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Biomedical subjects

V Y Yu

Publications and source records attributed to V Y Yu.

At least 73 records · Page 4Linked to original sources

Reduction in periventricular haemorrhage in preterm infants.

Our previous cerebral ultrasound study of antecedents of periventricular haemorrhage in infants weighing 1250 g or less at birth suggested that neonatal events that caused increased or fluctuating cerebral blood flow lead to periventricular haemorrhage. As the risk period for this type of haemorrhage was the first four days of life strict guidelines were introduced to avoid the previously identified neonatal risk factors. No attempt was made to modify obstetric practice. Over the next two years, although the obstetric risk profile, the frequency and severity of hyaline membrane disease, and the gestation, birth weight, and sex distributions of a similar cohort of infants did not change, the incidence of periventricular haemorrhage decreased significantly from 60% to 36%. Significant antecedents of haemorrhage similar to those found in the previous study included severe bruising, low arterial:fractional inspiratory oxygen ratio and low packed cell volume on admission, hyaline membrane disease, hypercarbia, and hypoxaemia. Assisted ventilation, pneumothorax, treatment with tubocurarine, and hypotension were no longer significant risk factors for periventricular haemorrhage. A multivariate discriminant analysis correctly predicted haemorrhage in 86% of the study group when bruising, hypercarbia, hypoxaemia, hyaline membrane disease, and low gestation were considered. These results suggest that changes in neonatal practices can reduce the incidence of periventricular haemorrhage and that drug studies indicating similar reduction in haemorrhage need to be evaluated carefully to ensure that placebo and treated groups are in fact comparable.

Birth Injuries

Neonatal and neurodevelopmental significance of behaviour in very low birthweight children.

73 (34%) of 213 inborn, long term survivors with a birthweight less than 1500 g showed characteristics of Attention Deficit Disorder (ADD) during psychological testing at 2 years of age corrected for prematurity. Agreement on the diagnosis of ADD made by the paediatrician and psychologist in separate examinations was statistically significant. Children with ADD differed from those with normal behaviour on a large number of neonatal variables which were reduced to the following five on stepwise discriminant function analysis: necrotizing enterocolitis, bronchopulmonary dysplasia, major apnoeas requiring bag and mask resuscitation, duration of feeding on intravenous fat and weight percentile at discharge. These neonatal variables correctly classified 69% of children into their actual behaviour group at 2 years. On psychological testing, children with ADD had a significantly lower mental score on the Bayley Scales of Infant Development and were found on their paediatric/neurological examination at 2 years to have a significantly smaller head circumference, more tone disorders, poorer visual tracking and visual motor co-ordination, poorer gross and fine motor co-ordination and significantly more minor physical and neurological disabilities than normally behaved children. The behaviour of very low birthweight infants during formal psychological testing at 2 years is a potent indicator of past neonatal experience and current neurodevelopmental status.

Attention

Outcome of intrauterine periventricular haemorrhage and leukomalacia.

This case study reports five very low birthweight infants with ultrasound evidence of intrauterine insult to the brain. Intrauterine periventricular haemorrhage (PVH) accompanied by ventricular dilation occurred in two preterm infants both of whom survived and were severely handicapped at follow-up. Three preterm infants had intrauterine periventricular leukomalacia (PVL); one survived and is severely handicapped at one year of age. Our experience and rare case reports in the literature indicate that intrauterine PVH and PVL carry a high risk of death in neonatal period and severe neurological sequelae in survivors.

Brain Ischemia

Post-haemorrhagic hydrocephalus in the preterm infant.

This prospective study documents the incidence, clinical features and risk factors for post-haemorrhagic hydrocephalus (PHH) as well as the short-term outcome after serial CSF taps. Serial real-time ultrasound scans were performed on 220 infants: on all admissions less than or equal to 1250 g and on an additional 130 infants with birthweights greater than 1250 g with risk factors for intraventricular haemorrhage (IVH). Based on percentile charts of postnatal increase in ventricular size and head circumference growth rate, PHH was defined as ventricular dilatation greater than 95th centile associated with either a head circumference growth greater than 95th centile or with clinical features of raised intracranial pressure (ICP). Forty-eight (22%) infants were found to have IVH of whom 14 had intracerebral extension of IVH. Sixteen (40%) of 40 infants who survived the acute episode of IVH developed PHH. PHH occurred more commonly in those who survived severe birth asphyxia and/or intracerebral extension of IVH. Fifteen infants who developed clinical features of raised ICP were treated with serial CSF taps. This procedure was effective in a staged treatment for PHH in relieving clinical symptoms and deferring ventriculo-peritoneal (VP) shunting. Morbidity associated with serial CSF taps and VP shunting is minimal. A high red cell count and protein concentration in the CSF at diagnosis of PHH identified all five infants who subsequently required VP shunting.

