Biomedical subjects

Greg Ryan

Publications and source records attributed to Greg Ryan.

At least 19 recordsLinked to original sources

PubMed2006

Doppler ultrasonography versus amniocentesis to predict fetal anemia.

BACKGROUND: Pregnancies complicated by Rh alloimmunization have been evaluated with the use of serial invasive amniocentesis to determine bilirubin levels by measuring in the amniotic fluid the change in optical density at a wavelength of 450 nm (DeltaOD450); however, this procedure carries risks. Noninvasive Doppler ultrasonographic measurement of the peak velocity of systolic blood flow in the middle cerebral artery also predicts severe fetal anemia, but this test has not been rigorously evaluated in comparison with amniotic-fluid DeltaOD450. METHODS: We performed a prospective, international, multicenter study including women with RhD-, Rhc-, RhE-, or Fy(a)-alloimmunized pregnancies with indirect antiglobulin titers of at least 1:64 and antigen-positive fetuses to assess whether Doppler ultrasonographic measurement of the peak systolic velocity of blood flow in the middle cerebral artery was at least as sensitive and accurate as measurement of amniotic-fluid DeltaOD450 for diagnosing severe fetal anemia. The results of the two tests were compared with the incidence of fetal anemia, as determined by measurement of hemoglobin levels in fetal blood. RESULTS: Of 165 fetuses, 74 had severe anemia. For the detection of severe fetal anemia, Doppler ultrasonography of the middle cerebral artery had a sensitivity of 88 percent (95 percent confidence interval, 78 to 93 percent), a specificity of 82 percent (95 percent confidence interval, 73 to 89 percent), and an accuracy of 85 percent (95 percent confidence interval, 79 to 90 percent). Amniotic-fluid DeltaOD450 had a sensitivity of 76 percent (95 percent confidence interval, 65 to 84 percent), a specificity of 77 percent (95 percent confidence interval, 67 to 84 percent), and an accuracy of 76 percent (95 percent confidence interval, 69 to 82 percent). Doppler ultrasonography was more sensitive, by 12 percentage points (95 percent confidence interval, 0.3 to 24.0), and more accurate, by 9 percentage points (95 percent confidence interval, 1.1 to 15.9), than measurement of amniotic-fluid DeltaOD450. CONCLUSIONS: Doppler measurement of the peak velocity of systolic blood flow in the middle cerebral artery can safely replace invasive testing in the management of Rh-alloimmunized pregnancies. (ClinicalTrials.gov number, NCT00295516.).

Amniocentesis↗

PubMed2006

Fetal pulmonary artery diameter measurements as a predictor of morbidity in antenatally diagnosed congenital diaphragmatic hernia: a prospective study.

OBJECTIVE: The objective of the study was to examine the size and growth of fetal pulmonary artery diameters in congenital diaphragmatic hernia and assess their correlation with postnatal survival and morbidity outcomes. STUDY DESIGN: Prospective antenatal echocardiographic examination of fetal branch pulmonary arteries were correlated with postnatal survival and respiratory morbidity in cases of congenital diaphragmatic hernia. Receiver operator curves were developed to assess their utilization as predictors of respiratory morbidity and survival. RESULTS: Twenty-one cases were diagnosed antenatally over 3 years. Fifteen subjects survived postnatally. The ipsilateral fetal branch pulmonary artery diameter was smaller throughout gestation in left-sided congenital diaphragmatic hernia (P = .008). The small left pulmonary diameter did not correlate with survival but correlated strongly with morbidity outcomes. Progressive ipsilateral fetal pulmonary artery hypoplasia was demonstrated throughout gestation in subjects who died or had severe morbidity. CONCLUSION: Fetal pulmonary artery diameter measurements correlate with respiratory morbidity in postnatal congenital diaphragmatic hernia and may assist with prediction of outcome. Survival has improved, possibly because of improved postnatal management of congenital diaphragmatic hernia, limiting this measurement in assessing survival.

Fetal Heart↗

PubMed2006

Impact of selective laser ablation of placental anastomoses on the cardiovascular pathology of the recipient twin in severe twin-twin transfusion syndrome.

