Slide 2:
A-a Gradient: P A O2 – P a O2 = [Fio2 X (P atm – P H20) – (PaCo2/0.8)] – PaO2 Normal gradient estimate: [Age/4] + 4 2.5 + [0.21 X age in yr] A-a gradient increases by age and higher Fio2 In one study the A-a in men breathing air and 100 oxygen varied from 8-82 in <40 y/o and 3-120 in >40.
Slide 3:
Pulmonary Emboli Clinical Features of Pulmonary emboli: New or worsening breathlessness, specially sudden onset Tachypnea Chest pain Tachycardia Hemoptysis Syncope Hypotension Cough or fever ( not specific) ABG: Hypoxemia, Hypocapnia, Resp Alk. High A-a Gradient (6% may be Nl) Elevated BNP Elevated Trop (30-50% of PEs) ECG: Tachycardia, S1Q3 ┴3, RBBB
Risk factors for Pulmonary Emboli:
Risk factors for Pulmonary Emboli Immobilization Acute medical illness Hypercoagulable state Surgery in last 3 months. Trauma (to LE and pelvis in last 3 months) Stroke Paresis, paralysis H/o DVT Malignancy Central venous catheter in last 3 months Chronic heart dx In women: Obesity, heavy smoking, HTN OCP, pregnancy
If you suspect PE:
If you suspect PE Modified Wells criteria PE is unlikely (score ≤4) or likely (score >4). Clinical symptoms of DVT (3 points) Other diagnoses less likely than PE (3 points) Heart rate >100 (1.5 points) Immobilization ≥3 days or surgery in previous four weeks (1.5 points) Previous DVT/PE (1.5 points) Hemoptysis (1 point) Malignancy (1 point) Our Pt: Hemoptysis + Immobilization + HR + ? Other = 4 or 7 Diagnosis: D-Dimer, V/Q scan, CT spiral CXR, Echocardiogram, Angiography DO NOT HOLD ANTICOAGULATION FOR DIAGNOSTIC STUDIES.
Slide 6:
Thank you