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Biomedical subjects

W Tin

Publications and source records attributed to W Tin.

14 recordsLinked to original sources
PubMed2001

Pulse oximetry, severe retinopathy, and outcome at one year in babies of less than 28 weeks gestation.

AIM: To determine whether differing policies with regard to the control of oxygen saturation have any impact on the number of babies who develop retinopathy of prematurity and the number surviving with or without signs of cerebral palsy at one year. METHODS: An examination of the case notes of all the 295 babies who survived infancy after delivery before 28 weeks gestation in the north of England in 1990-1994. RESULTS: Babies given enough supplemental oxygen to maintain an oxygen saturation of 88-98%, as measured by pulse oximetry, for at least the first 8 weeks of life developed retinopathy of prematurity severe enough to be treated with cryotherapy four times as often as babies only given enough oxygen to maintain an oxygen saturation of 70-90% (27.2% v 6.2%). Surviving babies were also ventilated longer (31.4 v 13.9 days), more likely to be in oxygen at a postmenstrual age of 36 weeks (46% v 18 %), and more likely to have a weight below the third centile at discharge (45% v 17%). There was no difference in the proportion who survived infancy (53% v 52%) or who later developed cerebral palsy (17% v 15%). The lowest incidence of retinopathy in the study was associated with a policy that made little use of arterial lines. CONCLUSIONS: Attempts to keep oxygen saturation at a normal "physiological" level may do more harm than good in babies of less than 28 weeks gestation.

Clinical Protocols↗
PubMed2000

Ocular abnormalities associated with cerebral palsy after preterm birth.

PURPOSE: To document the ocular abnormalities in children with cerebral palsy (CP) after premature birth. METHODS: All the children born before 32 weeks gestation between 1 January 1990 and 31 December 1991 in a geographically defined population of approximately 3 million, were examined by an ophthalmologist and a paediatrician at 2 years old. RESULTS: Five hundred and fifty-eight children (98.8% of the study group) were examined, of whom 41 had disabling CP and 13 had non-disabling CP. Children with CP had a higher incidence of abnormalities compared with children without CP: cicatricial retinopathy of prematurity occurred in 8 children with CP (14.8%) compared with 8 without CP (1.6%, p < 0.0001), cortical visual impairment occurred in 6 with CP (11.1%) compared with 1 child without CP (0.2%, p < 0.0001) and concomitant strabismus in 28 with CP (51.9%) compared with 42 without CP (8.4%, p < 0.0001). The prevalence of refractive error without other ocular abnormalities was similar for children with CP (4/54, 7.4%) and those without CP (54/504, 10.7%, p = 0.90). Significant ocular abnormalities had been previously unrecognised in 8 children with CP (14.8%). CONCLUSION: There are some differences between these results and previous series. These differences probably reflect the fact that previous work has studied severe CP of more diverse aetiology. The high frequency of abnormalities highlights the importance of ocular assessment of these children.

Cerebral Palsy↗
PubMed2000

Six years' experience of prophylactic oral vitamin K.

AIMS: The ability of oral vitamin K to eliminate all risk of vitamin K deficiency bleeding during the first three months of life was studied. METHODS: Babies (n=182,000) in the north of England judged well enough to be offered milk within 12 hours of birth were given 1 mg of phytomenadione (vitamin K(1)) suspended in a medium chain triglyceride oil by mouth at delivery between 1993 and 1998. The parents of those who were breastfed were given a further three doses to give to the baby once every two weeks after discharge. RESULTS: Four breastfed babies developed late vitamin K deficiency bleeding. In two, staff failed to follow policy guidelines, and in two there was undiagnosed alpha(1) antitrypsin deficiency. Audit suggested that 93% of breastfed babies had all four doses, as advised. CONCLUSIONS: An oral product that parents can administer themselves would be popular if licensed, but the total dose offered may need to be more than in this study if babies with undiagnosed liver disease are to be protected.

Administration, Oral↗
PubMed1999

Risk factors for strabismus in children born before 32 weeks' gestation.

