Effect of caffeine on neonatal splanchnic blood flow.
(33/4443)
Doppler ultrasound was used to study the effect of the first intravenous dose of caffeine on splanchnic haemodynamics in preterm neonates. Peak systolic velocity in the superior measenteric artery and coeliac axis was significantly reduced for 6 hours after caffeine infusion. The effect of this reduction in blood flow to the neonatal gut is not known. (+info)
Meta-analysis of elective high frequency ventilation in preterm infants with respiratory distress syndrome.
(34/4443)
AIM: To summarise the evidence on the efficacy of elective high frequency ventilation compared with conventional ventilation in preterm infants with respiratory distress syndrome. METHODS: A search from 1987 onwards was made on Embase, Medline, and the Cochrane Library. A questionnaire was also circulated during an international meeting on high frequency ventilation. To be included in the data synthesis, studies had to be randomised controlled trials comparing elective high frequency ventilation with conventional ventilation in preterm infants with respiratory failure due to respiratory distress syndrome; indices of mortality, chronic pulmonary morbidity, and other clinically relevant outcomes were compared. Studies were assessed for methodological validity according to explicit criteria. RESULTS: Ten studies (a total number of 1345 preterm infants) were considered for data synthesis. No difference in mortality at 28 or 30 days, nor in oxygen dependency at 28 days was found between both types of ventilation. Reduced oxygen dependency at the postconceptional age of 36 weeks (RR 0.50, 95% CI 0.32-0.78) was found, but so was an increase in grades 3 and 4 intraventricular haemorrhage (IVH) (RR 1.31, 95% CI 1.04-1.66). Those studies using a high lung volume ventilatory strategy showed a significant decrease in oxygen dependency at the postconceptional age of 36 weeks (RR 0.44, 95% CI 0.27-0.73), but no increase in severe IVH (RR 0.78, 95% CI 0.45-1.37). CONCLUSIONS: Although high frequency ventilation reduces chronic lung disease, it seems to increase the risk of severe IVH. These results are dominated by an early study where the absence of benefit on pulmonary outcomes, and the increase in adverse neurological events, could be related to the low volume ventilatory strategy used. Recent studies, using a high lung volume approach, show better pulmonary outcomes without any increase in intracranial morbidity. Still, uncertainty remains about long term pulmonary and neurodevelopmental outcome. (+info)
Raised concentrations of aldehyde lipid peroxidation products in premature infants with chronic lung disease.
(35/4443)
AIM: To indicate the extent of lipid peroxidation induced by oxidative stress, by measuring aldehyde end products in biological samples. METHODS: A highly specific gas chromatography and mass spectrometry (GC/MS) method was used to measure plasma concentrations of aliphatic aldehydes within the first week of life in 13 premature infants who subsequently developed chronic lung disease (CLD) and 11 infants without CLD (non-CLD). The oxime-tert-butyldimethylsilyl derivatives of aldehydes were analysed using 2,2,6,6-d4-cyclohexanone as the internal standard. RESULTS: All of the aldehydes measured were raised in those infants with CLD compared with non-CLD infants. Plasma concentrations of heptanal, 2-nonenal, and 4-hydroxynonenal (HNE) were significantly increased in CLD infants on the day of birth, while the differences in all aldehydes between the two groups were not significant at 4-6 days of age. Logistic regression analysis showed that the increase in these three aldehydes within the first 24 hours of life independently showed significant associations with the development of CLD. In particular, an HNE concentration of > or = 200 nM on day 0 was the best predictor for the early detection of CLD (odds ratio = 32.0), followed by a 2-nonenal concentration of > or = 150 nM (odds ratio = 16.0). CONCLUSIONS: These findings suggest that lipid peroxidation may have a role in the pathogenesis of neonatal CLD. (+info)
Measurement of protein flux with positron emission tomography in neonates.
(36/4443)
AIM: To determine whether abnormal transvascular protein flux can be measured with positron emission tomography (PET) in neonates with respiratory distress syndrome (RDS). METHODS: Fourteen infants with normal gas exchange (non-RDS group) underwent one PET measurement and 12 infants with RDS (the RDS group) underwent two measurements of protein flux, as determined by the pulmonary transcapillary escape rate for 68Gallium labelled transferrin (PTCER). RESULTS: The mean PTCER for the RDS infants (132 +/- 39 10(-4)/min) was significantly greater than that for infants without RDS (75 +/- 27 10(-4)/min). PTCER did not change between measurements in the infants with RDS, including five who received and responded to surfactant replacement between the two scans. CONCLUSIONS: Increased transvascular flux of large molecular weight proteins complicates RDS in preterm infants. PET provides a tool with which to evaluate the processes that contribute to pulmonary dysfunction in neonates. (+info)
Prostacyclin concentrations and transitional circulation in preterm infants requiring mechanical ventilation.
