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Development of a Novel Task Trainer for Second Trimester Ultrasound-guided Uterine Evacuation

Shumard, Kristina M. MD; Akoma, Ugochi N. MD; Street, Linda M. MD; Brost, Brian C. MD; Nitsche, Joshua F. MD, PhD

Author Information
Simulation in Healthcare: Journal of the Society for Simulation in Healthcare: February 2015 - Volume 10 - Issue 1 - p 49-53
doi: 10.1097/SIH.0000000000000063
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Abstract

Availability of family planning services vary by local provider availability, expertise, and gestational age of the pregnancy. In the second trimester, medical induction of labor or dilation and evacuation (D&E) are the main management options. Approximately 1720 providers offer termination services in the United States, representing a 4% decline in providers since 2008.1 Based on data from 2008, less than 65% of surveyed providers perform any second trimester procedures.2 Recent studies have indicated that surgical termination by D&E is a safer option for women in the second trimester.3–5 However, in some areas of the United States, women are directed toward medical induction methods because of a lack of local providers trained or skilled to perform D&E procedures.6

Providing residents and other learners with experience in these procedures is a challenge as the number of skilled providers decrease.7–9 Many residents and other learners train in an area with either no providers or a limited exposure to this surgical procedure. In a survey of family planning subspecialists, only 35% report being trained in D&E during their residency.10 Simulation may be one way in which learners might be exposed and gain experience with the procedure before performing it for the first time on a patient or to augment their training.

Simulation in medical education is an area of intense interest as duty hour restrictions have changed, limiting the available time for exposure to clinical opportunities. In other areas of medicine, medical simulation has been demonstrated to significantly improve learning outcomes such as knowledge, skill acquisition, and behaviors as well as smaller but significant effects on patient outcomes.11 Simulation models for obstetric training have been used with success in improving performance in obstetric ultrasound12–15 and management of obstetric emergencies such as shoulder dystocia.16,17 In addition, simulation models have been described for training in other rare procedures such as cervical cerclage,18 amniocentesis,19 chorionic villus sampling,20 or fetal stenting procedures.21 Availability of a task trainer for D&E undoubtedly improves the training of this increasingly rare but much needed skill. We discuss the construction and assessment of a model that will allow training of ultrasound-guided second trimester uterine evacuation.

METHODS

Model Construction

A second trimester uterine evacuation task trainer was created using a preserved adult pig heart, fetal pig, along with other materials listed in Table 1 according to the following steps:

T1-8
TABLE 1:
Supply List for Dilation and Evacuation Task Trainer
  1. Remove the pig heart from the preservative container, and rinse off the preservative.
  2. Enter the atria of the pig heart through the great vessels using scissors and/or scalpel.
  3. Continue sharp dissection into the ventricles of the heart, removing the majority of the intraventricular septum and heart valves (Fig. 1A)
  4. Using loop electrocautery, shave off the remaining septal tissue, and smooth out the ventricular trabeculations.
    • It is important to obtain a smooth inner surface in the heart because any irregularity will trap air and degrade ultrasound images.
  5. Amputate the apex of the heart to create an opening into the simulated uterine cavity of approximately 2 cm in diameter.
  6. Fill a condom with water to serve as the simulated bladder, and tie a knot at both ends.
  7. Place the bladder on the outside of the heart, and fasten it in place with suture.
  8. Place an appropriately sized fetal pig into the pig heart with a generous amount of ultrasound gel.
  9. Close the open end of the pig heart with a large binder clip.
  10. Place the heart into a rigid plastic pelvis model using towels and washcloths to hold the heart in place, making certain that the simulated cervical canal created in the apex of the heart is appropriately positioned (Fig. 1B).
  11. Create a simulated vagina. Attach the simulated perineum to the pelvis model. Create a ring using a rolled-up washcloth. Place speculum through this ring, and open it wide. Use tape around the outside of the ring to hold it firmly against the speculum.
  12. Place the washcloth ring and attached speculum through the perineum, positioning the heart apex at the top of the simulated vagina (Fig. 1C).
  13. Fill a gallon-sized Ziploc freezer bag with ultrasound gel. Tape the end of the bag with clear packing tape for reinforcement.
  14. Place ultrasound gel–filled Ziploc freezer bag over the heart and simulated bladder.
  15. Use an appropriate probe cover, and obtain ultrasound images (Figs. 1D and 2A, B)
  16. Simulate second trimester uterine evacuation.
    • A ring forceps is placed on the pig heart in the area representing the anterior cervical lip.
    • Ovum forceps are then used to simulate fetal evacuation under ultrasound guidance (Fig. 2C, D).
  17. At the conclusion of the training session, the ultrasound gel can be rinsed or wiped off, and the pig heart can be stored in preservative for use in future training sessions.
F1-8
FIGURE 1:
A D&E task trainer. A, Prepared pig heart (simulated uterus) with valves and intraventricular septum removed. B, Simulated uterus (with fetal pig inside) and simulated bladder placed in female pelvis model. C, Simulated cervical opening on speculum examination. D, Fully assembled model allowing ultrasound visualization of fetus and instruments.
F2-8
FIGURE 2:
Ultrasound images of D&E task trainer. A and B, Images of model before procedure. C and D, Images of model during the procedure. Ab, maternal abdominal tissue; Bl, maternal bladder; FH, fetal head; FT, fetal thorax, OF, ovum forceps; U, maternal uterus.

