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Biomedical subjects

S Arulkumaran

Publications and source records attributed to S Arulkumaran.

At least 127 records · Page 7Linked to original sources
PubMed1993

Induction of labour: does internal tocography result in better obstetric outcome than external tocography.

A prospective randomized study was undertaken to evaluate the benefit of intrauterine catheters in induced labour. Two hundred and thirty nine women who had induced labour were studied. The patients in one group had intrauterine catheters inserted and oxytocin was titrated to achieve the 75th percentile of uterine activity observed in spontaneous normal labour according to parity. Contractions were assessed by external tocography in the other group and oxytocin was titrated to achieve 6 to 7 contractions per 15 minutes each lasting > 40 seconds. Mean maximum dose of oxytocin, mode of delivery, Apgar score < 7 at 5 minutes, cord arterial blood pH < 7.15 and admission to neonatal intensive care unit did not differ significantly in the 2 groups. In conclusion, women who had intrauterine catheters did not have a shorter duration of labour, lower dose of oxytocin, fewer operative deliveries or fewer babies in poor condition at birth compared with those who had external tocography in induced labour.

Adult↗
PubMed1992

A case report: vesico-rectal fistula with ano-urethral atresia.

Vesico-rectal fistula is a rare congenital abnormality causing severe early second trimester oligohydramnios. Prenatal diagnosis of such a case is reported here. Ultrasound diagnosis could be aided by transabdominal amnio-infusion and, if necessary, fetal intraperitoneal saline installation. In a karyotypically normal fetus with normal somatic growth, demonstration of normal fetal kidneys together with a functioning urinary bladder, in presence of severe oligohydramnios, is very suggestive of the diagnosis. Since pulmonary hypoplasia is the major cause of neonatal mortality in these cases, restoration of normal amniotic fluid volume by serial amnio-infusion was attempted. Although amnio-infusion is an important diagnostic aid in the evaluation of severe midtrimester oligohydramnios, the role of multiple therapeutic amnio-infusion in improving lung growth remains to be evaluated.

Abnormalities, Multiple↗
PubMed1992

Fetal acidaemia, the cardiotocograph and the T/QRS ratio of the fetal ECG in labour.

OBJECTIVE: To relate the T/QRS ratio of the fetal electrocardiogram (ECG) to the cardiotocogram (CTG) and fetal pH during labour. DESIGN: Prospective data collection from selected monitored labours. SETTING: A postgraduate teaching hospital delivery suite. SUBJECTS: 113 women in labour at term. MAIN OUTCOME MEASURES: Correlation of fetal T/QRS ratio values with pH values at the time of fetal blood sampling and at birth (umbilical artery blood). Comparison of the predictive values of raised T/QRS ratio and a pathological CTG for fetal acidemia. RESULTS: Complete data sufficient for analysis was available for 51 fetal scalp blood samples and 93 umbilical artery pH samples. The median (range) of T/QRS ratio values before birth of 88 babies not requiring admission to the neonatal unit was 0.13 (0.00-0.32) with a 97.5th centile value of 0.28. T/QRS ratios did not correlate with fetal scalp pH values. Fetal scalp acidaemia (pH less than 7.20) was detected with rates of 50 and 13% respectively by a pathological CTG and by a T/QRS ratio above 0.28, the positive predictive values being 40% and 50%, respectively. There was a significant correlation between increasing T/QRS ratio and falling pH. Detection rates (sensitivities) for umbilical artery acidaemia (pH less than 7.12) were 76% and 29% whereas positive predictive values were 38% and 71% respectively for a pathological CTG and a T/QRS ratio above 0.28. CONCLUSION: A raised T/QRS ratio (greater than 0.28) had a considerably lower detection rate for fetal acidaemia during labour than a pathological CTG.

Acidosis↗
PubMed1992

In-utero sound levels when vibroacoustic stimulation is applied to the maternal abdomen: an assessment of the possibility of cochlea damage in the fetus.