(37/4443)
AIM: To describe the association between early postnatal prostacyclin concentrations in preterm infants; echocardiographic measurements of ductal diameter and ventricular output and clinical outcomes of intraventricular haemorrhage (IVH) and patent ductus arteriosus (PDA). METHODS: Forty nine preterm infants born before 30 weeks of gestational age (median birthweight 980 g, median gestational age 27 weeks) underwent echocardiographic studies at 5, 12, 24 and 48 hours of postnatal age. Measurements included ventricular outputs and the ductal shunt diameter as a measure of the shunt size. Simultaneous measurements of blood pressures, mean airway pressure and inspired fraction of oxygen (FIO2) were recorded. A blood sample for the prostacyclin metabolite 6-ketoprostaglandin F1-alpha (6KPGF1 alpha) was taken at the 5 and 24 hour echocardiogram. RESULTS: The mean 6KPGF1 alpha concentrations were higher than adult concentrations at 5 (515 pg/ml) and 24 (255 pg/ml) hours. There was no association with gestational age. Raised 6KPGF1 alpha concentrations were related to increased need for mechanical ventilation and severity of respiratory disease. At 5 hours, increased 6KPGF1 alpha concentrations were associated with larger PDA and at 24 hours with larger PDA and higher left ventricular output. Infants with higher 6KPGF1 alpha concentrations were more likely to develop clinically significant PDA. There was no association between early measurements of 6KPGF1 alpha and IVH. CONCLUSIONS: Early postnatal prostacyclin concentrations are markedly raised in preterm infants, particularly in those with more severe lung disease. Raised 6KPGF1 alpha concentrations were associated with an increased ductal diameter and subsequent PDA, but not IVH. (+info)
Systolic blood pressure in babies of less than 32 weeks gestation in the first year of life. Northern Neonatal Nursing Initiative.
(38/4443)
AIM: To define the normal range of systolic blood pressure in a non-selective population based sample of babies of low gestation throughout early infancy. METHODS: Daily measurements of systolic blood pressure were made in all the babies of less than 32 weeks gestation born in the North of England in 1990 and 1991 during the first 10 days of life. Additional measurements were obtained from 135 of these babies throughout the first year of life. Systolic pressure was measured by sensing arterial flow with a Doppler ultrasound probe. It was assumed that blood pressure had never been pathologically abnormal in the neonatal period if the child was alive and free from severe disability two years later. Data of adequate quality were available from 398 such children. Additional data wer collected, for comparative purposes, from 123 babies of 32, 36, or 40 weeks of gestation. RESULTS: Systolic pressure correlated with weight and gestation at birth, and rose progressively during the first 10 days of life. The coefficient of variation did not vary with gestational or postnatal age (mean value 17%), the relation with gestation being closer than with birthweight. Systolic pressure rose 20% during the first 10 days from an initial mean of 42 mm Hg in babies of 24 weeks gestation, and by 42% from an initial mean of 48 mm Hg in babies of 31 weeks gestation. These findings were not altered by the exclusion of data from 14 babies who had inotropic support during this time. Simultaneous measurements in three centres using an oscillometric technique revealed that this technique tended to overestimate systolic pressure when this was below average. Systolic pressure finally stabilised at a mean of 92 (95% CI 72-112) mm Hg at a postconceptional age of 44-48 weeks irrespective of gestation at birth. CONCLUSION: Systolic blood pressure 4-24 hours after birth was less than gestational age (in weeks) in only 3% of non-disabled long term survivors. Systolic pressure rose with increasing gestation and increasing postnatal age, but stabilised some six weeks after term, regardless of gestation at birth. (+info)
Randomised controlled trial of trophic feeding and gut motility.
(39/4443)
OBJECTIVES: To determine the effect of trophic feeding on gastric emptying and whole gut transit time in sick preterm infants. METHODS: A randomised, controlled, prospective study of 70 infants weighing less than 1750 g at birth, who were receiving ventilatory support, was performed. Group TF (33 infants) received trophic feeding from day 3 (0.5 ml/h if birthweight less than 1 kg, 1 ml/h if greater or equal to 1 kg) in addition to parenteral nutrition until ventilatory support finished. Group C (37 infants) received parenteral nutrition alone until ventilatory support finished. Expressed breast milk or a preterm formula were given according to maternal preference. Gastric emptying was assessed within 24 hours of nutritive milk feeding equal to 90 ml/kg/day, using ultrasound scans to measure the reduction in the gastric antral cross sectional area after a feed. Whole gut motility was assessed at both 3 and 6 weeks of age by measuring the whole gut transit time (WGTT) of the marker carmine red. RESULTS: There was no significant difference between groups in their gastric half emptying time, median difference (95% confidence interval) 2.6 (-5.9, 13.9) minutes. The WGTT was significantly faster (p < 0.05) in group TF at both 3 and 6 weeks; median difference -13 (-47, -0.1) and -12.5 (-44, -0.5) hours, respectively. CONCLUSIONS: Trophic feeding enhances whole gut motility but not gastric emptying. This effect could subsequently improve milk tolerance in sick preterm infants. (+info)
Pharmacokinetics and metabolism of rectally administered paracetamol in preterm neonates.
(40/4443)
AIM: To investigate the pharmacokinetics, metabolism, and dose-response relation of a single rectal dose of paracetamol in preterm infants in two different age groups. METHODS: Preterm infants stratified by gestational age groups 28-32 weeks (group 1) and 32-36 weeks (group 2) undergoing painful procedures were included in this study. Pain was assessed using a modified facies pain score. RESULTS: Twenty one infants in group 1 and seven in group 2 were given a single rectal dose of 20 mg/kg body weight. Therapeutic concentrations were reached in 16/21 and 1/7 infants in groups 1 and 2, respectively. Peak serum concentrations were significantly higher in group 1. Median time to reach peak concentrations was similar in the two groups. As serum concentration was still in the therapeutic range for some infants in group 1, elimination half life (T1/2) could not be determined in all infants: T1/2 was 11.0 +/- 5.7 in 11 infants in group 1 and 4.8 +/- 1.2 hours in group 2. Urinary excretion was mainly as paracetamol sulphate. The glucuronide:sulphate ratio was 0.12 +/- 0.09 (group 1) and 0.28 +/- 0.35 (group 2). The pain score did not correlate with therapeutic concentrations. CONCLUSIONS: A 20 mg/kg single dose of paracetamol can be safely given to preterm infants in whom sulphation is the major pathway of excretion. Multiple doses in 28-32 week old neonates would require an interval of more than 8 hours to prevent progressively increasing serum concentrations. (+info)