OBJECTIVES: We investigated the impact of selective laser ablation on the cardiovascular pathology of the recipient twin in twin-twin transfusion syndrome. STUDY DESIGN: Fetal echocardiograms and medical records were reviewed from 22 pregnancies with severe twin-twin transfusion syndrome where echocardiography was performed before and after laser. RESULTS: Before laser, cardiomegaly associated with right and/or left ventricular hypertrophy without ventricular dilatation, was observed in most cases. Right ventricular and left ventricular systolic dysfunction (shortening fraction <28%) was present in 59% and 27%, respectively, and diastolic dysfunction (based on inflow and venous Dopplers) in 73%. Shortly after laser, biventricular systolic function improved significantly and diastolic function tended to improve (50%, P = .06). Functional pulmonary atresia, secondary to right ventricular systolic dysfunction, resolved in 2 of 2 cases at post-laser echocardiography. On serial assessment, diastolic function was normal in 7 of 10, hydrops regressed in 4 of 5, and neither progressive myocardial hypertrophy nor anatomical right ventricular outflow obstruction were found. CONCLUSIONS: Selective laser ablation in severe twin-twin transfusion syndrome acutely improves biventricular systolic function and tends to improve diastolic function in the recipient twin.

Adult↗

PubMed2006

Fetal pericardial teratoma: presentation of two cases and review of literature.

We present the fetal ultrasound and echocardiographic findings and clinical outcome of two fetuses with intrapericardial teratoma encountered in our institution. In the first (diagnosed at 19 weeks of gestation) case there was elective termination of pregnancy; in the second case (diagnosed at 24 weeks), a pericardio-amniotic shunt was placed after reaccumulation of fluid following pericardiocentesis. We review the published experience of intrapericardial teratomas, focusing on the diagnosis, fetal echocardiographic findings, and outcome with and without prenatal intervention.

Adult↗

PubMed2005

Measuring the physical demands of work in hospital settings: design and implementation of an ergonomics assessment.

BACKGROUND: Assessing the physical demands of the heterogeneous jobs in hospitals requires appropriate and validated assessment methodologies. METHODS: As part of an integrated assessment, we adapted Rapid Entire Body Assessment (REBA), using it in a work sampling mode facilitated by a hand-held personal digital assistant, expanding it with selected items from the UC Computer Use Checklist, and developed a scoring algorithm for ergonomics risk factors for the upper (UB) and lower body (LB). RESULTS: The inter-rater reliability kappa was 0.54 for UB and 0.66 for LB. The scoring algorithm demonstrated significant variation (ANOVA p<0.05) by occupation in anticipated directions (administrators ranked lowest; support staff ranked highest on both scores). A supplemental self-assessment measure of spinal loading correlated with high strain LB scores (r=0.30; p<0.001). CONCLUSION: We developed and validated a scoring algorithm incorporating a revised REBA schema adding computer use items, appropriate for ergonomics assessment across a range of hospital jobs.

Algorithms↗

PubMed2005

Prenatal cardiovascular manifestations in the twin-to-twin transfusion syndrome recipients and the impact of therapeutic amnioreduction.

OBJECTIVE: We evaluated the cardiovascular pathologic condition in the recipient twin in twin-to-twin transfusion syndrome and the influence of amnioreduction. STUDY DESIGN: Fetal echocardiograms and medical records of 54 pregnancies that were complicated by twin-to-twin transfusion syndrome were reviewed. Recipient twin right and left ventricular wall thickness, diameters, systolic and diastolic function, valve regurgitation, and structural cardiac defects were assessed at examination and after amnioreduction. RESULTS: At examination (n = 28 pregnancies), cardiomegaly because of right ventricular and/or left ventricular hypertrophy was observed in 58% of recipient twins, and biventricular hypertrophy was observed in 33% of recipient twins, without ventricular dilation. Biventricular diastolic dysfunction was present in two thirds of recipient twins, and right ventricular systolic dysfunction and significant atrioventricular valve regurgitation was observed in one third of recipient twins. Serial assessment (n = 21 pregnancies) revealed progressive biventricular hypertrophy and right ventricular systolic and biventricular diastolic dysfunction in most recipient twins. Steeper progression of hypertrophy, diastolic dysfunction, and structural or functional right ventricular outflow disease (20% incidence) were associated with an increased perinatal mortality rate. CONCLUSION: In twin-to-twin transfusion syndrome, the recipient twin has progressive biventricular hypertrophy with predominant right ventricular systolic and biventricular diastolic dysfunction. Despite amnioreduction, the cardiovascular disease persists and even progresses in many recipient twins.

