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Aim: To establish a reference range for oxygen saturation (SpO(2)) in well preterm infants to guide home oxygen therapy using a pulse oximeter and Pulse Oximetry Data Analysis Software (PODS)., Methods: SpO(2) and heart-rate profiles of healthy preterm infants receiving mechanical ventilation for less than 6 h and supplemental oxygen for less than 48 h were monitored using a pulse oximeter. The stored data were downloaded from the monitor to a personal computer as individual files. Each infant's files of SpO(2) were subsequently displayed in graphic form, and a reference range was constructed using dedicated software, PODS., Results: 43 infants were studied. The median value of all infants mean SpO(2) values was 95% (range 92-99%). The median duration of saturations less than 85% and between 85% and 90 % were 1% and 2% respectively. Using the study group median, 5th and 95th percentiles, a cumulative frequency curve of time against SpO(2) value was constructed (representing the reference range of SpO(2) profiles in healthy preterm infants)., Conclusion: The SpO(2) reference range can be used as an easy and practical guide to compare SpO(2) profiles of infants on home oxygen therapy and guide their oxygen therapy.

Aim: To determine whether individualised limits for arterial oxyhaemaglobin saturation by pulse oximetry (SpO(2)) are more effective for detecting hypoxia and hyperoxia in sick newborn infants than setting fixed limits., Methods: Six hundred and ninety two simultaneous measurements of SpO(2) and partial pressure of oxygen in arterial blood (PaO(2)) were made in 95 infants. The sensitivity and specificity for predicting hypoxia and hyperoxia using various fixed SpO(2) limits and also individualised SpO(2) limits, calculated using a standard equation, were determined and compared., Results: None of the fixed limits for SpO(2) was both sensitive and specific for predicting hypoxia and/or hyperoxia. There was no difference between these and individualised limits., Conclusion: Individualised SpO(2) limits are no more effective than fixed SpO(2) limits for predicting hypoxia and/or hyperoxia in sick newborn infants. SpO(2) monitoring is not an ideal method for assessing PaO(2).

Aim: To construct a reference range of SpO2 values in healthy preterm infants using a simple data logging device., Methods: Thirty three healthy preterm infants were monitored for a continuous period of 4 hours at rest using an Ohmeda Biox 3700 E Pulse Oximeter and an electronic data logger (Rustrack Ranger). Stored data were downloaded and saved as individual files on a personal computer., Results: The study group median and 5th and 95th percentiles were used to construct a cumulative frequency curve of time against SpO2 value, representing the normal reference range of SpO2 profiles in healthy preterm infants., Conclusion: Comparison of an infant's SpO2 profile against this curve may be more helpful in guiding supplemental oxygen treatment in that individual than a figure for a mean SPO2 and its standard deviation.

Aim: To determine whether treatment with inhaled nitric oxide (NO) and/or dexamethasone reduces the incidence of chronic lung disease (CLD) and/or death in high risk preterm infants., Methods: Infants below 32 weeks of gestation were recruited at 96 hours of age if they were deemed to be at high risk of developing CLD. Infants were randomly assigned to one of four treatment groups using a factorial design: (1) 5-20 parts per million inhaled NO for 72 hours; (2) 0.5-1 mg/kg/day intravenous dexamethasone for 6 days; (3) both drugs together; (4) continued conventional management., Results: Forty two infants were randomised: 10 infants received inhaled NO alone; 11 dexamethasone alone; 10 both treatments; and 11 neither treatment. There was no difference in the combined incidence of CLD and/or death before discharge from hospital between either infants treated with inhaled NO and controls (RR 1.05, 95% CI 0.84-1.25), or those treated with dexamethasone and controls (RR 0.95, 95% CI 0.79-1.18)., Conclusions: At 96 hours of age, neither treatment with inhaled NO nor dexamethasone prevented CLD or death.

