Transplacental Passage of Acetaminophen in Term Pregnancy.

Objective The objective of this study was to determine the maternal and fetal pharmacokinetic (PK) profiles of acetaminophen after administration of a therapeutic oral dose. Study Design After obtaining Institutional Review Board approval and their written informed consent, pregnant women were given a single oral dose (1,000 mg) of acetaminophen upon admission for scheduled cesarean delivery. Maternal venous blood and fetal cord blood were obtained at the time of delivery and acetaminophen levels were measured using gas chromatography-mass spectroscopy. PK parameters were calculated by noncompartmental analysis. Nonparametric correlation of maternal/fetal acetaminophen levels and PK curves were calculated. Results In this study, 34 subjects were enrolled (median, 32 years; range, 25-39 years). The median maternal weight was 82 kg (range, 62-100 kg). All but two subjects were delivered beyond 39 weeks' gestation. The median newborn birth weight was 3,590 g (interquartile range, 3,403-3,848 g). Noncompartmental analysis described similar PK parameters in the maternal (T1/2, 84 minutes; apparent clearance [Cl/F], 28.8 L/h; apparent volume of distribution [Vd/F], 57.5 L) and fetal compartments (T1/2, 82 minutes; Cl/F, 31.2 L/h; Vd/F, 61.2 L). Paired maternal/fetal acetaminophen levels were highly correlated (p < 0.0001). Conclusion Fetal acetaminophen PKs in the fetus parallels that in the mother suggesting that placental transfer is flow limited. Maternal acetaminophen levels can be used as a surrogate for fetal exposure.

Impact of an Inexpensive Anatomy-Based Fetal Pig Simulator on Obstetric Ultrasound Training.

OBJECTIVES: The purpose of this study was to construct an inexpensive anatomy-based obstetric ultrasound task trainer and investigate whether introduction of this trainer into a hands-on obstetric ultrasound course improved course participants' ultrasound scanning skills. METHODS: The trainer was created by placing fetal pigs into preservative-filled heat-sealed polyethylene bags. Twenty-four participants in an obstetric ultrasound course at Wake Forest School of Medicine were randomized to receive hands-on scanning with pregnant women or hands-on scanning and fetal pig simulation. Biometric scans were performed before and after the course. The time to complete the scans, margin of error of biometric measurements, and number of technically adequate images per scan were compared between groups. RESULTS: Twelve participants were randomized into each group. Although a direct comparison of postcourse biometric scans demonstrated no difference between groups, participants that received simulation training showed significant improvements in the time to complete the biometric scan (P < .05) and number of technically adequate images obtained (P < .05), whereas those who did not receive simulation training did not show significant improvements. CONCLUSIONS: Addition of the fetal pig ultrasound task trainer resulted in improvements in the course participants' scanning efficiency even after very limited exposure. Incorporating the task trainer earlier and more broadly into obstetric ultrasound training may benefit trainees.

Low-Cost Task Trainer for In Utero Fetal Stent Placement.

INTRODUCTION: Some fetal procedures such as intrauterine fetal stent placement remain rare, and simulation is needed to help learners and specialists in attaining and maintaining technical competence. We sought to design and assess a low-cost, easily assembled yet clinically relevant task trainer for fetal stent placement. METHOD: The simulator was constructed using 2 quart-sized freezer bags filled with ultrasound gel and sealed with clear packing tape. The bags were stacked vertically in a transparent plastic container with ultrasound gel applied between the bags when ultrasound was used. This task trainer was used to deploy in utero stents with or without the use of ultrasound. It has been used at the annual meeting of the Society for Maternal-Fetal Medicine since 2015, the annual meeting of the International Society of Ultrasound in Obstetrics and Gynecology in 2015 and 2016, and at regional Maternal-Fetal Medicine Fellow simulation workshops since 2016. Participants were asked to complete a 5-point Likert scale survey regarding the model's realism and usefulness in training. RESULTS: One hundred thirty-three course participants evaluated the task trainer. The median rating for realism of the ultrasound images, haptic feel of stent deployment, and usefulness in training was 5 (interquartile range, 4-5). Seven physicians participated in the timed assessment of model assembly, stent deployment, and model reassembly. The average times required for the freezer bag task trainer were 2.3 minutes (2.20-2.35), 1.0 minutes (0.70-1.93), and 0.1 minutes (0.08-0.10), respectively. For the porcine tissue-based model tested in parallel, the average times were 6.0 minutes (5.00-7.06), 3.7 minutes (3.63-3.75), and 3.3 minutes (3.00-3.70), respectively. CONCLUSIONS: This low-cost simulator was rated highly when used to practice in utero stent deployment and allows for numerous repetitions in each training session. It could be a valuable tool in training novice providers and allow more experienced providers to maintain competence in this low-volume procedure.

