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Biomedical subjects

H L Halliday

Publications and source records attributed to H L Halliday.

At least 91 records · Page 5Linked to original sources
PubMed1993

Cord blood erythropoietin, pH, PaO2 and haematocrit following caesarean section before labour.

We have investigated the relationship between erythropoietin (Epo) and pH, PaO2 and haematocrit in 100 cord blood samples obtained at Caesarean section prior to labour. Of 82 term (> 37 weeks) infants, 64 were appropriately grown (10th-90th centiles), and their mean cord serum Epo and cord blood Epo was 23 +/- 8 mU/ml (mean +/- SD). Strong inverse correlations were found between cord serum Epo and cord blood pH (r = -0.74; p < 0.0001), and between cord serum Epo and cord blood PaO2 (r = -0.55; p < 0.0001), but not between cord serum Epo and cord haematocrit (r = 0.02; p < 0.9). For the 18 preterm babies (gestation 32.4 +/- 4.1 weeks, birth weight 1,820 +/- 476 g), the Epo level was 36 +/- 8 mU/ml, which was not significantly greater than for the term babies. Strong inverse correlations were again found between Epo and pH (r = -0.87; p < 0.0001) and Epo and PaO2 (r = -0.69; p < 0.002). Babies from complicated pregnancies (intra-uterine growth retardation, pre-eclampsia, antepartum haemorrhage, diabetes mellitus and fetal distress) tended to have higher Epo levels. Thirteen babies had Epo levels > 40 mU/ml, and 11 (85%) of these required neonatal intensive care. Cord serum Epo correlates better with oxygen tension and pH at birth than with fetal growth and haematocrit, which are measures of chronic stress to the fetus.

Cesarean Section↗
PubMed1993

Immune response after surfactant treatment of newborn infants with respiratory distress syndrome.

We examined the sera of 68 newborn infants with respiratory distress syndrome; 49 were treated with a natural porcine-derived surfactant preparation and 19 were controls. Serum of the patients was collected before, 3 weeks and 3 months after surfactant treatment. To detect any antibody that had been raised, we applied diluted serum of the babies in an indirect immunoperoxidase staining technique on frozen pig lung tissue specimens. With light microscopy an immune response could be appreciated as a brown reddish deposit in the porcine lung tissue specimens in 4 out of the 49 surfactant-treated and not in the control babies.

Animals↗
PubMed1993

[Effect of 2 different dosages of a porcine surfactant on pulmonary gas exchange of premature infants with severe respiratory distress syndrome].

BACKGROUND: Doses between 20 and 200 mg/kg body weight (bw) of different surfactant preparations have been recommended in clinical trials for the treatment of neonatal RDS; an optimal dose regimen of surfactant replacement therapy has not yet been defined. Aim of the present pilot study was the evaluation of pulmonary gas exchange in infants with severe RDS following the application of either a high (200 mg/kg bw) or a low (100 mg/kg bw) dose of a natural porcine surfactant (Curosurf). METHODS: 15 neonates were randomized to a high dose regimen, 17 infants to a low dose of surfactant. Apart from a lower 1 minute Apgar in the 100 mg/kg bw group, birth weight, gestational age, sex, 5 minute-Apgar and disease severity (arterial to alveolar oxygenation ratio (a/A-ratio): 0.10 +/- 0.03 [high dose], 0.11 +/- 0.06 [low dose], mean +/- SD) were well matched in both groups. RESULTS: Following surfactant instillation there was a rapid improvement in oxygenation in both groups. The a/A-ratio was slightly higher in the 200 mg/kg bw group during the first 12 hours following surfactant replacement, but statistically this was significantly higher only 4 hours after treatment (0.38 +/- 0.11 vs. 0.24 +/- 0.13, mean +/- SD, p < 0.05). CONCLUSION: The dose of 100 mg/kg bw Curosurf resulted in a rapid improvement in oxygenation and ventilatory requirements; only during the first hours following surfactant replacement there was a slight further improvement with the higher dose of 200 mg/kg bw. The impact of different dose regimens on outcome parameters still has to be defined by a larger clinical trial.

Biological Products↗
PubMed1992

The social competence of very-low-birthweight children: teacher, peer, and self-perceptions.

Whether very-low birthweight (VLBW less than or equal to 1500 gm) children differ from normal birthweight (NBW greater than 2500 gm) children with respect to social (as opposed to intellectual) competence has been a relatively neglected issue. The social competence at school age of 183 VLBW children was therefore compared with that of 183 NBW children born at the same hospital matched for age, gender, social class, parity, and maternal age. A multi-informant, multidefinitional approach to social competence was adopted involving teacher, (same-gender) peer, and self-ratings of the 366 children's levels of social maladjustment, social skill, and peer acceptance. VLBW children from the upper, middle, and lower social classes received significantly higher mean sadness/unhappiness scores (even with IQ covaried) than their NBW counterparts. Mean scores for the VLBW group were also higher for social withdrawal, and lower for both social skill and peer acceptance. Possible antecedents and consequences of such group differences in affect and sociability are suggested.

