Review

Question 1

how will the following change after acclimatization to altitude in a healthy adult?
a. Cardiac output.
b. Plasma volume
c. Urine HCO3 content
d. PaCO2.

Answer 1

a. Cardiac output —> increase
b. Plasma volume —> decrease
c. Urine HCO3 content —> increase
d. PaCO2 —> decrease

Question 2

A 64-year-old man is admitted to the ICU with pneumonia and septic shock. Medication‘s are amlodipine and HCTZ. Physical exam shows blood pressure is 85/50 mmHg pulse is 110/minute. Cardiac exam is remarkable for a grade 2/6 systolic murmur, and crackles are heard over the entire right lung field. Blood labs on admission are as follows:
Na+ = 135meq/L
K+ = 4.8 meq/L
Cl- = 103 meq/L
glucose = 115 mg/dL
HCO3- = 10 meq/L
BUN = 22 mg/dL
PCO2 = 48mmHg
PO2 = 51mmHg
pH = 6.94

What kind of acid base disorder does the patient have?

Answer 2

Acidemia + low bicarb = metabolic acidosis
PCO2 should be below 40 – because it is above 40 there’s coexisting respiratory acidosis

patient has anion gap metabolic acidosis with respiratory acidosis

[when given Na+, Cl-, and HCO3-, you should always calculate AG]

Question 3

A patient comes in to the emergency room after aspirating a peanut while sitting upright. The most likely location of the aspiration is:
a. Superior segmental bronchus of the lower lobe of the right lung.
b. Posterior basal bronchus of the lower lobe of the right lung
c. Posterior basal bronchus of the lower lobe of the left lung.
d. eparterial bronchus of the right lung

Answer 3

b. Posterior basal bronchus of the lower lobe of the right lung

Question 4

The thoracic duct can be found:
a. Anterior to the esophagus
b. To the right of the azygos vein
c. To the left of the hemiazygos vein
d. To the right of the descending aorta.

Answer 4

d. To the right of the descending aorta.

Question 5

A woman is found at home in a diminished state of alertness. On arrival to the ED her carbon monoxide level is 31.7% (normal <5%), her blood pH is 7.32 and PaCO2 is 42mmHg. Which statement most accurate describes the respiratory drive in this patient?
a. hypoxic drive is predominant.
b. She has hypoventilation with no hypoxic stimulation.
c. Ventilation is depressed by PaCO2.
d. Ventilation is elevated due to stimulation of the central chemoreceptors.
e. Ventilation is increased due to carbon monoxide.

Answer 5

b. She has hypoventilation with no hypoxic stimulation.

with carbon monoxide poisoning, PaO2 is not lowered, so there is no hypoxic drive - instead CO occupies O2 binding sites on hemoglobin, leading to hypoxemia/reduced CaO2. The very modest elevation in PCO2 is the result of some degree of hyperventilation.

Question 6

A 30 year old man presents to the ED due to two days of nausea, vomiting and weakness. His pulse is 85/minute. BP 110/60 mmHg, respiration 20/minute. Cardiac/lung exams are normal. Blood labs show the following:
Na+ = 135 meq/L
K+ = 5.3 meq/L
glucose = 500mg/dL
HCO3- = 10 meq/L
PCO2 = 38mmHg

which of the following would most likely present in this man?
a. V/Q mismatch
b. decreased 2,3 BPG production
c. right to left shunt and hypoxemia.
d. Decreased PAO2.
e. Reduced affinity for O2 by hemoglobin.
f. Increased alkalization of urine.

Answer 6

e. Reduced affinity for O2 by hemoglobin.

Low bicarb + reduced PaCO2 = metabolic acidosis
Combined with high glucose diabetic ketoacidosis is likely

Recall that low pH causes a right shift on oxygen dissociation curve

Question 7

A healthy adult living at sea level travels to hike at a high altitude (15,000ft). Within the first 24 hours at this altitude, which of the following most accurately describes the predominant mechanism controlling his minute ventilation?
a. Central chemoreceptors.
b. PaCO2.
c. Compensation for metabolic alkalosis.
d. Hypoxia.
e [HCO3-]/0.03(PCO2)

Answer 7

d. hypoxia

at high-altitude PO2 drops thus decreasing PaO2. 15,000 feet is high enough where PaO2 is low enough to trigger the hypoxic drive via the peripheral chemoreceptors. With increased minute ventilation PaCO2 drops and the development of respiratory alkalosis is likely. Compensation/acclimatization occurs over days via renal bicarb excretion.

