Ch. 17 Test, Effects of Positive Pressure Ventilation COPY Flashcards

1
Q

Biotrauma is caused directly by which of the following?

a. High oxygen levels
b. Overdistention of alveoli
c. Long expiratory times
d. Fast respiratory rates

A

ANS: B
High distending volumes result in overdistention of the alveoli, leading to the release of inflammatory mediators from the lungs, which can result in multiorgan failure. The release of these inflammatory mediators is called biotrauma.

DIF: 1 REF: p. 328

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2
Q

Alveolar tissue and pulmonary capillary injury is caused by which of the following?

a. Barotrauma
b. Biotrauma
c. Shear stress
d. Overdistention

A

ANS: C
Repeated opening and closing of lung units, also called recruitment/derecruitment, generates shear stress, which results in direct tissue injury at the alveolar and pulmonary capillary level. Barotrauma is lung injury caused by high pressure. Biotrauma refers to the release of inflammatory chemical mediators that cause multiorgan failure. Overdistention is the cause of biotrauma.

DIF: 1 REF: p. 328

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3
Q

Shear stress injury and loss of surfactant from the resulting unstable lung units result in a loss of surfactant. This type of pulmonary trauma is known as _____________.

a. atelectrauma
b. barotrauma
c. biotrauma
d. volutrauma

A

ANS: A
Shear stress injury and loss of surfactant constitute atelectrauma. Lung injury caused by high levels of pressure and volume is referred to as barotrauma or volutrauma. The release of inflammatory mediators from the lungs that can lead to multiorgan failure is called biotrauma.

DIF: 1 REF: p. 328

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4
Q

Ventilator-induced lung injury (VILI) is associated with which of the following?

a. Air trapping
b. Biotrauma
c. Patient-ventilator asynchrony
d. Ventilator-associated pneumonia

A

ANS: B
VILI is a lung injury that occurs at the level of the acinus. It is the microscopic level of injury that includes biotrauma, shear stress, and surfactant depletion (atelectrauma). The term ventilator-associated lung injury (VALI) generally is used to refer to lung injury identified as being a consequence of mechanical ventilation. The most common forms of VALI are ventilator-associated pneumonia (VAP), air trapping, patient-ventilator asynchrony, and extra-alveolar gas (barotrauma), such as pneumothorax and pneumomediastinum

DIF: 1 REF: p. 328

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5
Q

The RT performs a patient-ventilator system check on a 24-year-old, 5-foot, 10-inch male patient who has been intubated because of a drug overdose. The RT notices what appears to be swelling around the patient’s upper anterior chest and neck area. Palpation elicits a tissue paper feeling. The ventilator settings are: VC-CMV, rate 12/min with no patient assist, VT 900 mL, PEEP 5 cm H2O, FIO2 0.4, TI 1.2 sec. The most appropriate action for the RT to take is which of the following?

a. Increase the set flow rate.
b. Decrease the set tidal volume.
c. Reduce the set respiratory rate.
d. Perform emergency needle decompression.

A

ANS: B
Assessment of this patient reveals that he has subcutaneous emphysema, as evidenced by the swelling around the upper anterior chest and neck area and the tissue paper feeling on palpation. This is a form of barotrauma caused by alveolar rupture as a result of too much volume. The PEEP setting is only 5 cm H2O, which is physiologic. The VT setting, however, is too high. The IBW for this patient is 75 kg; 900 ÷ 75 = a set volume of 12 mL/kg. This needs to be adjusted to 8 to 10 mL/kg. The subcutaneous emphysema should subside on its own.

DIF: 3 REF: p. 328

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6
Q

The RT responds to the high pressure, high respiratory rate, low exhaled volume, and low exhaled minute volume alarms of a mechanically ventilated patient in the ICU. Upon entering the room, the RT notices that the patient, who is still attached to the ventilator, appears diaphoretic, tachypneic, tachycardic, and hypertensive. Breath sounds are absent on the left and distant on the right. The patient’s trachea is deviated to the left, and jugular vein distention is present. The endotracheal tube is 24 cm at the teeth. Immediate action should include which of the following?

a. Order a chest radiograph in the upright position.
b. Administer intravenous etomidate and succinylcholine.
c. Pull back the endotracheal tube to 22 cm at the teeth.
d. Insert a 14-gauage needle into the second intercostal space right midclavicular line.

A

ANS: D
The ringing of the high pressure alarm for a time has led to the sounding of the low volume and low minute volume alarms. The patient is in apparent respiratory distress, as evidenced by the tachypnea, tachycardia, and diaphoresis. The position of the ET tube at the 24-cm mark is evidence that the tube has slipped into the right mainstem bronchus. However, the absence of breath sounds on the left plus the tracheal deviation to the left, along with the jugular vein distention, is evidence of a tension pneumothorax on the right side. The ET tube appears to have slipped into the right mainstem bronchus and subsequently caused a pneumothorax. This is a life-threatening situation, and the pneumothorax must be decompressed immediately with a 14-gauge needle inserted into the second or third intercostal space on the right midclavicular line.

