PubMed Health⌕ Search

Biomedical subjects

M I Levene

Publications and source records attributed to M I Levene.

At least 19 recordsLinked to original sources
PubMed1992

Effect of morphine and pancuronium on the stress response in ventilated preterm infants.

Ninety-five premature newborns who had hyaline membrane disease and were struggling against the ventilator were randomised to one of three treatment groups: morphine (group M), pancuronium (group P) or morphine with pancuronium (group M+P). The dose of morphine was 50 micrograms/kg per h but was increased to 100 micrograms/kg per h in group M infants if they continued to struggle. The dosage of pancuronium was 100 micrograms/kg given as required to inhibit spontaneous respiration. Plasma catecholamine levels were measured on entry and at 24 h. Blood pressure and ventilatory requirements were determined on entry and at 6 h. The clinical outcome of the infants was documented. Group M infants (n = 29) showed a significant reduction in noradrenaline levels (median change -2.2 nmols/l (range -47.2 to +7.2 nmols/l), although seven were withdrawn from this group because of failure to settle. Group P (n = 28) and group M+P (n = 38) showed no significant change in noradrenaline levels. Comparison between the groups showed that group M infants had a significant reduction in noradrenaline levels compared with group P. The immediate effects of treatment on blood pressure and ventilatory requirements were similar in the three groups. The clinical outcome did not differ for any of the measured parameters. When adequate sedation is achieved, morphine may reduce the stress of newborn intensive care.

Blood Pressure↗
PubMed1992

Cerebral arterial and venous flow-velocity measurements in post-haemorrhagic ventricular dilatation and hydrocephalus.

Simultaneous anterior cerebral artery (ACA) and internal cerebral vein (ICV) flow-velocities were measured in 18 babies with post-haemorrhagic ventricular dilatation (PHVD) and hydrocephalus (PHH). Compared with a control group matched for post-conceptional age, the resistance index of the ACA was increased. This was shown to occur at an early stage of PHVD in a longitudinal study of seven of the babies. There were no significant changes in ACA or ICV time-averaged velocities. Eight babies with PHH had ventricular taps on 18 occasions to relieve raised intracranial pressure. There was a significant decrease in the resistance index of the ACA, accompanied by an increase in the ACA time-averaged velocity, but no change in the ICV time-averaged velocity.

Blood Flow Velocity↗
PubMed1992

Higher multiple births and the modern management of infertility in Britain. The British Association of Perinatal Medicine.

OBJECTIVE: To assess prospectively the number of triplet and higher multiple births born in 1989 and their methods of conception. To assess obstetric factors and the effect of these pregnancies on neonatal medical services. DESIGN: All consultant paediatricians received a monthly card asking whether they had been involved in the management of triplet and higher multiple pregnancies delivered after 22 weeks gestation. Detailed questionnaire sent to those giving a positive response. SETTING: British Paediatric Surveillance Unit organized mailings to all members of the British Paediatric Association working in the British Isles. SUBJECTS: 156 pregnancies resulting in 482 babies (143 triplets, 12 quadruplets and 1 quintuplet set). These data were compared to nationally collected OPCS data. MAIN OUTCOME MEASURES: Method of conception, obstetric performance, neonatal outcome. RESULTS: Of the 156 pregnancies, 47 (31%) were conceived naturally, 52 (34%) had ovarian stimulation (usually with clomiphene or gonadotrophins) 37 (24%) had IVF and 17 (11%) GIFT. All quadruplet and quintuplet pregnancies were established after assisted reproduction. Mothers who had had IVF were significantly older than those who had ovulation induction alone. The median gestation at birth was 33 weeks. Overall 181 (40%) of the babies required intensive care for a median duration of 5 days. The perinatal mortality of the triplets alone and quads and quins together was 70 and 104 per 1000 respectively. CONCLUSIONS: Assisted reproduction is the major cause of triplets and higher multiple births and ovarian stimulation is the single most important technique currently in use. These babies are very likely to be born pre term and make considerable demands on neonatal intensive care facilities.

Adult↗
PubMed1992

Measurement of plasma volume in neonates.

There is no reliable and safe method for measuring plasma volume in ill newborn infants. We describe an adaptation of the dye dilution technique using indocyanine green as the plasma label, which can be used in the sickest and smallest of infants with the minimum of disturbance. To avoid the need to take large volumes of blood from the infant, samples were diluted 1:1 with distilled water and pooled adult sera was used to construct the dye dilution standard curves. Eighteen preterm and fullterm infants were studied on 30 occasions. The measured plasma volume ranged between 21.4 and 106 ml/kg. Paired measurements were performed within 30-90 minutes of each other in seven infants. In five infants estimations of plasma volume were made shortly before and 30 minutes after the infusion of a known quantity of plasma. In eight out of 12 infants who had two measurements made there was close agreement between the second measured volume and the first measured volume, taking into account how much plasma had been given to or taken from the infant between the two measurements. The error ranged from 0.2 to 5.2 ml and the plasma recovery error ranged from -2.9% to +4.7%. In the remaining four infants the errors ranged from 2.1 to 9.5 ml and -14.2% to +8.8%. Errors in the measurement of plasma volume may arise as the result of sampling too early before full mixing of the dye has occurred, and there is a potential error in the measurement due to the distribution of albumin in the extracellular space in sick infants resulting in an overestimation of the plasma volume. Proposals for reducing sources of errors are discussed.

Blood Specimen Collection↗
PubMed1992

Somatosensory evoked potentials and outcome in perinatal asphyxia.