Cardiomegaly↗

PubMed2005

A randomised controlled trial of biopsy forceps and cannula aspiration for transcervical chorionic villus sampling.

OBJECTIVE: This trial compared two instruments for transcervical chorionic villus sampling (CVS). DESIGN: Randomised controlled trial. SETTING: Regional university prenatal diagnosis and treatment centre. POPULATION: Two hundred women were randomised at 10(+0)-12(+6) weeks of gestation to transcervical CVS using cannula aspiration (CA) or biopsy forceps (BF). METHODS: Women undergoing indicated CVS signed informed consent. Randomisation after decision to perform transcervical CVS. MAIN OUTCOME MEASURES PRIMARY OUTCOME: the rise in maternal serum alpha-fetoprotein (alpha-FP). SECONDARY OUTCOMES: (i) placental trauma (fetomaternal haemorrhage [FMH]); (ii) laboratory, procedure, and cytogenetic results and pregnancy outcomes; (iii) patient and operator satisfaction; and (iv) economic analyses. Analyses were performed by intention to treat. RESULTS: The -FP rise did not differ between groups; there was no other evidence of placental trauma. BF were better tolerated by women, provided culturable tissue, after fewer instrument passes, with greater ease and in less time. BF were associated with cost savings. CONCLUSIONS: Unlike -FP, other markers of FMH were unaltered, questioning the reliability of alpha-FP as an indicator of FMH. Compared with CA, transcervical BF caused comparable placental trauma, appeared to be similarly effective and safe and were preferred by operators and patients.

Biopsy, Needle↗

PubMed2004

Transplacental fetal treatment improves the outcome of prenatally diagnosed complete atrioventricular block without structural heart disease.

BACKGROUND: Untreated isolated fetal complete atrioventricular block (CAVB) has a significant mortality rate. A standardized treatment approach, including maternal dexamethasone at CAVB diagnosis and beta-stimulation for fetal heart rates <55 bpm, has been used at our institutions since 1997. The study presents the impact of this approach. METHODS AND RESULTS: Thirty-seven consecutive cases of fetal CAVB since 1990 were studied. Mean age at diagnosis was 25.6+/-5.2 gestational weeks. In 33 patients (92%), CAVB was associated with maternal anti-Ro/La autoantibodies. Patients were separated into those diagnosed between 1990 and 1996 (group 1; n=16) and those diagnosed between 1997 and 2003 (group 2; n=21). The 2 study groups were comparable in the clinical presentation at CAVB diagnosis but did differ in prenatal management (treated patients: group 1, 4/16; group 2, 18/21; P<0.0001). Overall, 22 fetuses were treated, 21 with dexamethasone and 9 with beta-stimulation for a mean of 7.5+/-4.5 weeks. Live-birth and 1-year survival rates of group 1 were 80% and 47%, and these improved to 95% for group 2 patients (P<0.01). The 21 patients treated with dexamethasone had a 1-year survival rate of 90%, compared with 46% without glucocorticoid therapy (P<0.02). Immune-mediated conditions (myocarditis, hepatitis, cardiomyopathy) resulting in postnatal death or heart transplantation were significantly more common in untreated anti-Ro/La antibody-associated pregnancies compared with patients treated with steroids (0/18 versus 4/9 live births; P=0.007). CONCLUSIONS: A standardized treatment approach, including transplacental fetal administration of dexamethasone and beta-stimulation at heart rates <55 bpm, reduced the morbidity and improved the outcome of isolated fetal CAVB.

Adrenergic beta-Agonists↗

PubMed2004

Randomized controlled trial of misoprostol for second-trimester pregnancy termination associated with fetal malformation.

