Ian A Laing

Deciding for imperilled newborns: medical authority or parental autonomy?

The ethical issues around decision making on behalf of infants have been illuminated by two empirical research studies carried out in Scotland. In-depth interviews with 176 medical and nursing staff and with 108 parents of babies for whom there was discussion of treatment withholding/withdrawal, generated a wealth of data on both the decision making process and the management of cases. Both staff and parents believe that parents should be involved in treatment limitation decisions on behalf of their babies. However, whilst many doctors and nurses consider the ultimate responsibility too great for families to carry, the majority of parents wish to be the final arbiters. We offer explanations for the differences in perception found in the two groups. The results of these empirical studies provide both aids to ethical reflection and guidance for clinicians dealing with these vulnerable families. They demonstrate the value of empirical data in the philosophical debate.

Clinical Diagnosis of Pneumothorax Is Late: Use of Trend Data and Decision Support Might Allow Preclinical Detection

Pneumothorax in the newborn has a significant mortality and morbidity. Early diagnosis would be likely to improve the outlook. Forty-two consecutive cases of pneumothorax that developed after admission to a tertiary referral neonatal medical intensive care unit over 4 y from 1993 to 1996 were reviewed. The time of onset of the pneumothorax was determined by retrospective evaluation of the computerized trend of transcutaneous carbon dioxide (tcpCO2) and oxygen tensions. The timing of the occurrence in the notes and x-rays determined the time of clinical diagnosis noted at the time. The difference was the time the condition was undiagnosed. The overall mortality before discharge was 45% (19cases), four patients succumbing within 2 h. The median time (range) between onset of pneumothorax and clinical diagnosis was 127 min (45–660 min). In most cases, the endotracheal tube was aspirated and the transcutaneous blood gas sensor was repositioned, and in at least 40% of the cases, the baby was reintubated before the diagnosis was made. Reference centiles were constructed for level of tcpCO2 and slope of the trended tcpCO2 over various time intervals (in minutes) from 729 infants from 23 to 42 wk gestation who needed intensive care during the first 7 d of life from the same time period. The 5-min tcpCO2 trend slopes were compared in index and matched control infants. The presence of five consecutive and overlapping 5-min slopes greater than the 90th centile showed good discrimination for a pneumothorax (area under the receiver operating characteristic curve, 89%). We concluded that 1) the clinical diagnosis of pneumothorax was late, occurring when infants decompensate;2) trend monitoring of tcpCO2 might allow the diagnosis to be made earlier if used properly; and 3) use of reference centiles of the trended slopes of tcpCO2 might be used for automatic decision support in the future.

Magnesium metabolism in preterm infants: Effects of calcium, magnesium, and phosphorus, and of postnatal and gestational age

This study tests the hypothesis that increasing the calcium and phosphorus content of formulas for very low birth weight (VLBW) infants to the level required to decrease the incidence of rickets has a negative impact on magnesium balance. Using formulas variously supplemented with these minerals, we measured absorption and retention in two groups of preterm infants: (1) VLBW infants, less than 1500 gm and at less than 32 weeks of gestational age, with 3-day mineral balances begun at days 10, 20, 30, and 40; and (2) low birth weight infants appropriately grown and at 32 to 34 weeks of gestational age, with a single 3-day balance begun at day 10. Magnesium did not affect calcium balance in VLBW or low birth weight infants but promoted phosphorus retention in VLBW infants from day 20 onward. Absorption and retention of magnesium increased with postnatal age in VLBW infants, but this effect was obvious only when calcium or phosphorus intakes were low or when magnesium intake was high. Calcium and phosphorus supplementation further reduced magnesium absorption and retention in VLBW infants to the extent that they were in negative balance throughout the study; however, magnesium supplementation improved absorption and retention in VLBW infants. The low birth weight infants absorbed and retained more magnesium than VLBW infants at the same postnatal age whether or not magnesium was supplemented. We conclude that magnesium deficits occur at currently recommended intakes of 10 mg/kg/day for VLBW infants with calcium and phosphorus intakes that allow retentions equivalent to in utero accretions; however, with magnesium intakes approaching 20 mg/kg/day, appropriate retention can be achieved.

Randomised controlled trial of respiratory system compliance measurements in mechanically ventilated neonates

AIM To determine whether outcomes of neonatal mechanical ventilation could be improved by regular pulmonary function testing. METHODS Two hundred and forty five neonates, without immediately life threatening congenital malformations, were mechanically ventilated in the newborn period. Infants were randomly allocated to conventional clinical management (control group) or conventional management supplemented by regular measurements of static respiratory system compliance, using the single breath technique, with standardised management advice based on the results. RESULTS Fifty five (45%) infants in each group experienced one or more adverse outcomes. The median (quartile) durations of ventilation and oxygen supplementation were 5 (2–12) and 6 (2–34) days for the control group, and 4 (2–9) and 6 (3–36) days for the experimental group (not significant). On post-hoc secondary analysis, control group survivors were ventilated for 1269 days with a median (quartile) of 5 (2–13) days, and experimental group survivors were ventilated for 775 days with a median (quartile) duration of 3 (2–8) days (p=0.03). CONCLUSIONS Although primary analysis did not show any substantial benefit associated with regular measurement of static respiratory system compliance, this may reflect a type II error, and a moderate benefit has not been excluded. Larger studies are required to establish the value of on-line monitoring techniques now available with neonatal ventilators.

