Dr. Khushboo Doctor, D14550, Dr. Bhavin Patel
Introduction:
Retinopathy of prematurity is one of the preventable cause of childhood blindness. It was first described by Terry in 1942 as Retrolental fibroplasia [1]with implication of oxygen therapy as the causative agent.It is a disorder of immature retinal blood vessels in immature retina of preterm infants. Several associated risk factors hampers the growth of this immature retinal blood vessels & lead to sequela of ROP in some of this babies.
In India,with the development of urban as well as rural neonatal intensive care units,extreme premature infants with extremely low birth weight are surviving and are at highest risk of developing ROP[2].
Objective :
This study aims to determine prevalence, associated risk factors & outcome of ROP in preterm infants in the Neonatal Intensive Care Unit(NICU) of Surat region.
MATERIALS AND METHODS:
ROP prospective screening survey was performed enrolling premature infants admitted to several NICUs of Surat region from June2014 to May2016 with GestationalAge(GA)<34wks & Birth Weight(BW) <1750 gm. Infants with GA between 34-36 weeks and/or BW between 1750-2000 gm with risk factors for ROP were also included.380 infants(760 eyes) had retinal evaluation done on 4th Postnatal week.All examinations were performed by single ROP consultant.
The pupils were dilated using cyclopentolate 0.5% & phenylephrine 2.5% eye drop three times at interval of 10 minutes. Proparacaine 0.5% eye drop(local anaesthetic agent) was instilled before each eye examination.Retinal evaluation was done withBIO(BinOcular Indirect Ophthalmoscope)& 20 D lens with alfonso speculum & pediatric wire vectis.
Retinal vascular changes were recorded in accordance with ICROP(International Classification of ROP).Data related to patient’s name,age,sex,mode of delivery, Gestational Age(GA),Birth Weight(BW),associated risk factors,NICU admission days& referring center were entered in Excel sheet as well as ROP file. Follow up schedule for ROP was also as per NNF(National Neonatology Forum) guidelines weekly or 2 weekly depending upon retinal findings and until complete vascularization of retina. Laser was done in cases of Stage 3 Zone 2/3 ROP. Intravitreal injections (Bevacizumab/Ranibizumab) (0.625mg/0.05ml) were given in case of APROP/Zone 1 ROP. Infants with Stage 4 or Stage 5 ROP were referred to higher centers.
Associated risk factors (Oxygen therapy, RDS, blood transfusion, sepsis, neonatal jaundice) were analysed using chi-square test. P-value less than 0.05 was considered as statistically significant.
RESULTS
Prevalence of ROPin our study was 48.6%.185 infants out of 380(223 M &157 F)were diagnosed as ROP. 75(19.7%) cases had Stage 1ROP, 65(17.1%) cases had Stage 2 ROP,37(9.7%) had Stage 3 ,1(0.3%) Stage 4 &7(1.8%) cases had Stage 5 ROP. Mean GAwas 30wks(Range 22-36wks)& Mean BWwas 1.310Kg (Range 0.470Kg-2.900Kg). Statistical Analysis(Chi-Square Test) between occurrence of ROP & GA (P =0.001),BW(P=0.001), Sepsis (P = 0.001), Oxygen Therapy (P =0.001),Respiratory Distress Syndrome(RDS) (P=<0.0001) & Blood Transfusions (P = 0.003). 21 Cases of Stage 3 ROP underwent laser & 5 cases who were treated with intravitrealinjection of bevacizumab(0.625mg/0.05ml) in Zone 1 ROP showed complete regression of ROP. None of the case treated with laser or intravitreal injection resulted in systemic complication.
Organisms isolated from blood cultures in cases of sepsis were E.Coli, MRSA(Methicillin resistant Staphylococcus Aureus),Pseudomonus, acenobacter and Klebsiella.
DISCUSSION
The overall incidence of ROP in our study is 48.6% .Overall incidence of ROP varies from 38% to 51.9% in India [3].Our hospital being a referral center catering to a large area receives cases referred by neonatologist which are high risk cases. Furthermore, some of the NICUs in South Gujarat (Charitable Unit) do not have highly advanced NICU as compared to Urban NICU.
Oxygen therapy is considered as one of the most important causative factor for ROP.However, reports have found ROP in cases without oxygen therapy and even after oxygen therapy, not all premature infants develop ROP[4].The incidence of ROP is slightly higher due to improved survival of lower birth-weight babies. The lowest birth-weight reported in our study is 480gm with Gestational Age Of 24wks with Stage 3 Zone 2 ROP.Laser was given to that baby. Our analysis is relatively specific for severe forms of ROP. Three factors have shown consistent and significant association with ROP in our study: low gestational age, low birth weight and prolonged exposure to supplementary oxygen following delivery.
Furthermore,IVF(In Vitro Fertilization) is the most common factor for prematurity among twin babies seen in our study. Similar study by and Friling et al showed 26.1% &27% infants born from IVF respectively[5][6].
List of Participating NICUs Centers of Surat Region
1-ABC Hospital, Varachha- Dr.VipulKachhadiya, Dr.Dilip Patel, Dr.Rakesh Patel, Dr.AshishSojitra
2-SAACHI Hospital, Surat -Dr.SaurinKhatiwala
3-Kasturba Hospital,Valsad-Dr.PramitMistry
4-Param NICU, Surat- Dr.BhavinBhuva
5-Rishi Children Hospital,Surat- Dr.DineshGosai, Dr.RenuGosai
6-Shri HariChildren Hospital,Varachha- Dr.JayeshSangani
7-Apple Hospital, Surat- Dr.BhavinBhuva
8-Anand Children Hospital, Surat-Dr.Sachin Shah
9-Shrimad RajchandraHospital,Valsad
10-Nirmal Children Hospital,Surat
CONCLUSION
The prevalence of ROP in our study was 48.6%. Low Gestational Age, Low Birth Weight, sepsis, Oxygen Therapy & Blood Transfusions were significant risk factors for ROP. Prevention of prematurity, control of Pre-eclempsia& risk factors are the only promising factors that may reduce the incidence & severity of ROP. The analysis of risk factors for ROP will help us to understand & predict its development in high risk Neonates.
Referances-
1-Terry TL.Extreme prematurity and fibroblastic overgrowth of persistent vascular sheath behind each crystalline lens: I Preliminary report. Am J Ophthalmol 25:203-204,1942.
2-Park JE, Park K. Preventive medicine in obstretics, paediatrics and geriatrics. In: Park JE, Park K (eds), Park’s Textbook of Preventive and Social Medicine. New Delhi,BanarasidasBahnotpp.306-320,1991
3-Anand Vinekar, SubhadraJalali.Retinopathy of prematurity.National Neonatology Forum. 253-257,2010.
4-Chawla D, Agarwal R,Deorari A. Retinopathy of prematurity. Indian J Pediatr Paul VK 75:73-6,2008.
5-Gordon S.K. Yau, Jacky W.Y.Lee, Ian Y.H. Wong. Incidence and risk factors for Retinopathy of prematurity in multiple gestations.Wolters Kluwer Health Apr 15;94(18):e867,2015.
6-Friling R,Axer-Siegel R,Hersocovici Z. Retinopathy of prematurity in assisted versus natural conception and singleton versus multiple births. Ophthalmology 114:321-324,2007.