Midpregnancy cordocentesis training of maternal-fetal medicine fellows

Cumulative sum learning curve for cordocentesis among maternal-fetal medicine fellows in a low-cost simulation model

OBJECTIVE

To determine the individual learning curves for cordocentesis in a low-cost simulator for maternal-fetal medicine (MFM) fellows.

METHODS

This observational, descriptive, educational, and prospective study was performed from July through November 2022. After an introductory course based on a standardized technique for cordocentesis, each second-year MFM fellow who accepted to participate in the study performed this procedure using a low-cost simulation model, and experienced operators supervised the cordocenteses. Learning curves were then created using cumulative sum analysis (CUSUM).

RESULTS

Seven second-year MFM fellows with no previous experience in cordocentesis accepted to participate in the study. A total of 2676 procedures were assessed. On average, residents performed 382 ± 70 procedures. The mean number of procedures to achieve proficiency was 369 ± 70, the overall success rate was 84.16%, and the corresponding failure rate was 15.84%. At the end of the study, all fellows were considered competent in cordocentesis. One fellow required 466 attempts to achieve competency, performing a total of 478 procedures, but the resident with the fewest attempts to reach competency required 219 procedures, completing 232 procedures. Some of the most frequent reasons for failed attempts included not reaching the indicated point for vascular access (20.99%) and being unable to retrieve the sample (69.10%).

CONCLUSION

CUSUM analysis to assess learning curves, in addition to using low-cost simulation models, helped to appraise individualized learning, allowing an objective demonstration of competency for cordocentesis among MFM fellows.

Continued Validation of Ultrasound Guidance Targeting Tasks: Relationship with Procedure Performance

RATIONALE AND OBJECTIVES

To determine if deliberative practice with novel ultrasound guidance targeting tasks improves simulated procedural skill.

MATERIALS AND METHODS

In a nonrandomized interventional trial first year medical students practiced the previous described dowel and straw targeting tasks 1 hour a week for 4 weeks (training group) or had no training (controls). Afterward, they each performed a simulated amniocentesis (AMN) and chorionic villus sampling (CVS) procedure. Procedures were scored using a global rating scale (GRS) and compared between groups with Mann-Whitney U tests. Two-way random effects intraclass correlation coefficients for the inter- and intra-rater variability were calculated for each item in both GRS's.

RESULTS

The training group (n = 22) had higher scores on several aspects and overall performance of AMN compared to controls (n = 15). There were no differences between groups for CVS. The inter-rater and intra-rater reliability of the GRS's for both AMN and CVS ranged from 0.16 to 0.89 with most values demonstrating good to excellent agreement.

CONCLUSION

This study demonstrates validity evidence in the content and internal structure domains for the AMN and CVS simulators and their accompanying GRS's. Repetitive practice of the targeting tasks improved student performance in simulated AMN, but modifications are needed for it to be relevant to other procedures such as CVS.

Cordocentesis-associated fetal loss and risk factors: single-center experience with 6650 cases

OBJECTIVES

To identify procedural risk factors associated with fetal loss following cordocentesis and to determine the rate of cordocentesis-related fetal loss associated with the current cordocentesis protocol used in our institution.

METHODS

This was a retrospective cohort study of pregnancies that underwent midpregnancy cordocentesis in a single center (a tertiary hospital, teaching school), between 1992 and 2018, based on data retrieved from our prospective database. All consecutive cases were validated to retrieve those meeting the eligibility criteria, which included: singleton pregnancy without underlying maternal disease, normal fetus (no structural or chromosomal abnormality or severe disorder), gestational age between 16 and 24 weeks at the time of the procedure and availability of pregnancy outcome. Cases that resulted in termination of pregnancy were excluded. We assessed the effect of prior cordocentesis model training on the fetal-loss rate and procedure-related complications, and evaluated potential risk factors of fetal loss secondary to cordocentesis, including procedure difficulty, placenta penetration, prolonged bleeding, fetal bradycardia, puncture site and early gestational age at procedure. Pregnancy outcomes were compared between the study group and a control group of women, who did not undergo cordocentesis, selected randomly at a 1:1 ratio from our obstetric database.

