Question 1

Which of the following is an alternative to inhaled NO₂ for lowering PVR?

Accepted Answer

Alternatives to inhaled NO₂ have been sought because of the complex technology associated with NO₂, high NO₂ costs, potential NO₂ toxicity, and NO₂'s failure to decrease overall mortality in ARDS. Some of these alternative vasodilators, which are inhaled as aerosols, include prostacyclin (PGI₂), sildenafil (Viagra), nitroprusside, and nitroglycerin.

Question 2

Which of the following are causes of pulmonary edema?
I.Increased hydrostatic pressure
II.Increased capillary permeability
III.Decreased plasma oncotic pressure
IV.Insufficient lymphatic drainage

Accepted Answer

Pulmonary edema is the accumulation of fluid in the interstitial spaces between capillaries and alveoli. Causes of pulmonary edema include 
(1) increased hydrostatic pressure, 
(2) increased capillary permeability, 
(3) decreased plasma oncotic pressure, and 
(4) insufficient lymphatic drainage.

Question 3

In the presence of a normal PaO₂, how low does the pH need to get before a significant increase in PVR is present?

Accepted Answer

At a normal PaO₂, arterial pH must decrease below 7.25 to cause a significant increase in PVR.

Question 4

Which of the following is a good example of edema associated with a high PCWP?

Accepted Answer

A common cause of hydrostatic pulmonary edema is left ventricular failure. This type of edema is associated with a high PCWP and is called cardiogenic pulmonary edema.

Question 5

Monitoring of a patient with a PAC reveals an elevated PAP due to left heart failure.Which of the following therapies will be specifically directed at decreasing the PAP?
I.Oxygen therapy
II.Diuretics
III.Vasodilators
IV.Inotropes

Accepted Answer

An elevated PAP caused by left heart failure (i.e., loss of left ventricular pumping action) may be treated with inotropic drugs, which increase the heart's contractility and pumping effectiveness. Diuretics decrease the blood volume by enhancing urine production and thus reducing venous return to the heart. Vasodilators decrease the resistance against which the left ventricle must pump, allowing it to pump blood more effectively. Thus, understanding the origins of high PAP is important because treatment approaches are completely different for different circumstances.

Question 6

Which of the following conditions are associated with pulmonary edema due to increased hydrostatic pressure?
I.Left ventricular failure
II.Mitral valve insufficiency
III.Hypervolemia
IV.ARDS

Accepted Answer

A common cause of hydrostatic pulmonary edema is left ventricular failure. Coronary artery disease may reduce blood flow to the left ventricular muscle, reducing the effectiveness of its pumping action. Blood then dams up in the left atrium and pulmonary circulation, increasing pulmonary capillary pressures. This type of edema is associated with a high PCWP, and is called cardiogenic pulmonary edema.
Mitral valve stenosis, or narrowing of the mitral valve orifice, may also cause blood to dam up in the pulmonary capillaries and cause pulmonary edema. Overadministration of IV fluids may create hypervolemia, or fluid overload, with similar results.

Question 7

Which of the following maneuvers can momentarily raise alveolar pressures, creating zone I conditions?
I.Coughing
II.Blowing a trumpet
III.Positive pressure mechanical ventilation
IV.Exercise

Accepted Answer

Respiratory maneuvers such as exhaling against a closed glottis, blowing a trumpet, or coughing can momentarily raise alveolar pressures above arterial pressures, creating zone I conditions in gravity-independent (uppermost) lung regions. Positive pressure mechanical ventilation may increase alveolar pressure enough to convert some zone II regions to zone I. This is one mechanism whereby positive pressure ventilation increases alveolar dead space. Likewise, a loss of blood volume or massive vasodilation, as in septic shock, may lower PAP enough to create zone I conditions.

Question 8

Which of the following concepts apply to zone I under positive pressure ventilation?
I.It constitutes shunt.
II.In healthy individuals zone I does not exist.
III.It constitutes alveolar dead space ventilation.
IV.Arterial pressures exceed alveolar pressures.

Accepted Answer

In zone I alveoli are ventilated but have no blood flow, which constitutes alveolar dead space ventilation. In spontaneously breathing healthy individuals with normal cardiac outputs and blood pressures, arterial pressures always exceed alveolar pressures, even in the uppermost apical lung regions, and zone I does not exist. However, a severe decrease in blood pressure can lower PAP so much that zone I conditions are created in the lung.

