Retinopathy of prematurity: a case series of treated infants

[摘要] Retinopathy of Prematurity (ROP) is still a major contributor to vision loss in children andaccount for around 10% of children in schools for the blind in South Africa (SA). Around14 000 infants are at risk for the development of ROP in SA each year.Oxygen supplementation to the premature infant causes a relative hyperoxia within theretina which results in cessation of normal vascular proliferation. After the supplementaloxygen is stopped, a relative hypoxia causes an abnormal over proliferation of retinalvessels. ROP is the clinical entity which results from this abnormal vascular response.Classification of ROP is clinical and includes three entities: vascular response, zone of retinainvolved and the presence of plus disease. Retinal detachments can result, and thiscomprises stage 4 and 5 of the classification.Treatment is according to the ETROP study. The classification above is used to furtherclassify the disease into Type 1 and 2, and then treated accordingly.Many risk factors have been identified in contributing to the development of ROP. Somemajor risk factors include: gestational age, birth weight, poor postnatal weight gain andsupplemental oxygen administration. Protective factors include human breastmilk and freshfrozen plasma.Three ROP epidemics have been identified. The first epidemic was with the advent ofsupplemental oxygen in the 1950's. Infants with ROP in the United Kingdom at the time hadbirth weights of 1370g. In the 1970's neonatal care improved, and we saw the secondepidemic as the birth weights of infants with ROP dropped to below 1000g. Now, at theturn of the century, we are seeing a 3rd epidemic in middle-income countries with infantshaving ROP with birth weights of 900g to 1500g. For comparison, infants with ROP indeveloped countries have birth weights of around 750g and below.Screening for ROP is necessary but sometimes difficult in resource constraint environments.Therefore, algorithms have been developed to try and decrease the number of infants thatneed screening. A major successful algorithm is the WINROP algorithm. This algorithm isweb based, and needs only the gestational age, birth weight and postnatal weight gain to determine whether an infant is at risk for the development of ROP. It has proven 100%sensitive in some developed countries.The aim of this study was to determine the risk factors present in infants with ROP in ourprovince. Secondary objectives included: the comparison of the WINROP detection rate inour infants with those in developed countries; to identify major issues in neonatal care inthe province; and to document the ROP stage prior to treatment and treatments given.This was a case series. Records were reviewed of all infants treated for ROP at a singlereferral unit, Universitas Academic Hospital, during the time period of 2009 to 2015. Ethicsapproval was obtained for this study.Most infants were of African race. All infants were from the two major referral centreswithin the Free State. The averages for gestational age and birth weight were 27.6 weeks(range 26 to 30 weeks) and 1061.2 grams (range 760 to 1405 grams) respectively. The dayoriginal birth weight was reached on average was on day 22 (range 9 to 56 days). Otherparameters which showed a high presence factor were: oxygen supplementation, provensepsis and breastmilk administration. The WINROP algorithm showed an alarm in 75% (n9)of cases. This means that 25% (n3) were not detected by 6 weeks of age when screeningwould already have been implemented. One unit showed a target oxygen saturation of>95% in all treated infants.In conclusion, the study confirms that SA forms part of the third epidemic of ROP. TheWINROP algorithm is not accurate in our population with larger infants. A site with poorpost-natal oxygen saturation monitoring was identified. It is recommended that furtherstudy is needed before the implementation of the WINROP algorithm in SA. Education ofstaff involved with neonatal care concerning oxygen saturation targets is important.

[发布机构] University of the Free State