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Biomedical subjects

S Arulkumaran

Publications and source records attributed to S Arulkumaran.

At least 145 records · Page 8Linked to original sources
PubMed1991

Oxytocin titration for induction of labour: a prospective randomized study of 15 versus 30 minute dose increment schedules.

Two hundred and twenty four patients admitted for induction of labour were randomized into 2 groups. The oxytocin dose was escalated every 15 minutes in the first group whilst for the second group the dose was increased every 30 minutes till optimal uterine activity was achieved. There was no significant difference in the mean maximum dose of oxytocin and length of labour in the 2 groups studied. Transient reduction of the dose of oxytocin was needed in 20.5% of patients in the '15 minute' group and 17.0% of cases in the '30 minute' group because of uterine hyperstimulation or fetal heart rate (FHR) changes; this difference was not statistically significant. The incidence of operative deliveries were similar in the 2 groups. The neonatal 1 and 5 minute Apgar scores, cord arterial blood pH, incidence of assisted ventilation and admission to the neonatal intensive care unit were similar in the 2 groups. The 15 minute schedule does not offer any advantage over the 30 minute escalation schedule for induction of labour. Hyperstimulation and FHR changes are a possibility with any regimen and close monitoring of FHR and uterine activity is advisable with the use of oxytocin.

Apgar Score↗
PubMed1991

Induction of labour in nulliparas with poor cervical score: oxytocin or prostaglandin vaginal pessaries?

In a previous study nulliparas with poor cervical score (less than 5 out of 10) had a 43.5% Caesarean section (CS) rate of which 55% were for failed induction when labour was induced by artificial rupture of membranes and oxytocin infusion. In this study induction of labour by 2 doses of 3 mg prostaglandin E2 (PGE2) vaginal pessaries, 4 hours apart, and if necessary by artificial rupture of membranes and oxytocin infusion 24 hours later, resulted in a CS rate of 23.7% of which 38.9% were for failed induction. The latter regimen resulted in a significantly lower CS rate compared with labour induced by oxytocin infusion and rupture of membranes without the use of prostaglandins (p less than 0.001). In the prostaglandin group 53.3% were established in labour within 24 hours of inserting the pessary and in these patients the CS rate was 18.5%. In those who did not start labour and needed rupture of membranes and oxytocin infusion 24 hours after the first pessary, 34 (47.9%) had a good cervical score (greater than or equal to 6 out of 10) and 37 (52.1%) had a poor cervical score (less than or equal to 5 out of 10) at the time of amniotomy. The CS rates in these groups were 8.8% and 48.6% respectively (p less than 0.001). In nulliparas with poor cervical score induction is better performed with vaginal prostaglandin pessaries in order to reduce the high CS rate associated with artificial rupture of membranes and oxytocin infusion.

Adult↗
PubMed1991

Can terbutaline be used as a nebuliser instead of intravenous injection for inhibition of uterine activity?

Terbutaline, a betamimetic drug, is used as bolus of 0.25 mg intravenously to inhibit uterine activity when encountered with uterine hyperstimulation and associated fetal heart rate changes. The effect of terbutaline used as a nebuliser in 1- and 2-mg doses on uterine activity in labor was investigated. It did not show any significant inhibition of the uterine activity in spontaneous term labor. Although convenient and easy to administer especially in an emergency, 1 or 2 mg terbutaline used in the form of nebuliser did not give the desired effect like 0.25 mg of terbutaline given intravenously for inhibition of uterine activity in term labor.

Administration, Intranasal↗
PubMed1991

Reliability of intrauterine pressure measurements.

The reliability of intrauterine pressure measurements was studied by placing two catheters in the same uterus in women in labor. Nineteen parturients were studied, five with two Intran I catheters in different pockets of amniotic fluid, five with two Intran II catheters in different pockets, and nine with two Intran II catheters in the same pocket of amniotic fluid. Among 1429 contractions studied, the catheters showed differences of pressure of less than 5 mmHg in 86% of contractions and of less than 10 mmHg in 94%. When cumulative uterine activity was calculated for each labor, the difference in the total active pressures shown by the two catheters was less than 5% in 17 cases and 5% or more in two cases. These differences are unlikely to be of any importance in the management of labor.