Somatosensory evoked potentials (SEP) can be measured in the term newborn infant and given an index of function in the areas of the brain most likely to be damaged in perinatal asphyxia. We studied the median nerve SEP in 30 asphyxiated term infants over the course of their encephalopathy and until discharge from the neonatal unit. Three types of response were noted: normal waveform, abnormal waveform, or absence of cortical response. Follow up of the survivors was undertaken at a mean age of 12 months by means of a Griffiths' assessment and neurological examination. Nine infants died of their asphyxial illness and one of spinal muscular atrophy. Of the 20 survivors, three have cerebral palsy, four have minor abnormalities, and 13 are neurodevelopmentally normal. There was a close correlation between outcome and SEP. All 13 infants with normal outcome had normal SEP by 4 days of age, whereas those with abnormal or absent responses beyond 4 days had abnormalities at follow up.

Asphyxia Neonatorum↗
PubMed1992

Intraventricular haemorrhage after aspiration of ventricular reservoirs.

A previously unrecognised complication of aspirating ventricular reservoirs is described. Four infants developed fresh bleeding into the cerebrospinal fluid after reservoir taps; ultrasound confirmed intraventricular blood clot in one case. The technique for aspirating the reservoir may have an important bearing on the incidence of this complication.

Cerebral Hemorrhage↗
PubMed1992

Cerebrovascular carbon dioxide reactivity and failure of autoregulation in preterm infants.

Changes in cerebral blood flow velocity (CBFV) in response to a rise in arterial carbon dioxide tension (PaCO2) in 94 ventilated preterm infants were determined using Doppler ultrasound to assess whether the nature of this change might predict subsequent neurological injury. Concomitant changes in mean arterial pressure (MAP) were recorded. Both CBFV and MAP rose significantly in response to the rise in PaCO2, the response being significantly less in the first 24 hours. Analysis indicated that the change in CBFV in the first day of life in infants less than or equal to 30 weeks' gestation was dependent to a great extent on the concomitant change in MAP. Similar dependence also occurred after administration of pancuronium to infants whose CBFV response was previously independent of changes in MAP. This dependency lasted for the duration of paralysis. Changes in CBFV after a rise in PaCO2 did not predict subsequent neurological injury. The influence of pancuronium on cerebrovascular regulation warrants further study.

Blood Flow Velocity↗
PubMed1991

Neonatal cerebral venous flow velocity measurement using a color flow Doppler system.

Color flow Doppler provides a simple means for studying blood flow velocity from the central cerebral veins in newborn infants. Twenty-two term infants were examined during the first four days of life to establish a normal range for velocity from the vein of Galen. A wide range of velocities was found between individuals (2.3 cm.s-1 to 9.5 cm.s-1), but short-term intraindividual variation was small (root mean square variation 1.1 cm.s-1). Light bilateral jugular venous compression was performed in 17 of the infants and produced a fall of up to 63% in venous flow velocity in 12 infants (p = 0.0005).

Blood Flow Velocity↗
PubMed1991

Subdural fat effusion complicating parenteral nutrition.

A preterm infant fed parenterally through a central venous catheter developed a subdural effusion containing fat emulsion. Subsequent postmortem examination failed to demonstrate any vascular abnormality that might have explained this rarely reported complication. Although retrograde flow of feeding solutions into cerebral veins seems a likely explanation, the exact mechanism remains uncertain.

Catheterization, Central Venous↗
PubMed1991

Cyclical variations in cerebral blood flow velocity.

Because little is known about spontaneous changes in cerebral blood flow in neonates, a newly developed online Doppler technique was used to insonate continuously the middle cerebral arteries of a group of sick (n = 20) and full term healthy (n = 16) newborn infants for a period of one minute. A total of 290 recordings of epochs each lasting one minute were analysed, and pronounced regular, cyclical variations were seen in the velocity traces of these infants. The cycles occurred 1.5-5 times/minute and were present for at least one epoch in all 20 of the sick infants and in 15 of the 16 healthy mature neonates. Simultaneous recordings of the systemic blood pressure in the sick infants rarely showed the same cyclical variations. The cyclical variation is different from the beat to beat variability seen in the waveforms previously described, and is an additional factor to account for the wide variation in 'normal' velocity recordings obtained when Doppler ultrasound is measured over a short period of time.

Blood Flow Velocity↗
PubMed1991

Development of the transdermal potential of human skin.

The development of the transdermal electrical potential (TDP) with postnatal age was studied in neonates born at gestational ages of 25 to 42 wk. The TDP of neonates born at less than 28 wk gestational age was of similar magnitude over the whole skin surface when measured in the first 5 d of life (mean value -5.4 mV; skin surface negative with respect to s.c. tissues). The TDP increased progressively with increasing gestational and postnatal age. The rate of increase of the TDP with postmenstrual age was not accelerated in neonates born prematurely. TDP values of infants born at term were lower than those of adults, but the sites of high and low TDP were similar in both term infants and adults.

Adult↗
PubMed1990

Normal range for blood flow velocity in cerebral arteries of newly born term infants.

A cross-sectional study of 128 healthy full term infants was made using duplex Doppler ultrasonography in order to establish a normal range for cerebral blood flow velocity (CBFV) in the first week of life. Recordings were made from both the anterior (ACA) and middle cerebral arteries (MCA). There was a statistically significant increase in CBFV in both the ACA and MCA over the first four days of life, which was particularly obvious in the first 24 h. There is a close relationship between measurement of CBFV from the ACA and the MCA, although the velocity tends to be higher in the MCA.

Age Factors↗