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Biomedical subjects

T C Pun

Publications and source records attributed to T C Pun.

35 records · Page 2Linked to original sources
PubMed1997

Gynaecological day surgery at a Hong Kong hospital.

A retrospective review was made of patients who underwent day surgery at a gynaecological day practice in Hong Kong from October 1993 to June 1994. The first three months of practice, which involved 326 patients, was analysed separately. During the initial period, 49.5% of patients who had gynaecological operations were managed as day patients. The rates for patients with prolonged hospital stay and cancelled operations were 15.6% and 3.0%, respectively. In the subsequent period, the incidence of prolonged hospital stay decreased to 7.4%, while the cancellation rate was similar, at 3.6%. Patients with a prolonged hospital stay were less likely to be Chinese, were more likely to have other medical problems, to be of American Society of Anesthesiologists Class II, and to have procedures that involved opening of the peritoneal cavity. Non-medical problems were an important reason for prolonged hospital stay (37.4%). The stay rate could be reduced by provision of a separate operating facility and by improved counselling and selection of patients.

Journal Article↗
PubMed1996

Fetal cerebral Doppler studies as a predictor of perinatal outcome and subsequent neurologic handicap.

OBJECTIVE: To study the use of middle cerebral arterial Doppler findings in a group of high-risk fetuses as a predictor of adverse perinatal outcome, including subsequent neurologic handicap. METHODS: A group of very high-risk fetuses was recruited over a 2-year period for study. Weekly fetal biometries and Doppler studies of the umbilical artery and middle cerebral arteries were carried out until delivery. Main outcome indices analyzed included birth weight ratio (ratio of observed birth weight to mean birth weight for gestation), days of ventilator requirement, neonatal intracranial hemorrhage or periventricular leukomalacia, necrotizing enterocolitis, and follow-up data on major neurologic handicap and death. RESULTS: Seventy-four patients were recruited. One hundred thirty-four sets of examinations were made and prospective follow-up data were available for up to 2 years. The ratio of the umbilical and middle cerebral arterial resistance index was found to be inversely proportional to the birth weight ratio. Fetuses who had a high prenatal umbilical-cerebral Doppler ratio had significantly lower birth weight ratios than those with normal findings (0.72 versus 0.92; P < .001). The ratio was a more sensitive marker for growth restriction (sensitivity 78%) than conventional fetal biometry and umbilical arterial systolic-diastolic ratio. However, fetuses with high ratios did not have higher incidences of perinatal complications or subsequent neurologic handicap. CONCLUSION: Prenatal cerebral vasodilation is a sensitive marker for growth restriction and it seems to be a physiologic response to hypoxia. Fetuses with intrauterine cerebral vasodilation do not have increased risk for subsequent gross neurologic damage.

Adult↗
PubMed1996

Anaemia in pregnancy--is the current definition meaningful?

OBJECTIVE: To determine if the current definition of antenatal anaemia (haemoglobin < 10 g/dl) has any clinical significance. STUDY DESIGN: A retrospective study on all singleton deliveries over a 3-year period in two teaching hospitals under one university department was conducted by the extraction of data from a computer database. The major pregnancy complications and perinatal outcome were compared between mothers with and without anaemia and adjusted for parity. RESULTS: The incidence of multiparity was significantly higher in the 817 anaemia patients compared to the 10125 non-anaemia patients, but there was no difference in the incidence of other major antenatal complications, type of labour or mode of delivery, incidence of preterm delivery, or perinatal mortality or morbidity, after adjusting for parity. Among the anaemia patients, those with thalassaemia trait (54.8%) had a significantly higher incidence of gestational glucose intolerance but the incidences of other complications and the perinatal outcome were similar to the iron deficiency patients. CONCLUSION: Antenatal anaemia, defined as a maternal haemoglobin of < 10 g/dl, does not adversely affect pregnancy outcome. This raises the question of whether the diagnosis of anaemia should be redefined.

