Third-trimester ultrasound dating algorithms derived from pregnancies conceived with artificial reproductive techniques

OBJECTIVE

To derive an accurate formula for ultrasound estimation of gestational age in late pregnancy.

METHODS

A database of 123 singleton pregnancies conceived by artificial reproductive techniques with third-trimester ultrasound measurements was studied. Biometry variables included the fetal head circumference (HC) and femur length (FL). The dataset was equally divided into a derivation sample and a target sample. To derive the equations of best fit, regression analysis was used, with true menstrual age as the dependent variable and fetal biometry measurements as independent variables. The formulae were tested on the target set and the menstrual age estimates were compared with the actual menstrual age. Clinical performance was estimated in terms of systematic and random errors, absolute errors and their 95% CI values.

RESULTS

The menstrual ages at time of scanning ranged from 26 to 41 weeks, with a mean of 33 weeks. The best performing derived formula was a combination of HC and FL. This had a random error of 7.5 days and prediction errors within a 95% confidence limit of -13 to +17 days. With FL only, the random error was 8.2 days, whereas using the HC only yielded a random error of 9.4 days.

CONCLUSIONS

Ultrasound estimation of gestational age in late pregnancy is better than indicated by older publications. It is more accurately estimated by combining the HC with the FL than by using the FL measurements alone.

Astigmatism in Chinese preschool children: prevalence, change, and effect on refractive development

AIM

To study the prevalence, type, and progression of astigmatism in Chinese preschool children, and its effect on refractive development.

METHODS

A cross sectional study of preschool children was carried out in two randomly selected kindergartens. A cohort study was performed on a subset of children, five years after initial examination. Refractive error (measured by cycloplegic autorefraction) and axial ocular dimensions (measured by ultrasonography) were the main study outcomes.

RESULTS

522 children participated in the study; the mean age was 55.7 months (SD 10.9; range 27 to 77). Mean cylinder reading was -0.65 D (SD 0.58; range 0.00 to -4.75), and with the rule astigmatism was predominant (53%). In the 108 children studied longitudinally, the mean cylinder reading reduced from -0.62 D to -0.50 D (p = 0.019). The presence of astigmatism in initial examination predisposed the eyes towards greater myopisation (p<0.001). In addition, children with increased astigmatism had greater myopic progression (p<0.001) and axial length growth (p = 0.002).

CONCLUSIONS

This study reports a high prevalence of astigmatism in Chinese preschool children. The presence of astigmatism, and particularly with increasing astigmatism, appears to predispose the children to progressive myopia. Further studies are warranted.

Diagnostic performance of CT versus MR in detecting aldosterone-producing adenoma in primary hyperaldosteronism (Conn's syndrome)

The aim of the present study is to compare the diagnostic performance of CT and MR imaging in detecting aldosterone-producing adenoma and to compare the interobserver variability in the detection of an aldosterone-producing adenoma on CT and MR. A retrospective study of 34 patients with primary hyperaldosteronism was performed. A total of 17 cases of aldosterone-producing adenoma and 17 cases of bilateral adrenal hyperplasia were included. The final diagnosis of an adenoma was made by surgery with histological confirmation, whereas that of bilateral adrenal hyperplasia was made on adrenal venous sampling or a good biochemical and clinical response following medical treatment alone and in the absence of a unilateral radiological abnormality. The CT (n=30) and MR (n=24) scans were reviewed independently by two radiologists experienced in adrenal imaging, who were unaware of the cause of the primary hyperaldosteronism. The diagnostic performances of both observers in detecting an aldosterone-producing adenoma on CT and MR imaging were compared. The 16 adenomatous nodules that were detected on imaging ranged from 1 to 4.75 cm in diameter. The calculated sensitivity and specificity for detecting aldosterone-producing adenoma were 87 and 93% for one observer and 85 and 82% for the other observer on CT, and 83 and 83% for one observer and 92 and 92% for the other observer on MR, respectively. Receptor operating characteristics curve analysis showed similar performances of both observers in detecting an aldosterone-producing adenoma on CT and MR imaging. There was good interobserver agreement on CT (k=0.71) and on MR (k=0.67). We have demonstrated comparable diagnostic performance and good interobserver agreement on CT and MR imaging for the detection of aldosterone-producing adenoma.

Accuracy of ultrasound dating formulae in the late second-trimester in pregnancies conceived with in-vitro fertilization

PURPOSE

To investigate the accuracy of ultrasound dating formulae in the late second trimester of pregnancy.

