Clinical features

Clinical prediction rule to rank your patient's risk of a PE

Ask about a	Score
Haemoptysis	1.0
Previously objectively diagnosed deep vein thrombosis or pulmonary embolism	1.0
Malignancy (patients with cancer receiving treatment, or treatment stopped within previous 6 months, or receiving palliative care):	1.0
Immobilisation (bedrest, except access to bathroom, for 3 or more days; or surgery in previous 4 weeks	1.5

Look for  a	Score
Heart rate > 100 beats/min	1.5
Clinical signs and symptoms of deep vein thrombosis (objectively measured leg swelling and pain with palpation in the deep-vein region)	3.0
Pulmonary embolism as likely or more likely than an alternative diagnosis (based on clinical information, chest X-ray, ECG and any blood tests required to diagnose PE):	3.0

Match your patient's score to the risk.

Score  a	Risk of PE
> 6.0	High
2.0 to 6.0	Moderate
< 2.0	Low

Why?

When combined with a diagnostic strategy (using d-dimer, ventilation-perfusion scanning, ultrasonography and pulmonary angiography):

• Few cases of PE are missed (0.6%: 95% CI: 0.2% to 1.4%). ^a
• 47% of patients receive no imaging, 7% undergo serial ultrasonography and 1.1% have angiography. ^a
• A similar prediction rule helped clinicians agree about the risk of a pulmonary embolism. K _{interobserver} for prediction rule = 0.85 ^a

A clinical prediction rule can help rank a patient for risk of a pulmonary embolism

Patient	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability
suspected pulmonary embolism a (pre-test probability: 9.5%)	pulmonary embolism (V/Q scan, lower limb, ultrasonography, pulmonary angiogram or follow-up at 3 months)	score: > 6.0	5.9 (3.7 to 9.3)	38%
		score: 2.0 to 6.0	1.9 (1.6 to 2.3)	16%
		score: < 2.0	0.13 (0.065 to 0.27)	1%