RESULTS

A total of 10 343 procedures were performed during the study period, of which 6650 met the eligibility criteria and were included in the analysis. The fetal-loss rate in the first 60 procedures (early practice) of six operators (n = 360 procedures), who did not have prior model training, was significantly higher than that during the early practice of 18 operators (n = 1080 procedures) with prior model training (6.9% vs 1.6%; P < 0.001); whereas the fetal-loss rate in the next 60 procedures of practice was comparable between the two groups. After excluding the first 360 procedures of the groups without prior model training, the overall fetal-loss rate in pregnancies that underwent cordocentesis was significantly higher than that in the control group (1.6% vs 1.0%; P < 0.001). Considering the fetal-loss rate in the normal controls as background loss, the incremental cordocentesis-associated fetal-loss rate was 0.6%. Penetration of the placenta (odds ratio (OR), 2.65 (95% CI, 1.71-4.10)), prolonged bleeding from the puncture site (OR, 10.85 (95% CI, 5.27-22.36)) and presence of fetal bradycardia (OR, 3.32 (95% CI, 1.83-6.04)) during cordocentesis were independent risk factors associated with fetal loss.

CONCLUSIONS

Cordocentesis model training markedly reduces fetal loss during the early learning curve of practice. Thus, cordocentesis practice without prior model training should not be acceptable. Significant procedural risk factors for fetal loss secondary to cordocentesis are placental penetration, prolonged bleeding and fetal bradycardia. Cordocentesis-related fetal loss may be only 0.6%, much lower than the rate reported previously. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

The performance of cardio-biparietal ratio measured by 2D ultrasound in predicting fetal hemoglobin Bart disease during midpregnancy: A pilot study

OBJECTIVE

The aim of this study was to assess the performance of cardio-biparietal ratio measured by real-time two-dimensional ultrasound in predicting hemoglobin (Hb) Bart disease among fetuses at risk.

METHOD

This prospective diagnostic study recruited pregnancies at risk for Hb Bart disease at 17 to 22 weeks' gestation. Cardio-biparietal ratio and cardiothoracic ratio were measured before cordocentesis for Hb typing. The performance of the cardio-biparietal ratio and cardiothoracic ratio for identifying affected fetuses was evaluated.

RESULTS

Among 72 fetuses at risk, 31 were diagnosed as affected by Hb Bart disease. By using a cutoff 0.45, cardio-biparietal ratio had a sensitivity of 83.9%, specificity of 92.7%, positive predictive value of 89.7%, and negative predictive value of 88.4%, whereas cardiothoracic ratio using cutoff 0.5 had a sensitivity of 94.3%, specificity of 65.1%, positive predictive value of 68.8%, and negative predictive value of 93.3%.

CONCLUSION

Cardio-biparietal ratio is a new sonomarker to predict Hb Bart disease among fetuses at risk. This sonomarker is relatively effective and may be useful in areas of high prevalence of alpha thalassemia disease, limited number of experts in prenatal ultrasound, and difficult access to prenatal diagnosis.

Second-Trimester Uterine Model for Teaching Ultrasound-Guided Obstetric Procedures

The declining number of ultrasound-guided obstetric procedures in clinical practice mandates a shift toward simulation-based teaching. Current uterine simulation aids are animal tissue-sourced or expensive, and improvement is needed. We describe a low-cost reusable uterine model with "fetus," cord and skin, constructed from synthetic gel and silicone rubber. Ultrasound appearance and tactile feedback approximate clinical use, and all parts of the model are portable, durable, and shelf-stable. Those made of ballistics gel can be recycled numerous times without noticeable effect. This appears to be ideal for proctored learning and independent practice within an ultrasound procedural curriculum.

Fetal septum primum excursion (SPE) and septum primum excursion index (SPEI) as sonomarkers of fetal anemia: using hemoglobin Bart's fetuses as a study model

OBJECTIVES

The objectives the study are to evaluate the effectiveness of septum primum excursion (SPE) and SPEI (SPE index, a ratio of SPE to left atrial diameter) in predicting fetal hemoglobin (Hb) Bart's disease and to determine the correlation between Hb levels and SPE/SPEI METHODS: The database of Cardio-STIC volume datasets (VDSs) of fetuses at risk of Hb Bart's disease at 18 to 22 weeks was assessed. The VDSs were blindly analyzed offline for measurements of SPE and SPEI.