OBJECTIVE: To measure sound pressure level in utero while a vibro acoustic stimulator is applied to maternal abdomen and to calculate whether the estimated effect on fetal cochlea cilia vibration would be hazardous. DESIGN: Prospective descriptive study. SETTING: Labour ward, National University Hospital, Singapore. SUBJECTS: Eight women undergoing induction of labour. INTERVENTION: A hydrophone was introduced via the cervix into the uterus and placed under ultrasound guidance near the fetal ear. Sound pressure was recorded when a vibroacoustic stimulator was applied directly to the maternal abdomen and also when separated by 2 cm of air. MAIN OUTCOME MEASURES: Sound pressure levels in utero. RESULTS: The sound level recorded from the vibrator diaphragm in air was 107 dB at 2 cm and 74 dB at 1 m. The mean sound pressure level in utero was 90.7 dB (range 75-96 dB) when the vibrator was in contact with the abdominal wall and 80.1 dB (range 70-88 dB) when separated by 2 cm of air. CONCLUSIONS: Analysis of factors affecting displacement of cochlear sensing cilia in utero show that, for equal sound pressures, sound intensity and sound vibration are about 4000 times less in amniotic fluid, compared to that produced in air. Further protection is provided by viscous and hydrodynamic features of the ear. The estimated effect on cilia vibration by the mean sound pressure registered in utero, about 90 dB, corresponds to that produced postnatally by an airborne sound registering about 40 dB, which would not be hazardous.

Cochlea↗
PubMed1992

The accuracy of catheter-tip pressure transducers for the measurement of intrauterine pressure in labour.

OBJECTIVE: To assess the reliability of intrauterine pressure measurements in labour with transducer tipped catheters. DESIGN: Prospective clinical study. SETTING: Delivery ward, National University Hospital, Singapore. SUBJECTS: 20 women admitted in early labour were randomly allocated to two groups. INTERVENTIONS: Women in the first group had two catheters that had been tied together introduced transcervically into the same amniotic fluid pocket. The second group had two catheters introduced in different directions so that each catheter tip was in a different pocket of amniotic fluid. MAIN OUTCOME MEASURE: The contraction to contraction pressure difference recorded by the two catheters in the same uterus. In addition, the cumulative uterine active pressure generated by one catheter was compared with that of the other. RESULTS: There were differences in peak pressure of up to 4-5.3 kPa (30-40 mmHg) during some contractions. The difference in pressure recordings between the two catheters could not be explained by effects of loculation of amniotic fluid. However, the pressures recorded were not systematically higher in one catheter than in the other. Cumulative uterine activity was very similar when assessed by each catheter in the same uterus. CONCLUSION: Intrauterine pressure measurements using transducer tipped catheters provide reliable information on the cumulative pressure wherever the catheter tip was sited in the uterus, but there are variations in pressures recorded during individual contractions.

Catheterization↗
PubMed1992

Amniocentesis and its complications.

This study was conducted in order to evaluate whether the performance of an experienced operator had any significant influence in reducing the incidence of complications in amniocentesis; 1,459 women had amniocentesis performed under ultrasound guidance; 1,324 were performed by experienced operators and 135 cases by less experienced operators. Complications like fetal loss, blood-stained amniotic fluid, culture failure, multiple needle puncture, leaking liquor, fetal trauma and error in results were compared in the 2 groups. This study demonstrated that amniocentesis performed by an experienced operator decreased the various complications associated with amniocentesis.

Amniocentesis↗
PubMed1992

Symptoms and signs with scar rupture--value of uterine activity measurements.