The effects of heparin, aspirin, and maternal clinical factors on the rate of nonreportable cell-free DNA results: a retrospective cohort study.

BACKGROUND: Technological advances in the analysis of cell-free DNA in maternal serum have allowed expanded prenatal screening possibilities for fetal aneuploidies. The sensitivity and positive predictive value of the assay are partly dependent on the amount of cell-free DNA present in maternal circulation. Thus, it is important to know what fetal and maternal factors influence the level of cell-free DNA in maternal circulation. Maternal heparin use has been associated with an increase in nonreportable cell-free DNA results because of a low fetal fraction in some, but not all, previous studies. In addition, there are likely additional factors that affect cell-free DNA that remain uncharacterized. OBJECTIVE: This study aimed to determine whether heparins, low-dose aspirin, and maternal clinical factors affect the rate of nonreportable cell-free DNA testing results. STUDY DESIGN: A retrospective cohort study was conducted using pregnant people receiving cell-free fetal DNA testing from January 1, 2014, to June 30, 2018. Data were collected on patient demographics, medical comorbidities, medication use, and cell-free DNA test results. Univariate and multivariate analyses were performed to determine which factors were independently associated with the rate of nonreportable results. RESULTS: From an original sample of 1117 pregnant people, 743 met the inclusion criteria. Maternal weight (odds ratio, 1.02), heparin use (odds ratio, 12.06), aspirin use (odds ratio, 4.70), chronic hypertension (odds ratio, 5.26), pregestational diabetes mellitus (odds ratio, 2.46), and autoimmune disease (odds ratio, 3.59) were significantly associated with an increased rate of nonreportable results in the univariate analysis. Moreover, the association was present for maternal weight (odds ratio, 1.02), heparin use (odds ratio, 21.87),and aspirin use (odds ratio, 2.85) in the multivariate analysis. CONCLUSION: The previously seen association between maternal heparin use and an increase in nonreportable cell-free DNA results was confirmed. Furthermore, there seems to be an increase in nonreportable results in pregnant people taking low-dose aspirin. Providers should consider the effect of these medications when counseling patients on prenatal genetic screening options.

Transabdominal and transcervical chorionic villus sampling models to teach maternal-fetal medicine fellows.

OBJECTIVE: Many fellowship programs in maternal-fetal medicine (MFM) lack sufficient exposure and training in chorionic villus sampling (CVS). We describe a novel training model of transabdominal and transcervical CVS. METHODS: A porcine heart simulated a 12-week human uterus with a cervical canal created at the apex of the heart. A piglet was placed within a water-filled condom, which was placed inside the "uterus." A second water-filled condom simulated a maternal bladder. Fresh human placenta was placed between the condom and uterine wall. A zipper-sealed freezer bag with ultrasonic gel simulated an abdominal wall. Transabdominal ultrasound was utilized with this model to perform CVS. RESULTS: The design involved four MFM specialists and three fellows. Twenty-three faculty MFM specialists and eight MFM fellows endorsed the fidelity of both models. One hundred percent of attendees of a procedural workshop agreed that these models could be used to teach proper technique to fellows and faculty. CONCLUSION: We report a novel training model for transabdominal and transcervical CVS to teach proper technique in a nonclinical setting.