AIM: To investigate risk factors associated with strabismus in children born prematurely. METHODS: Prospective study of all children born before 32 weeks' gestation between 1 January 1990 and 31 December 1991 in a geographically defined population of approximately 3 million in the Northern Region of the United Kingdom. All children were examined aged 2 years by the same ophthalmologist and paediatrician. RESULTS: 558 children (98.6% of study group) were examined. Logistic regression showed an increased risk of strabismus in children with cicatricial retinopathy of prematurity (p=0.02), refractive error (p=0.003), family history of strabismus (p<0.0001), and poor neurodevelopmental outcome (p<0.0001), in particular impaired locomotor skills (p=0.008) and hand-eye coordination (p=0. 001). Gestational age and regressed acute ROP were not independent risk factors for strabismus (p=0.92 and 0.85 respectively). CONCLUSIONS: This study has identified factors which are independently related to strabismus (although not necessarily causative) and others which are related only indirectly. This may contribute both to the management of children born prematurely and to future studies of the aetiology of strabismus.

Child Development↗
PubMed1999

Bias due to incomplete follow up in a cohort study.

AIM: To investigate the bias introduced by incomplete follow up in a cohort study of ocular outcome after premature birth. METHODS: A geographically defined cohort of children born before 32 weeks' gestation was prospectively recruited at birth to study the ocular outcome at 2 years. On the basis of attendance at 2 years, the children's families were allocated to one of three groups: group 1 attended for follow up, group 2 were difficult to trace, and group 3 were very reluctant for assessment. All children were examined by a single ophthalmologist, masked to these groupings. RESULTS: 558 children (98.8% of study group) were examined, of whom 505 were in group 1, 20 in group 2, and 33 in group 3. The groups which were more difficult to study (groups 2 and 3) showed a significantly higher prevalence of ocular abnormalities, including strabismus (p=0. 02) and cicatricial retinopathy of prematurity (p=0.002) compared with those attending for follow up. Further, not all of these cases could have been identified by review of the children's previous records. Ocular abnormalities would be underestimated by 16% (11.3% in group 1 compared with 13.4% in the total cohort, p=0.77). CONCLUSIONS: This study suggests that the prevalence of abnormalities would be underestimated by incomplete follow up, as those subjects who were most difficult to obtain for study had a significantly higher prevalence of abnormalities.

Bias↗
PubMed1998

A comparison of two methods of follow-up in a trial of prophylactic volume expansion in preterm babies.

The outcome at age 2 years of preterm babies recruited into a three-arm randomised controlled trial of prophylactic volume expansion was ascertained in two ways: from a neurodevelopmental assessment performed by a paediatrician and from responses on a brief questionnaire completed by the child's personal health visitor. Of 776 babies recruited into the trial, 604 survived to the age of 2 years and the findings of a paediatric assessment were available for all survivors. Questionnaires were sent to the health visitors of 601 of the survivors; 513 (85.4%) were returned. There was sufficient information on the returned questionnaires to categorise 449 of the children as normal, impaired, moderately disabled or severely disabled. We were unable to detect a response bias by severity of disability. Agreement on individual questions ranged between 86.3% and 98.4%. There was some mismatch in the reporting of vision (weighted kappa = 0.71) and hearing (weighted kappa = 0.73), with differences in perception of level of severity of sensory loss. Health visitors tended to underestimate the child's functional level compared with the paediatrician. However, of 56 children classified as severely disabled by the paediatrician, 48 were classified similarly and eight as moderately disabled on the basis of the questionnaire. The end point of the trial was death or severe disability at 2 years of age. There was close similarity in the trial results whether based on the paediatric assessment or on the questionnaire. Further refinement of the questionnaire is needed, but this methodology may be useful in ascertaining the frequency of severe disability in large cohorts of babies.

Chi-Square Distribution↗
PubMed1998

Outcome of very preterm birth: children reviewed with ease at 2 years differ from those followed up with difficulty.