Static respiratory compliance in the newborn. III: Early changes after exogenous surfactant treatment.

Static respiratory system compliance (Crs) was measured by a single breath passive expiratory flow technique in 73 newborn infants treated with exogenous surfactant. The first 39 received Curosurf, a natural porcine surfactant. The other 34 received Exosurf Neonatal, a synthetic surfactant. All had a diagnosis of respiratory distress syndrome with an arterial/alveolar oxygen ratio < 0.22. Static Crs and arterial blood gases were measured shortly before, and at three and 12 hours after the first dose of surfactant. In 32 infants treated with Curosurf with initial static Crs < 1.8 ml/cm H2O/m body length, which is consistent with surfactant deficiency, static Crs improved by 18% at three hours and by 39% at 12 hours along with a median reduction in fractional inspired oxygen (FIO2) at three hours by 0.32. In 26 infants treated with Exosurf with initial Crs < 1.8 ml/cm H2O/m, Crs did not improve three and 12 hours after treatment and oxygenation improved less than after Curosurf, with a median reduction in FIO2 at three hours of 0.11. Fifteen of the 73 (21%) infants had initial static Crs of > or = 1.8 ml/cm H2O/m, not consistent with surfactant deficiency. Thirteen of these 15 infants showed a fall in static Crs after surfactant treatment, raising the question whether exogenous surfactant did them more harm than good. Initial static Crs and surfactant type both appear to determine the early response to the first dose of surfactant. Only a considerably larger, randomised study can show which surfactant is more effective in reducing adverse clinical outcome.

Prevention of subglottic stenosis in neonatal ventilation

Mechanical ventilation of the newborn is now widely used in neonatal intensive care. The oro-tracheal route of intubation is simpler, but for long-term ventilation has been considered unstable. A method of fixation of oro-tracheal tubes is described which overcomes this instability. Five hundred consecutive ventilated infants were intubated by the oro-tracheal route and the tube was fixed by the method described. Of the 500 ventilated infants, 213 died without being extubated. Of the 287 survivors, 44 developed a degree of post-extubation stridor. No surviving infant developed clinical evidence of subglottic stenosis and in almost 200 postmortem examinations laryngeal narrowing was not identified. The method of oro-tracheal fixation described is stable and may reduce the incidence of subglottic stenosis.

Do phototherapy hoods really protect the neonate

The objective of the current study was to evaluate the protection given to the eyes of neonates by an Amber 300 phototherapy hood during blue‐light phototherapy from Drager Phototherapie 800 units, and to make recommendations for clinical practice. Hazard‐weighted blue‐light radiance of phototherapy lamps was measured inside neonatal incubators, with and without the use of a protective phototherapy hood. The study was carried out in a tertiary referral neonatal unit. No patients were involved. A mannequin was used as model of a jaundiced neonate being treated with blue‐light phototherapy. The study shows that hazard‐weighted blue‐light radiance levels detectable from within the space enclosed by the hood may be several times greater than accepted industrial threshold limits for adults.

Controlling an outbreak of MRSA in the neonatal unit: a steep learning curve

Meticillin resistant Staphylococcus aureus (MRSA) can cause serious infections in the newborn. While audit may show that a neonatal unit’s main cause of infective morbidity is the coagulase negative staphylococcus, health authorities and politicians fear the implications of MRSA and its impact on the general public. MRSA causes mortality and morbidity in other areas of hospitals in the UK and in many other countries and there is an uneasy acceptance that this is now the established norm. However, MRSA in the neonatal unit carries sensitivities which have a huge impact on the reactions of health authorities, politicians and the press.

Mean Blood Pressure (BP) Reference Values with Gestation in Preterm (PT) Infants During the First Week of Life † 1293

Background: There is little other than empiricle data on the reference values for blood pressure of preterm infants and what there is is unrelated to gestation and postnatal age. For 10 years we have monitored intravascular BP on all sick PT infants over the first week of life.

STATIC RESPIRETARY SYSTEM COMPLIANCE (CRS): AN EARLY INDEX OF PROGNOSIS AND DISEASE SEVERITY IN IHE NEWBORN

We compared the prognostic value of static Crs measured in the first 24 hr using a single breath airway occlusion technique (Le Souefet al, Am Rev Resp Dis 1984:129:552-6) with mean FiO2 in the first 12 hr in 48 ventilated new horn infants of median (range) birthweight 1270 (480-3500) g. In a further 33 infants, Crs measured before surfactant administration in the first 24 hr was compared to junior doctors visual estimates of respiratory compliance (i) using a visual analogue scale (analogue Crs) and (ii) based on their assesments of tidal volume (V1 Crs).Static Crs provides an estimate of repiratory discase severity which may be less distorted by ventilator management than indices based on blood gases, such as FiO2. Visual estimates of Crs by junior doctors were unreliable. Routine measurement of Crs may therefore be a valuable adjunct to clinical management.