Hands-on Simulation Workshop for Obstetric Ultrasound-Guided Invasive Procedures.

Introduction: Due to the introduction of cell-free DNA genetic testing options, the number of clinical ultrasound procedures has greatly diminished in recent years. With fewer real-life ultrasound-guided procedures being performed, it is difficult for OB/GYN and maternal-fetal medicine (MFM) trainees to achieve competency in doing them. Simulation can be utilized to address this issue and supplement a learner's real-life training. Methods: We developed a simulation workshop incorporating previously described ultrasound guidance task trainers and simulators of amniocentesis and chorionic villus sampling. The workshop had three parts: needle guidance basics, targeting task performance, and procedure-specific simulation. A form of this workshop has been held at the annual meeting of the Society for Maternal-Fetal Medicine since 2015 and as a regional course for MFM fellows since 2017. During the 2019 and 2020 courses, participants completed Likert-scale surveys evaluating the course. Results: Since the workshops began in 2015, approximately 300 people have participated. In 2019-2020, 41 MFM attending physicians, 136 MFM fellows, and three OB/GYN residents took our course and completed a postcourse survey. Participants rated the course highly and thought it was highly effective. Discussion: We created an introductory simulation workshop for obstetric ultrasound-guided invasive procedures that participants rated highly and thought was very effective. Objective clinical assessment of skill improvement after completion of this course is needed to verify its true impact. Repeated exposure to this introductory simulation and creation of more challenging workshops are needed to achieve a sustained high level of procedural skill.

ACOG Simulation Working Group: A Needs Assessment of Simulation Training in OB/GYN Residencies and Recommendations for Future Research.

OBJECTIVE: To evaluate current availability and needs of simulation training among obstetrics/gynecology (OB/GYN) residency programs. DESIGN: Cross-sectional survey. SETTING: Accreditation Council for Graduate Medical Education accredited OB/GYN residency programs in the United States. PARTICIPANTS: Residency program directors, gynecology simulation faculty, obstetrics simulation faculty, and fourth-year residents. RESULTS: Of 673 invited participants, 251 (37.3%) completed the survey. Among the survey responses, OB procedures were more broadly represented compared to the GYN procedures for simulation teaching: 8 (50%) of 16 OB procedures versus 4 (18.2%) of 22 GYN procedures had simulation teaching. Among the simulated procedures, a majority of residents and faculty reported that simulation teaching was available for operative vaginal delivery, postpartum hemorrhage, shoulder dystocia, perineal laceration repair, conventional laparoscopic procedures, and robotic surgery. There were significant differences between residents and faculty perceptions regarding the availability and needs of simulated procedures with a minority of residents having knowledge of Council on Resident Education in Obstetrics and Gynecology (47.2%) and American College of Obstetrics and Gynecology (27.8%) simulation tools compared to the majority of faculty (84.7% and 72.1%, respectively). More than 80% of trainees and faculty reported they felt the average graduating resident could perform vaginal, laparoscopic, and abdominal hysterectomies independently. CONCLUSIONS: Simulation is now widely available for both gynecologic and obstetric procedures, but there remains tremendous heterogeneity between programs and the perceptions of residents, program directors, and faculty. The variations in simulation training and readiness for performing different procedures following residency support the need for objective, validated assessments of actual performance to better guide resident learning and faculty teaching efforts.

Evaluation of the Patterns of Learning in the Labor Cervical Examination.