Aim: To investigate changes in various cardiorespiratory variables with inhaled nitric oxide (NO), as part of a randomised controlled trial., Methods: Infants were treated with inhaled NO for 72 hours. Changes in oxygenation were assessed using the oxygenation index (OI). Serial changes in pulmonary artery pressure (PAP) were assessed using the Doppler derived acceleration time to right ventricular ejection time ratio (AT:RVET). Doppler measurements of right ventricular output, pulmonary blood flow, and systolic PAP was performed in a subset of infants., Results: Twenty infants received inhaled NO and 22 acted as controls. Infants were treated at a median dose of 5 (range 5 to 20) ppm. There was a fall in median OI by 17% in treated infants within 30 minutes of treatment. The fall in OI in treated infants was significantly different from the response in controls until 96 hours. Infants treated with inhaled NO showed a rapid response with a median rise in AT:RVET of 0.04 (range -0.06 to 0.12) within 30 minutes. The change in AT:RVET was significantly different from controls until 4 hours. Median systolic PAP also fell in treated infants by 6.1 (range -14.4 to -4.4) mm Hg within 1 hour. Changes in OI were significantly associated with changes in PBF (r = 0.44), but not with changes in AT:RVET., Conclusion: Treatment with inhaled NO rapidly improves oxygenation and lowers PAP in preterm infants. However, these effects are transient and treatment does not influence long term outcome.

The gall bladder size was measured in 30 newborn infants: 18 had been fed parenterally and 12 enterally. The two groups were comparable for gestational age, birthweight, postnatal age and study weight. Exclusion criteria were haemodynamic instability, septicaemia, abdominal disease and opioid treatment. Gall bladder size was measured at 15 minute intervals for 90 minutes using real-time ultrasonography and the volume calculated using the ellipsoid method. Parenterally fed infants had further measurements at 120, 150, and 360 minutes. The gall bladder was significantly larger in parenterally fed infants than in enterally fed infants (p = 0.0001). In enterally fed infants a 50% reduction in gall bladder volume was observed 15 minutes after starting the feed with a return to baseline volume by 90 minutes. In parenterally fed infants there was no gall bladder contraction. Such information may give insight into the pathophysiology of hepato-biliary complications during parenteral nutrition in infants.

The pulmonary artery pressure (PAP) changes were studied using Doppler echocardiography in preterm infants treated with an artificial surfactant (Exosurf) during the acute phase of respiratory distress syndrome (RDS). The ratio of pulmonary artery acceleration time to the right ventricular ejection time (AT:RVET), measured from the Doppler wave form, was determined in 38 infants before the first dose of Exosurf, at one and six hours after the first dose, immediately before the second dose of Exosurf, and at one, six, 12, 36, and 60 hours subsequently. The median AT:RVET ratio corrected for heart rate (AT:RVET(c)) increased significantly an hour after administration of the first dose of Exosurf from 0.330 (0.273-0.410) to 0.380 (0.303-0.445) and similarly an hour after the second dose from 0.426 (0.252-0.495) to 0.440 (0.373-0.500). These changes occurred against a steady increase in the median AT:RVET(c) over the first 72 hours. It is concluded that the reduction in PAP correlates well with clinical parameters of disease severity and raises questions regarding the mode of action of Exosurf.

Thirty two infants born to mothers taking methadone and 32 matched controls were studied to determine the incidence, timing, and frequency of persistence of withdrawal signs in infants born to maternal methadone users. Twelve (37%) infants received treatment for symptoms of withdrawal. The median length of time from birth to initiation of treatment was 23 hours (range 15-64 hours), the median length of treatment was six days (range 1-22 days). In the first six weeks after birth there was no significant difference in minor withdrawal symptoms and signs, general practitioner or accident and emergency visits between the group who did not receive treatment for withdrawal and the control group. If immediate treatment for withdrawal is not required major symptoms do not subsequently occur with great frequency. Late withdrawal signs were not seen in this study.