Bladder volume/post-void residual
Use calc mode and measure in 3 dimensions (anterior posterior, right left, and superior inferior)
Normal PVR is <50mL, <100mL in patients >65.
Stones
Use calc mode and measure in 3 dimensions (anterior posterior, right left, and superior inferior)
Normal PVR is <50mL, <100mL in patients >65.
Ureteral jets can indicate patent ureter
Bladder bulge may indicated a UVJ stone
Twinkle Sign: Rapid alternation of color immediately behind a stationary echogenic object, acquiring a false appearance of movement in color Doppler mode
Free fluid
Anechoic (black) fluid outside the bladder is suggestive of free fluid
Look for 'pointy edges' which increases suspicion for fluid not in another structure (cyst, ovary, bowel, etc)
Ureteral jets can indicate patent ureter
Bladder bulge may indicated a UVJ stone
Twinkle Sign: Rapid alternation of color immediately behind a stationary echogenic object, acquiring a false appearance of movement in color Doppler mode
Anechoic (black) fluid outside the bladder is suggestive of free fluid
Look for 'pointy edges' which increases suspicion for fluid not in another structure (cyst, ovary, bowel, etc)
Bladder ultrasound
Bladder lavage
Suprapubic bladder aspiration
Renal ultrasound
Suprapubic catheter placement
Urine analysis
Pelvic ultrasound 
Digital EpiPen injection