Variable				Points
Age (years)
	60 to 79			1
		≥80		2
Previous PE or DVT				2
Recent surgery				3
Pulse rate > 100 beats per minute				1
PaCO2 (mm Hg)
	< 36			2
	36 to 39			1
Pao2 (mm Hg)
	< 48.8			4
	48.8 to 60.0			3
	60.1 to 71.3			2
	71.4 to 82.6			1
Chest radiograph
	Plate-like atelectasis			1
	Elevation of hemidiaphragm			1
			Total points:	_______