A complete list of materials for task trainer construction is provided in Table 1.

Assessment of Model Validity

The face validity of the model was assessed by 12 OB/GYN residents and 1 maternal-fetal medicine (MFM) fellow. The trainees had a lecture on termination of pregnancy that included specific instruction on surgical termination and D&E. During the simulation, residents were individually brought to the simulation model, instructed on how to use it, and then performed a simulated D&E under ultrasound guidance. A survey was provided to each participating resident with the following statements, and they were asked to rate their responses according to a 5-point Likert scale as follows: strongly disagree (1), disagree (2), neutral (3), agree (4), and strongly agree (5).

  1. I feel comfortable performing a D&E in a real-life setting.
  2. The fetal ultrasound images of the task trainer are similar to those I have seen during a real-life D&E.
  3. The fetal extraction skills I practiced with the task trainer approximate those I have seen or used during a real-life D&E.
  4. Using the task trainer will improve my proficiency with D&E.
  5. With sufficient practice with the task trainer, I will be able to perform a D&E in a real-life setting.

Their responses were recorded, and the means were calculated for each statement. Each resident was also asked to provide open-ended comments regarding the overall strengths and weaknesses of the model.

RESULTS

There were 12 OB/GYN residents (1 fourth year, 3 third year, 4 second year, 4 first year) and 1 first-year MFM fellow (without D&E experience in residency) who used the task trainer. Overall, the group had limited previous exposure to D&E. Eight of the participants had not actively participated in a D&E before the training, 3 had participated in 1 procedure, 1 participated in 3 procedures, and 1 participated in 7 procedures. The mean ± SEM number of observed clinical procedures was 3.5 ± 1.15. All of the residents and the MFM fellow responded to the survey, and the results are provided in Table 2.

T2-8
TABLE 2:
Resident Survey Results

Some of the open-ended comments regarding the strengths included the following:

Great way to practice seeing how to manipulate instruments to remove fetal parts.

This was similar to a recent D&E at 18 weeks. The tactile sensation was very similar. Ultrasound guidance for positioning of ovum forceps was near identical.

Challenging, elicits weaknesses in real-time US image interpretation, allowed for immediate feedback and assessment.

Very similar to actual procedure. Helps with becoming familiar with the instruments and procedure.

The residents identified the lack of cervical dilation, amniotomy, and placental extraction as weaknesses of the model.

DISCUSSION

We present a low-cost and easy-to-assemble D&E task trainer. Based on the responses of the residents, the task trainer seems to have excellent content and face validity. The majority of residents either agreed or strongly agreed that the model reliably reproduced fetal extraction, would improve their clinical skills, and would allow them to obtain the skills required to perform the task in real life. The use of this model in resident and fellow training will likely be of great benefit in acquiring this increasingly rare but much needed procedural skill.