MATERIAL AND METHODS

A dataset of 136 singleton pregnancies conceived by artificial reproductive techniques was studied to assess the accuracy of ultrasound dating formulae in the late second trimester, and compared with early second trimester. A total of 21 published ultrasound-dating formulae were tested.

RESULTS

For most formulae, late second trimester scans yielded results that were marginally less accurate than the early second trimester. The best performance was obtained with dating formulae based on femur length, either alone or combined with the biparietal diameter. These formulae had mean absolute errors of 3-3.5 days. Combining two or more parameters did not result in any substantial gain in accuracy.

CONCLUSIONS

Pregnancy dating by ultrasound in the late second trimester is sufficiently accurate for routine clinical use. Formulae based on femur length appear to be at least as accurate as head measurements.

Hormone replacement therapy (HRT) and ischaemic heart disease: getting to the heart of the matter

Numerous observational studies have previously shown that estrogen therapy (ERT) or estrogen/progestin hormone replacement therapy (HRT) can significantly reduce the risk of Coronary Artery Disease (CAD) in healthy postmenopausal women by up to 50%. However, due to statistical limitations inherent in these earlier studies, several large randomised trials are now under way. The results from some of these randomised trials are expected sometime in 2005 and will certainly help confirm or refute the present perceived cardio-protective effects of ERT/HRT in healthy menopausal women. On the other hand, the role of hormonal therapy in menopausal women with established CAD is more controversial. Although results from earlier observational trials have been encouraging, more recent randomised controlled data from the Heart and Estrogen/Progestin Replacement (HER) study and the Estrogen Replacement and Atherosclerosis (ERA) study have been more sober. In fact, both have generally reported on the failure of ERT/HRT to reduce the overall rate of ischaemic cardiovascular events or to halt the progression of coronary atherosclerosis in menopausal women with established CAD. However, these studies are not without their own limitations. As such, more future trials will be needed before the role of postmenopausal hormone therapy in the secondary prevention of CAD can be firmly established.

Initial experience of vocal cord evaluation using grey-scale, real-time, B-mode ultrasound

BACKGROUND

To evaluate whether grey-scale, real-time, B-mode ultrasound (US) is a reliable alternative to nasopharyngoscopy for assessing vocal cord function post-thyroid and post-parathyroid surgery.

METHODS

A prospective validation study was undertaken comparing grey-scale, real-time, B-mode vocal cord US with the standard of nasopharyngoscopy in 100 consecutive patients undergoing thyroid and parathyroid surgery between 1 February 1999 and 31 August 1999, with seven patients with known cord palsy. The sensitivity and specificity of grey-scale, real-time vocal cord US for the detection of vocal cord palsy when compared to the standard of nasopharyngoscopy was analysed.

RESULTS

In the postsurgical group, there were six nerves (3.2% of the nerves at risk) transient and no permanent vocal cord palsies. US identified four of six transient palsies and reported two false negatives and three false positives. US identified four of seven cord palsies in the non-surgical group with known cord palsy. Analysis of the 107 combined patients showed US had sensitivity of 62% (8/13), specificity of 97% (91/94), a positive predictive value of 73% (8/11) and a negative predictive value of 95% (91/96) for detecting cord paralysis compared to the standard of nasopharyngoscopy.

CONCLUSION

Despite the enthusiasm of earlier reports, our initial experience with grey-scale, real-time, B-mode US suggests it is not a reliable alternative to nasopharyngoscopy for assessing vocal cord function post-thyroid and post-parathyroid surgery. Further recruitment of patients with known vocal cord palsy is required to confirm or refute these initial impressions.

Medical management of cervical pregnancy--a report of two cases

Cervical ectopic pregnancy is a rare life-threatening condition that can be managed conservatively. In this report, the authors describe the use of systemic methotrexate and prostaglandin (sulprostone) in the management of two cases of viable cervical pregnancy. Both cases were successfully treated without the need for surgical intervention.

Laparoscopic treatment of a twisted hyperstimulated ovary after IVF

Ovarian Hyperstimulation Syndrome (OHSS) is a common problem associated with modern In-Vitro Fertilisation techniques (IVF). However, torsion of a hyperstimulated ovary occurring after IVF is a much rarer event. In this case report, we will describe the laparoscopic management of a pregnant patient with a twisted hyperstimulated ovary after an IVF programme.

The effects of 1.5T magnetic resonance imaging on early murine in-vitro embryo development

Although no ionizing radiation is involved, patients undergoing magnetic resonance imaging (MRI) are exposed to powerful static magnetic fields, magnetic field gradients, and radio-frequency fields that may be potentially damaging. Our study aims to document the effect of MRI imaging sequences on early murine embryo development (two-cell to blastocyst stage) in vitro. Two-cell murine embryos were exposed to various lengths of MRI using pulse sequences employed in present day clinical imaging. Early murine embryo development was documented in vitro, and blastocyst development rates were computed for both the control and exposed groups. There were no significant differences detected in the rate of blastocyst formation between the control groups and the embryos exposed to MRI.