Question 9

Which of the following will inhibit HPV?
I.Alkalemia
II.Endogenous nitric oxide and prostacyclin
III.Alpha-adrenergic blockers
IV.Beta-adrenergic stimulants

Accepted Answer

HPV is inhibited by various mediators present in the blood that cause vasodilation, such as the endothelial-derived substances nitric oxide and prostacyclin. HPV is also inhibited by drugs that block alpha-adrenergic or stimulate beta-adrenergic receptors; in addition, HPV is inhibited by increased left atrial pressure (a vascular distending effect), high alveolar pressure, and high blood pH (alkalemia).

Question 10

Which of the following conditions is associated with cardiac pulmonary edema?

Accepted Answer

Acute lung injuries that damage the alveolar capillary membrane may increase the membrane's permeability to fluids and cause pulmonary edema. This kind of edema is often called high-permeability pulmonary edema or noncardiac pulmonary edema. Causes of alveolar capillary membrane injury include severe infections such as pneumonia, endotoxins of sepsis, oxygen toxicity, ARDS (regardless of cause), and inhaled noxious substances.

Question 11

In which of the following conditions is the HPV response often diminished?
I.Smoke inhalation
II.ARDS
III.Emphysema
IV.Sepsis

Accepted Answer

The HPV response is often diminished in patients suffering acute lung injuries, such as burn and smoke inhalation, sepsis, and acute respiratory distress syndrome (ARDS).

Question 12

What is the PaO₂ at which the maximal vasoconstrictive response occurs when the pH is 7.40?

Accepted Answer

At a normal arterial pH of 7.40, the maximal vasoconstrictive response occurs at a P_AO₂ of 60 to 70 mm Hg. This corresponds to an arterial PO₂ (PaO₂) of about 50 to 60 mm Hg when the normal alveolar to arterial PO₂ gradient is taken into account.

Question 13

In the presence of exercise, the increased cardiac output and PAPs will recruit which of the following zones?
I.I
II.II
III.III
IV.It will not recruit any zone.

Accepted Answer

Exercise increases cardiac output and PAPs, recruiting any zone I to zone II or any zone II to zone III.

Question 14

What is the name of the force tending to move fluid into the capillary?

Accepted Answer

The only force tending to move fluid into the capillary is the blood's oncotic pressure of approximately 28 mm Hg. The total force favoring fluid movement out of the capillary is 29 mm Hg, whereas the total force favoring inward movement is 28 mm Hg. This yields a net mean filtration pressure of 1 mm Hg.

Quiz 6: Pulmonary Blood Flow

Which of the following is an alternative to inhaled NO2 for lowering PVR?

Which of the following are causes of pulmonary edema? I.Increased hydrostatic pressure II.Increased capillary permeability III.Decreased plasma oncotic pressure IV.Insufficient lymphatic drainage

In the presence of a normal PaO2, how low does the pH need to get before a significant increase in PVR is present?

Which of the following is a good example of edema associated with a high PCWP?

Monitoring of a patient with a PAC reveals an elevated PAP due to left heart failure.Which of the following therapies will be specifically directed at decreasing the PAP? I.Oxygen therapy II.Diuretics III.Vasodilators IV.Inotropes

Which of the following conditions are associated with pulmonary edema due to increased hydrostatic pressure? I.Left ventricular failure II.Mitral valve insufficiency III.Hypervolemia IV.ARDS

Which of the following maneuvers can momentarily raise alveolar pressures, creating zone I conditions? I.Coughing II.Blowing a trumpet III.Positive pressure mechanical ventilation IV.Exercise

Which of the following concepts apply to zone I under positive pressure ventilation? I.It constitutes shunt. II.In healthy individuals zone I does not exist. III.It constitutes alveolar dead space ventilation. IV.Arterial pressures exceed alveolar pressures.

Which of the following will inhibit HPV? I.Alkalemia II.Endogenous nitric oxide and prostacyclin III.Alpha-adrenergic blockers IV.Beta-adrenergic stimulants

Which of the following conditions is associated with cardiac pulmonary edema?

In which of the following conditions is the HPV response often diminished? I.Smoke inhalation II.ARDS III.Emphysema IV.Sepsis

What is the PaO2 at which the maximal vasoconstrictive response occurs when the pH is 7.40?

In the presence of exercise, the increased cardiac output and PAPs will recruit which of the following zones? I.I II.II III.III IV.It will not recruit any zone.

What is the name of the force tending to move fluid into the capillary?

Which of the following is an alternative to inhaled NO₂ for lowering PVR?

In the presence of a normal PaO₂, how low does the pH need to get before a significant increase in PVR is present?

What is the PaO₂ at which the maximal vasoconstrictive response occurs when the pH is 7.40?