Effects of fetal haemoglobin on systemic oxygenation in preterm infants and the development of retinopathy of prematurity PacIFiHER Report No. 2

Background/aimsFetal haemoglobin (HbF) has an oxyhaemoglobin dissociation curve that may affect systemic oxygenation and the development of retinopathy of prematurity (ROP). The study aim is to characterise the effects of HbF levels on systemic oxygenation and ROP development.MethodsProspective study conducted from 1 September 2017 through 31 December 2018 at the Johns Hopkins NICU. Preterm infants with HbF measured at birth, 31, 34 and 37 weeks post-menstrual age (PMA), complete blood gas and SpO2 recorded up to 42 weeks PMA, and at least one ROP exam were included.ResultsSixty-four preterm infants were enrolled. Higher HbF was associated with significantly higher SpO2, lower PCO2, lower FiO2 from birth to 31 weeks PMA and 31 to 34 weeks PMA (rs=0.51, rs=−0.62 and rs=−0.63; p<0.0001 and rs=0.71, rs=−0.58 and rs=−0.79; p<0.0001, respectively). To maintain oxygen saturation goals set by the neonatal intensive care unit, higher median FiO2 was required for HbF in the lowest tercile from birth compared with HbF in the highest tercile to 31 weeks and 31 to 34 weeks PMA; FiO2=35 (21–100) versus 21 (21–30) p<0.006 and FiO2=30 (28–100) versus 21 (21–30) p<0.001, respectively. Preterm infants with ROP had poorer indices of systemic oxygenation, as measured by median levels of SpO2 and PCO2, and lower levels of HbF (p<0.039 and p<0.0001, respectively) up to 34 weeks PMA.ConclusionLow HbF levels correlated with poor oxygenation indices and increased risk for ROP. O2 saturation goals to prevent ROP may need to incorporate relative amount of HbF.

Type 1 diabetes mellitus presenting with diabetic ketoacidosis in a child with Patau syndrome (trisomy 13) and persistent fetal haemoglobin

A 35-month-old boy with non-mosaic Patau syndrome presented in diabetic ketoacidosis and was diagnosed with type 1 diabetes mellitus. A decision to treat this unanticipated medical problem was made in conjunction with the child’s parent, and he improved with fluid resuscitation and insulin treatment. Acute kidney injury with hypernatraemia complicated his treatment, but this resolved with careful intravenous fluid management. The child survived and was followed up in the diabetes clinic where ongoing management was complicated by persistent fetal haemoglobin, which meant that glycated haemoglobin could not be used to gauge his glucose control.

Turning Back the Sickle Cell Disease: A New Drug into Play

Researchers at the Fulcrum Therapeutics developed a bioavailable drug candidate called FTX 6058 – (a novel small molecular fetal haemoglobin inducer for sickle cell disease) that can restore the body’s ability to produce fetal haemoglobin

Low fraction of fetal haemoglobin is associated with retinopathy of prematurity in the very preterm infant

BackgroundBlood loss and adult blood transfusions are common during the neonatal period in preterm infants. The objective of the study was to clarify if degree of loss of fetal haemoglobin (HbF) was associated with later retinopathy of prematurity (ROP).MethodsRetrospective observational cohort study. In total, 452 infants born <30 gestational weeks at a tertiary level neonatal intensive care unit in Sweden in 2009–2015 were included, 385 of whom had final ROP outcome. Mean fractions of HbF (%) during the first postnatal week were calculated from 11 861 arterial blood gas analyses. The relationship between fractions of HbF (%) and ROP was evaluated.ResultsThe mean (SD) gestational age (GA) at birth was 26.4 (1.8) weeks. In total, 104 (27 %) infants developed ROP. Higher fraction of HbF (%) was associated with a lower prevalence of ROP, OR by a 10% increase 0.83 (95% CI: 0.71 to 0.97; p=0.019), following adjustment for GA at birth, small for GA and sex. Infants with HbF (%) in the lowest quartile had OR of 22.0 (95% CI: 8.1 to 59.2; p<0.001) for ROP development compared with those in the highest quartile. The predictive ability (area under the curve) of HbF (%) in the full model during the first week was 0.849 for ROP.ConclusionsEarly low fraction of HbF is independently associated with abnormal retinal neurovascular development in the very preterm infant. The potential benefit of minimising blood loss on development of ROP will be investigated in a multicenter randomised trial (NCT04239690).