The sensitivity of the trivariate analysis using maternal serum alpha-feto protein, human chorionic gonadotrophin and maternal age in screening for fetal aneuploidy in mothers above the age of 35

This study was undertaken to assess the usefulness of maternal serum human chorionic gonadotrophin, alpha-fetoprotein and maternal age in screening for fetuses with abnormal chromosomes in pregnant women aged 35 years and over. From 1989 to 1991, 1208 women seen at the National University Hospital had karyotyping procedures performed for maternal age > 35 years as well as second trimester serum samples taken for alpha-fetoprotein and human chorionic gonadotrophin. Sixteen (1.3%) chromosomal abnormalities were present. Using cut off risk levels of 1:250 and 1:384, the sensitivity of the analysis in screening for Down's syndrome pregnancies was 71.5% and 86% respectively. For the non Down's chromosomal abnormalities, using cut off risk levels of 1:250 and 1:384, the sensitivity of the analysis was only 22.3% and 33.4% respectively. Thus risk calculations based on the two serum markers and maternal age failed to identify all fetuses with abnormal chromosomes.

Persistent left superior vena cava and partial anomalous pulmonary venous connection: incidental diagnosis by transesophageal echocardiography during coronary artery bypass surgery

Transesophageal echocardiography plays an important role in the intraoperative treatment of the heart surgery patient. Its utility in the description of both known and unexpected cardiac pathology is well established. We describe a patient with a previously undiagnosed partial anomalous pulmonary venous connection along with a persistent left superior vena cava scheduled for routine coronary artery bypass graft surgery (CABG).

The clinical management of male infertility

Male infertility is a common cause of subfertility for which sperm disorders are the single most common cause. Genetic abnormalities, for example, microdeletions associated with the Y chromosome, defects in the androgen receptor gene and cystic fibrosis have gained recent prominence and it is envisaged that many of the 60% of men for which no cause is found may have a genetic basis for their subfertility. Although an abnormal semen analysis is commonly the first indicator of a male factor problem, further tests are usually required. Empirical treatment with hormones, varicocelectomy and immunological treatment have been proven to be disappointing whilst the treatment of infection and obstruction do not always translate into significantly higher fertility rates. Ejaculatory disorders and impotence can be effectively treated today whilst donor insemination can be offered to men with untreatable infertility. The advent of assisted reproduction and micromanipulation has greatly improved prospects for fertility of men with very poor semen quality. However, the genetic implications of these procedures have to be quickly addressed so that fertility is maximised without risk to the progeny.

Laparoscopic adhesiolysis for subfertility

AIM

Laparoscopic adhesiolysis has been associated with pregnancy rates of 12% to 58%. This study looks at our experience with laparoscopic adhesiolysis in the management of subfertile patients.

METHOD & RESULTS

Between January 1992 and March 1995, 27 subfertile patients who had laparoscopic adhesiolysis done were studied. Four patients (15%) had a second look laparoscopy. The overall pregnancy rate (after excluding 6 patients with bilateral tubal blockage or severe male factor) was 33% (7/21). The take home baby rate was 14.3% (3/21) and the ectopic pregnancy rate was 4.7% (1/21).

CONCLUSION

Laparoscopic adhesiolysis still remains a useful and effective procedure for infertile couples with pelvic adhesions.

Relationship between stress, coping, and postconcussion symptoms in a healthy adult population

Study 1 examined the association between intensity of postconcussive symptoms (PCS), impact of daily stress, and level of perceived stress over the past month in a group of healthy young adults. There was a significant relationship between intensity of PCS and impact of daily stress, as well as level of perceived stress over the past month, independent of the frequency of stressful events experienced. Study 2 assessed the stability of the relationship between PCS and stress. Subjects rated intensity of PCS, impact of daily stress, and level of perceived stress on two separate occasions approximately 1 month apart. The Perceived Stress Scale demonstrated high test-retest reliability. Significant relationships were again found between intensity of PCS and level of perceived stress at both time points, independent of the frequency of stressful events. These results suggest that persistent symptoms in some individuals with postconcussive syndrome may be due, at least in part, to individual differences in the perceived stress of incurring a mild traumatic brain injury.