Child↗
PubMed1992

Long term predictive value of Doppler studies in high risk fetuses.

OBJECTIVE: To determine whether the predictive value of Doppler ultrasonography extends beyond the perinatal period. DESIGN: Descriptive follow-up study. SETTING: Specially designated paediatric clinic in Royal Maternity Hospital. SUBJECTS: 40 children who as high risk fetuses had had assessment of umbilical artery flow velocity waveforms. INTERVENTIONS: Parental history, physical examination, anthropometry, Denver developmental screening test. OUTCOME MEASURES: Weight, height, head circumference, neurological impairment, Denver development screening test RESULT: Abnormal waveforms were an accurate predictor of neonatal outcome, with significant differences in birthweight, gestational age, need for nursery admission, and frequency of intrauterine growth retardation between normal and abnormal waveform groups. However, abnormal Doppler studies were not predictive of long-term adverse sequelae. There were no significant differences in height, head circumference, proportion with neurological impairment, or results of Denver developmental screening test at a median age of five years. CONCLUSION: The predictive value of Doppler ultrasonography is less for long-term growth and neurodevelopment than for perinatal outcome in the high risk fetus.

Child↗
PubMed1992

Retinopathy of prematurity in surfactant treated infants.

Seventy six babies of less than 1500 g birth weight who had surfactant replacement therapy for severe respiratory distress syndrome were studied to assess the presence and stage of subsequent retinopathy of prematurity (ROP). A control group of 90 babies, matched for birth weight and gestational age, who did not have surfactant therapy were also studied. Threshold ROP or greater was found in 1.7% of the surfactant group and 7.8% of the controls. For the babies of less than 1000 g birth weight 4.0% of the surfactant babies and 16.3% of the controls reached threshold disease or greater. It is concluded that surfactant therapy is not associated with an increased incidence or severity of severe ROP in this preterm population.

Biological Products↗
PubMed1992

Plasma manganese levels in the very low birth weight infant are high in early life.

Plasma manganese levels were determined at birth and then serially to 3 months of age in 40 very low birth weight (VLBW) infants (mean birth weight 1,027 g). Mean plasma manganese concentration was 3.6 micrograms/l at birth and 3.0 micrograms/l at 3 months of age. These levels were approximately 3-fold greater than those of a group of 9 adults analysed using the same methods (mean 1.1 micrograms/l). Manganese was also measured in parenteral nutrition fluids, breast milk and 3 preterm formulas. There was no relationship between manganese intake and plasma manganese concentration.

Adult↗
PubMed1992

Factors influencing morbidity and mortality in infants with severe respiratory distress syndrome treated with single or multiple doses of a natural porcine surfactant.

In an international multicenter trial infants with clinical and radiological signs of severe RDS (age 2-15 h, birthweight 700-2,000 g, mechanical ventilation, FiO2 greater than or equal to 0.6, no complicating disease) were randomized to receive either a single dose (n = 176) or up to three subsequent doses (n = 167) of a natural porcine surfactant (Curosurf). Using a logistic regression model, the effects of therapy, birthweight, sex, hospital and other clinical factors on survival and various outcome parameters were evaluated. Mortality (13 vs. 21%, p less than 0.05) and the incidence of pneumothorax (9 vs. 18%, p less than 0.01) were significantly lower in the multiple-dose group. Low birthweight, hospital allocation, low Apgar score and initial disease severity were associated with an increased mortality. Low birthweight, hypothermia (admission temperature less than 36 degrees C) and acidosis (pH less than 7.25) prior to surfactant treatment could be identified as risk factors for the development of intracranial hemorrhage.

Biological Products↗
PubMed1992

Surfactant replacement therapy and the prevalence of acute retinopathy of prematurity.

To determine if surfactant replacement treatment is associated with an increase in the prevalence of retinopathy of prematurity (ROP) we studied 76 preterm babies who were treated with porcine surfactant (Curosurf) for severe respiratory distress syndrome from 1985 to 1990. Babies were first examined by indirect ophthalmoscopy at the equivalent of 32 weeks post-menstrual age and subsequently at 2-week intervals until discharge from hospital. Findings were documented according to the International Classification of ROP. Sixty-two (82%) babies survived to discharge, 7 survivors were not examined due to transfer elsewhere. Acute ROP developed in 14 (29%) of the 49 babies examined (7 stage I, 4 stage II, 2 stage III, and 1 stage IV); one baby required cryotherapy. No baby of birthweight greater than 1,500 g developed ROP. The prevalence of ROP was similar to that reported for non-surfactant-treated very-low-birthweight babies. We conclude that Curosurf treatment does not increase the risk of acute ROP in surviving very-low-birthweight babies.

Biological Products↗
PubMed1992

Raised plasma hypoxanthine levels as a prognostic sign in preterm babies with respiratory distress syndrome treated with natural surfactant.

