Mechanical Ventilation Flashcards Preview

001 Respiratory Therapy > Mechanical Ventilation > Flashcards

Flashcards in Mechanical Ventilation Deck (75)
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1
Q

Why is an endotracheal tube sometimes shortened?

A

Because a shorter ET tube facilitates airway management and secretion removal.

2
Q

The primary purpose of permissive hypercapnia is to reduce the patients ______ during mechanical ventilation?

A

Pulmonary pressures

3
Q

CPAP and PEEP may be used to decrease or correct refractory hypoxemia caused by what?

A

Intrapulmonary shunting

4
Q

Decreased muscle function, flattened T-wave and depressed ST segment on the electric cardiogram and diminished bowel sounds are some signs of what?

A

Hypokalemia

5
Q

What is a normal minute volume?

A

5-10 L/min

6
Q

When the ventilator frequency is over 20/min, the incidence of what is increased?

A

Auto-PEEP; especially when the pressure support ventilation is also used.

7
Q

Some practitioners prefer to titrate the pressure support level until the spontaneous respiratory rate is reduced to a desirable level. This change in respiratory rate is usually observed in conjunction with?

A

An increase in the spontaneous tidal volume.

8
Q

Why are patients with extremely high airway resistance or low compliance more likely to develop ventilator related lung injuries?

A

Patients with low compliance do not have very stretchable lungs, therefore, high pressure is going to strain the lungs more so than someone with good compliance.

9
Q

Severe acidosis may cause what?

A

Central nervous dysfunction, intracranial hypertension, and neuromuscular weakness.

10
Q

Refractory hypoxemia is usually caused by what?

A

Intrapulmonary shunting, and it does not respond very well to oxygen therapy alone.

11
Q

Anemic hypoxia is likely when the hemoglobin level is less than what?

A

10 g/100 ml of blood

12
Q

In HFOV, a lower PaCO2 may be achieved by using what?

A

A higher amplitude or a lower frequency.

13
Q

The mPaw is primarily affected by the what?

A

The power setting on HFOV.

14
Q

The low PEEP alarm is triggered when the actual PEEP level drops below the preset low PEEP limit. Failure of the ventilator circuit to hold the PEEP is usually due to what?

A

A leakage in the circuit or endotracheal (ET) tube cuff.

15
Q

Presence of excessive auto-PEEP may trigger the high PEEP alarm. What conditions may lead to the development of auto-PEEP?

A

Air trapping, insufficient inspiratory flow, insufficient expiratory time, and inadequate inspiratory time.

16
Q

Auto-PEEP caused by air trapping may be corrected or minimized by using a?

A

Bronchodilator

17
Q

Auto-PEEP is commonly associated with what?

A

Pressure support ventilation, sufficient airflow obstruction, respiratory frequencies of greater than 20/min, and insufficient inspiratory flow rates.

18
Q

Auto-PEEP may be reduced by?

A

Decreasing the tidal volume or mandatory frequency or increasing the inspiratory flow rate on the ventilator.

19
Q

Increasing the inspiratory flow rate on the ventilator does what?

A

Increasing the inspiratory flow rate on the ventilator does what?

20
Q

When setting changes cannot correct auto-PEEP, therapeutic PEEP may be for what?

A

It is used to reduce the effects of auto-PEEP that is due to air trapping in the small airways.

21
Q

The effective (delivered) tidal volume during mechanical ventilation is lower than the set tidal volume because the ventilator circuit is compliant to pressure and expands during inspiration. What does this cause?

A

As a result of this, a portion of the set tidal volume is not delivered to the patient.

22
Q

To minimize volume loss due to the effects of circuit compliance, the ventilator circuit should?

A

It should have a low circuit compliance.

23
Q

According to Poiseuille’s Law, when the radius of an airway is reduced by 50%, the driving pressure is affected how?

A

It is increased 16 times to maintain the same flow rate.

24
Q

What are the three goals of prone positioning?

A

Improve oxygenation, reduce inspiratory pressures (peak and plateau), and reduce atelectasis and shunting.

25
Q

What is the formula of Oxygen Index?

A

OI = (mPaw x FiO2) / PaO2

26
Q

What are the contraindications for prone positioning?