Amniotic Fluid↗
PubMed1991

Vibroacoustic stimulation and intrauterine sound pressure levels.

The sound pressure level in amniotic fluid generated by vibroacoustic stimulation, assessed with a hydrophone placed close to the fetal head, was studied in 16 subjects. The mean recorded sound pressure level was 115 dB and the highest level was 129 dB. The range of the background noise was 63.5-80.5 dB. There was no obvious relationship between the distance from the stimulator to the hydrophone and the intrauterine sound pressure level. Although sound pressure levels are high, they are probably reduced before reaching the cochlea of the fetus because of the surrounding amniotic fluid and the fluid in the middle ear.

Acoustic Stimulation↗
PubMed1991

Does prostaglandin confer significant advantage over oxytocin infusion for nulliparas with pre-labor rupture of membranes at term?

Ninety-four nulliparous women with a poor cervical score (less than 6) who had premature rupture of membranes at term were randomized by sealed envelope into two groups. One group received immediate stimulation of labor with oxytocin infusion. The second group received two prostaglandin E2 (PGE2) 3-mg pessaries 4 hours apart, followed by oxytocin infusion, if necessary. The interval between initiation of therapy to onset of labor was significantly longer in the PG group, but the length of labor was similar in both groups. The maximum dose of oxytocin needed was significantly higher in the oxytocin group. The cesarean delivery rate in the oxytocin group was 14.9%, compared with 19.1% in the PG group (not significantly different). All seven cesareans in the oxytocin group and seven of nine in the PG group were for failed stimulation of labor. Neonatal Apgar scores at 1 and 5 minutes and admission to the neonatal intensive care unit were similar in the two groups. The incidence of maternal and neonatal infection was small and was not different in the two groups. The use of PGE2 3-mg pessaries 4 hours apart, followed by oxytocin infusion if necessary, did not confer any benefit over the use of intravenous oxytocin in obstetric or neonatal outcome when both agents were started a few hours after admission.

Administration, Intravaginal↗
PubMed1991

Pharmacology of parturition.

Uterine contractions in labour are influenced by endogenous substances such as oestrogens, progesterone, cortisol, oxytocin, prostaglandins, relaxin, adrenergic and cholinergic secretions, cyclic nucleotides and calcium ions. Effects of progesterone and oestrogens are complimentary as well as antagonistic to each other. They regulate formation of gap junctions, influx of calcium ions, synthesis of oxytocin, adrenergic receptors and of prostaglandins and cyclic nucleotides. Cortisol shares a role in a more complex endocrine trigger but is ineffective alone in the initiation of human labour. Adrenaline inhibits and noradrenaline promotes uterine contractions. Cholinergic stimulation increases cyclic GMP promoting uterine contractions. Calcium ions play a key role in uterine contractility. Oxytocin, prostaglandins E and F are powerful stimulants of uterine contractions. Prostaglandins stimulate pregnant uterus from early gestation unlike oxytocin which has little effect in the first and second trimester. They are extensively used for initiating labour and to arrest intractable atonic postpartum haemorrhage. In experiments and in vivo, their effects are modulated by other hormones and substances. With discovery of new drugs, knowledge of how they act on the uterus becomes important. The pharmacology of parturition that may help to understand the interaction of various agents on the pregnant uterus has been discussed.

Calcium↗
PubMed1991

No evidence of hearing loss due to fetal acoustic stimulation test.