Question 8

Patient describes transient episodes of dyspnea over the past 24 hours and two weeks of cold and flu-like symptoms. PE shows that BP is 138/78mmHg, pulse 80/minute, temperature 37.7 C. SpO2 is 96%, respiration is 25/minute. Bilateral rales are heard over the lower lung fields with dullness to percussion and expiratory wheezing. Blood chemistries are as follows:
Na+ 138meq/L
K+ 4.8 meq/L
Cl- 99 meq/L
PO2 88mmHg
HCO3- 26 meq/L
pH 7.33

What is the predominant factor driving this patient’s ventilation?
a. respiratory alkalosis.
b. Hypercapnia.
c. Metabolic acidosis.
d. Hypoxemia.
e. Carotid/ aortic baroreceptor tone.

Answer 8

b. hypercapnia

Acidemia + elevated bicarb = respiratory acidosis

Most likely has pneumonia/bronchitis, which is causing elevated PaCO2

Question 9

A healthy adult has been strenuously exercising such that she has exceeded her anaerobic threshold. How will the following factors be affected relative to resting state?
a. Plasma pH.
b. Pulmonary vascular resistance.
c. Alveolar diffusing capacity.
d. MAP

Answer 9

a. Plasma pH —> decrease
b. Pulmonary vascular resistance. —> decrease
c. Alveolar diffusing capacity —> increase
d. MAP —> increase.

By exceeding anaerobic threshold, lactic acid production is exceeding its usage – plasma pH will drop. Increased cardiac output will enable previously under-perfused lung capillaries to achieve the critical opening pressure, thus lowering pulmonary vascular resistance. This goes with increased alveolar diffusing capacity - more ventilation/perfusion.

Question 10

A 65-year-old woman is brought to the ED due to shortness of breath and right sided stabbing chest pain that occurred after a severe coughing fit. BP is 150/85 mmHg, pulse 80/minute, respiration 24/minute. Cardiac auscultation is normal. There are absent breath sounds over the right lung fields. PO2 is 60 mmHg, PCO2 is 50 mmHg, HCO3- is 25 mmHg. Which of the following would most likely be present in this woman?
a. R intrapleural pressure of -5 mmHg
b. R transmural pressure = 10 cm H2O during inspiration.
c. Increased shunt fraction.
d. Increased residual volume.
e. Increased FEV1/FVC.

Answer 10

c. Increased shunt fraction.

patient has right tension pneumothorax - right lung is collapsed and right intrapleural pressures would increase. Because of this, there would be relatively more perfusion than ventilation, creating an elevated shunt fraction. Blood gases show respiratory acidosis

Question 11

pulmonary functional tests are performed on a patient with a history of several months of transient episodes of severe shortness of breath and a chronic cough. Results show that FEV1 is 73% of predicted value while FVC is 100% predicted. What will be the likely effect on the following factors?
a. effect of supplemental O2 on PaO2.
b. (A-a)DO2

Answer 11

a. effect of supplemental O2 on PaO2 —> increase
b. (A-a)DO2 —> increase

patient has an obstructive pattern - most likely asthma. Diffusion is adversely affected due to inflammation/mucus. This would cause increased (A-a)DO2. Impediment due to diffusion can be at least partially overcome with supplemental O2.

Question 12

In which hemithorax does intrapleural pressure increase following development of a tension pneumothorax?

Answer 12

Intrapleural pressure will be increased in the affected the hemithorax

One-way valve is created that enables air to enter, but not exit the pleural space. Overtime intrapleural pressures rise. This causes deviation of the trachea towards the contralateral hemithorax as well as compression of the heart, vena cava, and contralateral lung.