AIM: To determine whether those most easily reviewed in a population prevalence study differ from those followed up only with difficulty. METHODS: All babies born before 32 weeks of gestation in the North of England in 1983, 1990, and 1991 were traced, and all the survivors assessed at two years by one of two independent clinicians. RESULTS: 818 of the 1138 live born babies survived to discharge. There was some non-significant, excess disability in the 5% of long term survivors who were difficult to trace because of social mobility, but eight times as much severe disability in the 1% (9/796) in care and in the 5% (38/796) whose parents initially failed to keep a series of home or hospital appointments for interview, and five times as much emergent disability in the 2.7% (22/818) who died after discharge but before their second birthday. Had the babies who were seen without difficulty been considered representative of all the babies surviving to discharge, the reported disability rate would have been two thirds what it really was (6.9% instead of 11.0%). CONCLUSIONS: Population prevalence studies that ignore those who seem reluctant to cooperate risk serious ascertainment bias.

Appointments and Schedules↗
PubMed1997

Changing prognosis for babies of less than 28 weeks' gestation in the north of England between 1983 and 1994. Northern Neonatal Network.

OBJECTIVE: To investigate the changing prognosis for babies of less than 28 weeks' gestation. DESIGN: A prospective, collaborative, population based survey. SETTING: The former Northern Regional Health Authority. SUBJECTS: All the births between 1983 and 1994 at 22 to 27 completed weeks' gestation to women normally resident in the region. MAIN OUTCOME MEASURES: Miscarriage, stillbirth, death in the first year of life, and disability in survivors. RESULTS: There were 479070 registered births in the study period. No baby of 22 weeks' gestation survived; only eight (4%) of the 197 babies of 23 weeks who were alive at the onset of labour survived for a year-a proportion that did not change during the study period. Survival among other babies of less than 28 weeks improved progressively between 1983-6 and 1991-4, but administration of artificial surfactant to babies requiring ventilation from mid-1990 was associated with further improvement in survival only in those over 25 weeks' gestation. Babies of 24 weeks required three times as much high dependency care per survivor as babies of 27 weeks (76 v 26 days). The rate of severe disability in the one year survivors of less than 26 weeks' gestation (30/123; 24%) was similar to that seen in the sampled survivors of 26 and 27 weeks (29/108; 27%); the proportion disabled did not change significantly during the study period. All the children born in 1983, 1987, and 1991 were later reassessed in greater detail: 10% (13/136) seemed destined for a continuing life of total dependency. CONCLUSIONS: Gestation, if accurately assessed, can give a woman facing very preterm delivery a clear indication of the prognosis for her baby and help her judge the appropriateness of accepting obstetric intervention and sustained perinatal support.

Abortion, Spontaneous↗
PubMed1997

Refractive errors in children born before 32 weeks gestation.

PURPOSE: To document the refractive errors in a cohort of children born before 32 weeks gestation. METHODS: All children born before 32 weeks gestation between 1 January 1990 and 31 December 1991 to mothers resident in the Northern Region of the National Health Service were examined at 2 years old (n = 558). RESULTS: Stage 3 or worse retinopathy of prematurity (ROP) was associated with myopia. In those not developing stage 3 or worse ROP, the refractive errors were myopia in 1.5%, hypermetropia > 4 dioptres (D) in 5.4%, anisometropia > 1 D in 1.1% and astigmatism > 1.25 D in 5.7%. CONCLUSION: The incidence of refractive errors in those not developing stage 3 or worse ROP was similar to that in the general population.

Acute Disease↗
PubMed1997

Selection biases invalidate current low birthweight weight-for-gestation standards. The Northern Neonatal Network.

OBJECTIVE: To obtain unbiased estimates of the variation of birthweight with gestation in infants born before 32 weeks of gestation. SETTING: The former Northern Regional Health Authority. DESIGN: Information on birthweight was collected during a collaborative study of every registered and unregistered birth at 22 to 31 weeks of gestation in the region in 1983 and 1990 to 1991. These birthweights were then related to computer-generated Tyneside norms for all registered births at 28 to 42 weeks of gestation between 1984 and 1991. Some local information was also collected on fetal weight after termination of pregnancy on social grounds at 16 to 21 weeks of gestation. RESULTS: Weight centiles constructed after excluding infants with a gross, externally visible, malformation and those dying before the onset of labour suggest that previously published European standards have overestimated birthweight in infants < 28 weeks of gestation, some low centiles being 30% in error. Female and first-born infants weighed 4% less than their male and later-born counterparts at all gestations studied. A single correction factor can therefore be used to correct for sex and parity, eliminating the need for separate centile graphs. Twin pregnancy was associated with a 10% reduction in mean birthweight in pregnancies lasting < 37 weeks, and this difference increased progressively in pregnancies lasting longer than this. CONCLUSION: The small number of low birthweight infants in previous datasets and the selective exclusion of all nonregistered births have made previous second trimester weight-for-gestation norms unreliable.

