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Biomedical subjects

J A Low

Publications and source records attributed to J A Low.

At least 73 records · Page 4Linked to original sources

Motor and cognitive deficits after intrapartum asphyxia in the mature fetus.

The incidence of major and minor motor and/or cognitive deficits at 1 year of age, in 37 mature children who had experienced an intrapartum fetal asphyxial insult, was compared with the incidence of deficits at 1 year in 76 children of the control group. The incidence of both major and minor deficits was significantly greater in the group with intrapartum fetal asphyxia in relation to the control group. These findings support the concept that, beyond a critical threshold of fetal asphyxia, a continuum of casualty in the surviving newborn infants exists.

Asphyxia Neonatorum↗

The role of blood gas and acid-base assessment in the diagnosis of intrapartum fetal asphyxia.

The diagnosis of fetal asphyxia requires a blood gas and acid-base assessment demonstrating a significant metabolic acidosis. However, the fetus may tolerate an asphyxial insult without central nervous system injury because of the fetal cardiovascular adaptation to hypoxemia. Prediction of the significance of an asphyxial insult to the fetus requires a measure of both the duration and degree of the asphyxia as well as an expression of the fetal compensatory response to the asphyxia.

Acid-Base Equilibrium↗

The relationship between antepartum fetal heart rate, intrapartum fetal heart rate, and fetal acid-base status.

The relationships between antepartum baseline fetal heart rate, baseline variability, accelerations, decelerations, and fetal movement and intrapartum fetal heart rate, fetal acid-base assessment at delivery, and Apgar scores 1 and 5 minutes after delivery were studied in 290 mature pregnancies. There was a significant relationship between antepartum and intrapartum baseline fetal heart rate and baseline variability. There was no relationship between antepartum and intrapartum accelerations or decelerations. There was no correlation between antepartum fetal heart rate or fetal movement and fetal acid-base status at delivery or Apgar scores 1 and 5 minutes after delivery. There was a trend for decreased accelerations and decreased fetal movements to be associated with a low Apgar score 1 minute after delivery.

Acid-Base Equilibrium↗

Maternal, fetal, and newborn complications associated with newborn intracranial hemorrhage.

Two hundred twenty newborn infants with one or more fetal or newborn complications and 54 newborn infants without fetal or newborn complications were prospectively studied to assess the relationship between maternal, obstetric, fetal, and newborn complications and intracranial hemorrhage. Intracranial hemorrhage occurred in 47 newborn infants with fetal or newborn complications (21%) and in one infant with no fetal or newborn complications (2%). Maternal and obstetric complications, duration of labor, and mode of delivery were not associated with intracranial hemorrhage. Newborn immaturity at delivery is an important factor in the occurrence of intracranial hemorrhage. There is little evidence that fetal hypoxia is a contributing factor. Severe respiratory complications and major infections are newborn complications associated with intracranial hemorrhage.

Cerebral Hemorrhage↗

Motor and cognitive development of infants with intraventricular hemorrhage, ventriculomegaly, or periventricular parenchymal lesions.

Two hundred twenty-six moderate- or high-risk newborn infants were studied to examine the relationship between ultrasound findings in the newborn period and at 6 months and motor and cognitive deficits at 1 year. A three-part classification of abnormal ultrasound findings was used to grade intraventricular hemorrhage, ventriculomegaly, and parenchymal lesions. Abnormal ultrasound findings were observed in 48 infants, of whom 21 had intraventricular hemorrhage, 18 persistent ventriculomegaly, and nine parenchymal lesions. The incidence of deficits was as follows: normal ultrasound examination, 20%; intraventricular hemorrhage, 33%; persistent ventriculomegaly, 67%; and parenchymal lesions, 89%. The present study indicates that serial ultrasound examinations are indicated in preterm newborn infants less than 1500 gm and in selected newborn infants at risk and greater than 1500 gm at birth. The three-part classification of abnormal ultrasound findings should be used because of the predictive significance of persistent ventriculomegaly and parenchymal lesions for motor and cognitive deficits at 1 year of age.

Cerebral Hemorrhage↗

The relationship between perinatal hypoxia and newborn encephalopathy.