OBJECTIVE: The aim of the study was to evaluate patterns of skill acquisition in the labor cervical examination in novice providers, such as the change in accuracy and overestimation and underestimation over time and the impact of dilation and effacement on accuracy. METHODS: In this descriptive longitudinal study, medical students each performed 120 simulated cervical examinations. Accuracy and how often students overestimated and underestimated dilation and effacement during was determined for each set of 10 repetitions. Accuracy data were grouped and compared by dilation (1-3, 4-6, and 7-10 cm) and effacement (90%, 75%, 50%, and 25%). RESULTS: Student accuracy in dilation significantly improved throughout the course of the study (P < 0.001). At the beginning of the study, students more often overestimated dilation, but this decreased over time (P < 0.001). In addition, the accuracy of the students' estimations was 84%, 62%, and 52% for dilations of 1-3, 4-6, and 7-10 cm, respectively (P < 0.001). Student accuracy in effacement significantly improved throughout the course of the study (P < 0.001). At the beginning of the study, students more often overestimated effacement, but as training progressed, more students tended to overestimate and underestimate equally often (P < 0.001). In addition, accuracy of the students' estimations was 93%, 88%, 81%, and 35% for effacements of 90%, 75%, 50%, and 25%, respectively (P < 0.001). CONCLUSIONS: Knowing that students tend to overestimate cervical dilation and effacement early in training and that cervices of high dilation and low effacement are more difficult to assess will be helpful in designing more efficient cervical examination training regimens.

Using Simulation to Define the Learning Curve for the Digital Cervical Examination.

INTRODUCTION: To assess how skill in the digital cervical examination is acquired in medical students. METHODS: In a longitudinal study, medical students completed 200 simulated cervical examinations. We performed regressions of each student's cumulative accuracy using the linear, power, and sigmoidal models to determine best fit. We also constructed multilevel models to determine the influence of dilation and effacement on accuracy and to determine whether the starting level and rate of learning varied between individuals. To assess skill decay, we assessed accuracy at 1, 2, and 5 months after training. We defined the amount of sustained accuracy needed to achieve competence using cumulative summation analyses and determined the amount of practice needed to reach this level of skill. RESULTS: Twenty-five medical students participated. The median (interquartile range) of cumulative accuracy at the end of the study was 69% (65-78) for dilation and 80% (76-91) for effacement. The sigmoidal model had the best fit. All students achieved competence during the study. The multilevel models showed that accuracy decreased with higher dilation and lower effacement and found that starting level and rate of learning varied between individuals. Maximal accuracy in both dilation and effacement was seen after 150 repetitions. Accuracy of the medical students persisted for 1 month for dilation and 2 months for effacement. The average±SD number of repetitions needed to achieve competence was 89±46 (range 35-195) for dilation and 48±38 (range 11-174) for effacement. DISCUSSION: Based on the variability in skill between individuals and the rate of skill acquisition and decay, we feel that a competence-based rather than time-based approach is most appropriate, that trainee performance should be monitored both during and after training, and that 150 repetitions, or more, should be included in any digital cervical examination simulation regimen.

Novel Approach to Reduction of an Incarcerated Uterus.

BACKGROUND: Incarceration of the pregnant uterus is a rare condition and can lead to bladder obstruction, renal failure, or uterine rupture. We present a novel, noninvasive technique to reduce an incarcerated uterus. METHOD: With conscious sedation, the patient was placed in all-fours position. The physician's hands were placed on the patient's abdomen and pressure applied until the uterine fundus was palpated. Gentle, steady fundal pressure on both sides was directed toward the maternal chest (bilateral mediocephalad pressure) elevating the uterus out of the pelvis. This approach successfully reduced the gravid incarcerated uterus and was well tolerated by the patient and fetus. EXPERIENCE: The author's experience with this method is limited to this case. Prior experience with reduction of the incarcerated uterus has been with methods previously described in the literature. CONCLUSION: In conjunction with conscious sedation and all-fours positioning, transabdominal manipulation of the uterine fundus with bilateral mediocephalad pressure may facilitate reduction of an incarcerated uterus. This method may obviate the need for more invasive procedures.

Optimizing the amount of simulation training used to teach vaginal delivery skills to medical students.

