Ch. 40 SOB 5 days postop

Question 1

What is the most likely dx?

Answer 1

• Hypoxia
• Respiratory alkalosis
• Tachycardia
• Wide A-a gradient

PULMONARY EMBOLISM (usually from DVT in pelvic or leg veins)

Further reinforced by normal CXR and ECG

Phenomenon = venous thromboembolism (VTE)

Question 2

Why is the left leg 2x more commonly affected by DVT?

Answer 2

Because L iliac vein often compressed by R iliac artery

May-Thurner syndrome

Question 3

The 5 Classic Causes of Postop Fever

Answer 3

• Wind - atelectasis POD 1-2
• Water - UTI POD 3
• Wound - Infection POD 5
• Walking - DVT/thrombophlebitis POD 7-10
• Wonder drugs - Drug fever (e.g., abx) Anytime

Question 4

What is the cause of cardiogenic pulmonary edema on POD3?

Answer 4

Result of third spacing

The large volume of IV fluids administered to the patient perioperatively, which equilibrated in all body compartments, will return back to the vasculature often on POD3. Elderly pts or those with poor heart function are particularly at risk, as the increased intravascular volume may overwhelm the heart and lead to elevated ventricular filling pressures, which can be transmitted into the pulmonary circulation.

Question 5

What is an A-a gradient? What is the differential of a wide A-a gradient?

Answer 5

A-a gradient refers to the difference in partial pressure of oxygen between the alveolie and arterial blood.

The different dx of a wide A-a graident in postop setting: atelectasis, pneumonia, PE

Question 6

Pt has suspected PE, what do you do?

When should tPA be considered?

Answer 6

Start heparin (anticoagulant) RIGHT AWAY before dx is even establish

Purpose of heparin in VTE is not to dissolve the clot, but rather to prevent it from progressing/propogating

Following heparin administration, obtain CTA of the pulmonary arteries

tPA = massive PE

Question 7

What is the recommendation for long-term anticoagulation after first-time VTE?

Answer 7

Heparin or LMWH should be given for first 5 days after VTE, and warfarin should be started on first or second day such that the two overlap for 4-5 days.

Goal INR = 2-3

3 mo therapy

Question 8

Virchow’s Triad

Answer 8

Stasis, hypercoagulability, endothelial injury

Question 9

Special conditions:

• VTE with malignancy
• VTE in pregnancy
• VTE with HIT

Answer 9

• VTE with malignancy: LMWH: treatment of choice
• VTE in pregnancy: avoid WARFARIN
• VTE with HIT: Direct thrombin inhibitors