A

Increased intracranial pressure, hemodynamic instability, spinal cord injury, history of abdominal or thoracic surgery, flail chest, and inability to tolerate the position.

27
Q

What is Tracheal Gas Insufflation?

A

Tracheal gas insufflation (TGI) provides a continuous or phasic flow directly into the ET tube during mechanical ventilation.

28
Q

What are some strategies used to improve ventilation?

A

Increase the tidal volume, increase the respiratory rate, use ventilator circuits with low compressible volume, and decrease dead space.

29
Q

What are some strategies used to improve oxygenation?

A

Increase the FiO2, increase the PEEP, improve ventilation to improve oxygenation, normal hemoglobin levels, initiate CPAP, improve circulation, and initiate IRV, ECMO, or HFOV.

30
Q

What are the two ways that pressure support is used?

A

Low: used to overcome resistance in the circuit.

High: used to target a tidal volume.

31
Q

What is permissive hypercapnia?

A

It is the act of letting the CO2 build up to prevent barotrauma and letting the body compensate by increasing the bicarb.

32
Q

What type of trigger is best for reducing work of breathing?

A

Flow trigger

33
Q

What is the formula for finding dynamic compliance?

A

Exhaled Volume/ PIP – PEEP

34
Q

What is the formula for finding static compliance?

A

Exhaled Volume/ Plateau – PEEP

35
Q

What the normal value for static lung compliance?

A

60 to 100 mL/cm H2O

36
Q

What is the value for normal airway resistance?

A

0.6 to 2.4 cm H2O/L/min/sec

37
Q

What is the most influential control that directly affects Paw?

A

PEEP

38
Q

What are the early signs of hypoxia?

A

Tachycardia (1st response), Dyspnea, Shortness of breath, Restlessness, Tachypnea, and Diaphoresis.

39
Q

What is the late response to hypoxia?

A

Bradycardia, because the patient is decompensating.

40
Q

What is the first immediate response to hypoxemia/tissue hypoxia?

A

An increase in heart rate that occurs because the patient is compensating.

41
Q

COPD lungs have lost airway caliber and tend to collapse prematurely due to what?

A

Due to increased intrathoracic pressures surrounding the airway during exhalation.

42
Q

What is the purpose of permissive hypercapnia?

A

To decrease PIP and the likelihood of causing barotrauma.

43
Q

What is permissive hypercapnia?

A

The process of allowing the PaCO2 to rise slightly in order to give small tidal volumes and a higher respiratory rate in order to decrease the chance of barotrauma.

44
Q

Which flow patterns are the most common on a ventilator?

A

Square- often seen in volume modes.

Descending- often seen in pressure modes.

45
Q

What changes in the patient’s status can affect their compliance?

A

The static compliance will decrease with resistance or increase with air-trapping. The dynamic compliance will decrease or become less with an obstruction.

46
Q

What are the various factors used to trigger ventilator breaths?

A

Pressure and Flow (from the patient), Timed (from the ventilator), Manuel (from the operator)

47
Q

What is the normal HME % humidity?

A

70%

48
Q

What is the normal heated wick % humidity?

A

100%

49
Q

How can the inspiratory time improve blood oxygenation?

A

It allows for a longer inhalation time, which provides a longer contact time for diffusion to take place.

50
Q

What ventilator changes could be made to correct respiratory acidosis?

A

Increase the tidal volume or respiratory rate in order to blow off more CO2. Adjust the tidal volume first, but if the tidal volume is already in the ideal range, then adjust the respiratory rate.

51
Q

Why would PSV be added to SIMV?

A

PSV can be added to help “fine tune” incremental changes and maintain an adequate spontaneous tidal volume.

52
Q

What is an advantage of a flow vs pressure trigger?

A

Flow is more sensitive to the patient’s effort.

53
Q

How would you assess a rupture or leakage of the cuff?

A

(1) Is the leak positional? If so, change the patient’s head/neck position, (2) Is there a hole in the cuff? If so, the tube must be changed, and (3) Is there a leak in the pilot balloon or severed balloon line? If so, use needle & syringe to temporarily refill cuff or replace pilot balloon or change tube.

54
Q

How would you fix kinking or biting of the endotracheal tube?

A

(1) Insert oral airway if the patient is biting the tube, or (2) If kinking is occurring, which is rare, it usually requires removal/replacement.

