Ch. 17 Test, Effects of Positive Pressure Ventilation Flashcards
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
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
Alveolar tissue and pulmonary capillary injury is caused by which of the following?
a. Barotrauma
b. Biotrauma
c. Shear stress
d. Overdistention
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
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
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
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
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
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.
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
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.
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
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
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
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
ANS: A
Studies show that pressures as low as 30 to 35 cm H2O cause lung injury in animals.
DIF: 1 REF: p. 330
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
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
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.
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
Overdistention of the lungs causes the release of which inflammatory mediators?
a. Tumor necrosis factor
b. Alpha-1 antitrypsin
c. Histamine
d. Macrophages
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
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
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
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
ANS: C
The dependent lung areas receive a higher portion of ventilation and perfusion.
DIF: 1 REF: p. 333
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
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
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.
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