Plasma hypoxanthine concentration was measured in twelve preterm babies with respiratory distress syndrome (RDS) treated with 200 mg/kg of a porcine surfactant (Curosurf). Five of the babies died within one week and seven survived the neonatal period. Surviving babies had no significant changes in plasma hypoxanthine concentration throughout a one hour study period following the administration of surfactant. By contrast, in nonsurvivors the mean plasma hypoxanthine concentrations increased from 6.8 mumol/l before surfactant administration to 14.2 mumol/l 15 minutes after surfactant treatment. Survivors had a mean maximal increase in plasma hypoxanthine of 1.9 mumol/l 15-30 min factor surfactant treatment compared with 9.4 mumol/l in nonsurvivors (p < 0.05). The babies who developed intracranial hemorrhage had significantly higher maximal plasma hypoxanthine increase (mean 9.6 mumol/l) compared with babies who did not develop intracranial hemorrhage (mean 1.1 mumol/l) (p < 0.01). The combination of high PaO2 and high hypoxanthine concentration could lead to an increased production of oxygen radicals which might be harmful. We conclude that plasma hypoxanthine concentration may serve as an indicator of the prognosis in preterm babies treated with natural surfactant. Further, it seems important to reduce oxygen supplementation as soon as surfactant is given to possibly limit oxygen radical production.

Biomarkers↗
PubMed1992

Randomized European multicenter trial of surfactant replacement therapy for severe neonatal respiratory distress syndrome: single versus multiple doses of Curosurf.

There is now convincing evidence that the severity of neonatal respiratory distress syndrome can be reduced by surfactant replacement therapy; however, the optimal therapeutic regimen has not been defined. This randomized European multicenter trial was designed to determine whether the beneficial effects of a single large dose of Curosurf (200 mg/kg) in babies with severe respiratory distress syndrome (arterial to alveolar oxygen tension ratio approximately 0.10) could be enhanced by using multiple doses of surfactant. Preterm neonates (birth weight 700 to 2000 g) with severe respiratory distress syndrome requiring artificial ventilation with fraction of inspired oxygen greater than or equal to 0.6 were randomized into two groups at an age of 2 to 15 hours. Both groups received the usual dose of Curosurf (200 mg/kg) immediately after randomization. In neonates randomized to receive multiple-dose treatment, two additional doses of Curosurf (100 mg/kg each) were instilled into the airways (12 and 24 hours after the initial dose) provided that the patients still needed artificial ventilation with fraction of inspired oxygen greater than 0.21. In both groups (single dose: n = 176, multiple doses: n = 167) there was a rapid improvement in oxygenation as reflected by a threefold increase in arterial to alveolar oxygen tension ratio within 5 minutes after surfactant instillation (P less than .001), and peak inspiratory pressure and mean airway pressure could be reduced significantly during the first 6 hours after surfactant treatment. In addition, ventilatory requirement (peak inspiratory pressure, ventilatory efficiency index) was reduced in the multiple-dose group 2 to 4 days after randomization (P less than .05 to .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Products↗
PubMed1991

Plasma manganese, selenium and glutathione peroxidase levels in the mother and newborn infant.

Manganese (Mn), selenium (Se) and glutathione peroxidase (GPX) levels were determined in 56 paired samples of maternal and cord blood plasma at birth in both term and preterm pregnancies. Correlations existed between maternal and newborn plasma levels for Se, but not for Mn or GPX. Values of Mn, Se and GPX were all greater in the term than the preterm infant. Levels of Mn were greater in the pregnant than the non-pregnant woman, but levels of Se and GPX were lower during pregnancy.

Female↗
PubMed1991

Surfactant replacement therapy for severe neonatal respiratory distress syndrome: implications for nursing care.

This study, which was part of a European multicentre randomised controlled trial of surfactant administration for severe respiratory distress syndrome, monitored the progress and nursing care of the group of babies enrolled in Belfast. In total 33 preterm babies with birth weights between 700-2000 g were studied. Nineteen babies were treated with surfactant and fourteen acted as controls, receiving conventional therapy with mechanical ventilation alone. All the babies had severe respiratory distress syndrome requiring mechanical ventilation in oxygen concentrations greater than 60% by the age of fifteen hours. The aim of the study was to determine the effect on nursing workload of giving surfactant to babies with severe respiratory distress syndrome. The duration of care, such as the length of time the babies required intensive care and subsequent hospitalisation was calculated for each baby. The characteristics of the treated and control babies were similar but survival in the treated group was significantly greater (79% vs 36%, p less than 0.05). There were no significant differences between the groups for individual nursing requirements. However due to the increase in numbers of surviving surfactant treated babies there was a threefold increase in cumulative nursing workload. Surfactant replacement therapy effectively modifies the course of respiratory distress syndrome but also increases the nursing workload and the need for intensive care. This has implications for staffing and financial support of Neonatal Intensive Care Units once surfactant replacement becomes a routine treatment.

Humans↗