DIF: 3 REF: p. 329

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7
Q

Lung injury is more likely to occur with which of the following with normal lung tissue?

a. PA = 25 cm H2O; Ppl = 18 cm H2O
b. PA = 29 cm H2O; Ppl = 10 cm H2O
c. PA = 30 cm H2O; Ppl = 21 cm H2O
d. PA = 45 cm H2O; Ppl = 34 cm H2O

A

ANS: B
Situations in which the lung-distending pressure (i.e., transpulmonary pressure, or PA – Ppl) is abnormally high can cause lung injury. PA can be high by itself without causing lung damage, but if PA – Ppl is high, lung damage is more likely. The highest transpulmonary pressure is 19 cm H2O, when the PA = 29 cm H2O and the Ppl = 10 cm H2O.

DIF: 2 REF: p. 330

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8
Q

What is the minimum transpulmonary pressure that has been associated with lung injury in animals?

a. 30 cm H2O
b. 40 cm H2O
c. 50 cm H2O
d. 60 cm H2O

A

ANS: A
Studies show that pressures as low as 30 to 35 cm H2O cause lung injury in animals.

DIF: 1 REF: p. 330

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9
Q

Shear stress is most likely to affect a patient with which of the following?

a. PA = 35 cm H2O; Ppl = 21 cm H2O
b. PA = 35 cm H2O; Ppl = 12 cm H2O
c. PA = 45 cm H2O; Ppl = 33 cm H2O
d. PA = 50 cm H2O; Ppl = 38 cm H2O

A

ANS: B
The amount of shear stress across the entire lung can be estimated using the transpulmonary pressure (Pplateau – Ppl), where Pplateau represents PA and Ppl is the intrapleural pressure.

DIF: 2 REF: p. 00

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10
Q

Healthy areas of lung tissue in a patient with ARDS can be protected from lung injury caused by overdistention by which of the following?

a. Increasing FIO2.
b. Decreasing PEEP.
c. Using the prone position.
d. Using a VT of 10 to 12 mL/kg.

A

ANS: C
Placing a patient with ARDS in a prone position restricts chest wall movement, thereby preventing severe transpulmonary pressure from causing alveolar stretch and edema, or shear stress. Increasing the FIO2 may cause more atelectasis, which could worsen the situation. Decreasing PEEP would derecruit alveoli, shifting the volume to more compliant areas, which could increase the amount of lung injury. Using tidal volumes of 10 to 12 mL/kg would increase the risk of lung injury.

DIF: 1 REF: p. 339

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11
Q

Overdistention of the lungs causes the release of which inflammatory mediators?

a. Tumor necrosis factor
b. Alpha-1 antitrypsin
c. Histamine
d. Macrophages

A

ANS: A
Overdistention of the lungs causes the release of inflammatory mediators such as cytokines, tumor necrosis factor, platelet-activating factor, thromboxane-B2, tumor necrosis factor alpha, and interleukin-1B. Macrophages are the actual source of some of these mediators.

DIF: 1 REF: p. 332

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12
Q

Inappropriate ventilator settings can cause the release of inflammatory mediators within _______.

a. 1 to 3 hours
b. 5 to 10 hours
c. 10 to 12 hours
d. 24 hours

A

ANS: A
Pulmonary epithelial and alveolar macrophages are partly responsible for the production of inflammatory mediators in response to harmful ventilator strategies. This can occur within 1 to 3 hours of initiation of ventilation.

DIF: 1 REF: p. 332

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13
Q

In what areas of the lung are ventilation and perfusion best matched during spontaneous ventilation in the supine position?

a. Apices of the lungs
b. Nondependent anterior lung areas
c. Dependent posterior lung areas
d. Basilar segments of lower lobes

A

ANS: C
The dependent lung areas receive a higher portion of ventilation and perfusion.

DIF: 1 REF: p. 333

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14
Q

Preservation of spontaneous breathing during mechanical ventilation favors the distribution of gas to which areas of the lung?

a. Peribronchial area
b. Upper airway
c. Lung periphery
d. Central airways

A

ANS: C
The distribution of gas during spontaneous ventilation favors the dependent lung areas and also appears to favor the periphery of the lung closest to the moving pleural surfaces. The peripheral areas receive more ventilation than the central areas. However, during a positive pressure breath with passive inflation of the lung (paralysis), the central, upper airway, or peribronchial portions of the lung are preferentially filled with air.

DIF: 1 REF: p. 334

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15
Q

Which of the following mechanically ventilated patients shows clinical signs of hypoventilation?

a. A patient who is cool to the touch and has negative T waves on the ECG.
b. A patient who has twitchy extremities and also atrial flutter on the ECG.
c. A patient who is anxious and hypertensive and has elevated T waves on the ECG.
d. A patient who has cool, twitchy extremities and also low, rounded T waves on the ECG.

A

Anxiety and hypertension (mild to moderate acidosis) are clinical signs of hypoventilation, along with elevated T waves on an ECG. Patients with hyperventilation are cool to the touch, have twitchy muscles from hypokalemia, and have low, rounded T waves, atrial flutter, or negative T waves on the ECG.