Anemia↗
PubMed1996

The role of Doppler sonography in assessment of malignant trophoblastic disease.

An observational study on the role of Doppler sonography in the assessment of patients with malignant trophoblastic disease was performed in an Oncology Unit of a University teaching hospital. A total of 32 consecutive patients referred for chemotherapy were recruited. Twenty-three non-pregnant and 18 women in the first trimester of pregnancy acted as controls. The patients were prospectively followed-up for 2 years. It was found that the uterine arterial resistance index and pulsatility index in patients who required chemotherapy were significantly lower when compared with the non-pregnant and pregnant controls; (Student t-test; P < 0.001 and P < 0.01, respectively). Stepwise regression analysis of beta-hCG titres on uterine artery resistance index showed significant correlation, after controlling for uterine volume (adjusted multiple R = 0.71, P < 0.00001). There were, however, no significant independent associations between the initial uterine artery resistance index and the need for chemotherapy, number of courses of chemotherapy required, duration required for the beta-hCG titre to return to normal, presence of metastatic disease, or the subsequent development of drug resistance or relapse. It was concluded that uterine arterial Doppler indices are significantly correlated with trophoblastic activity (beta-hCG titres) in malignant trophoblastic disease. However, their role in the prediction of subsequent tumour behaviour need to be assessed in larger series.

Chorionic Gonadotropin, beta Subunit, Human↗
PubMed1995

Pregnancy screening by uterine artery Doppler velocimetry--which criterion performs best?

OBJECTIVE: To test whether repeating Doppler studies of the uteroplacental circulation late in gestation will improve the test's power for predicting pregnancy-induced hypertension and fetal growth restriction (FGR), and whether analysis based on a combination of quantitative and qualitative assessments of the uterine arterial waveforms will yield better results than analysis based on either alone. METHODS: A total of 358 patients considered to be at medium risk for the development of pregnancy-induced hypertension and FGR were recruited. Continuous-wave Doppler studies of the uterine arteries were performed serially at 20, 28, and 36 weeks' gestation. The values of various Doppler indices in the prediction of subsequent pregnancy complications were tested at different gestations and different cutoff levels. The overall significance of performance of the Doppler indices was assessed by the Cohen kappa index, which tests the extent of agreement between the test and the "truth" over that by random chance agreement. RESULTS: A total of 974 examination results on 334 patients were available for analysis. We found that Doppler studies of the uterine arteries at 28 and 36 weeks were less useful than studies performed at 20 weeks. Serial studies at 20 and 28 weeks showed only marginal improvement when compared with a single study at 20 weeks. The best criteria were a mean resistance index (RI) of uterine arteries above the 90th percentile and the presence of diastolic notches in both uterine arteries at 20 weeks. Although the overall kappa index only suggested fair to good agreement beyond chance, the positive predictive value for subsequent complications was good: 57% for severe complications and 93% for any complications. CONCLUSION: Doppler studies of the uterine artery as a test for the subsequent development of pregnancy complications are best performed at 20 weeks with a combination of RI measurements and the assessment of the presence of diastolic notches.

Adult↗
PubMed1995

A comparison of colour Doppler sonography and the pelvic arteriogram in assessment of patients with gestational trophoblastic disease.

OBJECTIVE: To assess whether colour Doppler sonography can replace pelvic arteriography in the assessment of patients with gestational trophoblastic disease. DESIGN: An observational study in which patients with gestational trophoblastic disease were assessed with both pelvic arteriography and colour Doppler sonography. SETTING: The oncology unit of the Department of Obstetrics and Gynaecology, University of Hong Kong. The unit is the main tertiary referral centre for treatment of trophoblastic diseases in Hong Kong. SUBJECTS: Thirty-two consecutive women referred over an 18 month period. MAIN OUTCOME MEASURES: The site of localisation of the tumour and the size of the tumour as assessed by both methods. RESULTS: Eleven patients had a spontaneous fall of beta-hCG titres and did not have pelvic arteriograms performed. The remaining 21 patients had both investigations performed. Four patients had no evidence of abnormal pelvic vessels either on colour Doppler sonography or on pelvic arteriography. Their raised beta hCG titres were due to metastatic disease elsewhere. In the remaining patients the location of the tumour vessels was found to be concordant between the two methods of imaging. Measurements of the mean diameter of tumour bulk by the two methods also agreed well (r = 0.93, P < 0.0001). Pelvic arteriogram over-estimated the size of the tumour in two patients by 2 and 3 cm, respectively, but this did not alter the risk categories of the patients. CONCLUSION: Colour Doppler sonography is a noninvasive technique that can replace pelvic arteriography in the assessment of patients with trophoblastic diseases.