Birth Weight↗
PubMed1997

Gestational assessment assessed.

AIMS: To review the accuracy with which obstetric information on gestation is recorded in the neonatal records; and the reliability of the methods used for assessing gestational age after birth. METHODS: Service information on all babies born in 1989, and research information on all babies of < 32 weeks gestation born in the Northern Region in 1990-91, were reviewed to determine the accuracy with which antenatally collected information had been recorded in the neonatal records after birth. A prospective study was also mounted to assess how reliably paediatric staff could assess the gestational age of babies born to mothers with certain obstetric dates under service conditions. Paediatric residents looked at 347 babies of > 32 weeks gestation, and senior staff looked at 105 babies of < 30 weeks gestation. RESULTS: The best techniques for estimating gestation immediately after birth were only half as accurate (95% CI +/- 17 days) as estimates based on antenatal ultrasound at 15-19 weeks gestation. Assessments that relied on the tone, posture, and appearance of the baby at birth in those of < 32 weeks gestation were less reliable than assessments based on a retrospective review of when various reflex responses first appeared. They also tended to overestimate true gestation. Antenatal information of high quality was ignored, and arithmetic and transcription errors were introduced during the transfer of antenatal information into over 10% of postnatal records. CONCLUSIONS: Current ultrasound techniques for "dating" pregnancy antenatally are better than any of the methods of postnatal assessment. Given the reliability of the antenatal information now available, it is regrettable that so many inaccuracies have been allowed to creep into the routine computation and recording of gestation at birth.

England↗
PubMed1996

Retinopathy of prematurity in a controlled trial of prophylactic surfactant treatment.

AIMS: To investigate the incidence of acute and cicatricial retinopathy of prematurity (ROP) in a cohort of premature neonates entered into a randomised, multicentre trial of prophylactic exogenous surfactant for respiratory distress syndrome (RDS) compared with controls receiving surfactant only if severe RDS developed. METHODS: The incidence of acute and cicatricial ROP was assessed in 304 neonates born at less than 30 weeks' gestation in a geographically defined population of approximately three million. RESULTS: There was a trend towards improved survival in the group receiving prophylactic surfactant with 102/151 (67.5%) surviving compared with 82/141 controls (58.2%, p = 0.12). The prophylactic surfactant group would be expected to have an increased risk of ROP due to improved survival, particularly of the most premature infants. However, there was no statistically significant difference in the incidence of acute ROP between the two groups and the incidence of cicatricial ROP was lower in the group receiving prophylactic surfactant (4/100 survivors, 4.0%) compared with neonates receiving rescue surfactant as required (6/81, 7.4%). This difference did not reach statistical significance (p = 0.35). CONCLUSION: The trend for a lower incidence of cicatricial ROP in those neonates treated with prophylactic surfactant compared with the rescue surfactant group, despite improved survival, suggests that the use of prophylactic surfactant also had a beneficial effect on the development of cicatricial ROP.

Drug Combinations↗
PubMed1995

Ocular outcome in children born before 32 weeks gestation.

Ocular outcome was assessed in a 2 year cohort of all children born before 32 weeks gestation within a geographically defined population of approximately 3 million. Five hundred and sixty-five children were born within the study period; 558 children (98.8% of the study group) were assessed at approximately 2 years old. There was a high incidence of abnormalities, particularly strabismus (70, 12.5%), cortical visual loss (7, 1.3%), sequelae of retinopathy of prematurity (16, 2.9%) and other significant refractive errors (69, 12.7%). These data provide a recent estimate of gestational age-specific prognosis and suggest that follow-up yields a significant proportion of children with visual abnormalities who could benefit from treatment.

Child, Preschool↗