DIF: 2 REF: p. 335

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16
Q

Which of the following mechanically ventilated patients shows clinical signs of hyperventilation?

a. A patient who has hot skin and also long P-R intervals on the ECG.
b. A patient who has cool skin and also shows paroxysmal tachycardia on the ECG.
c. A patient who is hypertensive and agitated and has S-T segment depression on the ECG.
d. A patient who is hypotensive and dyspneic and has widened QRS complexes on the ECG.

A

ANS: B
Cool skin and paroxysmal tachycardia are signs of decreased PaCO2. All the other answers are signs of hypoventilation.

DIF: 2 REF: p. 335

17
Q

Prolonged ventilator-induced hyperventilation can lead to which of the following?

a. Hypokalemia
b. Hyperkalemia
c. Increased ICP
d. Headaches

A

ANS: A
Reduced hydrogen ion concentrations in the blood often are accompanied by hypokalemia. The other answers are problems that hypoventilation can induce.

DIF: 1 REF: p. 335

18
Q

What is the minimum range of time constants necessary for the lungs to empty 98% of the inspired volume?

a. 1 to 2
b. 2 to 3
c. 3 to 4
d. 4 to 5

A

ANS: C
An expiratory time of at least 3 to 4 time constants is needed for the lungs to empty 98% of the inspired volume.

DIF: 1 REF: p. 337

19
Q

The acceptable lower limit of PaO2 for a mechanically ventilated patient with ARDS is which of the following?

a. 50 mm Hg
b. 60 mm Hg
c. 70 mm Hg
d. 80 mm Hg

A

ANS: B
The lower limits of permissive hypoxemia remain controversial. However, most clinicians agree that a target of PaO2 = 60 mm Hg and SpO2 = 90% are acceptable lower limits.

DIF: 1 REF: p. 339

20
Q

Calculate the static compliance for a patient who has the following: auto PEEP = 8 cm H2O, set PEEP = 12 cm H2O, VT = 425 mL, PIP = 45 cm H2O, and Pplateau = 36 cm H2O.

a. 15 mL/cm H2O
b. 18 mL/cm H2O
c. 21 mL/cm H2O
d. 27 mL/cm H2O

A

ANS: D
Static compliance values normally are calculated as VT/(Pplateau – PEEP). For this calculation to be accurate, the PEEP value must include the set PEEP and any auto PEEP.

DIF: 2 REF: p. 339

21
Q

The combination of __________________ and ____________________ increases the risk of absorption atelectasis.

a. high tidal volumes, FIO2 >0.4
b. high tidal volumes, FIO2 >=0.7
c. low tidal volumes, FIOs >0.5
d. low tidal volumes, FIO2 >0.7

A

ANS: D
High oxygen concentrations (>70% oxygen) lead to rapid absorption atelectasis, particularly in hypoventilated lung units.

DIF: 1 REF: p. 339

22
Q

Assessment of a mechanically ventilated patient reveals use of accessory muscles and a respiratory rate of 26 breaths/min. The mode is CPAP with 5 cm H2O and an FIO2 of 0.4. The most appropriate action is which of the following?

a. Return the patient to full ventilatory support.
b. Add pressure support to the CPAP.
c. Increase the CPAP to 8 cm H2O.
d. Deflate the cuff of the ET tube.

A

ANS: B
This patient is suffering from an increased WOB, as evidenced by the use of accessory muscles and elevated respiratory rate. Adding pressure support will decrease the patient’s WOB by eliminating the airway resistance caused by the ET tube. Returning the patient to full ventilatory support before trying pressure support may add time to the patient’s length of stay on the ventilator. Increasing the CPAP is not appropriate, because there is no evidence of hypoxemia. Deflating the cuff would negate the CPAP and also increase the risk of ventilator-associated pneumonia.

DIF: 3 REF: p. 340

23
Q

When setting up a patient on volume ventilation with constant flow, the initial flow setting should be ________.

a. 50 L/min
b. 60 L/min
c. 70 L/min
d. 80 L/min

A

ANS: D
An initial flow of 80 L/min typically is suggested when setting up a patient on volume ventilation with a constant flow. The pressure-time scalar should be evaluated for its appearance to ensure an appropriate flow rate.

DIF: 1 REF: p. 343

24
Q

The pressure-time scalar of a patient with COPD who is receiving PSV shows positive deflection toward the end of inspiration. The most appropriate way to alleviate this is to do which of the following?

a. Increase the PSV level.
b. Decrease the PSV level.
c. Increase the flow cycle percentage.
d. Decrease the flow cycle percentage.

A

ANS: C
This patient has cycle asynchrony. The positive deflection at the end of inspiration is caused by active exhalation. A patient with COPD needs a short inspiratory time and a long expiratory time. If the patient shows active exhalation before the end of inspiration, inspiration is too long. In PSV, inspiration ends when the flow cycle percent setting is reached. Increasing the flow cycle percentage will cause the ventilator to end inspiration earlier, thus allowing a longer time for expiration.

DIF: 3 REF: p. 343