Angiography↗
PubMed1994

Umbilical artery Doppler velocimetry compared with fetal heart rate monitoring as a labor admission test.

A total of 155 patients admitted in early labor to the delivery unit of the University of Hong Kong were recruited into a study comparing the value of umbilical artery Doppler velocimetry and fetal heart rate (FHR) monitoring in early labor as an admission test. FHR monitoring for 30 min was recorded on admission, and umbilical A/B ratio was simultaneously performed. The FHR tracing was scored according to the Lyons score by a third independent observer after delivery. Outcome variables studied included small for gestational age (SGA), intrapartum FHR abnormalities, operative deliveries for fetal distress, umbilical cord pH, Apgar scores, admission into the special care baby unit, and a combination of the variables. It was found that at cut-off values of Lyons score < 7 and umbilical A/B ratio > 2.6 at term, about 19% of cases were abnormal for either tests, with only a few cases of overlap. Umbilical A/B ratio was found to be significantly correlated with SGA. The sensitivity and positive predictive values were, however, low. Both tests were relatively poor predictors for most of the outcome variables studied. Interestingly, FHR monitoring did not seem to have any advantage over Doppler velocimetry as a labor admission test. Further larger scale studies to evaluate their usefulness in medium and low risk populations are indicated.

Apgar Score↗
PubMed1994

Limitations of transvaginal sonography and color Doppler imaging in the differentiation of endometrial carcinoma from benign lesions.

We conducted this study to test the hypothesis that transvaginal ultrasonography and color Doppler imaging of the uterine arteries are complementary methods in the assessment of patients with postmenopausal bleeding. Sixty-seven patients were studied. Seventeen suffered from endometrial carcinoma, 12 from benign endometrial lesions (six polyp, six hyperplasia) and 38 had no organic pathology. Transvaginal ultrasonography was found to be superior to CDI in the detection of pathologic conditions of the endometrium, but neither method can distinguish benign lesions from their malignant counterparts. CDI does not give additional information over that obtained by transvaginal ultrasonography in the assessment of patients with postmenopausal bleeding, and the limitations of both methods in the differentiation of endometrial carcinoma from benign lesions need to be recognized.

Arteries↗
PubMed1993

Shared antenatal care between family health services and hospital (consultant) services for low risk women.

Four thousand four hundred and seventy-two patients were recruited into a project to test the efficacy of a Shared Care System in the management of low risk antenatal patients. The patients were scored according to a simple point scoring system. Three thousand three hundred and fourty-seven (74.8%) were scored as low risk. Fifty point two percent (1,682) of these low risk patients received the conventional system of care and acted as controls; while 49.8% (1,665) received shared care, where they were seen jointly by midwives, general doctors and hospital specialists. It was found that with the use of shared care, there was a significant decrease in workload to the hospital specialty clinics. Not only was the antenatal diagnostic rate of intrauterine growth retardation (IUGR) significantly improved, but the mean gestations at which IUGR, malpresentations, and pregnancy induced hypertension were diagnosed were also significantly earlier. The number of antenatal cardiotocographs performed, as well as the number of hospital admissions and mean duration of stay were decreased in the study group. The overall cost savings to the hospital was calculated if the shared care system was generally adopted.

