Shoulder dystocia complicates up to 2% of all vaginal deliveries and can have significant long-term complications, including permanent brachial plexus injury, clavicular fracture, hypoxic brain injury, and neonatal death (Rodis JF. Shoulder dystocia. UpToDate 11.2; Wellesley, MA, April 2003).1,2 Because most of these deliveries occur in the absence of risk factors, all practitioners who deliver babies must have a well-prepared plan for how to quickly resolve a shoulder dystocia in the safest manner possible. For this reason, the management of a shoulder dystocia is a critical skill that must be taught during residency.
Medical simulation is a relatively new field and is well suited to emergencies such as shoulder dystocia. While several articles have endorsed the use of simulation in obstetrics and gynecology for a variety of procedures, there is little objective evidence documenting an improvement in resident performance.3 The primary objective of this current report was to assess whether training incorporating an obstetric birthing simulator improved resident competency in the management of shoulder dystocia.
MATERIALS AND METHODS
The study group and control subjects consisted of obstetric and gynecologic residents from 2 university-based training programs. Participating residents were randomly assigned by both year-group and institution to either a training session on shoulder dystocia management that used an obstetric birthing simulator (NOELLE; Gaumard Scientific, Coral Gables, FL) (Figure 1) or the control arm with no training before the testing. Residents were excluded if they were unavailable because of a night float rotation (n = 4) or being in a postcall status (n = 3) or if they were on vacation (n = 3). Residents voluntarily participated in the exercise. This investigation was performed in accordance with the guidelines of the institutional review boards of both Georgetown University Hospital and the Uniformed Services University of the Health Sciences. The simulation environment used a combination of human actors in role playing as well as the modified NOELLE birth simulation system in a mock-up labor and delivery suite. Internal modifications of the NOELLE System included the use of a single restraining harness that could control or delay delivery of the simulated infant.
Residents randomly assigned to training were given instruction according to the following protocol: small group sessions were conducted, with a maximum of 9 residents in each group, during which 1) residents received a brief lecture about risk factors for shoulder dystocia, 2) maneuvers and a basic algorithm for management were discussed and then demonstrated on the obstetric birthing simulator, and 3) each resident performed a delivery on the model, which was complicated by a shoulder dystocia, and then practiced the various maneuvers, as well as other important tasks, such as calling for assistance and asking for a pediatrician to be present at delivery. Residents who were not randomly assigned to training attended their regularly scheduled academic meetings during the days training was done. No specific instructions were given to the trained residents about discussing the simulation training they received.
Two weeks after the training session, and without prior notice, all residents were tested with a standardized shoulder dystocia scenario. The encounters were digitally recorded for evaluation. Before entering the room for testing, residents were given a clinical history to review. It described a 35-year-old multiparous patient who had been pushing for approximately 90 minutes and whose only prenatal complications included advanced maternal age and an abnormal 1-hour glucose challenge test, with a normal 3-hour glucose tolerance test. The residents were instructed to treat the simulation as a real situation and to use instruments, gloves, and whatever else would be needed in a real labor and delivery room. The human actors had been trained not to break character during the simulation. A standard delivery table was present in the room, which included, among other common instruments, clamps, scissors, and 2 sets of forceps. When the resident entered the room, an assistant playing the role of the nurse told the resident that the patient was pushing well, and then the fetal head was made to deliver in the right occiput anterior position. When the resident applied downward traction to the fetal head for delivery, a harness around the fetus, which was not visible to the resident because it was located inside the abdomen, was used by the testing staff to prevent the fetal shoulder from delivering. Additional assistants, who were acting as a second nurse and a pediatrician, were available in the room and would come to help if the resident asked for their assistance. The resident's actions were then monitored by the testing staff, and the fetus was allowed to deliver if the resident successfully delivered the posterior arm. If the resident could not or did not attempt to deliver the posterior arm, then the scenario was stopped when either a cephalic replacement was performed or when the resident was unable to perform any other maneuvers. After delivery, the resident, in a structured self-critique, was asked to describe all maneuvers used, as well as any other maneuvers that could have been used if needed. Residents were also asked to estimate the head-to-body delivery time. The scenario and simulation events were held confidential by the residents and evaluation staff.