OBJECTIVE: Our purpose was to compare the effectiveness, women's views of the termination procedure, and success of umbilical cord culture for vaginal and oral misoprostol versus intra-amniotic prostaglandin PGF(2alpha) for second-trimester pregnancy termination (STPT). STUDY DESIGN: We randomized 217 women, 15 to 24 weeks' gestation, into 3 groups. Oral (OM) and vaginal (VM) misoprostol groups received 400 microg of misoprostol every 4 hours for 24 hours. The intra-amniotic PGF(2alpha) (IAPG) group received 40 mg of PGF(2alpha) followed by oxytocin infusion. Women completed self-administered questionnaires 3 weeks after the termination procedure. Umbilical cord samples were collected at delivery for karyotype analysis. The primary outcome was the time from start of the procedure to placental delivery. Secondary outcomes were maternal complications, women's acceptance of the termination procedure, and success rates of umbilical cord culture. RESULTS: The time was longer for the OM group (30.5+/-14.4 hours) compared with the VM group (18.3+/-8.2 hours) and the IAPG group (21.1+/-10.2 hours), P<.001 for both comparisons. Women in the VM group reported being more willing to repeat the termination method in the future and reported fewer side effects than those in the other groups, P<.001. Failure rates for umbilical cord cultures were 9.6%, 17.0%, and 45.6% for the VM, OM, and IAPG groups, respectively. CONCLUSION: Oral misoprostol is less effective than intra-amniotic PGF(2alpha) or vaginal misoprostol for STPT. Women report vaginal misoprostol more acceptable than other methods. Umbilical cord culture failure rate is highest in the IAPG group.

Abortifacient Agents, Nonsteroidal↗

PubMed2004

Fetoscopic surgery in triplet pregnancies: a multicenter case series.

OBJECTIVE: The purpose of this study was to evaluate the feasibility of fetoscopic surgery in complicated monochorionic and dichorionic triplet pregnancies. STUDY DESIGN: This was a case series of fetoscopic surgery in 12 cases of monochorionic (n = 5) or dichorionic (n = 7) triamniotic triplets complicated by severe feto-fetal transfusion (n = 8), twin reversed arterial perfusion sequence (n = 3), or discordant for an anomaly (n = 1). Six underwent cord occlusion, and 6 had laser coagulation of the vascular anastomoses. RESULTS: All procedures were successfully completed, and the outcome was comparable to that reported for similar procedures in twins. Eighty-three percent of fetuses survived, and 13% had long-term problems. CONCLUSION: Fetoscopic surgery may be considered as a therapeutic option in complicated triplet pregnancies, with results similar to those found in twins.

Adult↗

PubMed2004

Perinatally diagnosed asymptomatic congenital cystic adenomatoid malformation: to resect or not?

BACKGROUND: Management of asymptomatic congenital cystic adenomatoid malformation (CCAM) is controversial. The natural history of untreated asymptomatic CCAM is unknown, although most surgeons recommend resection of these lesions to prevent future infection. The aim of this study was to determine the relative surgical risk of resection compared with the risk of observation for these patients. METHODS: A retrospective review of hospital records between 1996 and 2002 in a tertiary care pediatric referral center was conducted. All perinatally (prenatal or neonatal) diagnosed CCAMs were included. In addition, patients presenting with late diagnosis of CCAM were also reviewed. RESULTS: Forty-eight children had CCAM diagnosed perinatally. Thirteen of these were symptomatic and required surgery within 6 months; these were excluded from the analysis. Of the 35 asymptomatic infants, 6 were operated on electively before 6 months of age (median age, 4.5 months). The other 29 asymptomatic infants were followed up for more than 6 months. Of these, 9 remained asymptomatic and were eventually operated on electively (median age, 13 months). Three (10%) had CCAM infections at 7, 8, and 11 months of age and required resection. The remaining 17 children have not undergone resection and are still asymptomatic (median follow-up, 3 years). An additional 12 patients presented with a late diagnosis of CCAM. All of these presented with complications (infection or pneumothorax) and underwent resection (median age, 6 years). Overall, the complication rate after resection of an asymptomatic CCAM was not significantly different from those of resected CCAM that had already developed infection or pneumothorax (P =.64). CONCLUSIONS: Ten percent of perinatally diagnosed asymptomatic patients had 5 complications requiring surgery during follow-up. The true incidence is probably higher given the relatively short follow-up in our series. Morbidity after resection of a complicated CCAM was not statistically significantly higher than after elective resection for an asymptomatic CCAM. Although conservative management of asymptomatic CCAM may be warranted, a more extended period of follow-up is necessary before this approach can be recommended.

Cystic Adenomatoid Malformation of Lung, Congenita↗

PubMed2004

Treatment options in fetomaternal hemorrhage: four case studies.

