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Biomedical subjects

S G Oei

Publications and source records attributed to S G Oei.

At least 19 recordsLinked to original sources
PubMed2006

Calcium channel blockers for tocolysis: a review of their role and safety following reports of serious adverse events.

The use of nifedipine and other calcium channel blockers has become commonplace in the management of preterm labour. Several relatively small randomised trials have compared calcium channel blockers with beta-agonists and the meta-analyses of these studies have demonstrated superior or comparable efficacy and a superior adverse events profile. The safety of calcium channel blockers in pregnancy has not been rigorously evaluated and they remain unlicensed for use as tocolytics. Indeed, there is concern following a number of recent case studies that have reported serious adverse events after the administration of a calcium channel blocker as a tocolytic. In this article all these recently reported cases are critically reviewed and the pros and cons of tocolytic treatment options are discussed. Based on the findings of this review the following recommendations can be made with regard to tocolysis with calcium channel blockers: firstly, calcium channel blockers should not be combined with intravenous beta-agonists; secondly, intravenous nicardipine or high oral doses of nifedipine should not be used in cases where the mother is cardiovascular compromised or in cases of multiple gestation; finally, blood pressure should be monitored and cardiotocography recorded during the administration of immediate release tablets and patients should be advised to avoid chewing them. To truly establish the safety of tocolytics, all serious adverse effects of tocolytics should be reported to a central point and be critically reviewed.

Adrenergic beta-Agonists↗
PubMed2004

Customized spectral band analysis compared with conventional Fourier analysis of heart rate variability in neonates.

A customized filtering technique is introduced and compared with fast Fourier transformation (FFT) for analyzing heart rate variability (HRV) in neonates from short-term recordings. FFT is classically the most commonly used spectral technique to investigate cardiovascular fluctuations. FFT requires stability of the physiological signal within a 300 s time window that is usually analyzed in adults. Preterm infants, however, show characteristics of rapidly fluctuating heart rate and blood pressure due to an immature autonomic regulation, resulting in non-stationarity of these signals. Therefore neonatal studies use (half-overlapping or moving) windows of 64 s length within a recording time of 2-5 min. The proposed filtering technique performs a filtering operation in the frequency range of interest before calculating the spectrum, which allows it to perform an analysis of shorter periods of only 42 s. The frequency bands of interest are 0.04-0.15 Hz (low frequency, LF) and 0.4-1.5 Hz (high frequency, HF). Although conventional FFT analysis as well as the proposed alternative technique result in errors in the estimation of LF power, due to spectral leakage from the very low frequencies, FFT analysis is more sensitive to this effect. The response times show comparable behavior for both the techniques. Applying both the methods to heart rate data obtained from a neonate before and after atropine administration (inducing a wide range of HRV), shows a very significant correlation between the two methods in estimating LF and HF power. We conclude that a customized filtering technique might be beneficial for analyzing HRV in neonates because it reduces the necessary time window for signal stability.

Algorithms↗
PubMed2004

Recurrence rate of pre-eclampsia in women with thrombophilia influenced by low-molecular-weight heparin treatment?

OBJECTIVES: (1) To assess the recurrence rate of pre-eclampsia in women with this history before 34 weeks of pregnancy and thrombophilia. (2) To evaluate the effects of low-molecular-weight heparin (LMWH) on pregnancy outcome. METHODS: In a multicentre retrospective study subsequent pregnancies of women with a history of pre-eclampsia necessitating birth before 34 weeks and thrombophilia were analysed. Of 58 women, 26 received LMWH and aspirin (ASA) and 32 ASA (22) or no (10) medication in their subsequent pregnancies. RESULTS: In eight women treated with LMWH and ASA and in 16 women receiving ASA or no medication pre-eclampsia recurred in the subsequent pregnancy. (OR 0.55, 95% CI 0.15-1.31) There were no significant differences in birth weight or gestational age between both groups. CONCLUSIONS: The recurrence rate of pre-eclampsia in women with thrombophilic disorders is high in this small retrospective study. No positive effect was found for LMWH treatment. A multicentred randomised study has been started to reach an adequate number of patients to evaluate the influence of LMWH treatment.

Anticoagulants↗
PubMed2002

[Nifedipine first choice in management of threatening preterm labor].