Cerebral Hemorrhage

Effect of neonatal periventricular haemorrhage on neurodevelopmental outcome.

All 56 infants born between 23 and 28 weeks' gestation admitted to this hospital in 1981 were examined for periventricular haemorrhage with cerebral ultrasonography. Haemorrhage was diagnosed in 34 (61%)-12 (22%) had germinal layer haemorrhage, 18 (32%) had intraventricular haemorrhage, and four (7%) had intracerebral haemorrhage. The two year outcome of survivors with and without periventricular haemorrhage was compared to determine the effect on neurodevelopment. Only three (16%) of 19 infants with normal scans or germinal layer haemorrhages had evidence of major disability but nine (75%) of 12 infants with intraventricular or intracerebral haemorrhage had major disability. The mental and psychomotor performance on the Bayley scales of infant development was also significantly worse in the latter group. All three survivors with intracerebral haemorrhage had major disability. The continuation of life support treatment for extremely preterm infants who are at very high risk of severe handicap is a matter of increasing concern in neonatal intensive care. Our results show that if extensive periventricular haemorrhage, in particular intracerebral haemorrhage, occurs in this gestational group, extreme pessimism is warranted.

Birth Weight

Viability of infants born at 24 to 26 weeks gestation.

81 inborn infants of 24-26 weeks gestation were studied. Overall survival rate excluding 2 lethal malformations was 44%: it was 36% at 24 wk, 32% at 25 wk and 57% at 26 wk. 68% of the multiparous mothers had a previous reproductive loss and 30% had a previous preterm birth. Antepartum haemorrhage and chorioamnionitis were the 2 most common obstetric associations. Perinatal asphyxia and severe respiratory disorders were significantly associated with increased mortality. Management of respiratory failure and provision of adequate nutrition were the 2 main therapeutic challenges. 30% of the deaths occurred in the delivery room and 68% by 24 hours. Periventricular haemorrhage was the most common necropsy finding. The mean gestation at discharge for the 35 survivors was 40 wk. On assessment at 2 years of age, corrected for prematurity, 10 (28%) had cerebral palsy, 3(9%) had developmental delay, 2 (6%) were blind, and 1 (3%) had sensorineural deafness. There were 4 children who had more than 1 disability; 9 of the 12 children with disability were considered to have a significant functional handicap. The proportions of survivors without significant functional handicap, born at 24-25 wk compared with those at 26 wk, were not statistically different (67% versus 80%). Common medical conditions in the first 2 years included respiratory illness, otitis media and gastroenteritis. 13 (37%) children required rehospitalisation for an average of 3 times; total days in hospital averaged 15 d. The most common reason for admission was respiratory illness. At 2 years, 24% were below the 10th centile for weight as were 26% for height; head circumferences were normal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Intraventricular hemorrhage. Incidence and outcome in a population of very-low-birth-weight infants.

The incidence, extent, and outcome of germinal matrix hemorrhage-intraventricular hemorrhage (GMH-IVH) were determined with the use of ultrasound and autopsy findings in 100 consecutive infants, with a birth weight of less than 1,500 g. Serial ultrasound examinations once or twice weekly were performed with the use of a portable real-time linear-array scanner. The overall incidence of GMH-IVH was 46%. Twenty infants had grade 1 (GMH), 24 had grade 2 (IVH +/- GMH), and two had grade 3 (IVH +/- GMH with intracerebral hemorrhage) conditions. The mortality in infants with GMH-IVH was 35%, compared with 13% in infants without GMH-IVH. Although 11 (37%) of 30 survivors with GMH-IVH had ventricular dilatation, only two infants required ventriculoperitoneal shunts for progressive hydrocephalus. The incidence of GMH-IVH was increased in outborn infants, in those delivered vaginally, and in those who required mechanical ventilation, bicarbonate therapy, or volume expansion in the first 24 hours. The long-term prognostic significance of the ultrasound findings was unknown and will be determined by follow-up studies.