To evaluate the symptoms and signs of scar rupture with special reference to intrauterine pressure measurement a retrospective analysis of labour records of those women who had trial of labour with a previous Caesarean scar in the National University Hospital over a period of 6 years (1985-1990) was carried out. Known symptoms and signs associated with scar rupture, cardiotocographic tracings and fetal and maternal outcome in these patients were studied. Of the 1,018 women with previous Caesarean scar (4.2% of our pregnant population at term) 722 (70.9%) had trial of labour; 70% delivered vaginally. There were 4 (0.55%) incomplete and 5 (0.69%) complete scar ruptures. All 9 women had an oxytocin infusion; 3 were diagnosed postdelivery (all 3 had complete ruptures); 3 of the 6 who had rupture prior to delivery had sudden reduction in uterine activity, 1 had scar pain and prolonged bradycardia and 2 had no symptoms or signs. Continuous cardiotocography with intrauterine pressure measurements may help to identify scar rupture early and may be of value especially in those who have an oxytocin infusion.

Apgar Score↗
PubMed1992

Vibro-acoustic stimulation in high-risk pregnancies; maternal perception of fetal movements, fetal heart rate and fetal outcome.

Maternal perception of fetal movement in response to vibro-acoustic stimulation was compared with antenatal fetal heart rate monitoring as a test of fetal well-being in a population of gravidae with high-risk pregnancies (n = 517), admitted to the high-risk ward at Danderyd Hospital, Karolinska Institutet; a total of 2,015 tests were performed. The sensitivity and the specificity of the test compared to the fetal heart rate tracing was 81% and 89% respectively. If the test was performed within 24 hours of delivery, its predictive value for fetal asphyxia (i.e. a 5-minute Apgar score < 7) was 14% (7/49). Ten per cent of the patients felt no fetal movement in response to stimulation (irrespective of gestational age). In five cases where fetal heart rate tracings were pathological, stimulation nonetheless produced fetal movement and fetal outcome was good. Pathological heart rate tracings and no fetal movement in response to stimulation were present in 30 cases (out of 251 with no fetal movements at stimulation), in seven of which the infants had 5-minute Apgar scores < 7. Although many patients underwent repeated vibro-acoustic stimulation, there was no evidence of fetal habituation to the test. On 24 occasions (i.e. 1.2%), the patient denied vibro-acoustic stimulation, mostly because of previous discomfort due to vigorous fetal response. Where resources are limited, maternal perception of fetal movements in response to vibro-acoustic stimulation might be a useful alternative for preliminary screening of high-risk pregnancies.

Acoustic Stimulation↗
PubMed1992

Vibro-acoustic stimulation does not alter the duration of high and low fetal heart rate variability episodes.

To study the effect of vibro-acoustic stimulation on high and low fetal heart rate (FHR) variability episodes. Prospective control study, in 21 high risk pregnancies between 32 to 39 weeks gestation. FHR pattern was recorded with cardiotocograph (CTG). After 5 min low FHR variability a vibro-acoustic stimulator was activated in contact with or above the maternal abdomen (sham) on a random basis on two consecutive days, and CTG was continued to obtain a complete high and low FHR variability cycle. Complete high and low FHR variability cycles were obtained in 12 patients with mean recording time of 129.5 minutes (range 69-185 min). The mean baseline FHR increased by 32.5 +/- 9.4 bpm after contact vibro-acoustic stimulation, but remained unchanged after sham stimulation. Mean duration of high FHR variability was 56.6 +/- 32.9 min and 47.3 +/- 23.7 min, respectively, and mean duration of the consecutive low FHR variability episode was similar after contact and sham stimulation. The complete cycles were 71.1 +/- 34.7 min and 66.2 +/- 21.2 min, respectively. Vibro-acoustic stimulation induced an abrupt change from low to high FHR variability, but the complete cycle of high and low FHR variability was not altered, when compared with the corresponding cycle following sham stimulation on the same fetus.

Acoustic Stimulation↗
PubMed1992

Computerised cardiotocography following vibro-acoustic stimulation.