Question 13

how would carbon monoxide poisoning affect the following?
a. PaO2
b. O2 content.
c. P50 hemoglobin

Answer 13

a. PaO2 —> normal
b. O2 content —> decreased
c. P50 hemoglobin —> decreased

Recall carbon monoxide displaces oxygen from hemoglobin, and also stabilize hemoglobin in the taut state, making it hold O2 more tightly. Carbon monoxide does not affect the PaO2, which is typically normal. The O2 content of the blood is diminished because the majority of O2 should be bound to hemoglobin, but is displaced by carbon monoxide.

Question 14

A 27-year-old woman comes to the ED complaining of dyspnea over several hours. History includes use of birth control pills. She is tachypneic but PE is otherwise normal. PaO2 = 90 mmHg, PaCO2 = 36 mmHg. However, mixed expired/exhaled CO2 equals 18 mmHg (normal 24-28). This date is most consistent with a diagnosis of:
a. alveolar hypoventilation
b. Increased intrapulmonary shunt
c. Increased anatomic dead space
d. Increased physiologic dead space

Answer 14

d. Increased physiologic dead space

Patient has pulmonary embolism. PaO2 is 90 which is not consistent with a shunt. Recall that all CO2 in the expired air is coming from the alveoli and reflects alveolar ventilation. If there is less CO2 in the expired air than expected, this implies that a larger portion of the inspired air is wasted and does not eliminate CO2. a.k.a. physiological dead space has increased – when there is ventilation without perfusion.

Question 15

how will anemia affect the following values?
a. Arterial O2 content.
b. Arterial O2 saturation of hemoglobin.
c. Arterial O2 tension.

Answer 15

a. Arterial O2 content —> decreased
b. Arterial O2 saturation of hemoglobin —> normal
c. Arterial O2 tension —> normal

Question 16

You and a friend are breathing the same tidal volume and respiratory rate. If you double your tidal volume and half your respiratory rate, while your friend halves their tidal volume and doubles their respiratory rate, which of the following will occur?
a. You will increase your alveolar ventilation.
b. Your friend will increase their alveolar ventilation
c. In both cases, the alveolar ventilation will be unchanged.

Answer 16

a. You will increase your alveolar ventilation.

minute ventilation and alveolar ventilation are not the same thing

Tidal volume linked to alveolar ventilation

Question 17

A patient’s arterial blood gas on room air shows pH 7.48, PaO2 64mmHg, PaCO2 30.3 mmHg, HCO3- 20 MEQ/L. What is the calculated A – a gradient?

Answer 17

150 - PCO2/0.8 =
150 - 30/0.8 = 112 alveolar pressure

112 - 64 = 48, A-a gradient

[150 is pressure of inspired oxygen]

Question 18

patient has dry cough lasting over a month and has difficulty lying flat. There is JVD, PMI, and S3. Breath sounds are decreased over the left lung base. Ultrasound confirmed there is left plural effusion. Which of the additional physical findings would be consistent with his diagnosis?
a. Increased resonance to percussion.
b. Presence of vesicular lung sounds.
c. Diminished tactile fremitus.
d. Clear auscultation of whispered words.

Answer 18

c. Diminished tactile fremitus.

plural effusion occurs when there is increased fluid in the pleural space – this fluid separates the lung away from the chest wall so there is a large amount of fluid between the visceral pleura of the lung and the parietal pleura of the chest – this dampens sound transmission and decreases tactile fremitus

Clear auscultation of whispered words would occur when the alveoli are filled with fluid, because sound travels faster through liquids than air.

Question 19

Do patients with kyphoscoliosis have obstructive or restrictive lung dysfunction?

Answer 19

Kyphoscoliosis can decrease chest wall compliance, which will result in a restrictive pulmonary functional test

Question 20

if a patient with a history of smoking presents with a Pancost tumor, what kind of lung cancer do they most likely have?

Answer 20

Most Pancost tumors are non-small cell lung carcinoma’s. About 50% of these are adenocarcinoma, and the rest are squamous cell carcinoma. In a patient with a smoking history it is most likely a squamous cell cancer.