RESULTS

Of 180 VDSs recruited, 44 were acquired from fetuses with Hb Bart's disease, while 136 were derived from unaffected fetuses. SPE and SPEI was inversely correlated with Hb levels (p < 0.0001). The SPE and SPEI were significantly higher in the affected group (4.1 + 1.1 mm vs 3.0 + 0.8 mm and 0.61 + 1.1 vs 0.49.1 + 0.1, respectively). SPE, at cut-off 1.3 multiple of median, gave a sensitivity and specificity of 75.0% and 72.7%, respectively, but less than a sensitivity (81.4%) and specificity (95.4%) of middle cerebral artery peak systolic velocity.

CONCLUSIONS

In anemic fetuses, SPE and SPEI was inversely correlated with Hb level. Additionally, SPE, better than SPEI, may be used as an adjunctive sonographic sign to predict Hb Bart's disease but its accuracy of prediction is not good enough to be used independently or as a diagnostic test. © 2016 John Wiley & Sons, Ltd.

The impact of noninvasive fetal evaluation: its effect on education, training, and the maintenance of clinical competence in prenatal diagnosis

PURPOSE OF REVIEW

To highlight the evolution of prenatal diagnosis from invasive procedures to noninvasive assessments and to describe the efforts to educate both trainees and experienced physicians via simulation techniques.

RECENT FINDINGS

The rapid development of noninvasive serum analyte screening as well as molecular genetic and sonographic techniques to evaluate the fetus has altered our ability to both educate trainees as well as to maintain physician competence to perform invasive procedures. Simulation-based learning is being incorporated into medical training across a broad range of specialties, including obstetrics and gynecology.

SUMMARY

Prenatal diagnosis procedures will continue to be necessary for direct fetal assessment but on a much more limited scale. It is possible that all trainees will not be able to become competent in amniocentesis and other even less common procedures. Furthermore, experienced physicians may lose competence, given the lack of available procedures for skill retention. Innovative methods of skill acquisition and maintenance may be required in the near future. Although long-term assessments of efficacy are currently lacking, the introduction of comprehensive, simulation-based curriculia has the potential to both educate trainees and help maintain physician competence.

Screening for hemoglobin Bart's disease among fetuses at risk at mid-pregnancy using the fetal cardiac diameter to biparietal diameter ratio

Background

All sonomarkers used to screen for fetal hemoglobin (Hb) Bart’s disease need high expertise, preventing them from being widely used. Fetal cardiac diameter to biparietal diameter (C/B) ratio is a simple marker which has never been evaluated for its effectiveness. Therefore, we conducted this study to evaluate the effectiveness of C/B ratio in predicting fetal Hb Bart’s disease among fetuses at risk.

Methods

Fetuses at risk of Hb Bart’s disease scheduled for diagnostic cordocentesis at 18 to 22 weeks of pregnancy were prospectively enrolled. All underwent ultrasound for fetal biometry and cardio-STIC acquisition for subsequent off-line analysis. Cardio-STIC volume datasets (VDS) were analyzed for cardiac diameter measurement and C/B ratio was calculated by the authors who did not know the fetal diagnosis. Final diagnosis of Hb Bart’s disease was based on fetal blood Hb typing.

Results

Of 131 pregnancies enrolled to the study, 11 were excluded because of poor quality VDS. The remaining 120 were available for analysis. C/B ratio was significantly higher in the fetuses with Hb Bart’s disease than that in the unaffected ones (53.16% vs 41.68%, P < 0.001). C/B ratio could detect fetuses with Hb Bart’s disease with sensitivity of 91.5% and specificity of 77.6% (AUC ROC 0.929), using a cut-off point of greater than 45%.

Conclusions

Among fetuses at risk, C/B ratio measurement at mid-pregnancy, using cut-off point of 45%, could effectively differentiate fetuses with Hb Bart’s disease from unaffected fetuses.

Fetal cardiac circumference derived by spatiotemporal image correlation as a predictor of fetal hemoglobin Bart disease at midpregnancy

OBJECTIVES

The purpose of this study was to evaluate the efficacy of the fetal cardiac circumference derived by spatiotemporal image correlation (STIC) for predicting fetal hemoglobin (Hb) Bart disease.

METHODS

Pregnancies at risk of fetal Hb Bart disease at 17 to 22 weeks' gestation were enrolled. All underwent STIC volume acquisition for analysis of fetal cardiac dimensions and cordocentesis for Hb level and Hb typing analysis. Spatiotemporal image correlation volume data sets were subsequently analyzed offline for cardiac circumference measurements, which were used to evaluate the efficacy in predicting fetal anemia and fetal Hb Bart disease.

