Pulmonary #9 (PE, ARDS, Sleep Apnea) Flashcards
A pulmonary embolism is an obstruction of the pulmonary blood flow due to a blood clot. 70% arise from
the deep vein in the legs
Risk factors for a PE (Virchow’s Triad)
-Intimal damage: trauma, infection, inflammation
-Stasis: immobilization, surgery, sitting > 4 hours
-Hypercoagulability: OCP use, malignancy, pregnancy, smoking, Factor V Leiden, antithrombin III deficiency
Symptoms of a PE
-Triad of sudden onset dyspnea (MC), pleuritic chest pain, hemoptysis
-Tachypnea (MC)
-Fever, tachycardia
-Positive Homan Sign
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
hypoxia
What are two classic but rare findings on CXR for a PE?
Westermark’s sign: avascular markings distal to the PE
Hampton’s Hump: wedge-shaped infiltrate due to infarction
What is seen on ECG for a PE?
Nonspecific ST/T changes and sinus tachycardia MC
S1Q3T3 (wide deep S in lead 1, isolated Q and T wave inversion in lead III)
ABG for PE shows
Respiratory alkalosis + hypoxemia
When should you do a d-dimer for a PE?
ONLY if negative and a low suspicion for a PE
What is the BEST initial test to confirm a PE
Helical (spiral) CT angiography
When should you perform a V/Q scan?
When CT can’t be performed (pregnancy, increased creatinine).
-If negative, proceed to angiography. If positive = PE
GOLD standard diagnostic for PE
Pulmonary angiography (not usually performed)
What is the first-line therapy in most patients with a PE?
Anticoagulation (Heparin bridge plus Warfarin or a novel anticoagulant such as Dabigatran, Rivaroxaban, Apixaban, or Edoxaban)
However, an IVC filter should be used in 3 patients
-If anticoagulation is contraindicated: recent bleed, bleeding disorder
-Anticoagulation is unsuccessful
-If RV dysfunction seen on echocardiogram (the next embolus can be fatal)
If the patient is hemodynamically unstable (SBP < 90, RV dysfunction, etc.), what should be done
Thombolysis with LMWH or Thombectomy/Embolectomy
MOA of LMWH
Potentiates antithrombin III
-Duration of action 12 hours
-DO NOT USE if renal failure present
What is the antidote for LMWH
Protamine Sulfate
Unfractionated Heparin (UFH), also potentiates antithrombin III, but also inhibits ….
thrombin and other coagulation factors
UFH has a duration of action of
1 hour after IV drip is discontinued
True or False: With LMWH, you do not need to monitor INR. With UFH, PTT must be at 1.5 - 2.5x normal value.
True
Antidote for UFH
Protamine Sulfate
What criteria are used for PE probability?
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
What are some examples of ways to prophylaxis against PE?
Early ambulation: low risk, minor procedures in patients < 40 years old
Elastic stockings/compression devices: moderate risk
LMWH: orthopedic or neurosurgery, trauma
Acute respiratory distress syndrome MC develops in
critically ill patients (Gram-negative sepsis MC, severe trauma, pancreatitis, near drowning, etc)
Symptoms of ARDS
-Acute dyspnea and hypoxemia
-Multi-organ failure if severe
What are the three main components to diagnose ARDS?
-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
Treatment for ARDS
-Noninvasive or mechanical ventilation + treat underlying cause (CPAP will full face mask, PEEP, and low tidal volume)
PEEP (positive end-expiration pressure) improves _______ by preventing alveolar collapse, which improves the V/Q mismatch and increases functional residual capacity
Hypoxemia
Risk factors for sleep apnea
Obesity (strongest risk factor)
Males
Age (in 60’s and 70’s)
Differentiate central sleep apnea and obstructive sleep apnea
-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)
Symptoms of sleep apnea
-Snoring
-Unrestful sleep
-Daytime sleepiness
-Nocturnal choking
-Large neck circumference
-Crowded oropharynx
-Micrognathia (lower jaw undersized)
First-line diagnostic test for sleep apnea
In-lab polysomnography (15 or more events/hr)
Labs for sleep apnea show________, due to chronic hypoxemia
Polycythemia (increased RBCs)
What scale is used to determine a patient’s perception of fatigue and sleep?
Epworth sleepiness scale
Treatment for Sleep Apnea
-behavioral changes: weight loss, abstaining from alcohol, change sleep positioning
-CPAP (mainstay of treatment)
-Surgical correction of tracheostomy is the definitive treatment.
How to prevent meconium aspiration in an infant
Prevention of postterm delivery (>41 weeks) via labor induction and prevention of fetal hypoxia