Post-keratoplasty endophthalmitis caused by Proteus mirabilis

A diabetic patient who underwent a triple procedure (penetrating keratoplasty, cataract extraction and posterior chamber intraocular lens implantation), developed endophthalmitis caused by Proteus mirabilis. The source of infection was the infected donor cornea, which was imported from Sri Lanka. The organism was resistant to gentamicin, which was the only antibiotic present in the storage medium. On top of an aggressive antibiotic treatment regime (topical, systemic and intravitreal), exchange of the infected with a fresh corneal graft and pars plana vitrectomy were performed. The patient had a speedy recovery and the visual outcome was 20/40 two and a half years after the incident. To our knowledge, post-keratoplasty endophthalmitis caused by P. mirabilis has never been reported in the literature. We report herein such a case with good visual outcome. Newer storage medium, such as Optisol GS, might have a role in preventing keratoplasty-related infection.

Intraoperative mitomycin C to prevent recurrence of pterygium after excision: a 30-month follow-up study

OBJECTIVE

The purpose of the study was to examine the efficacy of intraoperative mitomycin C (MMC) in preventing recurrence of pterygium after excision and the postoperative complications encountered.

DESIGN

The study design was a prospective, randomized, clinical trial.

PARTICIPANTS

A total of 180 primary and recurrent pterygia were recruited for the study. They were randomized into five groups: A, control with no MMC; B, 0.02% MMC for 5 minutes; C, 0.04% MMC for 5 minutes; D, 0.02% MMC for 3 minutes; and E, 0.04% MMC for 3 minutes.

INTERVENTION

All patients received pterygium excision with or without the above four modes of intraoperative MMC application.

MAIN OUTCOME MEASURES

Recurrence of pterygium and postoperative complications such as superficial scleral melting were measured.

RESULTS

At a mean follow-up of 30 (groups A-C) and 20 months (groups D and E), the respective recurrence rates in groups A through E were 75%, 8.3%, 8.6%, 42.9%, and 22.9%. There were two cases of postoperative superficial scleral melting in group C. Otherwise, no major postoperative complications were encountered.

CONCLUSIONS

The midterm results of a single intraoperative application of MMC at the concentration of 0.02% for 5 minutes are encouraging. Its application as an adjunctive therapy for the surgical treatment of pterygium appeared to be safe and effective. However, because of the possibility of serious late complications, the authors suggest that this procedure be reserved for patients who have high probability of recurrence after excision of pterygium.

Effects of tea tree oil on Escherichia coli

Tea tree oil (TTO) stimulates autolysis in exponential and stationary phase cells of Escherichia coli. Electron micrographs of cells grown in the presence of TTO showed the loss of electron dense material, coagulation of cell cytoplasm and formation of extracellular blebs. Stationary phase cells demonstrated less TTO-stimulated autolysis and also had greater tolerance to TTO-induced cell death, compared to exponentially grown cells. It was also revealed that subpopulation of stationary phase cells demonstrated increased tolerance to TTO-bactericidal effects.

Caesarean and postpartum hysterectomy

AIM OF STUDY

To review the cases of caesarean and post-partum hysterectomy performed over a 10-year period (1986-1996) in a teaching hospital, looking specifically at the associated morbidity.

METHOD

Retrospective review of case files.

RESULTS

During the study period, there were 14 cases of caesarean and post-partum hysterectomy. Caesarean hysterectomy was performed in 0.17% of caesarean sections and a hysterectomy was done in 0.02% of cases following a vaginal delivery. Uterine atony was associated with 43% of cases. Histological evidence of placenta accreta or increta was noted in 7 (50%) cases, while 8 (57%) cases had placenta praevia. A subtotal hysterectomy was performed in 7 cases, where the mean operating time was significantly shorter than that in cases of total hysterectomy. There were no maternal deaths. Fever (28%), urinary tract infection (21%) and chest infection/atelectasis (21%) were the common post-operative morbidity. Relaparotomy for continuing vaginal bleeding was required in 2 cases.

CONCLUSIONS

Emergency peri-partum hysterectomy for obstetric haemorrhage is a rare operation (1 in 2,550 deliveries). In spite of the intra-operative risks and post-operative morbidity, it remains a potentially life-saving procedure.

Rostering: placing the nurse in the picture

A funded study to investigate best practice in nursing rosters in a busy metropolitan Melbourne children's hospital, identified the complexity of the shiftwork issues when the people who work them are placed centre stage. This paper explores a key finding of the study, which strongly endorses the need to take account of scientific knowledge on health and safety issues of shiftwork, but argues that the personal, socio-cultural and environmental perspective of the nurse needs to be given more attention by the various stakeholders involved with rostering.