Preterm birth is the most important cause of perinatal mortality in Europe and North America. Tocolytic agents named beta 2-sympathicomimetics postpone delivery for 24-48 hours, but do not reduce perinatal mortality or morbidity. Calcium antagonists, in particular nifedipine, are more effective tocolytic agents than beta 2-sympathicomimetics in terms of delaying delivery. Meta-analyses have found that calcium antagonists statistically significantly reduced perinatal morbidity and that the number of maternal side effects was statistically significantly lower compared with beta 2-sympathicomimetics. Nifedipine also has the benefit of oral administration, in contrast with beta 2-sympathicomimetics which are administered intravenously. Nifedipine is therefore the first choice in the management of threatening preterm labour.

Administration, Oral↗
PubMed2001

Distinguishing the benign and malignant adnexal mass: an external validation of prognostic models.

OBJECTIVE: Because external validation of the present models has not been reported, the purpose of the present study was to assess existing diagnostic models that are used to distinguish malignant from benign masses. METHODS: We tested the performance of existing models in a prospectively assembled data set of 170 patients with an adnexal mass. Twenty-one models that have been reported previously were assessed. The models were based on combinations of ultrasound findings, color Doppler tests, CA-125 measurement, age, and/or menopausal status. For each model, we constructed ROC curves and calculated an area under the ROC curve. RESULTS: Of the 170 adnexal masses that were operated on, 30 (18%) were malignant. The area under the ROC curve of 21 models that were externally validated varied between 0.69 and 0.90. We found the performance of the existing models to be inferior to the performance reported in the initial studies. Even models that incorporated multiple diagnostic tools and that were developed using logistic regression models or neural networks had an area under the ROC curve of 0.86 at maximum. In the case where we focused on almost perfect sensitivity, the highest specificities varied between 0.45 and 0.60. CONCLUSION: Although diagnostic models might be of value in the preoperative assessment of the adnexal mass, their diagnostic performance is not as good as that reported in the original publications.

Adnexal Diseases↗
PubMed2001

Arterial balloon occlusion of the hypogastric arteries: a life-saving procedure for severe obstetric hemorrhage.

In this case report we describe two patients with life-threatening postpartum hemorrhage who were treated successfully with arterial balloon occlusion of the hypogastric arteries. Arterial balloon occlusion is easy to perform and is applicable under difficult circumstances. The technique should be available in all hospitals that provide obstetric services. Obstetricians should know about it so they can ask their radiologic colleagues to perform the procedure.

Adult↗
PubMed2000

Intraventricular haemorrhage in utero. A case-report and review of the literature.

Intraventricular haemorrhages (IVH) are the most commonly occurring intracranial haemorrhages in neonates, especially in preterm infants. The origin of IVHs is located in the germinal matrix. The cause of an IVH is a combination of intravascular, vascular and extravascular factors. The diagnosis is made by ultrasound. Knowledge on the causes of antenatal haemorrhages lags far behind knowledge on the causes of postnatal haemorrhages. In cases of haemodynamic changes in utero, ultrasound could be useful to examine the foetal brain. The presence of an intracranial haemorrhage in utero greatly influences the prognosis of the infant.

Adult↗
PubMed2000

A severe case of myasthenia gravis during pregnancy.

Myasthenia gravis is characterised by muscle weakness and fatigability, particularly of the facial and extremity muscles, deteriorating during the day. During pregnancy, myasthenia gravis is rare and the course of illness is unpredictable. The present case illustrates that first diagnosed during pregnancy, recurrent exacerbations can appear and lead to life-threatening situations.

Adult↗
PubMed2000

Randomized trial of administration of prostaglandin E2 gel for induction of labor in the morning or the evening.

OBJECTIVE: To compare the outcome of induction of labor and patient's preferences using a protocol with the first dose of prostaglandin E2 endocervical gel in the evening versus a protocol with the first dose in the morning. DESIGN: We performed a randomized trial comparing administration of prostaglandin E2 endocervical gel in the morning with administration of prostaglandin E2 gel in the evening, followed if necessary by a second dose being given after six hours if labor had not started or the cervix was still unripe. Formal induction of labor by amniotomy and oxytocin infusion was performed the morning after the initial prostaglandin E2 dose. Patients' preferences were assessed using a questionnaire that was completed after delivery. SETTING: Tertiary care hospital in the Netherlands with 1,600 deliveries per year. PARTICIPANTS: One-hundred and twenty-six women with viable singleton pregnancies at term who had induction of labor with prostaglandins. MAIN OUTCOME MEASURES: Time of delivery (daytime, evening or night) and patient's satisfaction. RESULTS: Fifty-eight women were allocated for administration of gel in the morning, whereas 68 had their gel in the evening. Administration of gel in the evening did not significantly reduce delivery between 23.00 hours and 08.00 hours, although there was a reduction in delivery between 23.00 hours and 08.00 hours in nulliparae. None of the multiparous women delivered between 18.00 hours and 23.00 hours after induction of labor in the evening. The relative risk for delivery by vacuum or forceps was increased after allocation of gel in the evening (4.2; 95% confidence limits 1.4 to 13). Patients' preferences favored administration of gel in the morning. CONCLUSIONS: There was no benefit in starting induction of labor with prostaglandin E2 in the evening, compared with starting in the morning.