To study the effect of vibro-acoustic stimulation (VAS) to the mean fetal heart rate (FHR), period of high and low FHR variation, overall variation (msec and bpm) and short term variation (msec). In a prospective study 17 pregnant women between 34-42 weeks gestation admitted to antenatal ward for obstetric complications two 60 min FHR recording was carried out with an interval of 30 min in between recordings. On a random basis the fetus was stimulated by a vibro-acoustic stimulator for 5 sec at the beginning of one of the two 60 min FHR recordings. Automated analysis of the FHR, tocodynamometry, and maternal perception of fetal movements was done by a commercially available computerized programme (System 8000). It was possible to obtain the two 60 min recordings with signal loss of < 10% in 12 out of 17 patients. No changes were observed when the FHR parameters for 60 min after VAS was compared with the control period. When analyzed in segments of 0 to 10, 11 to 20, 20 to 40 and 41 to 60 min the mean baseline FHR was significantly higher after VAS during the first 10 minutes compared with any 10 or 20 min segment of the control period or any such segments 10 min after VAS. Concomitantly the overall variation and short-term variation was significantly lower during the first 10 minutes following VAS (p < 0.05) compared with the parameters in the corresponding periods during the control period.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1992

Obstetric admissions to the intensive care unit--a retrospective review.

A five-year retrospective study of obstetric admissions to the Surgical Intensive Care Unit (SICU) in the National University Hospital, Singapore was carried out with the aim of determining the incidence, causes and outcome of these admissions. Most of the patients were admitted following emergency caesarean sections. Obstetric complications was the reason for admission in 56.8% with hypertensive disease of pregnancy being the major cause and haemorrhage accounting for the rest. Anaesthetic complications accounted for 21.6% of admissions and these included difficult intubation, aspiration pneumonitis, cardiac arrhythmias and respiratory depression. Medical complications due to cardiovascular disease, autoimmune disease and malignancy also accounted for 21.6% of admissions. Only 37 out of 16264 deliveries (0.22%) required intensive care support. The median of duration of stay was one day.

Adult↗
PubMed1992

Umbilical artery blood flow in intra-uterine growth retarded fetuses and fetal outcome: a study of 102 cases.

The 102 fetuses diagnosed by ultrasound to be asymmetrically growth-retarded had blood flow velocity waveforms of the umbilical artery studied. Sixty-two cases had normal blood flow, 28 had abnormal blood flow but with present end-diastolic flow, 8 had absent end-diastolic flow, and 4 had reversal of end-diastolic flow. Comparison was made between the blood flow status and other biophysical methods of antenatal surveillance and perinatal outcome. There is a strong correlation between abnormal blood flow and abnormalities detected by other biophysical methods of antenatal surveillance. Our study shows that fetuses with severe blood flow impairment tend to be more severely growth-retarded and to be delivered earlier. Our results also show abnormal blood flow to be associated with a poor perinatal outcome. Those fetuses with severe impairment of blood flow suffered a high incidence of operative delivery for fetal distress, acidosis at birth, perinatal mortality and morbidity. The association between abnormal blood flow and the 5-minute Apgar score is significant only in those with the severest impairment of blood flow. Our results are in close agreement with similar studies recorded in the literature.

Apgar Score↗
PubMed1991

Fetal heart rate response to vibroacoustic stimulation during low and high heart rate variability episodes in late pregnancy.

In 52 women in late pregnancy, the mean durations of transient fetal tachycardia after vibroacoustic stimulation during low fetal heart rate variability (4.8 minutes) and high fetal heart rate variability (6.3 minutes) were similar. The fetal heart rate continued with high variability in all cases, suggesting that the fetus did not return to its prestimulation state after vibroacoustic stimulation during quiescence. In 10 women, the duration of high variability after vibroacoustic stimulation during low fetal heart rate variability was significantly shorter (mean, 22 minutes) than the preceding (mean, 36 minutes) or subsequent (mean, 43 minutes) high-variability components of complete rest activity cycles. In another 10 women, the duration of high variability after vibroacoustic stimulation during high fetal heart rate variability was similar to preceding and subsequent high-variability episodes. In these 20 women, the next complete rest-activity cycle after vibroacoustic stimulation was not different in duration to the complete cycle recorded on the previous day.

