David W A Milligan

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% v17%). 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.

Lung function in children following repair of tracheoesophageal fistula

Lung function and bronchial reactivity by methacholine challenge were studied in 24 patients seven to 18 years after repair of type I tracheoesophageal fistula. Only one patient had no abnormalities of the variables tested. Thirteen patients had obstructive airways disease, five had a restrictive defect, and 15 had a positive methacholine challenge. It is postulated that continuing subclinical aspiration of esophageal contents causes lung damage and renders the airways hyperreactive.

Accelerated telomere shortening following allogeneic transplantation is independent of the cell source and occurs within the first year post transplant.

Telomere shortening has been documented in the blood cells of recipients of allogeneic bone marrow transplants compared with their donors. Allogeneic peripheral blood progenitor cells (PBPCs) have been increasingly used as an alternative to bone marrow. Their advantages include earlier engraftment and immune reconstitution following transplantation. We have measured telomere length of neutrophils and T cells in fully engrafted recipients of allogeneic bone marrow (n = 19) and allogeneic PBPC (n = 17) and also measured sequential telomere length in four patients after transplantation. Overall, significant telomere shortening occurred in recipients in neutrophils (0.3 kb, P < 0.001) and T cells (0.2 kb, P = 0.045). The data demonstrate that first, the degree of shortening was the same for BM and PBPC transplants and was not related to the time taken to engraft neutrophils and platelets and second, telomere shortening occurs in the first year post transplant without further shortening during the period of observation. These data suggest that the superiority of engraftment seen in PBPC transplants is independent of telomere shortening and other mechanisms such as homing or seeding may be more important. Bone Marrow Transplantation (2001) 27, 1283–1286.

Foot length, an accurate predictor of nasotracheal tube length in neonates.

BACKGROUND Existing guidelines for optimal positioning of endotracheal tubes in neonates are based on scanty data and relate to measurements that are either non-linear or poorly reproducible in sick infants. Foot length can be measured simply and rapidly and is related to a number of external body measurements. OBJECTIVES To evaluate the relation of foot length to nasotracheal length in direct measurements at post mortem examinations, and then compare its clinical relevance with traditional weight based estimates in a randomised controlled trial. METHODS The dimensions of the upper airway were measured at autopsy in 39 infants with median (range) postmenstrual age and birth weight of 32 (24–43) weeks and 1630 (640–3530) g. The regression equations with 95% prediction intervals were calculated to estimate the optimal nasotracheal length from foot length. In a randomised trial, 59 neonates were nasally intubated according to foot length and body weight based estimates to assess the achievement of “optimal” and “satisfactory” tube placements. RESULTS In the direct measurements of the airway at autopsy, foot length was a better predictor of nasotracheal distances (r 2 = 0.79) than body weight, gestational age, and head circumference (r 2 = 0.67, 0.58, and 0.60 respectively). Measurement of foot length was easy and highly reproducible. In the randomised controlled trial, there were no significant differences between the foot length and body weight based estimates in the rates of optimal (44% v56%) and satisfactory (83% v 72%) endotracheal tube placements. CONCLUSIONS Foot length is a reliable and reproducible predictor of nasotracheal tube length and is at least as accurate as the conventional weight based estimation. This method may be particularly valuable in sick unstable infants.

Haemodynamic effects of altering arterial oxygen saturation in preterm infants with respiratory failure

AIMS To examine the haemodynamic effects of brief alteration in arterial oxygenation in preterm infants with respiratory failure. METHODS Eighteen preterm infants with respiratory failure, aged 9–76 hours, underwent detailed Doppler echocardiographic assessment at 86%, 96%, and 100% SaO2, achieved by altering the FIO2. Sixteen were receiving intermittent positive pressure ventilation, median FIO2 0.45 (0.20–0.65), median mean airway pressure 12 cm H2O (0–20). SaO2 was stable for 15 minutes at each stage. Four parameters of pulmonary arterial pressure were measured: peak velocity of tricuspid regurgitation and peak velocity of left to right ductal flow, TPV:RVET ratio and PEP:RVET ratio, measured at the pulmonary valve, along with flow velocity integrals at the aortic and pulmonary valves, and systemic arterial pressure. Ductal size was graded into closed, small, moderate, large with imaging, pulsed and continuous wave Doppler. RESULTS Between 86% and 96% SaO2, there were no consistent changes, but in three of the 12 with a patent ductus arteriosus (PDA) there was ductal constriction, with complete closure in one. Between 96% and 100% SaO2, peak ductal flow velocity rose significantly in four of eight with a PDA. Ductal constriction occurred in four infants; in three this was associated with a significant fall in aortic flow integral and a rise in aortic pressure (4–6 mm Hg). Overall, 11 infants went from 86% to 100% SaO2 and pulmonary arterial pressure fell significantly in seven. CONCLUSION A brief rise in SaO2 within the range maintained by most neonatal units can cause significant ductal constriction. The fall in pulmonary arterial pressure with 100% SaO2 seen in most infants was associated with a fall in pulmonary blood flow (or no change), rather than a rise, indicating that the dominant haemodynamic effect was ductal constriction rather than pulmonary vasodilation.

Positive pressure ventilation and cranial volume in newborn infants.

The relationship between changes in airways pressure, pleural pressure, and cranial volume was studied in a group of sick newborn infants requiring ventilatory assistance. Cranial volume increased appreciably only when lung compliance was such that more than 20% of the applied airways pressure was transmitted to the pleural space, or if the absolute pleural pressure was greater than 4 cmH2O above atmospheric pressure. The findings stress the need for more-critical monitoring during periods of rapid change in lung compliance.

Changes in management policies for extremely preterm births and neonatal outcomes from 2003 to 2012: two population‐based studies in ten European regions

To investigate changes in maternity and neonatal unit policies towards extremely preterm infants (EPTIs) between 2003 and 2012, and concurrent trends in their mortality and morbidity in ten European regions.

Oxygen saturation and retinopathy of prematurity—Authors' response

Editor—We are happy to make it clear that we have never suggested that hypoxia is “beneficial” to babies with chronic lung disease. Indeed in describing our own practice we said, quite specifically, that “babies who were at least 8 weeks …