A maternal–fetal medicine staff physician, who was from an outside institution and blinded to both the resident's year-level and prior training, graded and rated the resident's performance using a standardized evaluation sheet. The evaluation included a checklist of all maneuvers performed, demonstrated, and/or explained and a 9-point Likert scale to grade performance and preparation. For evaluation purposes, the following actions were considered “critical” tasks: recognizing shoulder dystocia, asking for additional help, calling for pediatrics to be present, applying gentle downward traction on the fetal head, placing the patient in McRobert's position, and applying suprapubic pressure. One point was awarded for each of these components and a total critical objectives score was calculated for each resident that ranged from 1 to 6. Critical objective scores were compared between both trained and untrained residents. Other maneuvers and actions that were considered “important” tasks included the following: attempt to perform rotational maneuver (Rubin's or Woodscrew), episiotomy, delivery of the posterior arm, fracture of clavicle, symphysiotomy, all-fours maneuver, a cephalic replacement (Zavenelli) maneuver if other maneuvers were not successful, and collection of blood for cord gases (Table 1). Four questions used a 9-point Likert scale to evaluate these aspects of the resident's performance: the timeliness of their interventions, whether maneuvers were performed correctly, overall performance, and overall preparedness. The results from these 4 questions were analyzed individually and added to produce a total overall score, which could range from 4 to 36. Scores were then compared between the groups. Another checklist was provided for the evaluators to enable them to record whether or not the resident performed or described the listed maneuvers during their testing, and whether they performed or described the maneuver correctly. The total number of maneuvers described or performed and the total number of maneuvers described or performed correctly were then calculated for each resident and compared between the trained and untrained groups.
The actual head-to-body delivery intervals were obtained from the digital recordings and entered into the data sheet. These data were then compared between the trained and untrained groups. Statistical analyses included the Student t test for continuous variables, the Mann–Whitney U test for ordinal data, linear regression, and χ2 analysis, as appropriate. P < .05 was considered significant.
By design, the ratio of trained-to-untrained residents by year-group was approximately 1:1, with a total of 16 trained residents and 17 untrained residents undergoing testing with the shoulder dystocia scenario. Of the 16 trained residents, 9 were from one institution and 7 were from another (Table 2). Residents who were trained had significantly higher scores in all evaluation categories (timeliness of their interventions, proper performance of maneuvers, overall performance, and overall preparedness) and a higher mean overall total score (29.88 ± 7.23 versus 22.24 ± 10.7, P = .012; Table 3). The mean time needed to complete delivery was significantly less in the group of trained residents compared with those who did not undergo training with the simulator before testing (61 ± 47.4 versus 146 ± 93.0 seconds, P = .003).
Analysis of “critical” components revealed that trained residents were more likely to call for additional help (94% [15 of 16] versus 35% [6 of 17], P = .001) and for a pediatrician to be present for the delivery (75% [12 of 16] versus 18% [3 of 17], P = .002) than untrained residents. There were no significant differences in the other 4 critical components (Table 4). The overall critical component score was also significantly higher in the trained group (5.37 ± 0.62 versus 4.24 ± 1.25, P = .003; 95% confidence interval [CI] −1.85, −0.43).
The total number of maneuvers that each resident was able to perform and describe was not different between the 2 groups (6.75 ± 1.6 versus 5.94 ± 1.6, P = .15; 95% CI −1.95, 0.33; Table 5). Regression analysis failed to demonstrate a significant association between the residents’ year-levels and their overall scores (P = .327; 95% CI −1.47, −4.29).