55
Q

How would you rectify secretion/mucus plugging problems?

A

You would suction or use hydration.

56
Q

How would you fix cuff herniation over the end of an endotracheal tube?

A

You would deflate the cuff.

57
Q

What is the proper endotracheal tube placement for men?

A

Tube marking at the teeth is 22-24 cm

58
Q

What is the proper endotracheal tube placement for women?

A

Tube marking at the teeth is 20-22 cm

59
Q

What should be done if there is an occlusion in the ET tube?

A

Deflate the cuff to allow some ventilation and replace the tube.

60
Q

How would you fix a tracheal fistula?

A

It requires surgery to repair.

61
Q

What immediate treatment would you use for a tension pneumothorax?

A

You would place a chest tube into the 2nd intercostal space at the midclavicular line.

62
Q

How would you rectify any secretion problems?

A

(1) Suction & monitor thickness/color/amount, (2) Add heated humidification if thickening occurs, and (3) Send sample for testing if it’s yellow, green, or brown.

63
Q

What is pulmonary edema and how do you treat it?

A

For cardiogenic – pink, frothy secretions (cardiac problem); You treat with Lasix, digoxin, Vasotec, etc.

64
Q

What is dynamic hyperinflation also known as?

A

Auto-PEEP

It can cause cardiac compromise and makes it more difficult to trigger breaths. You can treat it by adding PEEP, increasing expiratory time.

65
Q

How can changing the body position of a patient cause problems?

A

It can cause accidental extubation, kinking of ventilator circuit, and changes in oxygenation (can be caused by repositioning of the diseased lung into dependent position, mucus plugging, dislodgement of the clot).

66
Q

What is abdominal distention?

A

An upward pressure on the diaphragm & can lead to atelectasis in lung bases, VQ abnormalities, and hypoxemia.

67
Q

What are the 4 causes of abdominal distention?

A

Air (common during intubation, PPV), Ascites (abnormal fluid accumulation in peritoneal space), Blood, and Obstruction.

68
Q

What alarms are set off when a leak occurs?

A

Low-pressure alarms and low volume alarms.

69
Q

If there is an inadequate inspiratory flow that is set, what could this cause?

A

This is a frequent cause of increased work of breathing.

70
Q

If the low-pressure alarm is going off, what should the Respiratory Therapist check?

A

Check for patient disconnection, Check for leaks in the patient circuit related to the artificial airway and through chest tubes, and Check the proximal pressure line to make sure it is connected and unobstructed.

71
Q

What do you need to determine if the low PEEP/CPAP alarm is going off?

A

If the patient is actively inspiring below baseline or if a leak is present/ventilator has not been disconnected from the circuit.

72
Q

Why would High tidal volume, minute ventilation and/or respiratory rate alarm go off?

A

Check the machine sensitivity for auto-triggering, make sure the alarms are set correctly; if using an external nebulizer – reset the alarms until the treatment is done.

73
Q

What are the signs and symptoms associated with patient-ventilator asynchrony?

A

Use of accessory muscles to breathe (inspiration: Sternocleidomastoid, chest retractions, due to inadequate flow or low Vt delivery/ expiration: abdominal muscle usage), Pursed-lip breathing (to keep patient’s airways open), Minimal or absent cough, Tripoding (leaning forward to breathe), Barrel chest (air-trapping), Digital clubbing, Dyspnea on exertion (late sign), Tachypnea, and Tachycardia (sign of hypoxemia).

74
Q

What would you see with the presence of unintended PEEP (auto-PEEP) by looking at the ventilator graphics?

A

You can observe and assess the flow-time or volume-time curve. Flow-time curve: The Respiratory Therapist would see that the peak expiratory flow does not return to the baseline before the next breath. Volume-time curve: During the expiratory phase, the tidal volume does not return to the ventilator before the next breath.

75
Q

What are the ways that the addition of a nebulizer powered by an external source gas can affect ventilator function?

A

High tidal volume delivery from the flow meter or E-cylinder application, Increased work for the patient to trigger the ventilator if the nebulizer is used in PSV, Triggering difficulty for patients in VC-CMV receiving a nebulizer treatment from an external source, and it also affects neonates significantly.