Pulmonary #9 (PE, ARDS, Sleep Apnea)

Question 1

A pulmonary embolism is an obstruction of the pulmonary blood flow due to a blood clot. 70% arise from

Answer 1

the deep vein in the legs

Question 2

Risk factors for a PE (Virchow’s Triad)

Answer 2

-Intimal damage: trauma, infection, inflammation
-Stasis: immobilization, surgery, sitting > 4 hours
-Hypercoagulability: OCP use, malignancy, pregnancy, smoking, Factor V Leiden, antithrombin III deficiency

Question 3

Symptoms of a PE

Answer 3

-Triad of sudden onset dyspnea (MC), pleuritic chest pain, hemoptysis
-Tachypnea (MC)
-Fever, tachycardia
-Positive Homan Sign

Question 4

Although CXR is usually done first to evaluate the chest pain, it is usually normal. A Normal CXR in the setting of ______ is highly suspicious of a PE

Answer 4

hypoxia

Question 5

What are two classic but rare findings on CXR for a PE?

Answer 5

Westermark’s sign: avascular markings distal to the PE

Hampton’s Hump: wedge-shaped infiltrate due to infarction

Question 6

What is seen on ECG for a PE?

Answer 6

Nonspecific ST/T changes and sinus tachycardia MC

S1Q3T3 (wide deep S in lead 1, isolated Q and T wave inversion in lead III)

Question 7

ABG for PE shows

Answer 7

Respiratory alkalosis + hypoxemia

Question 8

When should you do a d-dimer for a PE?

Answer 8

ONLY if negative and a low suspicion for a PE

Question 9

What is the BEST initial test to confirm a PE

Answer 9

Helical (spiral) CT angiography

Question 10

When should you perform a V/Q scan?

Answer 10

When CT can’t be performed (pregnancy, increased creatinine).

-If negative, proceed to angiography. If positive = PE

Question 11

GOLD standard diagnostic for PE

Answer 11

Pulmonary angiography (not usually performed)

Question 12

What is the first-line therapy in most patients with a PE?

Answer 12

Anticoagulation (Heparin bridge plus Warfarin or a novel anticoagulant such as Dabigatran, Rivaroxaban, Apixaban, or Edoxaban)

Question 13

However, an IVC filter should be used in 3 patients

Answer 13

-If anticoagulation is contraindicated: recent bleed, bleeding disorder
-Anticoagulation is unsuccessful
-If RV dysfunction seen on echocardiogram (the next embolus can be fatal)

Question 14

If the patient is hemodynamically unstable (SBP < 90, RV dysfunction, etc.), what should be done

Answer 14

Thombolysis with LMWH or Thombectomy/Embolectomy

Question 15

MOA of LMWH

Answer 15

Potentiates antithrombin III

-Duration of action 12 hours
-DO NOT USE if renal failure present

Question 16

What is the antidote for LMWH

Answer 16

Protamine Sulfate

Question 17

Unfractionated Heparin (UFH), also potentiates antithrombin III, but also inhibits ….

Answer 17

thrombin and other coagulation factors

Question 18

UFH has a duration of action of

Answer 18

1 hour after IV drip is discontinued

Question 19

True or False: With LMWH, you do not need to monitor INR. With UFH, PTT must be at 1.5 - 2.5x normal value.

Answer 19

True

Question 20

Antidote for UFH

Answer 20

Protamine Sulfate

Question 21

What criteria are used for PE probability?

Answer 21

Well’s Criteria

3 points each: Symptoms of DVT, #1 diagnosis

1.5 points each: HR > 100, Immobilization for 3 days or surgery within 4 weeks, previous DVT or PE

1 point each: hemoptysis, malignancy diagnosed

Low < 2 points –> d-dimer
Moderate 2-6 points –> CTA or d-dimer
High > 6 points –> CTA

Question 22

What are some examples of ways to prophylaxis against PE?

Answer 22

Early ambulation: low risk, minor procedures in patients < 40 years old

Elastic stockings/compression devices: moderate risk

LMWH: orthopedic or neurosurgery, trauma

Question 23

Acute respiratory distress syndrome MC develops in

Answer 23

critically ill patients (Gram-negative sepsis MC, severe trauma, pancreatitis, near drowning, etc)

Question 24

Symptoms of ARDS

Answer 24

-Acute dyspnea and hypoxemia
-Multi-organ failure if severe

Question 25

What are the three main components to diagnose ARDS?

Answer 25

-Severe hypoxemia refractory to supplemental oxygen
-CXR: bilateral diffuse pulmonary infiltrates (spares costophrenic angles)
Absence of cardiogenic pulmonary edema: pulmonary capillary wedge pressure < 18 mm hG with right heart catheterization

Question 26

Treatment for ARDS

Answer 26

-Noninvasive or mechanical ventilation + treat underlying cause (CPAP will full face mask, PEEP, and low tidal volume)

Question 27

PEEP (positive end-expiration pressure) improves _______ by preventing alveolar collapse, which improves the V/Q mismatch and increases functional residual capacity

Answer 27

Hypoxemia

Question 28

Risk factors for sleep apnea

Answer 28

Obesity (strongest risk factor)
Males
Age (in 60’s and 70’s)

Question 29

Differentiate central sleep apnea and obstructive sleep apnea

Answer 29

-Central: reduced CNS respiratory drive leads to decreased respiratory effort

-Obstructive: physical airway obstruction (due to increased tonsil size, deviated septum, external airway compression, decreased pharyngeal muscle tone)

Question 30

Symptoms of sleep apnea

Answer 30

-Snoring
-Unrestful sleep
-Daytime sleepiness
-Nocturnal choking
-Large neck circumference
-Crowded oropharynx
-Micrognathia (lower jaw undersized)

Question 31

First-line diagnostic test for sleep apnea

Answer 31

In-lab polysomnography (15 or more events/hr)

Question 32

Labs for sleep apnea show________, due to chronic hypoxemia

Answer 32

Polycythemia (increased RBCs)

Question 33

What scale is used to determine a patient’s perception of fatigue and sleep?

Answer 33

Epworth sleepiness scale

Question 34

Treatment for Sleep Apnea

Answer 34

-behavioral changes: weight loss, abstaining from alcohol, change sleep positioning

-CPAP (mainstay of treatment)

-Surgical correction of tracheostomy is the definitive treatment.

Question 35

How to prevent meconium aspiration in an infant

Answer 35

Prevention of postterm delivery (>41 weeks) via labor induction and prevention of fetal hypoxia