OBJECTIVE: To determine the amount of simulation training required for students to attain minimal competence and mastery of a vaginal delivery. METHODS: An observational study was conducted at a US medical school between May 11, 2015, and May 8, 2016. Using a modified Angoff method, 10 members of the Obstetrics and Gynecology faculty evaluated a vaginal delivery procedural checklist and established cutoff scores for minimal competence and mastery. During a 5-week period, all third-year students received between two and five 45-minute vaginal delivery simulation sessions; performance was assessed during week 6. Performance according to the checklist was compared. RESULTS: The cutoff score was 20 and 26 out of 30 for minimal competence and mastery, respectively. Among 115 students, mean checklist scores in final assessment rose with increasing number of simulations: 23.6, 25.1, 27.5, and 27.6 points for two, three, four, and five training sessions, respectively (P<0.001). The proportion of patients achieving mastery also increased with number of simulations: 34%, 59%, 73%, and 93% for two, three, four, and five training sessions, respectively (P<0.001). Two or three training sessions were sufficient to attain minimal competence in most students; however, no significant between-group difference was found. CONCLUSION: Simulation training exerts an increasing effect on performance with each additional session that students receive.

Development and Assessment of a Novel Task Trainer and Targeting Tasks for Ultrasound-guided Invasive Procedures.

RATIONALE AND OBJECTIVES: The American Institute of Ultrasound in Medicine (AIUM) recommends that all providers performing ultrasound-guided invasive procedures be competent in a core set of guidance skills common to all ultrasound-guided procedures, including in-plane and out-of-plane needle guidance and needle imaging optimization techniques such as probe translation, rotation, and heel-toe standoff. To allow for the practice and assessment of these core skills, we have created a novel task trainer and set of targeting tasks, and sought to obtain validity evidence in the content and response process domains for this training and assessment system according to the Standards for Educational and Psychological Testing. MATERIALS AND METHODS: We have constructed an ultrasound-guided invasive procedure training system and five targeting tasks that focused on the needle guidance skills outlined by the AIUM. All tasks were performed by obstetrics and gynecology or maternal-fetal medicine physicians with and without experience in ultrasound-guided invasive procedures during a series of simulation workshops. All participants completed a survey regarding the trainer's and the tasks' usefulness in the training of inexperienced physicians. RESULTS: The physicians who completed the tasks had favorable views of task trainer and curriculum. The targeting curriculum was felt to allow practice of all of the core guidance skills outlined by the AIUM. The average response provided for all of the tasks was 4.0 or greater, with half of the items having an average response of 4.5 or higher. CONCLUSIONS: We have constructed a task trainer that incorporates all of the core skills outlined by the AIUM. All five tasks received very favorable reviews from both experienced and inexperienced providers. Taken together, our findings suggest they have strong content and response process validity evidence.

Validation of Ultrasound Guidance Targeting Tasks: Relationship of Performance and Clinical Experience.

OBJECTIVE: To assess whether health care provider performance on a novel task trainer and a set of newly created ultrasound guidance targeting tasks relates with their level of clinical experience. METHODS: In a prospective cohort study, two assessment sessions were carried out in which inexperienced (n=21 and n=15) and experienced (n=14 and n=10) health care providers completed five previously described ultrasound guidance targeting tasks. Raw completion time, number of targeting errors, and error-adjusted completion time for each task were compared between groups with a t test for independent measures. Receiver operating characteristic analyses were performed to estimate whether error-adjusted completion time or number of errors could accurately differentiate between groups. RESULTS: Raw completion time was similar between groups. The number of errors and error-adjusted completion time were significantly lower in the experienced health care providers in all but the out-of-plane dowel task. The receiver operating characteristic analyses of number of errors demonstrated very high areas under the curve (0.93-0.98), sensitivities (100%), specificities (76-86%), positive likelihood ratios (4.2-7.0), and negative likelihood ratios (<0.001) indicating excellent differentiation between experienced and inexperienced health care providers. These values were notably lower in the receiver operating characteristic analyses of error-adjusted completion times. CONCLUSION: Task performance related well with a health care provider's level of clinical experience providing evidence of construct validity. For each task, we were able to determine a cutoff for number of errors that categorized experienced and inexperienced health care providers with very favorable sensitivity, specificity, positive likelihood ratios, and negative likelihood ratios. Our findings suggest it may be possible to use these cutoffs to objectively classify trainees as competent or not competent.