Question 21

A patient with a heavy smoking history and mild COPD presents to the office with exacerbation of her cough. She has been experiencing increased frequency/severity of her cough with purulent sputum production and occasional streaks of blood. CXR is obtained, which shows a mass. Pathologic examination shows keratinization. Which of the following clinical or pathologic features would you expect with this diagnosis?
a. Small peripheral module.
b. Lipidic growth along alveolar septae.
c. Central necrosis with cavitation
d. Neuroendocrine features.

Answer 21

c. Central necrosis with cavitation

squamous cell cancer demonstrate keratin pearls - nests of keratin within the tumor. One of the key features of squamous cell carcinoma is that the tumors tend to involve central airways, and commonly undergo central cavitation – necrosis of the center of the tumor. This may be that the tumors get large enough that the blood supply is not good enough.

a/b. small peripheral nodule + lipidic growth along alveolar septae = adenocarcinoma
d. neuroendocrine features = small cell carcinoma

Question 22

why does dynamic hyperinflation occur in obstructive lung disease?

Answer 22

Respiratory rate increases such that there is not enough time to exhale and the lung volumes tend to increase

Shortened time for expiration

Question 23

what characteristic pathologic changes associated with asthma include:
a. Bronchiectasis.
b. Subepithelial fibrosis in the airways.
c. Epithelial proliferation.
d. Collagen deposition in the alveolar interstitium.
e. Destruction of the alveolar walls.

Answer 23

b. Subepithelial fibrosis in the airways.

Changes in asthma include: thickening of airway mucosa caused by edema/cellular infiltrates (especially eosinophils and lymphocytes), hypertrophied bronchial smooth muscle with hyperplasia, collagen deposition in a layer beneath the epithelium, hypertrophy of mucous glands and increased goblet cells, damaged, epithelial cells

Question 24

A 16 year old girl with a history of moderate asthma is in the emergency room receiving nasal oxygen. She has been receiving albuterol via a nebulizer with minimal relief. Appropriate therapy at this time would be to administer inhaled:
a. budesonide
b. zileuton
c. Ipratropium
d. omalizumab
e. Montelukast

Answer 24

c. Ipratropium

do you need to add a drug that is another bronchodilator, not choose a drug that is an anti-inflammatory drug. That would be more for long-term management.

Question 25

A 21-year-old woman suffers from frequent a cute episodes of asthma, despite standard therapy with inhaled fluticasone. Which of the following drugs is a beta2 selective agonist that in combination with fluticasone would be most useful for asthma prophylaxis in this patient?
a. pirbuterol
b. salmeterol
c. beclomethasone
d. propranolol
e. epinephrine

Answer 25

b. salmeterol

Salmeterol is a chronic medication and is not used in similar fashion to short-acting β agonists (e.g., albuterol).

Question 26

what are patients with asbestos is at increased risk for? (4)

Answer 26

pulmonary fibrosis (restrictive lung disease), lung cancer, plural plaques, mesothelioma

Question 27

which of these is increased in restrictive lung disease?
a. Functional residual capacity.
b. Airway resistance.
c. lung compliance.
d. Lung elastic recoil.

Answer 27

d. Lung elastic recoil

a-c are indicative of obstructive lung disease

Question 28

in a patient with diffuse parenchymal lung disease, the maximal expiratory flow rate at low lung volumes may be higher than a normal subject because:
a. Airways have a smaller diameter.
b. Radial traction on the airways is increased.
c. Dynamic compression of the airways is more likely.
d. Airway resistance is increased.

Answer 28

b. Radial traction on the airways is increased.

at low lung volumes, the fibrotic parenchyma creates traction on small airways, allowing them to stay open longer - patients with restrictive diseases do not have air flow restriction and have better airflow at low lung volumes than normal

Question 29

how would ARDS affect the following?
a. Pulmonary capillary pressure.
b. Capillary oncotic pressure.
c. Pulmonary capillary permeability.

