USING MVA AND EVA EQUIPMENT

• Cap
• Cap release
• Valve buttons
• Clasp
• Plunger O-ring
• Collar stop Retaining Clip
• Collar stop
• Cylinder base
• Plunger arms
• Plunger handle

Prepare the aspirator

• Begin with valve buttons open and plunger pushed fully into the barrel.
• Close valve by pushing the buttons down and forward until locked in place.

Create the vacuum

• Pull the plunger back until its arms snap outward over the rim at the end of the barrel.
• Make sure plunger arms are positioned over wide edges of the barrel rim.

Attach the tenaculum

• Gently attach the tenaculum to the cervix (either anterior lip, as shown here) or posterior lip (for a retroverted uterus), closing slowly 1-2 clicks.
• Exert gradual traction to straighten cervical canal.

Gently dilate the cervix after paracervical block

• Use dilators of increasing size to accommodate cannula size chosen based on gestational weeks.
• Dilator:
  • Denniston – dilate to cannula size (e.g. size 7 for 7 mm cannula)
  • Pratt – dilate to cannula size x 3 (e.g. 21 French for 7mm cannula)

Choose a cannula

• Flexible: longer with two openings at tip
• Rigid: larger single opening at tip
• No significant difference safety or efficacy (Kulier 2001)
• Larger cannula: faster aspiration, more intact tissue
• Smaller cannula: less dilation and less resistance

Last NAF Provider’s survey (O’Connell 2009):

• • 54% used size (in mm) = weeks gestation
  • 37% used 1-2 mm < weeks gestation
  • 9% used 1-3 mm > weeks gestation

• Apply traction to tenaculum to straighten uterus. While holding cannula with fingertips, gently insert through cervix with rotating motion.
• Attach aspirator to cannula.
• Do not grasp aspirator by plunger arms.

Release the valve buttons

• When the pinch valve is released, the vacuum is transferred through the cannula into the uterus.
• Blood, tissue, and bubbles will flow through the cannula into the aspirator.

Evacuate the uterus

• Rotate the cannula and move it gently from fundus to the internal os, applying a back and forth motion as clinically indicated until:
  • Grittiness is felt through cannula
  • Uterus contracts and grips cannula
  • There is increased cramping, and / or
  • No more blood passes through cannula.

Choice of Vacuum for Aspiration

• Availability / preference determine use
• Some use > 1 MVA to facilitate emptying, or switch to EVA > 9 weeks
• Minimal differences in pain, anxiety, bleeding, or acceptability (Dean 2003)
• EVA sound may be audible to patients; silent, in-wall suction is available.

EVA use:

• Turn on and check suction gauge, turn dial to adjust
• Attach cannula
• Open thumb valve, keep open while placing cannula in uterus
• Once at fundus, close thumb valve to initiate suction
• Release suction by opening thumb valve when passing out of the cervical canal.

Inspect the tissue

• Rinse and strain the tissue
• Place tissue in a clear container
• Backlight is recommended to inspect tissue if gross visual inspection is non-diagnostic.

Gestational sac at 6 weeks

• Shredded (on left) vs. intact
• To minimize shredding, consider using MVA and/or a slightly larger cannula.

Membranes and Villi (POC)

• Frond-like villi
• Clumps held by membrane
• Transparent like plastic wrap
• Luminescent; light refractory
• Turns white if vinegar added
• More stretchy
• Floats more in liquid media

Decidua (not POC)

• No fronds
• No villi or thin membrane 
• Opaque like wax paper
• Less light refractory
• Minimal color change 
• More breakable
• Sinks more in liquid media
• Quantity variable

Caution not to confuse
a) gestational sac (8 wk) with

b) decidua capsularis,  a portion of the decidua which grows proportionally to gestational sac but is thicker and tougher (Paul 2009).

Parts may be seen earlier.

≥ 10W look for 4 extremities, spine, calvarium and gestational sac.

≥12W must find all fetal parts + placenta.