Clinical Model of Wells et al for Predicting Probability of Pulmonary Embolism in a Patient

Patient selection: presence of pulmonary and/or cardiac symptoms

 

Typical signs and symptoms:

(1) respiratory score >= 2 based on respiratory findings present

(2) other signs and symptoms score >= 1

 

Respiratory findings:

(1) dyspnea or worsening of chronic dyspnea

(2) pleuritic chest pain

(3) chest pain that is nonretrosternal and nonpleuritic

(4) arterial oxygen saturation < 92% while breathing room air that corrects with oxygen supplementation < 40%

(5) hemoptysis

(6) pleural rub

 

respiratory score =

= SUM(number of respiratory findings present)

 

Other signs and symptoms:

(1) heart rate > 90 beats per minute

(2) leg symptoms of deep vein thrombosis

(3) low grade fever

(4) results of chest radiograph compatible with PE

 

other signs and symptoms score =

= SUM(number of other signs and symptoms present)

 

Severe if one or both of the following:

(1) typical signs and symptoms AND one or more severe finding

(2) severe finding 4 (new onset heart failure) AND one or more of the other severe findings

 

Severe findings:

(1) syncope

(2) blood pressure < 90 mm Hg with heart rate > 100 beats/minute

(3) requires ventilation or oxygen supplementation > 40%

(4) new onset right heart failure (elevated jugular venous pressure + new S1, Q3 and T3 sounds OR elevated jugular venous pressure + RBBB)

 

Risk factors:

(1) major surgery within 12 weeks

(2) immobilization (complete bedrest) for 3 or more days in the 4 weeks before presentation

(3) previous deep vein thrombosis or objectively diagnosed pulmonary embolism

(4) fracture of a lower extremity and immobilization of the fracture within 12 weeks

(5) strong family history of deep vein thrombosis or pulmonary embolism (>= 2 family members with objectively proven events, OR 1 first degree relative with hereditary thrombophilia)

(6) cancer (ongoing treatment, within past months, or in palliative stage)

(7) postpartum

(8) lower extremity paralysis

 

Signs and Symptoms	Alternative Diagnosis to PE	Number of Risk Factors	Probability of PE
typical	as or more likely	0	low
typical	as or more likely	>= 1	moderate
typical	less likely than PE	0	moderate
typical	less likely than PE	>= 1	high
severe (typical plus)	as or more likely	0	moderate
severe (typical plus)	less likely than PE	>= 1	high
atypical	as or more likely	0	low
atypical	as or more likely	>= 1	low
atypical	less likely than PE	0	low
atypical	less likely than PE	>= 1	moderate

 

where:

• Atypical is defined as having respiratory or cardiac signs and symptoms but these do not meet the criteria for typical or severe.

 

If this data is reanalyzed in a different way:

 

Parameters:

(1) signs and symptoms

(2) alternative diagnosis

(3) number of risk factors

 

Parameter	Finding	Points
signs and symptoms	atypical	0
	typical	1
	severe	2
alternative diagnosis	yes	0
	no	1
number of risk factors	0	0
	1 or more	1

 

total score =

= SUM(points for all 3 parameters)

 

Total Score	Likelihood of PE
0	very low
1	low
2	moderate
3	high
4	very high