The fetal acoustic stimulation test is used increasingly for fetal assessment. To evaluate the possibility of acoustic trauma, 465 children who had been exposed to vibroacoustic stimulation in utero were screened at 4 years of age for high-frequency hearing loss. A hand-held audiometer with test tones at 25 dB for 1000 and 4000 Hz was used because responses at this level indicate hearing within normal limits for middle and high frequencies. Thirty-one children failed the test. Failure to respond was followed by inspection of the ear canal for wax, tympanometry, and reflex measurement to assess the tympanic membrane, middle ear, and eustachian tube. Hearing was retested across the full frequency range using conventional audiometric technique, and referral for otolaryngologic examination and treatment was made if necessary. The causes of hearing loss were impacted wax in 12, current or recent upper respiratory tract infection with eustachian tube dysfunction and middle ear effusion in 15, and unresolved middle ear effusion after treatment with antibiotics for otitis media in two. Profound bilateral sensorineural hearing loss of unknown origin was found in one and slight bilateral gently sloping hearing loss in another. Retesting of all children with conductive hearing loss indicated that hearing had returned to normal after treatment. None of the children showed evidence of hearing loss.

Acoustic Stimulation↗
PubMed1990

Fetal cystic hygromata: insights gained from fetal blood sampling.

Twelve second-trimester fetuses with cystic hygroma underwent fetal blood sampling for rapid karyotyping, haematologic evaluation, and blood gas analysis. An abnormal karyotype was found in seven cases: monosomy X in five, trisomy 21 in one, and trisomy 13 in the other. Eight of ten fetuses undergoing blood gas analysis showed hypoxaemia, five of which were growth-retarded. Nine pregnancies were terminated. Of the remaining three, only one fetus survived the perinatal period.

Blood Gas Analysis↗
PubMed1990

Effectiveness of transcutaneous electric nerve stimulator for pain relief in labour.

The effectiveness of transcutaneous electric nerve stimulation (TENS) for pain relief in labour was compared to inhalation analgesia consisting of 50% nitrous oxide and 50% oxygen (ENTONOX). In the first part of the study 101 patients in early labour were allocated to using TENS (Group A) or ENTONOX (Group B) for pain relief. Our results did not show any beneficial effect on pain relief in labour with the use of TENS over ENTONOX; 18.8% of patients in Group A went through labour without any further form of analgesia as opposed to 17.0% in Group B. In the second part of the study 20 nulliparous patients having induced labour were randomly allocated to use TENS (Group C) or ENTONOX (Group D) as the first modality of pain relief. A switchover was made when labour pains were no longer tolerable. The results showed that both TENS and ENTONOX could be used in early labour up to 5-6 cm cervical dilatation till the frequency of contractions was nearly 5 in 10 min or the first 3-4 hr from the time patients first requested pain relief in labour when frequency of contractions was nearly 4 in 10 min. TENS could be used in early labour for patients who wish to be ambulant and is as effective as ENTONOX. Either modality of pain relief was not adequate for pain relief throughout labour.

Adult↗
PubMed1990

Effects of isradipine, a new calcium antagonist, on maternal cardiovascular system and uterine activity in labour.

The effects of isradipine (a new calcium antagonist of the dihydropyridine type) on maternal blood pressure and heart rate, fetal heart rate, and uterine activity in labour were measured. Uterine activity was recorded by an intrauterine microtip transducer catheter connected to a fetal monitor. Isradipine was given as a slow injection in doses of 0.5 mg (10 women), 1 mg (11 women), and 1.5 mg (6 women). A reduction of systolic (6-16%) and diastolic (19-22%) blood pressure was seen, and concomitantly there was an increase in maternal (29-34%) and fetal (3-10%) heart rates. Reduction in uterine activity was not dose-related (maximum reduction 17%). Side effects (headache, palpitations) were minor and well tolerated. One women in the high-dose group had a shortlasting episode of hypotension. The results suggest that isradipine given as a bolus dose decreases blood pressure in pregnant women with little effects on uterine activity and fetal heart rate.

Adult↗
PubMed1990

Fetal ECG waveform analysis should improve fetal surveillance in labour.