BACKGROUND: Significant fetomaternal hemorrhage (FMH) is an uncommon event that places the fetus at risk of severe morbidity and mortality. Symptoms and signs at presentation are subtle and, if promptly recognized, appropriate management may permit the fetus to escape serious injury. CASES: Four cases of significant FMH were diagnosed in the high-risk obstetrical unit at Mount Sinai Hospital, Toronto, during 2003. Three of the women complained of reduced fetal movements and were investigated initially with a non-stress test, a Kleihauer-Betke test, and ultrasound, including Doppler of the middle cerebral artery. These women all required emergency Caesarean section for non-reassuring fetal status. One fetus was treated by intravascular transfusion. Another identified case was transfused postnatally. One asymptomatic case was identified after spontaneous vaginal birth and also treated by neonatal transfusion. Neurological outcomes were good in all four cases. CONCLUSIONS: Reduced fetal movements may be the only complaint of FMH. Increased awareness is required to ensure a diagnosis is made. When a non-stress test for reduced fetal movement is non-reactive, a Kleihauer-Betke test should be ordered, as well as detailed ultrasonography, including fetal Doppler studies. The perinatal prognosis for FMH may improve by facilitating the appropriate use of fetal blood transfusion or delivery by Caesarean section.

Adult↗

PubMed2004

Supporting the problem-based learning process in the clinical years: evaluation of an online Clinical Reasoning Guide.

PURPOSE: Implementing problem-based learning (PBL) in the clinical years of a medical degree presents particular challenges. This study investigated the effectiveness of using an online Clinical Reasoning Guide to assist integration of PBL in the clinical setting and promote further development of students' clinical reasoning abilities. METHOD: A total of 52 students in 6 PBL groups, together with their 6 clinical tutors, participated in the study. Data were analysed from videotaped observations of tutorial activity and follow-up, semistructured interviews. RESULTS: From both the student facilitators' and the clinical tutors' perspectives, the Guide proved an effective tool for augmenting the PBL process in clinical settings and promoting the development of clinical reasoning. By combining computer-aided learning with collaborative PBL tutorials it promoted individual as well as collaborative reasoning. There is also evidence to suggest that the Guide prompted students to look more critically at their own, their colleagues' and other clinicians' reasoning processes.

Clinical Competence↗

PubMed2003

Human maternal and fetal plasma glyceryl trinitrate concentrations.

OBJECTIVE: This study was undertaken to determine the maternal and fetal steady-state concentrations of glyceryl trinitrate (GTN) and its dinitrate metabolites during transdermal administration, at the time of fetal blood sampling for obstetric indications. STUDY DESIGN: Transdermal GTN (0.4 mg/h) was applied approximately 2 hours before investigative fetal blood sampling to maintain uterine quiescence. Serial maternal venous (MV) and a single fetal venous (FV) plasma samples were collected and assayed for GTN and its metabolites, 1,2- and 1,3-glyceryl dinitrate. RESULTS: The steady-state MV plasma concentration was 4.3+/-0.84 nmol/L (mean+/-SEM, n=7), and the dinitrate metabolites were detectable in the MV but not quantifiable. GTN was detectable in the FV (n=7) but was not quantifiable as the levels were less than the lower limit of sensitivity of the assay (<1 nmol/L). CONCLUSION: During transdermal GTN administration, the steady-state FV/MV concentration ratio is less than 0.23 at the time of fetal blood sampling.

Administration, Cutaneous↗

PubMed2003

Noninvasive tests to predict fetal anemia: a study comparing Doppler and ultrasound parameters.

OBJECTIVE: This study was undertaken to compare test characteristics of ultrasound and Doppler parameters in the prediction of fetal anemia in alloimmunized pregnancies. STUDY DESIGN: In a prospective cohort study, 16 nonhydropic fetuses with red blood cell alloimmunization were evaluated with ultrasound and Doppler imaging. Middle cerebral artery (MCA) peak systolic velocity, intrahepatic umbilical venous (IHUV) maximum velocity, liver length, and spleen perimeter were measured. Results before first fetal blood sampling (FBS) or delivery were analyzed. Fetal anemia was defined as hemoglobin deficit 5 SD or greater. Sensitivity and specificity were calculated. RESULTS: Six fetuses were anemic and required intrauterine transfusion, and 10 were not severely anemic at birth. MCA Doppler imaging was the best predictor of fetal anemia (100%), followed by IHUV (83%). Sensitivity was low for spleen perimeter (66%) and liver length (33%). CONCLUSION: Doppler evaluation of MCA peak systolic velocity is better than IHUV maximum velocity, liver, or spleen size in the prediction of fetal anemia in red blood cell alloimmunization.