Effectiveness of a Labor Cervical Exam Model in Family Medicine and OB-GYN Residents.

BACKGROUND AND OBJECTIVES: Labor cervical exam accuracy is an essential skill for family medicine and OB-GYN residents to master. To determine the effectiveness of simulation on labor cervical exam training, family medicine and OB-GYN residents were trained using a self-constructed PVC pipe-based cervical exam model during a short and intensive simulation workshop or "boot camp." METHODS: A task trainer was constructed that allows for the blind examination of cervical dilation and effacement. This model was used in the training of first-year family medicine and OB-GYN residents during an 8 day simulation course. A longitudinal comparison of pre- and post-training accuracy was performed. Using a cohort design, the post-training accuracy of first-year family medicine and OB-GYN residents (interns) was also compared to second-fourth year OB-GYN residents. RESULTS: Use of the model by interns (n=25) resulted in significant improvements in the accuracy of their assessments of cervical dilation, but not effacement, and decreased intra-rater variability. When compared to the second-fourth year residents (n=25) who received traditional training, but not simulation training, interns were significantly more accurate and showed less intra-rater variability in their assessments of both dilation and effacement immediately after training compared to their senior colleagues. CONCLUSIONS: Training with the cervical exam model improved interns' accuracy and precision immediately after an 8-day simulation course. Use of this model in resident education may aid in the early stages of training and benefit more experienced trainees by augmenting traditional clinical training.

Effectiveness of Vaginal Delivery Simulation in Novice Trainees.

OBJECTIVE: Simulation training has been demonstrated to increase medical student confidence with vaginal deliveries; however, effect on skill performance is still lacking. To determine if integration of simulation training into the OB/GYN clerkship improves performance of vaginal deliveries, we assessed the effectiveness of simulation in third-year medical students. METHODS: During the OB/GYN clerkship, third-year students were assigned to receive vaginal delivery simulation (n=54) or cervical exam simulation (n=56), with each group serving as a simulation naïve control for the other skill. As a final assessment of their skill, students performed a simulated vaginal delivery scored by a blinded observer using a procedural checklist (score 0-30). A satisfactory score was considered 26 or greater. The individual scores and percentage of satisfactory scores were compared between both groups using a Mann-Whitney U test and chi-square test, respectively. RESULTS: Vaginal delivery students had a significantly higher mean score (27 +/- 3.2) and percentage of students achieving a passing score (85%) than the cervical exam students (22 +/- 3.5 and 15%). There were no differences in vaginal delivery performance based on gender, nor was there any difference in the number of real-life deliveries performed between vaginal delivery and cervical exam students. CONCLUSIONS: Even though medical students had an equivalent clinical rotation experience, a short period of simulation training had a marked effect on their end-of-rotation performance. During initial resident or midwife training more than 5 hours of simulation will likely be required to properly prepare 100% of trainees.

Genetic dissociation of opiate tolerance and physical dependence in delta-opioid receptor-1 and preproenkephalin knock-out mice.

Previous experiments have shown that mice lacking a functional delta-opioid receptor (DOR-1) gene do not develop analgesic tolerance to morphine. Here we report that mice lacking a functional gene for the endogenous ligand preproenkephalin (ppENK) show a similar tolerance deficit. In addition, we found that the DOR-1 and ppENK knock-outs as well as the NMDA receptor-deficient 129S6 inbred mouse strain, which also lacks tolerance, exhibit antagonist-induced opioid withdrawal. These data demonstrate that although signaling pathways involving ppENK, DOR, and NMDA receptor are necessary for the expression of morphine tolerance, other pathways independent of these factors can mediate physical dependence. Moreover, these studies illustrate that morphine tolerance can be genetically dissociated from physical dependence, and thus provide a genetic framework to assess more precisely the contribution of various cellular and molecular changes that accompany morphine administration to these processes.