Fetal heart rate (FHR) and fetal electrocardiogram (ECG) recordings were obtained from a scalp electrode with maternal thigh as reference and used for ST waveform analysis in 201 patients in labour. Nearly 45% had suspicious or abnormal FHR traces whilst only 27% had T/QRS ratio greater than 0.25 (mean +/- 2 SD). A normal T/QRS ratio identified 99.3% of fetuses with normal buffering capacity in cord artery blood. Of 13 infants with a cord artery blood pH less than 7.15, standard bicarbonate was less than 15.0 mmol/l in five who had an average T/QRS ratio less than 0.25 throughout labour. Of the eight with respiratory acidosis, five had an increase in T/QRS ratio greater than 0.25 for longer than 20 minutes prior to delivery, in two the ratio increased during the last few minutes and one had no change (pH 7.14). Persistent elevation of T/QRS in the first stage of labour identified those with decrease in buffer capacity in cord arterial blood (sensitivity of 94.1%). Acute hypoxia was recognized by the rapid rise in T/QRS. The specificity of T/QRS to identify fetuses at risk increased by combining the ST waveform analysis with FHR changes.

Electrocardiography↗
PubMed1990

Augmentation of labor: does internal tocography result in better obstetric outcome than external tocography?

Labor was augmented in 250 patients for slow progress. These women were randomized to have uterine contractions recorded by either an external tocotransducer or an intrauterine catheter. Oxytocin was titrated to achieve an optimal frequency of contractions of six to seven every 15 minutes in each group; additional information on active contraction area profiles was available for those patients who had an intrauterine catheter. There was no statistically significant difference between the groups in the length of the post-augmentation period. The mean maximum dose of oxytocin was 11.1 mU/minute in the external tocography group and 11.0 mU/minute in the internal tocography group. Evidence of uterine hyperstimulation requiring temporary reduction of the oxytocin dose occurred in 19 and 20.2% of the patients in the external and internal tocography groups, respectively. Cesarean delivery was necessary in 12.6 and 16.9% of patients in the external and internal tocography groups, respectively, which is a nonsignificant difference. The incidence of low Apgar scores in the neonates and admission to neonatal intensive care was similar in both groups. The incidence of poor Apgar scores was not different between those who had transient hyperstimulation and those who had no hyperstimulation. In the management of augmented labor, monitoring of uterine contractions by intrauterine pressure catheters did not confer any advantage over tocography by external transducers.

Apgar Score↗
PubMed1989

Preinduction cervical priming with PGE2 vaginal film in primigravidae--a randomised, double blind, placebo controlled study.

Previous reports with an 850 micrograms prostaglandin E2 film for cervical ripening before induction of labour in term pregnancy have been favourable. These studies however had no controls. The present study compares this PGE2 vaginal film with a nonmedicated similar vaginal film (placebo) for preinduction cervical ripening in primigravid women at term. A total of 69 women with modified Bishop's cervical scores 1-5 were assigned randomly to either the PGE2 group (33 women) or placebo group (36 women). Cervical score assessments were made at 12 and 24 hours after which labour was induced by amniotomy and oxytocin infusion. Although the cervical scores between placebo and PGE2 groups at 12 and 24 hours were not significantly different, the scores were marginally better with the prostaglandin film. Pregnancy outcome was satisfactory in both groups with no perinatal or maternal mortality and morbidity. The caesarean rate was 30.6% in the placebo group and 24.2% in the PGE2 group. This study emphasizes the need for a control group when studying the success of agents used for ripening the pregnant cervix at term.

Administration, Intravaginal↗
PubMed1989

Comparative study of a two dose schedule of PGE2 3 mg pessary and 1700 micrograms film for induction of labour in nulliparae with poor cervical score.

Efficacy of a two dose schedule of 3 mg pessary or 1700 micrograms film of PGE2 for induction of labour was compared in nulliparae with poor cervical score. Patient characteristics in the two groups (43 in 3 mg and 40 in 1700 micrograms group) were comparable in age, period of gestation, indications for induction of labour and in their initial cervical score. The number of patients who started labour with a two dose schedule 4 hours apart were similar in each group. The improvement of cervical score, length of labour, mode of delivery and the neonatal outcome were not different in the two groups. There was no advantage of using a film preparation over that in the form of a pessary and the use of 3 mg dose did not give significantly better results compared with the 1700 micrograms dose, in terms of obstetric or neonatal outcome.

Adult↗