With this task trainer, novices will now have the opportunity to practice the procedural skills needed to perform a second trimester uterine evacuation in a safe nonclinical setting. Although much of the D&E procedure is similar to the more familiar dilation and curettage (D&C), there are notable differences including the greater size of the uterus, increased reliance on ultrasound guidance, and the need for ovum forceps to complete uterine evacuation after suction curettage. All these unfamiliar skills can now be practiced in a safe learning environment.

Although many of the instruments used in a D&E will be familiar to most residents, ovum forceps are not often used in other OB/GYN procedures. Exposure to the task trainer will allow trainees to become familiar with the use of this instrument before their initial clinical exposure to D&E. Although it is used in other uterine procedures, such as D&C or intrauterine device placement, the safety of D&E relies on ultrasound to a much greater degree. This task trainer allows the focused practice of the ultrasound guidance skills used in this procedure. Trainees can manipulate the ovum forceps in ways that would not be appropriate in a clinical setting to allow them to better appreciate how the ultrasound images correspond to their hand movements. Trainees can also perform postprocedure verification of the removal of major tissue and bones. The opportunity for repetitive and deliberate practice will increase the educational value of a trainee’s initial clinical exposure to D&E, and it will also improve patient safety because the trainee will have already gained proficiency with many of the needed procedural skills.

Although the survey responses were very favorable and the trainees felt the task trainer would allow them to obtain the skills required to perform the task in real life, it is important to note that simulation alone has not been shown to produce providers competent in second trimester uterine evacuation. The task trainer will not completely replace the need for training in real-life clinical procedures. Instead, the resident responses reflect an increased confidence in their ability to perform a second trimester uterine evacuation and may allow trainees to achieve competence more quickly as well as maintain skills in settings where there is infrequent need for the procedure. Further evaluation of the task trainer is required to determine just how much traditional clinical training can be replaced with simulation.

In addition to the benefits for more junior learners described earlier, the model will also benefit more experienced residents who have some clinical experience with D&E. The model has several features to capture clinical variation and levels of difficulty encountered in the operating room. The amount of ultrasound gel placed in the Ziploc bag serving as the simulated maternal abdomen can be increased to represent an obese patient. The size of the fetal pig used can be varied to represent procedures performed at different gestational ages. Finally, the orientation of the simulated uterus within the pelvis can be altered to represent uterine anteversion versus retroversion or various levels of uterine descent toward the vaginal introitus.

The model is inexpensive and easy to construct, which should make it available to any training program with the desire to improve D&E training. Pig hearts and fetal pigs are readily available from biologic supply companies and cost between $10 and $15. Fetal pigs are expended with each use of the model, but the pig heart can be reused multiple times. However, it must be replaced after several uses because of tissue wear and tear. Preparing the heart for use by removing the valves and intraventricular septum requires approximately 30 minutes of dissection. Once the hearts are prepared, the model can be set up in 15 minutes or less, allowing for it to be used outside scheduled education time for self-directed practice if so desired by the trainee. After the training, the pig heart can be reused by rinsing or wiping off the ultrasound gel and placing it back in a preservative such as Carolina Perfect solution until the next training session.

The model limitations include a lack of simulated cervical dilation and placental extraction. Although it would be preferable to incorporate these points into the task trainer, their absence does not significantly diminish the models educational value. Both cervical dilation and placental extraction are key parts of a D&C, a procedure in which most residents receive adequate exposure during their training. Thus, residents would be expected to gain these skills elsewhere in their training. When the use of the model is combined with traditional clinical training in D&C, residents should gain experience in all the skills required to safely perform a D&E.

For a variety of reasons, the availability of D&E is limited in many areas of the country. Lack of skilled providers puts the health of women in these communities at risk as D&E is a safer alternative to induction of labor for second trimester uterine evacuation. Unfortunately, training in the procedure has not increased to compensate because in part of the lack of clinical training opportunities. Here, we describe a low-cost and easy-to-assemble D&E task trainer with excellent face validity. Broader use of the model in clinical training has the potential to increase the number of residents who graduate from training competent and more importantly credentialed, to perform the procedure, thereby improving women’s access to this important part of comprehensive women’s health care.

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Keywords:

Dilation and evacuation; Simulation; Resident training

© 2015 Society for Simulation in Healthcare