After bimanual examination is performed to determine uterine size and orientation, a speculum is inserted, and the cervix is swabbed with povidone-iodine or equivalent solution. he anterior cervical lip is grasped with a toothed tenaculum. The cervix, vagina, and uterus are richly supplied by nerves of Frankenhauser plexus, which lies within connective tissue lateral to the uterosacral and cardinal ligaments. Thus, vacuum aspiration at minimum requires intravenously or orally administered sedatives or analgesics, and some add a paracervical or intracervical blockade with lidocaine (llen, 2009; Renner, 2012). For local blocks, 5 mL of 1-or 2-percent lidocaine is most efective if placed immediately lateral to the insertion of the uterosacral ligaments into the uterus at 4 and 8 o'clock. An intracervical block with 5-mL aliquots of I-percent lidocaine injected at 12, 3, 6, and 9 o'clock was reported to be equally efective (Mankowski, 2009). Alternatively, general or regional anesthesia may be elected.
Uterine sounding measures the depth and inclination of the cavity before other instrument insertion. If required, the cervix
FIGURE 18-7 Dilatation of cervix with a Hegar dilator. Note that the fourth and fifth fingers rest against the perineum and buttocks, lateral to the vagina. This maneuver is an important safety measure because if the cervix relaxes abruptly, these fingers prevent a sudden and uncontrolled thrust of the dilator, a common cause of uterine perforation.
is further dilated with Hegar, Hank, or Pratt dilators until a suction cannula of the appropriate diameter can be inserted. he degree of required cervical dilation roughly approximates gestational age. Hegar sizes reflect their diameter in millimeters. Pratt and Hank dilators are sized in French units, which can be converted to millimeters by dividing the French number by three.
With dilation, the fourth and fifth ingers of the hand introducing the dilator should rest on the perineum and buttocks as the instrument is pushed through the internal os (Fig. 18-7). his technique minimizes forceful expansion and provides a safeguard against uterine perforation.
Following dilation, for most first-trimester aspiration procedures, an 8-to 12-mm Karman cannula is appropriate. Small cannulas carry the risk of leaving retained intrauterine tissue postoperatively, whereas large cannulas risk cervical injury and more discomfort. To begin, the cannula is slowly moved toward the fundus until resistance is met. Suction is then activated. he cannula is gradually pulled back toward the os and is slowly turned circumferentially to cover the entire surface of the uterine cavity (Fig. 18-8). his is repeated until no more tissue is aspirated. A gentle sharp curettage can follow to remove any remaining tissue fragments (Fig. 18-9). Strong and consistent evidence supports high eicacy, safety, and patient acceptability for both MVA and EVA (Lichtenberg, 2013).
For abortion done at $6 weeks' gestation, a distinct drawback is that the pregnancy may be small and missed by the curette. To identiy placenta, the aspirated contents are rinsed in a strainer to remove blood, and then placed in a clear plastic container with saline and examined with back lighting (MacIsaac, 2000). Placental tissue macroscopically appears soft, luy, and feathery. A magniying lens, colposcope, or microscope can augment visualization. With gestations $7 weeks, the failed abortion rate approximates 2 percent (Kaunitz, 1985;