Acoustic Stimulation↗
PubMed1991

Uterine activity in dysfunctional labour and target uterine activity to be aimed with oxytocin titration.

Uterine activity was quantified using a transducer tipped intrauterine catheter in 75 nulliparous women with dysfunctional labour. The active contraction area profiles in these women were below the median levels reported for those who had normal progress of labour from our institution. When uterine activity was augmented with oxytocin, 90.7% progressed in labour and delivered vaginally. Six patients (8%) showed poor progress despite good uterine activity and had to be delivered by caesarean section (CS) for failure to progress and signs of cephalopelvic disproportion. The pre- and post-augmentation uterine activity were similar in those who delivered vaginally or by CS and was not helpful in identifying those who had cephalopelvic disproportion. Of the 75 women who had slow progress of labour, 50 had a contraction frequency of less than 1 in 3 min whilst 25 had a minimum frequency of 1 in 3 min or more. All except one in the latter group delivered vaginally when oxytocin was titrated to achieve a contraction frequency of 1 in 2 to 2 1/2 min which were clinically judged to be adequate based on a duration greater than 40 sec. Oxytocin should be titrated to achieve a target contraction frequency of 1 in 2 to 2 1/2 min lasting greater than 40 sec to achieve good obstetric outcome in those with dysfunctional labour.

Adult↗
PubMed1991

A comparison between fibreoptic and catheter-tip bridge strain gauge transducers for measurement of intrauterine pressure in labour.

A new fibreoptic pressure transducer was used to measure uterine activity in labour, and the results were compared with those obtained with the catheter-tip bridge strain gauge transducer. Readings were obtained from 8 patients in spontaneous labour, and a total of 565 contractions were analysed. When all contractions were analysed the coefficient of variation ranged from 11.24 to 42.74. In 2 patients with vast difference in pressure readings one of the catheters had slipped into the lower uterine segment, when these 2 cases were not considered the coefficient of variation ranged from 11.24 to 21.18. Even in the others there were transient periods lasting 5 to 15 minutes when the pressure difference was greater than 10 mmHg between the 2 catheters. When they were excluded from analysis, along with the 2 cases where one of the catheters was displaced, the coefficient of variation ranged from 9.30 to 16.05. The fibreoptic pressure transducer appears to be a safe, convenient and fairly accurate means of assessing uterine activity. But one must be aware that a catheter giving low readings compared with the initial period soon after insertion may be due to displacement of the transducer tip to the uterine lower segment.

Evaluation Studies as Topic↗
PubMed1991

Direct antenatal fetal electrocardiographic waveform analysis.

OBJECTIVE: To establish a technique for continuous recording of fetal electrocardiograms (ECG) for waveform analysis in the antenatal period. DESIGN: Prospective descriptive study. SETTING: Fetal Medicine Unit, Queen Charlotte's and Chelsea Hospital, London, UK. SUBJECTS: 35 women undergoing antenatal fetal blood sampling. INTERVENTIONS: One end of an insulated Cooner wire was attached to the sampling needle and the other to an automatic ECG-ST waveform analyser. MAIN OUTCOME MEASURES: ECG signals were obtained with the needle in the fetal abdomen during intrahepatic umbilical vein sampling or aspiration of fetal urine but not when it was in the placental cord insertion. RESULTS: Continuous recording of the T/QRS ratio was obtained for a total of 166 min (mean 8 min per fetus) from 20 fetuses (16-38 weeks). The T/QRS ratio had no correlation with gestational age and fetal heart rate and was similar to values described in term fetuses in labour. CONCLUSIONS: The technique described can identify ST waveform changes and may be useful in the investigation of fetal cardiac arrhythmias, intrauterine growth retardation and in monitoring fetal transfusions.

Electrocardiography↗