Blood Transfusion, Intrauterine↗

PubMed2003

Fetal rhabdomyoma: prenatal diagnosis, clinical outcome, and incidence of associated tuberous sclerosis complex.

OBJECTIVES: We reviewed our institution's experience with fetal cardiac rhabdomyoma to document the clinical outcome and incidence of associated tuberous sclerosis complex (TSC) and compared our findings with those of patients diagnosed with cardiac rhabdomyoma after birth. STUDY DESIGN: We reviewed the medical records of all cases diagnosed prenatally and postnatally with cardiac rhabdomyoma between January 1990 and June 2002. RESULTS: Twenty fetuses with cardiac rhabdomyoma were diagnosed at 28.4+/-6.0 weeks' gestational age. Of 19 continued pregnancies, there was one spontaneous intrauterine death, and 18 were delivered at term. Although none had prenatal hemodynamic complications, after birth seven had cardiac symptoms requiring medical (n=4) or surgical intervention (n=3). On follow-up, 15 of 19 with available outcome had TSC (79%), including six with neurodevelopmental disease. Over the same period, 26 patients were diagnosed with cardiac rhabdomyoma postnatally. Most (77%) were referred for cardiac assessment after findings suggesting TSC. On follow-up, TSC was confirmed in 25 (96%), including 22 with neurodevelopmental disease. The incidence of cardiac symptoms and TSC was not statistically different between the prenatal and postnatal diagnosis groups. CONCLUSIONS: Cardiac rhabdomyomas are benign from the cardiovascular standpoint in most affected fetuses. As observed in postnatally diagnosed cardiac rhabdomyoma, TSC is diagnosed in most cases of fetal cardiac rhabdomyoma.

Brain↗

PubMed2003

Group problems in problem-based learning.

Successful small-group learning in problem-based learning (PBL) educational programmes relies on functional group processes. However, there has been limited research on PBL group problems, and no studies have been conducted on problems as perceived by both students and tutors in the same educational context. The authors investigated PBL group problems in a graduate-entry medical programme, and report the most common group problems, and those that hinder students' learning the most. The possible causes of individual quietness and dominant behaviour, and potential influences that group problems may have on the tutorial process are summarized in an exploratory model of PBL group dysfunction that could be used to guide further research. Specifically, there is a need for further evidence on which to base guidelines for tutors and students to effectively manage group problems.

Adaptation, Psychological↗

PubMed2003

The association between early membrane rupture, latency, clinical chorioamnionitis, neonatal infection, and adverse perinatal outcomes in twin pregnancies complicated by preterm prelabour rupture of membranes.

The objective of this study was to evaluate associations between adverse outcomes in twin pregnancies and preterm prelabour rupture of membranes (PPROM). A chart review of 246 consecutive twin pregnancies with confirmed PPROM was conducted. Regression analysis (beta [natural log of the odds ratio] and odds ratio [OR]) was performed to identify independent predictors. Two hundred and forty-six twin pregnancies, 492 liveborns, and 20 neonatal deaths. Mean (SD) PPROM gestational age (GA): 31.3 (3.8) wk; delivery GA: 32.0 (3.3) wk. PPROM < 30 wk was associated with increased parity (OR: 2.66), and log (admission leukocyte count) (OR: 9.99). Shortened latency was associated with PPROM GA (beta = -0.17) and chorioamnionitis (beta = 0.95). Neonatal sepsis was predicted by lower delivery GA (OR: 2.04). Adverse perinatal outcomes were protected against by older GA at PPROM (OR 0.53) and shortened latency (OR 0.73). It was concluded that increased leukocytosis and parity implies an infectious aetiology in earlier PPROM. Increased risk for neonatal sepsis at earlier delivery GA is consistent with gestation-dependent fetal immunocompetence. Early PPROM and long latencies were associated with increased adverse perinatal outcomes.

Adult↗