Training residents with an obstetric birthing simulator resulted in better overall performance during a simulated shoulder dystocia scenario and less time needed to accomplish the simulated delivery. Trained residents were more likely to perform more “critical” initial maneuvers, including calling for additional help and pediatric support than were untrained residents. Although the mean number of maneuvers that trained and untrained residents could describe were not significantly different, this is not surprising because we assume that both groups have a similar baseline knowledge of which maneuvers can be attempted. Importantly, this report demonstrates that the practical application of this “book knowledge” can be significantly enhanced by simulation training.
Training residents in the management of shoulder dystocia is usually done in a lecture or as an informal, impromptu teaching session after one has occurred. Although this is necessary and beneficial, medical simulation offers educators the ability to evaluate how well residents actually perform during the situation and not just whether or not they can recite the list of actions they should take. Shoulder dystocia lends itself well to simulation because it is relatively rare, yet encountered by all practicing obstetricians, and when it does occur, the situation may be too medically risky to permit significant participation by trainees. Furthermore, shoulder dystocia tends to occur in the absence of risk factors and rapid and correct interventions can decrease both maternal and neonatal morbidity, and it can be simulated with minimal difficulty with existing technology.
Because nearly 60% of shoulder dystocias will be resolved with only the McRobert's maneuver and suprapubic pressure, we chose to include these maneuvers, as well as the recognition of the problem and calling for assistance, in our list of critical tasks.4 However, because a significant number of shoulder dystocias will require additional maneuvers and we wanted to evaluate how these residents would perform with a more complicated situation, we chose to not allow the fetus to deliver unless either the posterior arm delivered or a cephalic replacement maneuver was performed.
We theorize that the reason the head-to-body delivery time was shorter in the trained resident group was that members of this group had practiced performing different maneuvers and were more willing and ready to go on to another maneuver when their initial interventions had failed.
Because we did not specifically instruct trained residents to not discuss their training with the other residents, it is possible that some of the untrained residents may have read more about the management of shoulder dystocia before their testing. If this was the case, then it serves to strengthen the conclusions of our study because the trained residents performed better regardless of whether the untrained residents had prepared on their own.
Although we trained residents from 2 separate programs, who had different experiences and teaching before this testing, both the training and testing scenarios were standardized by using the same equipment and the same instructor to decrease the chances for different experiences in training or testing. Graders were chosen for their expertise in the field and because they did not know any of the residents they were evaluating. The blinding of the graders to the training status of residents, ie, whether they were trained with the simulator before testing, and the fact that the graders did not know what year-group the residents were in as they graded them, were aspects of the study designed to prevent any bias from preconceived notions about residents’ expected levels of performance. In addition, stratification of the data by institution and grader demonstrated similar differences between trained and untrained residents in the overall performance scores at both sites.
These results support our belief that simulation training improves resident competency in the management of shoulder dystocia. Simulation laboratories have huge potential to enhance and monitor training, but new initiatives should be evaluated and not just assumed to be beneficial. Changes in residency training requirements, curricula, and evaluation techniques are sometimes introduced based only on expert opinion without data or subsequent evaluation, and although simulation training in obstetrics intuitively seems beneficial, it is imperative to validate its use rather than simply endorsing it as effective.3,5
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2. Gherman RB, Ouzounian JG, Goodwin TM. Obstetric maneuvers for shoulder dystocia and associated fetal morbidity. Am J Obstet Gynecol 1998;178:1126–30.
3. Letterie GS. Medical education as a science: the quality of evidence for computer-assisted instruction. Am J Obstet Gynecol 2003;188:849–53.
4. McFarland MD, Langer O, Piper JM, Berkus MD. Perinatal outcome and the type and number of maneuvers in shoulder dystocia. Int J Gynaecol Obstet 1996;55:219–24.
© 2004 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.
5. Macedonia CR, Gherman RB, Satin AJ. Simulation laboratories for training in obstetrics and gynecology. Obstet Gynecol 2003;102:388–92.