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 the valve by pushing the buttons inward 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.

• Single-tooth (works for any cervix) vs. atraumatic (Allis or Ring; most useful for more flexible, multiparous flexible cervices).

Place the tenaculum

• Administer local anesthesia and gently grasp the cervix at anterior lip (shown here), or posterior lip (for a retroverted uterus) with tenaculum, quietly, slowly closing 1-2 clicks.
• Either vertical (shown here) or horizontal tenaculum grasp are effective with 1×1 cm purchase, and do not obstruct dilator passage.
• Place paracervical block
• 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 x3 (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 in safety or efficacy (Kulier 2001)
• Larger cannula: faster aspiration, more intact tissue
• Smaller cannula: less dilation and less resistance, less intact tissue

• Apply traction to the tenaculum to straighten the uterus/cervix. While holding the cannula with fingertips, gently insert it through the cervix. If meeting resistance, see Step 15 above. Attach the aspirator to the cannula, avoiding grasping the MVA by the plunger arms. Alternatively, attach the cannula to the prepared aspirator and carefully, maintaining the cannula tip’s sterility, insert the cannula through the cervix.

Release the valve buttons

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

Evacuate the uterus

• Rotate the cannula and move it gently from the 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 or tissue passes through the cannula.

Choice of Vacuum for Aspiration

• Availability/preference determine use
• Some providers use >1 MVA to facilitate emptying, or switch to EVA >8-9 weeks
• Minimal differences in pain, anxiety, bleeding, or acceptability (Dean 2003)
• EVA sound may be audible; silent, in-wall suction may be available

EVA use:

• Turn on, check suction gauge, may adjust with thumb value or dial to (>60 mm Hg or green color zone)
• Attach cannula to handle of tubing
• Open thumb valve on tubing handle, keep open while placing cannula in uterus
• Once at fundus, close thumb valve to initiate suction
• Release suction by opening the thumb valve when passing out of the cervical canal.

• Rinse and strain the tissue
• Place tissue in a clear container
• Use backlight to inspect tissue if gross visual inspection is non-diagnostic.
• Normalize & accommodate patient-centered tissue viewing, if requested
• If incomplete, consider US (if available) and re-aspiration

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 + gestational sac.

Other Images:

MYAnetwork.org or Perinatology.com