Table 1.

Study timeline.

		Study period
		Enrolment	Assessment	Close-out	Allocation
Time point		0 hours	0 hours	72 hours	Analysis
Enrolment
	Eligibility	X
	Informed consent	X
Optical device intervention			X
Assessment and analysis
	Optical device data acquisition		X		X
	Standard ultrasound	X			X
	Case-control nested study		X	X