Biomedical subjects

Deirdre J Lyell

Publications and source records attributed to Deirdre J Lyell.

9 recordsLinked to original sources

PubMed2006

Ultrasound screening of fetuses at increased risk for Down syndrome: how many missed diagnoses?

OBJECTIVE: To determine the number of Down syndrome (DS) fetuses identified, amniocenteses performed, and procedure-related losses incurred when second-trimester ultrasound is used to screen high-risk patients in order to determine who should undergo an amniocentesis. METHODS: A decision analytic model was designed for women at increased risk for a DS fetus due to either advanced maternal age (AMA) or a positive expanded maternal serum alpha fetoprotein (MSAFP) screening test, also known as a triple screen (+triple) test. The model compared: (1) the current standard of offering all at-risk women amniocentesis to (2) a policy of performing amniocentesis only when sonographic markers of DS are seen on ultrasound. Baseline assumptions included a sensitivity of 60.6% for targeted ultrasound and a screen-positive rate of 16.2%. RESULTS: If targeted ultrasound is used to determine whether high-risk patients should undergo amniocentesis, 56% (3933/7025) of all DS fetuses are missed. The diagnosis of DS is missed most frequently among women at highest risk for DS (AMA and +triple). In this subgroup of patients, there are 3152 DS fetuses in the second trimester, of which 2815 (89%) are identified by triple screen test. When an ultrasound screen is added, only 1709 (54%) of DS fetuses will be identified. CONCLUSION: Substantially fewer DS fetuses will be detected when targeted ultrasound is used as a screen among already identified high-risk patients.

Decision Support Techniques↗

PubMed2006

Induction of labor and cesarean delivery by gestational age.

OBJECTIVE: Studies of cesarean delivery (CD) rates among women undergoing induction of labor (IOL) often compare such women to women experiencing spontaneous labor at similar gestational ages. We sought to examine the association between IOL at various gestational ages and CD, accounting for the effect of increased gestational age among the comparison group who were managed expectantly. STUDY DESIGN: We conducted a retrospective cohort study of all term, singleton, cephalic presentation pregnancies delivered at our institution over 15 years excluding cesarean deliveries before labor. For each gestational age of induction, we created a comparison group of women who were undelivered at that gestational age, and who experienced labor at some future gestational age. RESULTS: In women undergoing IOL at 38 weeks gestation, the CD rate was 11.9% as compared to 13.3% (P = .42) of women beyond 38 weeks gestation. The CD rate for induction of labor compared to ongoing pregnancy was 14.3% versus 15.0% (P = .62) at 39 weeks, 20.4% versus 19.0% (P = .41) at 40 weeks, and 24.3% versus 26.0% (P = .39) at 41 weeks. When controlling for potential confounding, there was a higher rate of CD among women with expectant management beyond 38 weeks (adjusted odds ratio [AOR] 1.80; 95% CI 1.29-2.53), 39 weeks (1.39; 95% CI 1.08-1.80), and 40 weeks (AOR 1.27; 95% CI 1.00-1.62). CONCLUSION: Our findings suggest that IOL may not increase a woman's risk of CD when compared to expectant management. While this question has been addressed prospectively at 41 weeks gestation, it requires further examination at earlier gestations and among various subgroups.

Cesarean Section↗

PubMed2005

Percutaneous transluminal coronary angioplasty and stent placement in pregnancy.

BACKGROUND: Myocardial infarction (MI) is uncommon during pregnancy. As the average maternal age increases and assisted reproductive technology allows for very advanced maternal ages, so too may the incidence of MI during pregnancy. Percutaneous transluminal coronary angioplasty (PTCA) with stent placement is an attractive option for treatment of MI in pregnancy when revascularization is required. CASE: We present a gravida with an ST elevation MI during the third trimester, who was treated with emergent PTCA, stent placement, and platelet inhibitors, and we discuss the patient's subsequent obstetric and anesthetic management. CONCLUSION: Percutaneous transluminal coronary angioplasty with stent placement may be used during the third trimester with successful outcome.

Adult↗

PubMed2005

Peritoneal closure at primary cesarean delivery and adhesions.

OBJECTIVE: To evaluate the effect of parietal peritoneal closure at cesarean delivery on adhesion formation. METHODS: A prospective cohort study of women undergoing first repeat cesarean delivery was designed. All surgeons were asked immediately after surgery to score the severity and location of adhesions. Patient records were then abstracted to assess prior surgical technique, including parietal peritoneal closure, other attributes of first surgery, and patient characteristics. Exclusion criteria included adhesions, other surgery, or use of permanent suture at the first cesarean, unavailable first postoperative note and course, wound infection or breakdown following first surgery, intervening pelvic surgery, insulin-dependent diabetes mellitus, and steroid-dependent disease. The chi2 test and multivariable logistic regression were used for statistical comparison and analysis. A total of 128 patients was required to have 80% power to detect a 50% reduction in adhesions when the parietal peritoneum was left open. RESULTS: One hundred seventy-three patients were enrolled. Prior parietal peritoneal closure was associated with significantly fewer dense and filmy adhesions (52% versus 73%, P = .006) and significantly fewer dense adhesions (30% versus 45%, P = .043). When controlling for potential confounding variables, including prior infection, visceral peritoneal closure, rectus muscle closure, payor status, ethnicity, maternal age, gestational diabetes, and labor, parietal peritoneal closure at primary cesarean delivery was 5-fold protective against all adhesions (odds ratio 0.20, 95% confidence interval 0.08-0.49), and 3-fold protective against dense adhesions (odds ratio 0.32, 95% confidence interval 0.13-0.79). Omental-fascial adhesions were decreased most consistently. CONCLUSION: Parietal peritoneal closure at primary cesarean delivery was associated with significantly fewer dense and filmy adhesions. The practice of nonclosure of the parietal peritoneum at cesarean delivery should be questioned.

