USING MVA AND EVA EQUIPMENT

prepare the aspirator 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 Create the vacuum

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

  • 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 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: faster aspiration, intact tissue
  • Smaller: less dilation and resistance

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
Insert the cannula Insert the cannula

  • Apply traction to tenaculum to straighten uterus.
    Then holding cannula with fingertips, gently
    insert through cervix with rotating motion.
  • Attach aspirator to cannula.
  • Do not grasp aspirator by plunger arms.
Release the pinch valve 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 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
stand Choice of Vacuum for Aspiration

  • Availability / preference determine use
  • MVA is FDA approved to 12 weeks
  • 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 disturbs some patients; silent, in-wall suction is available.

EVA use:

  • Attach cannula and close thumb valve
  • Place cannula into uterus
  • Turn on and check suction gauge
  • To modify: turn dial or adjust valve
  • Release suction (open thumb valve) when passing through cervical canal.
inspect tissue 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 in blue Gestational sac at 6 weeks

  • Shredded (on left) vs. intact
  • To minimize shredding, consider using MVA
    (< pressure than EVA); slightly larger cannula.
image
membranes and villi 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
  • Size: see coin sizes above
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
image Decidua capsularis
Caution not to confuse
a) gestational sac (8 week) with
b) decidua capsularis, a portion of the decidua
which grows proportionally to gestational sac
but is thicker and tougher(Image: Edwards, J).
Fetal part development
Parts may be seen earlier.
≥ 10W look for 4 extremities, spine,
calvarium and gestational sac.≥12W must find all
fetal parts + placenta

Illustrated images adapted from MVA, a presentation by Physicians and ARHP, 2000; 2012.

License

EARLY ABORTION TRAINING CURRICULUM Copyright © 2020 by UCSF Bixby Center for Global Reproductive Health. All Rights Reserved.