Development of a novel task trainer for second trimester ultrasound-guided uterine evacuation.

INTRODUCTION: Second trimester surgical termination of pregnancy by dilation and evacuation (D&E) is a procedure that the Obstetrics and Gynecology (OB/GYN) Residency Review Committee requires training programs to offer to their residents and that many residents desire to learn. However, because of limited numbers of credentialed providers, clinical training opportunities may be limited or not available at their training institutions. Simulated procedures may allow for residents and other learners to be more prepared and capable at the time of their first clinical procedures or advanced skill acquisition. METHODS: We describe the construction of a low-cost task trainer for simulation of ultrasound-guided second trimester uterine evacuation procedures using a preserved pig heart and fetal pig. Residents of OB/GYN used the task trainer and completed a survey to determine its effectiveness as a teaching tool. RESULTS: With the use of a 5-point Likert scale survey (1 inferior, 5 superior), 13 OB/GYN trainees felt that the task trainer reliably reproduced fetal extraction (4.08), would improve their clinical skills (4.46), and would allow them to obtain the skills required to perform the task in real life (4.38). The similarity of ultrasound images to real-life images had a mean score of 3.69. Additional comments about the usefulness of this task trainer in learning the skills necessary for D&E procedures from the participants were overall positive. CONCLUSIONS: The task trainer for ultrasound-guided second trimester uterine evacuation showed excellent face validity. This low-cost task trainer provides residents and other trainees with a tool to practice ultrasound-guided fetal extraction skills and improve proficiency with D&E outside the operating room. In addition, it increases their confidence in being able to perform the procedure on patients.

Effectiveness of Labor Cervical Examination Simulation in Medical Student Education.

OBJECTIVE: To estimate whether simulation training improves medical students' cervical examination accuracy. BACKGROUND: The training paradigm for the labor cervical examination exposes patients to additional examinations, lacks a gold standard, and does not objectively assess trainee competence. To address these issues and optimize training, we assessed the effectiveness of cervical examination simulation in third-year medical students. METHODS: During the obstetrics and gynecology clerkship, a cohort study was performed in which third-year students were assigned to receive cervical examination simulation (n=50) or vaginal delivery simulation (n=48), with each group serving as a simulation-naive control for the other skill. As a final assessment, students performed 10 cervical examinations using task trainers. Exact accuracy and accuracy within 1 cm were compared between groups. Cumulative summation analyses were performed on the cervical examination group to assess competence and the average number of repetitions needed to achieve it. RESULTS: Cervical examination students were significantly more accurate (Mann-Whitney, P<.001) in assessing dilation (73% exact, 98% within 1 cm) and effacement (83% and 100%) than vaginal delivery students (dilation 52% and 82%, effacement 51% and 96%). In the cumulative summation analyses, 65-100% of students attained competence during the clerkship depending on the level of accuracy and cervical parameter assessed. On average, competence was achieved with 27-44 repetitions. CONCLUSION: Simulation training dramatically improved student accuracy in labor cervical examinations. Because not all students achieved competence, the cumulative summation analyses suggest that more than 100 repetitions would be needed if the goal was for the entire class of students to achieve competence. LEVEL OF EVIDENCE: II.

The delta-opioid receptor participates in T-cell development by promoting negative selection.

The delta-opioid receptor-1 (DOR-1) as well as delta-opioid enkephalin peptides are expressed during maturation of T cells, although the functional significance of their expression remains unclear. Based on results which show that the administration of the highly selective delta-opioid agonist D-Pen2, D-Pen5]enkephalin (DPDPE) induces an altered pattern of T-cell differentiation in fetal thymic organ culture (FTOC), we hypothesized that DOR-1 is involved in the negative selection process. Our results show that superantigen-induced clonal deletion is promoted by DPDPE and significantly impaired in DOR-1-deficient mice. These results suggest that delta-opioids may play a homeostatic role in the negative selection process during T-cell development.