C. VACUUM ASPIRATION (≤ 13 Weeks)

Vacuum aspiration can be performed easily and safely with little discomfort in the first trimester under local anaesthetic and premedication with narcotics or sedation if necessary.

Advantages
1. Decreased risk from complications of general anaesthesia
2.  Decreased incidence of blood loss, perforation, cervical laceration31
3. Quicker recovery from anaesthesia with less disorientation
4. Faster turnover in the recovery room
5. Quicker discharge and resumption of normal activity30
6. Patient acceptance
7. Greater economy

Exceptions
The same as for manual vaccum aspiration.

Preprocedural Cervical Dilatation

The advantage of preprocedural cervical dilatation is the gradual, safe dilatation of the cervix compared with the forcible and instrumental dilatation during the procedure.

Thus preprocedural cervical dilatation facilitates vacuum aspiration and significantly decreases the incidence of cervical lacerations and uterine perforation by up to 80%.

a) Chemical Dilators
The administration of 400 ìg of misoprostol, orally or vaginally, 4 to 12 hours prior to first trimester surgical abortion will effectively provide cervical dilatation and softening similar to osmotic dilators.

Advantages
1. Convenience: the patient can insert the tablets at home
2. Minimal pain on application
3. Highly cost effective

Potential Disadvantages
1. Cramping
2. Bleeding
3. Incomplete abortion before the surgical procedure If these occur, the patient must be encouraged to continue with the surgical procedure.

b) Osmotic Dilators
There are two types of osmotic dilators available in Canada: laminaria osmotic dilators and a synthetic polyacrylonitrile osmotic dilator (Dilapan).  A potential disadvantage to osmotic dilators is that if they are wrongly placed, a false passage may be dilated and make access to the endocervical canal difficult. Osmotic dilators can be challenging to place in women who have difficulty with vaginal examinations or who are primigravid. There is also pain associated with the placement of the tenaculum and the insertion into the cervical canal. Laminaria osmotic dilators require six to eight hours to achieve dilatation; the polyacrylonitrile osmotic dilators take only four hours and also soften the cervix.

After insertion of laminaria tents there is the possibility of cramps,  bleeding,  and   in   less   than 5%  of   patients, abortion.

Insertion of Osmotic Dilators
1. Visualize the cervix using a speculum and wash with antiseptic solution.

2.  Grasp the anterior lip of the cervix with a single-toothed tenaculum or other appropriate instrument.

3.  Straighten the cervical canal by gentle traction on the tenaculum, followed by the use of a uterine sound to probe the canal to determine the position, length, and diameter of the internal os. This will aid in determining the size and number of osmotic dilators to be used.

4.  Determine the size and number of laminaria osmotic dilators needed.

5.  Grasp the osmotic dilator longitudinally at its distal end by uterine forceps and insert it into the cervical canal just through the internal os while applying counter traction to the cervix. The osmotic dilator should traverse both the internal and external os.

6. The osmotic dilator should be held in place for several seconds to reduce expulsion.

7.  Place gauze (4 x 4) sponges against the cervix and leave in place until removal of the osmotic dilator.

Preoperative Medications
The American Heart Association, in its most recent recommendations,  states   that   prophylaxis   for   bacterial endocarditis is not required for abortion or dilatation and curettage “in the absence of infection.”

A meta-analysis of a large number of studies demonstrates that routine antibiotic prophylaxis is safe and effective in preventing post-abortal infection. Almost all studies have found that prophylactic antibiotics have a beneficial effect, are inexpensive, and rarely cause serious allergic reactions. Prophylactic regimens include (1) doxycycline 200 mg orally 30 to 60 minutes preoperatively or postoperatively and (2)  metronidazole 1 g orally preoperatively followed by 500 mg every six hours for three doses. Risk factors for post-abortal infection include a history of pelvic inflammatory     disease     or     previous     post-abortal endometritis, chlamydial or gonococcal infection in the past year, intrauterine device removed at or prior to the abortion,  and   immunocompromise   (HIV,  lupus,  steroids, insulin- dependent diabetes).

Pain Management
Several analgesic/conscious sedation regimens exist using various doses and routes of administration. The choice of anaesthetic depends on the wishes of the patient, the provider’s preferences, and the risk assessment.  It must be kept in mind that 34% of women having first trimester vacuum aspiration under paracervical block report “severe” or “very   severe”  pain.  Preprocedural   non-steroidal anti-inflammatory medication can help to reduce the pain.

Although often used, conscious sedation with midazolam and fentanyl is only slightly more effective than paracervical block for pain relief.  Therefore, current practices for pain relief with first trimester abortion are not optimal. If an anaesthetist is not present during the procedure, the attending physician must be prepared to initiate management should complications arise. All physicians using intravenous medications and local anaesthesia must be trained in resuscitation and stabilization techniques and equipment.

Patients receiving analgesics or sedation should have their blood pressure monitored and be attached to a pulse oxymeter to measure blood oxygen saturation.

Summary of Recommendations

REFERENCES

Victoria Jane Davis, MD
These guidelines were reviewed by the Clinical
Practice - Gynaecology Committee and the Social and Sexual
Issues Committee and approved by the Executive and Council of
the Society of Obstetricians and Gynaecologists of Canada.