Cervix Uteri↗
PubMed1999

[Two neonates with severe rhesus antagonism inspite of low values in recent tests of antibody dependent cellular cytotoxicity (ADCC)].

In two female newborn babies severe haemolytic disease of the newborn developed due to anti-RhD antibodies of the mother. In both cases the results of the last antibody-dependent cellular cytotoxicity (ADCC) test had been < 10% (two and three weeks before parturition respectively) making haemolytic disease unlikely. The ADCC test is used to determine the destructive power of the responsible maternal antibodies. It is believed that with a low ADCC value (< 10%), there is no danger of clinically relevant haemolytic disease. The first neonate recovered after exchange transfusion, the second died notwithstanding extensive supportive therapy. A recent low ADCC value makes serious haemolytic disease unlikely, but does not completely exclude it, as the titre of the causative antibodies can rise very quickly.

Adult↗
PubMed1999

Preeclampsia and genetic risk factors for thrombosis: a case-control study.

OBJECTIVE: Recently, it has been proposed that hereditary coagulation abnormalities leading to an increased venous thrombosis risk may play a role in the development of preeclampsia. We tested this hypothesis in women who have had preeclampsia compared with matched control subjects. STUDY DESIGN: We conducted a case-control study of 163 women with preeclampsia during 1991-1996. Control subjects were matched for age and delivery date. Patients and control subjects were tested for the presence of factor V Leiden, prothrombin 20210A allele, protein C, protein S, and antithrombin deficiency. Logistic regression methods were used for data analysis. RESULTS: The prevalence of these genetic risk factors was similar in the patient group (12.9%) and the control group (12.9%; odds ratio, 1.0; 95% confidence interval, 0.5-3.9). Unexpectedly, we found a high prevalence of factor V Leiden in the control group (9.2%). CONCLUSION: We found no differences in the prevalence of genetic risk factors of thrombosis in women with preeclampsia compared with control subjects.

Antithrombins↗
PubMed1999

The monoamniotic twin: a riskful event.

The monoamniotic twin is at risk for high perinatal mortality because of cord accidents. There is no consensus in literature for the obstetric management in these cases. Contradictory results are reported according to fatal complications by cord accidents after 32 weeks gestation and safety of vaginal delivery. Recently two patients were admitted to our hospital with monoamniotic twin pregnancies and a fetal death in the third trimester. On the basis of these cases a review of the literature is presented and a case registry is recommended.

Adolescent↗
PubMed1999

Nifedipine versus ritodrine for suppression of preterm labor; a meta-analysis.

BACKGROUND: Since large randomized clinical trials comparing the effectiveness of nifedipine and ritodrine in the suppression of preterm labor are lacking, we performed a meta-analysis on the subject. METHODS: We searched the databases Medline and EMBASE using the keywords 'nifedipine', 'ritodrine' and 'randomized' or 'randomised'. The studies were scored for blinding, method of randomization and type of analysis ('intention-to-treat' versus 'par protocol'). Subsequently, two by two tables were constructed using 'delay of labor by 48 hours or more', 'delay of labor beyond 36 weeks gestation', perinatal mortality, respiratory distress syndrome and admission to a neonatal intensive care unit as end points. Homogeneity between the studies was tested with a Breslow-Day test. Pooled odds ratios were calculated in case homogeneity could not be rejected. RESULTS: We could detect ten studies that were published between 1986 and 1998, incorporating data of 681 patients. Nifedipine reduced the risk of delivery within 48 hours compared to ritodrine, but this difference was not statistically significant (odds ratio 0.85, 95% confidence interval 0.54 to 1.1). Nifedipine also reduced the risk of delivery before 36 weeks compared to ritodrine, and this difference was statistically significant (odds ratio 0.59, 95% confidence interval 0.39 to 0.90). We are not aware of studies reporting on long-term outcome. CONCLUSION: Since studies reporting on long-term outcome are lacking, the choice between nifedipine and ritodrine can only be based on obstetrical and short-term neonatal outcomes. From that perspective, nifedipine should be the drug of first choice for the suppression of preterm labor.

Female↗