Answer 29

a. Pulmonary capillary pressure. —> normal
b. Capillary oncotic pressure. —> normal
c. Pulmonary capillary permeability. —> increased

ARDS is non-cardiogenic pulmonary edema – pulmonary capillary pressures would not be increased, and similarly you would not expect a change in the oncotic pressure – the pathology is in the capillary permeability

Question 30

most common opportunistic infection in person with HIV

Answer 30

Pneumocystis pneumonia, a.k.a. pneumocystis jiroveci pneumonia, formally known as pneumocystis carinii pneumonia

Question 31

how does the presentation of pneumonia differ in pneumonia caused by streptococcus pneumonia versus mycoplasma pneumonia?

Answer 31

streptococcus pneumonia - sudden onset of symptoms, lobar pneumonia, most common cause of community acquired pneumonia

mycoplasma pneumonia - slower onset (prodrome comes before), interstitial infiltrate, healthy young individuals (dorms, barracks, closed communities)

Question 32

A patient’s ventilator is set to deliver a tidal volume of 750mL, 10 times per minute. The tidal volume is then decreased to 500mL and the respiratory rate raised to 15 breaths/minute. Which of the following changes would you expect to see as a result of this change?
a. Decreased airway resistance.
b. Decreased arterial PCO2.
c. Increased alveolar ventilation.
d. Increased CO2 production.
e. Increased dead space fraction.

Answer 32

e. Increased dead space fraction.

When tidal volume decreases, alveolar dead space fraction increases –> decreased alveolar ventilation

Question 33

A patient receiving invasive mechanical ventilation shows decreased PaCO2 on the second day. The patient is in a coma/does not take any breaths manually, and no changes were made in ventilator settings. Which of the following go to count for the observed changed in his PaCO2?
a. New infection
b. Increase in minute ventilation.
c. Initiation of a protocol to lower his body temperature.
d. Initiation of nutritional intake through a feeding tube.
e. Recurrent seizures.

Answer 33

c. Initiation of a protocol to lower his body temperature.

PCO2 is determined by CO2 production and alveolar ventilation - hypothermia decreases CO2 production (slows metabolic processes)

recall hypothermia also causes left shift in O2 dissociation curve

Question 34

in what condition might you see an increased diffusing capacity for carbon monoxide (DLCO)?

Answer 34

diffuse alveolar hemorrhage in which red blood cells leak into the alveolar space and take up carbon monoxide

Question 35

which of the following muscles is involved in expiration?
a. Diaphragm.
b. External intercostals.
c. Rectus abdominis.
d. Scalene.
e. Sternocleidomastoid.

Answer 35

c. rectus abdominis.

Question 36

When is airway resistance lowest in the lungs?

Answer 36

end of inspiration right before beginning of expiration – lung volume is the greatest

Question 37

Patient is a 35-year-old female presenting with one year history of progressive dyspnea and fatigue. Examination of the lungs revealed symmetric tactile fremitus, resonance to percussion, and vesicular breath sounds. No wheezing or rales. Elevated jugular venous pressure is noted. There is a left parasternal heave and P2 is accentuated. There is a 2/6 holosystolic murmur at the left sternal border that increases with inspiration. Oxygen saturation is 94%. Chest x-ray is unremarkable. Pulmonary functional tests are likely to demonstrate:
a. Decreased peak expiratory flow
b. Increased residual volume
c. Deceased DLCO
d. Increased TLC
e. Decreased FEV1/FVC ratio

Answer 37

c. Deceased DLCO (diffusing capacity for CO)

Patient has primary pulmonary arterial HTN

Question 38

What is the cause of pleural effusion in a patient with cirrhosis?

Answer 38

Decreased pleural capillary oncotic pressure

[recall CHF causes pleural effusion because of increased pleural capillary hydrostatic pressure]

Question 39

Acute respiratory distress syndrome is associated with an increase in:
A. Lung compliance
B. Surfactant production
C. Intrapulmonary shunt
D. PaO2/FIO2 ratio

Answer 39

C. Intrapulmonary shunt

Question 40

Pulmonary embolism is associated with a decrease in:
A. A-a gradient
B. Physiologic dead space
C. Arterial pH
D. Surfactant production
E. Pulmonary vascular resistance

Answer 40

D. Surfactant production

Via damage to Type II pneumocytes

There will be increased A-a gradient, increased physiologic dead space, increased pulmonary vascular resistance