Newborn encephalopathy was observed in 30% of 303 selected high-risk preterm and term newborn infants. The newborn encephalopathy was mild or moderate in 65 children and severe in 27. The predictive significance of newborn encephalopathy to motor and cognitive deficits at 1 year was evident from the incidence of deficits in the children with no encephalopathy (17%), in children with mild or moderate encephalopathy (25%), and in children with severe encephalopathy (55%). The biologic risk factors with a significant association with newborn encephalopathy included severe intrapartum fetal hypoxia, moderate and severe newborn respiratory complications, and major infections. Perinatal hypoxia was associated with, and may have contributed to, 26% of the cases of mild and moderate newborn encephalopathy and 66% of the cases of severe newborn encephalopathy. Fetal and newborn hypoxia occurred with equal frequencies in cases of mild and moderate encephalopathy; however, newborn hypoxia was twice as frequent as fetal hypoxia in cases of severe newborn encephalopathy.

Brain Diseases↗

The contribution of fetal-newborn complications to motor and cognitive deficits.

A total of 364 selected high-risk premature and mature infants were studied prospectively to assess the relationship between fetal-newborn complications and motor and cognitive deficits identified during the first year of life. Deficits occurred in 24 per cent of the children: 14 per cent had one or more major deficit and the other 10 per cent had one or more minor deficit. Prematurity was one of the fetal-newborn complications not associated with deficits at one year. Complications that were associated with deficits included fetal hypoxia, respiratory difficulties, infection and newborn encephalopathy. There was also a significant association between fetal hypoxia, newborn respiratory complications, infection and newborn encephalopathy, which is in keeping with the concept that the first three may be mechanisms in CNS injury and subsequent deficits, while newborn encephalopathy reflects the injury and is an important predictor of such deficits.

Aging↗

Diagnosis of the unstable detrusor: comparison of an incremental and continuous infusion technique.

Incremental infusion cystometry and continuous infusion urethrocystometry were performed on sequential days in 52 patients with an unstable detrusor. Bladder compliance was the same in both techniques. However, continuous infusion urethrocystometry demonstrated involuntary detrusor contractions in three times as many patients as incremental infusion cystometry. It is concluded that in the supine position, medium rate continuous infusion urethrocystometry is more discriminating than rapid rate incremental infusion cystometry with a Lewis recording cystometer in the demonstration of involuntary detrusor contractions.

Female↗

Factors associated with motor and cognitive deficits in children after intrapartum fetal hypoxia.

Sixty children with biochemical evidence of intrapartum fetal hypoxia were studied to define the factors which distinguish the children with deficits from those without deficits of motor and cognitive development. Follow-up assessment included growth measures, neurological examination, Bayley Scales of Infant Development, and a modified Uzgiris and Hunt Scale. Eight children (13%) had a major deficit and 10 children (16%) had a minor deficit at 1 year. Children with deficits had an episode of hypoxia that was more severe and prolonged and, subsequent to delivery, a greater incidence of severe respiratory complications, apnea, and newborn encephalopathy. No other significant risk factors were identified. It is concluded that an episode of hypoxia less than one hour may occur without subsequent deficits. However, an episode of hypoxia in excess of 1 hour resulting in a metabolic acidosis of the order of 25 mEq/L will be followed by motor and cognitive deficits in approximately 50% of children.

Acidosis↗

The predictive significance of biologic risk factors for deficits in children of a high-risk population.

Two hundred forty-two high-risk children and 47 low-risk children were prospectively studied to assess the relationship between biologic risk factors that occurred during the perinatal period and the motor and cognitive deficits that were identified during the first year of life. Multiple risk factors were present in 80% of the children of the high-risk group. Provisional deficits were classified on the degree of abnormality found in a clinical and behavioral assessment that included neurological examinations, Bayley Physical and Mental Development Scales, and the Uzgiris and Hunt Scale. Provisional deficits occurred in 10% of the children of the low-risk group. High-risk children had a significantly greater incidence of provisional deficits, particularly in respect to positive deficits. In high-risk children, the probability of a deficit was 17% in those without infection or encephalopathy, 30% in those with infection, and 40% in those with encephalopathy.

Cognition Disorders↗

Intrapartum fetal hypoxia: a study of long-term morbidity.

Reported is the second phase of a prospective follow-up study of 37 children who had episodes of intrapartum fetal hypoxia at delivery identified by an acid-base assessment and of a control group of 59 children who had no evidence of intrapartum fetal hypoxia. The newborn infants were normally grown and mature at delivery. Follow-up assessments of motor, cognitive, and language development were made between 1 and 6 years of age. There was no significant difference in the pattern of physical growth and the incidences of motor and cognitive handicap or developmental delay, language developmental delay, and tests of vision and hearing in the children of the hypoxia group and the children of the control group. These findings suggest that acid-base measures of metabolic acidosis can be used as a method of assessment of the mature normally grown fetus during labor without compromising the long-term outcome of the child.

Acid-Base Imbalance↗

Intrauterine growth retardation: a study of long-term morbidity.