Adolescent↗
PubMed1991

A comparative study of continuous- and pulsed-wave Doppler velocimetry in fetal and uteroplacental circulation.

Continuous-wave and pulsed-wave Doppler ultrasonography are the two common methods used to study the fetal and uteroplacental circulation. We used both methods in the same patient population in three different gestations and in various fetal and uteroplacental vessels to compare the results from both machines. Thirty-one normal patients were studied at 20, 28, and 36 weeks gestation. The results showed significant correlation with no statistically significant differences between the two types of machines for the peak systolic/end-diastolic ratios and resistance index for the umbilical artery and uterine arteries. Significant differences, however, were demonstrated when the arcuate artery was studied, or when the pulsatility index was used for comparison. We therefore conclude that when different machines are used for study, comparison of the results is only valid for selected vessels and indices. Results for arcuate arteries and pulsatility index should be compared with caution.

Blood Flow Velocity↗
PubMed1990

Human papillomavirus infection in the cervix of pregnant females in Hong Kong.

Routine cytological examination and HPV-DNA probing were performed on cervical cells obtained from 215 pregnant Chinese females. The procedure utilized the specific binding of a mixture of complementary [32P]-labelled RNA probes to membrane-bound target HPV DNA types 6, 11, 16, 18, 31, 33 and 35. Positive results for HPV-DNA were obtained in 11/215 (5%) of the cases. The cervical smears were routinely processed and in 3/215 (1.5%) cases a cytological diagnosis of wart virus infection was made. All three were included in the 11 probe-positive cases. Using similar molecular biological techniques, pregnant Western females have an incidence of HPV infection of the cervix which is up to five times that of the present series. This is an unexpected finding in view of the fact that the incidence of cervical cancer is higher in Chinese women than American women.

Female↗
PubMedDate not supplied

Transperineal versus transvaginal color Doppler imaging of the uterine circulation.

Transperineal sonography has been described as being useful in assessing patients in special clinical situations such as posterior placenta previa, preterm labor, stress incontinence, and vaginal atresia. We explored the feasibility of this approach in assessing the uterine circulation in 54 subjects, of whom 36 were postmenopausal. We found that visualization of the uterine artery by the transperineal approach was satisfactory in most patients. The uterine arterial Doppler indices obtained from this approach were compared with those obtained by the transvaginal route. Highly significant correlations were found (correlation coefficient tau for pulsatility index = 0.74, p < 0.0001). No significant differences in results between the two approaches were detected using the Wilcoxon Matched-Pairs Signed-Rank test. We conclude that transperineal Doppler studies of the uterine circulation are possible and may be useful in certain patient groups.

Adult↗
PubMedDate not supplied

Preterm birth unrelated to maternal height in Asian women with singleton gestations.

OBJECTIVE: To determine whether maternal height has a significant effect on the length of gestation or the incidence of preterm birth in Asian women with singleton gestations. METHODS: We retrospectively studied a cohort of consecutive adult Asian women with singleton gestations who delivered in a 2-year period, to determine the relationship between maternal height, expressed in quartiles, and the mean gestational age and incidence of preterm birth. RESULTS: Of the 9819 deliveries during that period, 449 were excluded from analysis because of multiple gestation, maternal age less than 20 years, or incomplete data because of no antenatal care in our hospital. The 25th, 50th, and 75th percentile values of maternal height were 152, 156, and 160 cm, respectively. Significant differences were found in the maternal age, weight and body mass index (BMI), birth weight, and birth weight as a percentage of maternal weight, among the four quartiles, but the trend for age, BMI, and birth weight percentage was opposite to that of maternal weight and birth weight. However, there was no significant difference in the mean gestational age or incidence of preterm birth at less than 28, 28-31, or 32-36 weeks' gestation. There was no difference in the incidence of pregnancies beyond 41 weeks' gestation. CONCLUSION: Maternal stature does not have a significant influence on the mean gestational age or incidence of preterm birth in adult Asian women with singleton gestations.

Adult↗