Adult↗

PubMed2004

Developmental response to hypoxia.

Molecular mechanisms underlying fetal growth restriction due to placental insufficiency and in utero hypoxia are not well understood. In the current study, time-dependent (3 h-11 days) changes in fetal tissue gene expression in a rat model of in utero hypoxia compared with normoxic controls were investigated as an initial approach to understand molecular events underlying fetal development in response to hypoxia. Under hypoxic conditions, litter size was reduced and IGFBP-1 was up-regulated in maternal serum and in fetal liver and heart. Tissue-specific, distinct regulatory patterns of gene expression were observed under acute vs. chronic hypoxic conditions. Induction of glycolytic enzymes was an early event in response to hypoxia during organ development; consistently, tissue-specific induction of calcium homeostasis-related genes and suppression of growth-related genes were observed, suggesting mechanisms underlying hypoxia-related fetal growth restriction. Furthermore, induction of inflammation-related genes in placentas exposed to long-term hypoxia (11 days) suggests a mechanism for placental dysfunction and impaired pregnancy outcome accompanying in utero hypoxia.

Animals↗

PubMed2004

Postpartum uterine arteriovenous fistula.

BACKGROUND: Uterine arteriovenous communications are uncommon lesions that may be associated with life-threatening postpartum and postinstrumentation hemorrhage. CASE: A primigravida presented with infected retained products of conception. Excessive hemorrhage of unclear etiology occurred at dilation and curettage. After a second episode of bleeding, the patient received a diagnosis of uterine arteriovenous fistula. CONCLUSION: Uterine arteriovenous communications should be included in the differential diagnosis in patients with excessive postpartum or postinstrumentation bleeding. Color and spectral flow Doppler can aid diagnosis and clinical management.

Adult↗

PubMed2003

Training and competency assessment in electronic fetal monitoring: a national survey.

OBJECTIVE: To investigate current patterns of training and competency assessment in electronic fetal monitoring (EFM) for obstetrics and gynecology residents and maternal-fetal medicine fellows. METHODS: A questionnaire was mailed to the directors of all 254 accredited US residencies in obstetrics and gynecology and 61 accredited US fellowships in maternal-fetal medicine. Questions focused on the methods used for teaching and assessing competency in EFM. RESULTS: Two hundred thirty-nine programs (76%) responded to the survey. Clinical experience is used by 219 programs (92%) to teach EFM, both initially and on an ongoing basis. Significantly more residencies than fellowships use written materials and lectures to teach EFM. More than half of all programs require trainees to participate in some type of EFM training at least every 6 months; 23 programs (10%) have no requirement at all. Subjective evaluation is used by 174 programs (73%) to assess competency in EFM. Written or oral examinations, skills checklists, and logbooks are used exclusively by residencies as means of competency assessment. Two thirds of all programs assess EFM skills at least every 6 months; 40 programs (17%), the majority of which are fellowships, have no formal requirement. CONCLUSION: Most US training programs use supervised clinical experience as both their primary source of teaching EFM and their principal competency assessment tool. Residencies are more likely to have formal instruction and assessment than are fellowships. Few programs are using novel strategies (eg, computers or simulators) in their curriculum.

Clinical Competence↗

PubMed2003

Prenatal screening, epidemiology, diagnosis, and management of preeclampsia.

The cause of preeclampsia remains unknown. The disease manifests itself across a broad clinical spectrum from mild to severe, conferring vastly different morbidities and suggesting possibly different disease processes. Oxidative stress, endothelial dysfunction, maternal-fetal immune incompatibility, and abnormal placental implantation are among the suggested causes. The need for a marker or set of markers that allow for definitive diagnosis and assessment of future risk of preeclampsia is tremendous. Ultrasound techniques and several markers have been identified that are increased among patients with preeclampsia, but no test is highly sensitive. In the future, a combination of markers likely will be used to assess risk and, establish the diagnosis, and test treatment strategies. Such an approach would allow for more refined treatment studies of patients who are at highest risk for preeclampsia.

Adult↗

PubMed2003

Evaluation of a novel electronic fetal monitor simulator.

The purpose of this study was to evaluate the content validity and construct validity of a novel electronic fetal monitor (EFM) simulator. Fourteen residents in Gynecology and Obstetrics (OB/GYN) and 7 medical students in their OB/GYN clerkship interpreted 10 fetal heart rate (FHR) tracings and 4 clinical scenarios generated by the EFM simulator. Their responses were scored by experts in maternal-fetal medicine. Construct validity was determined by comparing subjects' scores to their level of experience. Subjects assessed content validity of the EFM simulator by rating the realism of its various elements on a 4-point Likert scale. Residents achieved statistically significant higher mean scores in the description of FHR tracings generated by the simulator than medical students and statistically significant higher mean scores in the correct interpretation of and interventions in 2 of 4 clinical scenarios. Two-thirds of the residents rated the simulator-generated FHR tracings and clinical scenarios as "real" or "very real." The EFM simulator exhibited both content and construct validity, supporting its use in an educational setting.

Adult↗