Cerebral Hemorrhage

Necrotizing enterocolitis in very low birthweight infants: a four-year experience.

Fifty (13%) of 375 infants who weighed 1500 g or less at birth had necrotizing enterocolitis (NEC). Haematological changes suggestive of sepsis occurred in 83% and positive bacteriological cultures were found in 38%, the most common organism isolated being Clostridium perfringens. Complications included intestinal perforation in six patients and recurrence of NEC in five, of whom one subsequently developed an intestinal stricture. Five of the eight nursery deaths were secondary to peritonitis and overwhelming sepsis from NEC. In spite of the discontinuation of milk feeds for prolonged periods, satisfactory caloric intake and weight gain were achieved with parenteral nutrition in the survivors. Of the 41 long-term survivors, six (15%) were found to have a disability at 2 years of age, corrected for prematurity, compared with 48 (20%) of 241 very low birthweight survivors from the same study period who did not have NEC. None had evidence of gastrointestinal dysfunction. Six (15%) children remained below the 10th percentile for both weight and height. This study showed that early diagnosis and therapy for NEC in very low birthweight infants were associated with a favourable short- and long-term outcome.

Bacterial Infections

Outcome of very low birthweight infants who required prolonged hospitalization.

Over a 4 year study period, 294 infants with a birthweight less than or equal to 1500 g survived their initial hospitalization; 103 (35%) were discharged after a gestational age of 40 weeks. The postdischarge infant mortality was significantly higher in those with prolonged initial hospitalization compared with the remaining survivors (6% vs 1%). During the first 2 years, significant infections were found in 66% and rehospitalization in 54% of the children who had prolonged initial hospitalization. At 2 years, 34% were below the 10th centile for weight as were 39% for height; head circumferences were normal. Major disability (27% vs 15%) and developmental delay (13% vs 4%) were significantly more common in survivors with prolonged initial hospitalization compared with the remaining survivors. The study demonstrated the continuing toll of perinatal morbidity among very low birthweight infants who required prolonged hospitalization and emphasized the need for comprehensive medical and social support, not only during their initial hospitalization, but also after discharge.

Australia

Effect of mode of delivery on outcome of very-low-birthweight infants.

The hospital survival rate was 47% in 111 inborn infants who weighed 501-1000 g and 90% in 211 who weighed 1001-1500 g. The survival rate after caesarean birth was significantly higher than that after vaginal delivery in the 1001-1500 g group but not in the 501-1000 g group. At 2 years of age, 73% of survivors born at 501-1000 g and 85% of those born at 1001-1500 g had no neurological or developmental disability; no significant difference was found between caesarean and vaginal births. The mode of delivery did not significantly affect survival or late outcome of the 192 singleton infants with cephalic presentation. Although the survival rate was not significantly different between infants with breech and cephalic presentations, the former had a significantly higher disability rate. Within the group of 72 singleton infants with breech presentation, the survival rate after caesarean birth was significantly higher than after vaginal delivery in the 1001-1500 g group but not in the 501-1000 g group. No significant difference in late outcome was found between caesarean and vaginal births in this subgroup.

Breech Presentation

Survival and 2-year outcome of extremely preterm infants.

The survival of 163 infants born within the hospital at 24-28 weeks gestation during a 4 1/2-year period and the morbidity in survivors at 2 years of age were reported. Hospital survival rates from 24-28 weeks at each week of gestation, excluding six infants with birth defects, were 36%, 32%, 57%, 70% and 74% respectively. The late outcome of children born at 24-26 weeks was compared with those born at 27-28 weeks. Of the 81 infants in the former group 46 (57%) died, nine (11%) survived with significant functional handicap and 26 (32%) were developing within the normal range. Of the 82 infants in the latter group, 28 (34%) died, eight (10%) survived with significant functional handicap and 46 (56%) were developing within the normal range. Although the mortality rate was significantly higher in the 24-26-weeks group, the physical disability and functional handicap rates in survivors were not statistically different between the two groups. Neither was developmental progress, as determined by psychological assessment, different.

Child Development