An international comparison of Retinopathy of Prematurity grading performance within the Benefits of Oxygen Saturation Targeting (BOOST) II trials. International variation in ROP grading.

PurposeTo investigate whether the observed international differences in retinopathy of prematurity (ROP) treatment rates within the Benefits of Oxygen Saturation Targeting (BOOST) II trials might have been caused by international variation in ROP disease grading.MethodsGroups of BOOST II trial ophthalmologists in UK, Australia, and New Zealand (ANZ), and an international reference group (INT) used a web based system to grade a selection of RetCam images of ROP acquired during the BOOST II UK trial. Rates of decisions to treat, plus disease grading, ROP stage grading, ROP zone grading, inter-observer variation within groups and intra-observer variation within groups were measured.ResultsForty-two eye examinations were graded. UK ophthalmologists diagnosed treat-requiring ROP more frequently than ANZ ophthalmologists, 13.9 (3.49) compared to 9.4 (4.46) eye examinations, P=0.038. UK ophthalmologists diagnosed plus disease more frequently than ANZ ophthalmologists, 14.1 (6.23) compared to 8.5 (3.24) eye examinations, P=0.021. ANZ ophthalmologists diagnosed stage 2 ROP more frequently than UK ophthalmologists, 20.2 (5.8) compared to 12.7 (7.1) eye examinations, P=0.026. There were no other significant differences in the grading of ROP stage or zone. Inter-observer variation was higher within the UK group than within the ANZ group. Intra-observer variation was low in both groups.ConclusionsWe have found evidence of international variation in the diagnosis of treatment-requiring ROP. Improved standardisation of the diagnosis of treatment-requiring ROP is required. Measures might include improved training in the grading of ROP, using an international approach, and further development of ROP image analysis software.Eye advance online publication, 28 July 2017; doi:10.1038/eye.2017.150

An Analysis of Monte Carlo Simulation as an Estimator of Original Oil In Place and Original Gas In Place

The Monte Carlo Method has been increasingly used in the petroleum industry as a means of quantifying uncertainty. Most commonly, this technique is used to calculate a range of values for hydrocarbon volumes originally in place. The distributions of the input variables input into the Monte Carlo simulator are estimated by obtaining a sufficient number of measurements of reservoir and fluid properties. This report will analyze several depleted or very mature fields for which the ultimate hydrocarbon recovery is known. For each of these fields, distributions of porosity, water saturation, reservoir thickness, and reservoir size are obtained from cores, openhole logs, seismic, and other data. These distributions are input into the Crystal Ball computer program to obtain the cumulative distribution function (CDF) and probability density function (PDF) of oil or gas volume originally in place for each of the fields. By comparing the actual ultimate recovered volumes of hydrocarbons to the range of original in place volumes predicted by the Monte Carlo calculations, the accuracy of the Monte Carlo method will be analyzed.Petroleum and Geosystems Engineerin

N-terminal B-type natriuretic peptide urinary concentrations and retinopathy of prematurity

BACKGROUND: To validate the findings of a single-center pilot study showing elevated urinary N-terminal B-type natriuretic peptide (NTproBNP) concentrations in preterm infants subsequently developing severe retinopathy of prematurity (ROP) in a multicenter setting across eight European and Middle East countries. METHODS: Prospective observational study in 967 preterm infants <30 weeks' gestational age assessing the capacity of urinary NTproBNP on days of life (DOLs) 14 and 28 to predict ROP requiring treatment. RESULTS: Urinary NTproBNP concentrations were markedly elevated in infants who developed ROP requiring treatment (n = 94) compared with survivors without ROP treatment (n = 837), at both time points (median (interquartile range) DOL14: 8,950 (1,925-23,783) vs. 3,083 (1,193-17,393) vs. 816 (290-3,078) pg/ml, P <0.001) and DOL28 (2,203 (611-4,063) vs. 1,671 (254-11,340) vs. 408 (162-1,126) pg/ml, P <0.001). C-statistic of NTproBNP for treated ROP or death was 0.731 (95% confidence interval 0.654-0.774) for DOL14 and 0.683 (0.622-0.745) for DOL28 (P <0.001). Threshold scores were calculated, potentially enabling around 20% of infants with low NTproBNP scores never to be screened with ophthalmoscopy. CONCLUSION: There is a strong association between early urinary NTproBNP and subsequent ROP development, which can be used to further refine subgroups of patients with high or low risk of severe RO