J.A. Low

The association between preterm newborn hypotension and hypoxemia and outcome during the first year

Ninety‐eight newborn infants, less than 34 weeks at birth, were studied to examine the relationship between newborn hypotension and hypoxemia and brain damage. Heart rate, blood pressure and oxygen tension were recorded continuously during the 96 h following delivery. Outcome measures included neuropathology in children who died, and motor and cognitive development at one year corrected age in children who survived. There were 22 children with a minor and 27 with a major abnormal outcome. There was a relationship between newborn hypotension, newborn hypoxemia and low birth weight, and a major abnormal outcome. The probability of a major abnormal outcome increased from 8% in newborns with no hypotension or hypoxemia, to 53% in children with both hypotension and hypoxemia. These findings support the contention that combinations of sustained newborn hypotension and hypoxemia are important factors in the development of brain damage, accounting for a major abnormal outcome.

Predictive value of electronic fetal monitoring for intrapartum fetal asphyxia with metabolic acidosis

OBJECTIVEnTo determine the predictive value of each fetal heart rate (FHR) variable and of patterns of FHR variables for fetal asphyxia during labor.nnnMETHODSnThis matched case-control study included an asphyxia group of 71 term infants with umbilical artery base deficit greater than 16 mmol/L and a control group of 71 term infants with umbilical artery base deficit less than 8 mmol/L. Each FHR record available for the 4 hours before delivery was scored in 10-minute cycles for each FHR variable. Selected patterns of important FHR variables were examined during the last hour before delivery for their predictive value for fetal asphyxia.nnnRESULTSnThe FHR variables associated with fetal asphyxia included absent and minimal baseline variability and late and prolonged decelerations. Fetal heart rate patterns with absent baseline variability were the most specific but identified only 17% of the asphyxia group. The sensitivity of this test increased to 93% with the addition of less specific patterns. The estimated positive predictive value ranged from 18.1% to 2.6%, and the negative predictive value ranged from 98.3% to 99.5%.nnnCONCLUSIONnA narrow 1-hour window of FHR patterns including minimal baseline variability and late or prolonged decelerations will predict fetal asphyxial exposure before decompensation and newborn morbidity. Thus, with careful interpretation, predictive FHR patterns can be a useful screening test for fetal asphyxia. However, supplementary tests are required to confirm the diagnosis and to identify the large number of false-positive patterns to avoid unnecessary intervention.

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.

The effect of Wertheim hysterectomy upon bladder and urethral function

Abstract Bladder and urethral function after Wertheim hysterectomy was assessed by cystometry and urethral pressure profiles. There was a marked reduction in bladder compliance with a striking rise in baseline bladder pressure during bladder filling, and hyperreflexia with involuntary contractions of the detrusor muscle at low bladder capacity. This was attributed to a loss of sympathetic beta-adrenergic inhibition of the detrusor muscle and, possibly, a loss of sympathetic alpha-adrenergic modulation of parasympathetic stimulation of the detrusor muscle. There was a significant decrease in the urethral pressure profile which was greatest in patients with the highest preoperative urethral pressures. This was attributed to loss of sympathetic alpha-adrenergic stimulation of urethral smooth muscle.

Determining the contribution of asphyxia to brain damage in the neonate

Studies in the research laboratory have demonstrated the complex relationship between fetal and newborn asphyxia and brain damage, a balance between the degree, duration and nature of the asphyxia and the quality of the cardiovascular compensatory response. Clinical studies would support the contention that the human fetus and newborn behave in a similar manner. An accurate diagnosis of asphyxia requires a blood gas and acid base assessment. The clinical classification of fetal asphyxia is based on a measure of metabolic acidosis to confirm that fetal asphyxia has occurred and the expression of neonatal encephalopathy and other organ system complications to express the severity of the asphyxia. The prevalence of fetal asphyxia at delivery is at term, 25 per 1000 live births of whom 15% are moderate or severe; and in the preterm, 73 per 1000 live births of whom 50% are moderate or severe. It remains to be determined how often the asphyxia recognized at delivery may have been present before the onset of labor. There is a growing body of indirect and direct evidence to support the contention that antepartum fetal asphyxia is important in the occurrence of brain damage. Although much of the brain damage observed in the newborn reflects events that occurred before delivery, newborn asphyxia and hypotension, particularly in the preterm newborn, may contribute to the brain damage accounting for deficits in surviving children

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.

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.

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.

Intrauterine growth retardation: a preliminary report of long-term morbidity.

This is a preliminary report of a prospective follow-up study of 88 intrauterine growth-retarded (IUGR) babies and a control group of 97 babies with weights appropriate for gestational age. The characteristic clinical features of IUGR pregnancies were observed in the obstetric patients of the IUGR group. The babies of the IUGR group have a phase of accelerated growth during the 3 months following delivery although they continue to be smaller than the babies of the control group at 12 months of age. No major neurologic abnormalities have been noted in the IUGR babies although behavioral differences were observed during the neonatal period and at 12 months of age. There were lower mental and physical development indices at 12 months of age which were due to the IUGR babies of lowest birth weight and those with a low maternal urinary estrogen index.

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.