Reported is the second phase of a prospective follow-up study of 76 growth-retarded children who were mature at birth and a control group of 88 children who had weights appropriate for gestational age at birth. Follow-up assessments of motor, cognitive, and language development were made between 1 and 6 years of age. The children of the intrauterine growth retardation (IUGR) group continued to be smaller than the children of the control group between 12 and 60 months of age. There was no significant difference in the incidences of motor and cognitive handicap or developmental delay, language developmental delay, and tests of vision and hearing between the children of the IUGR group and the children of the control group. There was no significant differences in performance in senior kindergarten between the children of the IUGR group and those of the control group. There was a significant relationship between the socioeconomic status, as measured by the Blishen score at birth, and the subsequent occurrence of motor and cognitive deficits.

Body Height↗

The probability of fetal metabolic acidosis during labor in a population at risk as determined by clinical factors.

The clinical data derived from 2,772 pregnancies managed in an intrapartum intensive care unit have been analyzed to establish which criteria will indicate in a more definite manner the probability that fetal metabolic acidosis will occur during labor and delivery. All antepartum and intrapartum clinical factors indicate a pregnancy and fetus with an increased probability of fetal metabolic acidosis. However, there is a remarkably consistent relationship between decreasing fetal weight in each week of gestational age and in increasing probability of fetal metabolic acidosis that will permit the magnitude of the risk to be determined with greater precision. The following clinical guidelines are proposed: (1) Current antepartum and intrapartum risk factors are appropriate for the selection of patients for intrapartum intensive care. (2) An accurate gestational age and an estimate of fetal weight within 200 gm will provide an indication of the probability of fetal metabolic acidosis in the individual fetus ranging from 15% to 50%. (3) The presence of meconium in the amniotic fluid increases the probability of metabolic acidosis as defined by fetal weight in relation to gestational age.

Acidosis↗

The prediction of intrapartum fetal metabolic acidosis by fetal heart rate monitoring.

Fetal heart rate characteristics during the 8 hours prior to delivery have been studied in 200 patients in whom the fetus had evidence of a metabolic acidosis at delivery, and compared to those in 200 patients in whom the fetus had a normal acid-base at delivery. Baseline fetal heart rate moderate bradycardia and tachycardia, decreased baseline variability, and decreased fetal heart rate accelerations are predictors of intrapartum fetal hypoxia with metabolic acidosis. Marked patterns of total decelerations and late decelerations are predictive of intrapartum fetal hypoxia with metabolic acidosis. The probability of fetal metabolic acidosis in the presence of a marked pattern of total decelerations is 25%, and with late decelerations it is 48%, in a population of high-risk pregnancies.

Acidosis↗

The effect of maternal, labor, and fetal factors upon fetal heart rate during the intrapartum period.

The effect of maternal labor, and fetal characteristics upon fetal heart rate behavior during the intrapartum period has been studied in 400 patients. Abnormal labor in comparison to normal labor has a higher baseline fetal heart rate with an increased incidence of baseline tachycardia and an increased incidence of absent or decreased baseline variability. A decreasing fetal weight gestational age percentile is associated with an increased incidence of variable decelerations. Segmental epidural and Demerol analgesia carefully administered has little effect upon fetal heart rate behavior.

Anesthesia, Epidural↗

The clinical prediction of intrauterine growth retardation.

From a total study group of 8,030 deliveries, 2,788 patients with risk factors and 292 representative patients from the 5,242 patients without risk factors were selected for detailed analysis of predictors of intrauterine growth retardation (IUGR). Two thirds of the IUGR infants came from the population with risk factors and a weighting was assigned to individual risk factors. One third of the IUGR infants came from the population without risk factors, and their mothers demonstrated significantly differing maternal characteristics from those with a normally grown infant. The perinatal mortality rate was higher in the IUGR group and particularly in the population with risk factors.

Body Weight↗

Intrapartum fetal asphyxia: a preliminary report in regard to long-term morbidity.

This is a preliminary report of a prospective follow-up study of 42 infants who had episodes of intrapartum fetal asphyxia at delivery identified by an acid-base assessment and a control group of 69 babies who had no evidence of intrapartum fetal asphyxia. The newborn infants were mature at delivery. There were no major neurologic disabilities in the asphyxia group. The pattern of physical growth and the mental and physical development indices of the babies of the asphyxia group were similar to those of the control group babies at 12 months of age. Results have not as yet indicated that the mature fetus with at least a terminal episode of asphyxia will exhibit evidence of handicap due to central nervous system injury.

Asphyxia Neonatorum↗