisitng ventilatory support and then mechanical ventilation is discontinued.

Then they are observed for spontaneous respirations for 10 minutes. if respirations are observed then apnea test is negative and pt is not brain dead.

pt must be HDS, body temp >36 C and normal pH and normal PaCO2/PaO2 levels.

Apnea testing objectively confirms brainstem failure if pt cannot generate sponataneous breaths or trigger the ventilator in response to PaCO2 >10 minutes after disabling control mode.