RESULTS

A total of 88 pregnancies at risk of fetal Hb Bart disease at 17 to 22 weeks were recruited into the study. The cardiac circumference was significantly higher in fetuses with Hb Bart disease than in unaffected fetuses (1.33 and 1.02 multiples of the median [MoM], respectively; P < .001). The cardiac circumference effectively predicted fetal Hb Bart disease (area under the receiver operating characteristic curve, 0.85; 95% confidence interval [CI], 0.73-0.97), with sensitivity of 86.4% (95% CI, 72.0%-100%) and specificity of 78.1% (95% CI, 68.0%-88.3%) using a cutoff point of greater than 1.17 MoM, whereas the cardiothoracic ratio had better efficacy, with sensitivity of 90.9% (95% CI, 78.9%-100%) and specificity of 85.9% (95% CI, 77.4%-94.5%) using a cutoff point of greater than 0.50.

CONCLUSIONS

At midpregnancy, a cardiac circumference of greater than 1.17 MoM can be used as an alternative sonographic marker for predicting fetal Hb Bart disease, although not perfectly. However, the cardiothoracic ratio seems to be more accurate than the cardiac circumference for such a purpose.

The use of simulation in maternal-fetal medicine procedure training

Many fields of medicine now routinely employ simulation while educating all levels of medical trainees. Unfortunately, OB-GYN has been slow to incorporate these beneficial adjuncts to traditional medical education, but thankfully the use of simulation is now increasing. Maternal-Fetal medicine procedures such as amniocentesis, in-utero stent placement, chorionic villus sampling, percutaneous umbilical blood sampling, and cervical cerclage placements are an area where simulation has great potential benefit. Here we describe the currently available simulation models for these procedures and outline specific training curricula designed to aid trainees in obtaining procedural competency in each. Although initial experiences with these training models and the curricula centered around them have been positive, in many cases their use remains limited. Our hope is that this manuscript will encourage others to incorporate simulation into their training programs as we believe it will enhance medical training and improve patient safety.

The birds and the beans: a low-fidelity simulator for chorionic villus sampling skill acquisition

Because no simulation models are described for chorionic villus sampling (CVS), we sought to design and construct a CVS training simulator. Using materials available from our labor floor and local supermarket, we built and demonstrated a practical model for learning transabdominal and transcervical CVS. The simulator can be used to teach single- or dual-operator transabdominal CVS and traditional transcervical CVS. Aspirated "villi" immediately inform the teacher and learner of successful procedures. No image degradation or sonographically visible tracks resulted from use, permitting more than one trainee to benefit from a model. This model for transabdominal and transcervical CVS provides realistic imaging, tactile sensations, and immediate feedback.

SYTO9 and SYBR GREEN1 with a high-resolution melting analysis for prenatal diagnosis of β⁰-thalassemia/hemoglobin-E

The β⁰-thalassemia/Hb-E causes a wide range of severe conditions. A high medical cost is incurred in severe cases. Thus, the prevention of new cases of β⁰-thalassemia/Hb-E is required. The aim of this study is to use the SYTO9 and SYBR GREEN1 high-resolution melting (HRM) analysis for prenatal diagnosis of β⁰-thalassemia/Hb-E. DNA samples were extracted from amniotic fluid or cord blood of 11 pregnancies whose fetuses were at risk for β-thalassemia/Hb-E. PCR products from multiplex amplification refractory mutation system PCR for the detection of β⁰-thalassemia mutations at codons 17(A>T), 41/42(-TCTT), and 71/72(+A) and from amplification refractory mutation system PCR for the detection of Hb-E were characterized by SYTO9 HRM analysis. Moreover, β⁰-thalassemia 3.5- kb deletion was detected using real-time PCR with SYBR GREEN1 HRM analysis. Seven of 11 fetuses (64%) were diagnosed as β⁰-thalassemia/Hb-E (4 fetuses with mutation at codon 17, 2 with mutation at codon 41/42, and 1 with 3.5- kb deletion). Results from HRM analysis were completely consistent with those from fetal blood samplings analyzed at the time of delivery or pregnancy termination using HPLC. Therefore, the HRM analysis is easy to use. It is simple, flexible, non-destructive and has superb sensitivity and specificity. This approach might facilitate the laboratory diagnosis and genetic counseling for regions with a high prevalence of β⁰-thalassemia/Hb-E.