Proceedings of the Third International Symposium on Retinopathy of Prematurity: an update on ROP from the lab to the nursery (November 2003, Anaheim, California).

The Third International Symposium on Retinopathy of Prematurity (ROP) was convened with the aim of cross fertilizing the horizons of basic and clinical scientists with an interest in the pathogenesis and management of infants with ROP. Ten speakers in the clinical sciences and ten speakers in the basic sciences were recruited on the basis of their research to provide state of the art talks. The meeting was held November 9, 2003 immediately prior to the American Academy of Ophthalmology meeting; scholarships were provided for outreach to developing countries and young investigators. This review contain the summaries of the 20 platform presentations prepared by the authors and the abstracts of presented posters. Each author was asked to encapsulate the current state of understanding, identify areas of controversy, and make recommendations for future research. The basic science presentations included insights into the development of the human retinal vasculature, animal models for ROP, growth factors that affect normal development and ROP, and promising new therapeutic approaches to treating ROP like VEGF targeting, inhibition of proteases, stem cells, ribozymes to silence genes, and gene therapy to deliver antiangiogenic agents. The clinical presentations included new insights into oxygen management, updates on the CRYO-ROP and ETROP studies, visual function in childhood following ROP, the neural retina in ROP, screening for ROP, management of stage 3 and 4 ROP, ROP in the third world, and the complications of ROP in adult life. The meeting resulted in a penetrating exchange between clinicians and basic scientists, which provided great insights for conference attendees. The effect of preterm delivery on the normal cross-talk of neuroretinal and retinal vascular development is a fertile ground for discovering new understanding of the processes involved both in normal development and in retinal neovascular disorders. The meeting also suggested promising potential therapeutic interventions on the horizon for ROP.

Effect of dose on response to adrenocorticotropin in extremely low birth weight infants.

CONTEXT: Various cosyntropin doses are used to test adrenal function in premature infants, without consensus on appropriate dose or adequate response. OBJECTIVE: The objective of this study was to test the cortisol response of extremely low birth weight infants to different cosyntropin doses and evaluate whether these doses differentiate between groups of infants with clinical conditions previously associated with differential response to cosyntropin. DESIGN: The design was a prospective, nested study conducted within a randomized clinical trial of low-dose hydrocortisone from November 1, 2001, to April 30, 2003. SETTING: The setting was nine newborn intensive care units. PATIENTS: The patients included infants with 500-999 g birth weight. INTERVENTION: The drug used was cosyntropin, at 1.0 or 0.1 microg/kg, given between 18 and 28 d of birth. MAIN OUTCOME MEASURE: We measured the cortisol response to cosyntropin. RESULTS: Two hundred seventy-six infants were tested. Previous hydrocortisone treatment did not suppress basal or stimulated cortisol values. Cosyntropin, at 1.0 vs. 0.1 microg/kg, yielded higher cortisol values (P < 0.001) and fewer negative responses (2 vs. 21%). The higher dose, but not the lower dose, showed different responses for girls vs. boys (P = 0.02), infants receiving enteral nutrition vs. not (P < 0.001), infants exposed to chorioamnionitis vs. not (P = 0.04), and those receiving mechanical ventilation vs. not (P = 0.02), as well as a positive correlation with fetal growth (P = 0.03). A response curve for the 1.0-microg/kg dose for infants receiving enteral nutrition (proxy for clinically well infants) showed a 10th percentile of 16.96 microg/dl. Infants with responses less than the 10th percentile had more bronchopulmonary dysplasia and longer length of stay. CONCLUSIONS: A cosyntropin dose of 0.1 microg/kg did not differentiate between groups of infants with clinical conditions that affect response. We recommend 1.0 microg/kg cosyntropin to test adrenal function in these infants.

Cost-effectiveness of early treatment for retinopathy of prematurity.

BACKGROUND: The Early Treatment for Retinopathy of Prematurity trial demonstrated that peripheral retinal ablation of eyes with high-risk prethreshold retinopathy of prematurity (early treatment) is associated with improved visual outcomes at 9 months' corrected gestational age compared with treatment at threshold disease (conventional management). However, early treatment increased the frequency of laser therapy, anesthesia with intubation, treatment-related systemic complications, and the need for repeat treatments. OBJECTIVE: To determine the cost-effectiveness of an early treatment strategy for retinopathy of prematurity compared with conventional management. DESIGN/METHODS: We developed a stochastic decision analytic model to assess the incremental cost of early treatment per eye with severe visual impairment prevented. We derived resource-use and efficacy estimates from the Early Treatment for Retinopathy of Prematurity trial's published outcome data. We used a third-party payer perspective. Our primary analysis focused on outcomes from birth through 9 months' corrected gestational age. A secondary analysis used a lifetime horizon. Parameter uncertainty was quantified by using probabilistic and deterministic sensitivity analyses. RESULTS: The incremental cost-effectiveness of early treatment was $14,200 per eye with severe visual impairment prevented. There was a 90% probability that the cost-effectiveness of early treatment would be less than $40,000 per eye with severe visual impairment prevented and a 0.5% probability that early treatment would be cost-saving (less costly and more effective). Limiting early treatment to more severely affected eyes (eyes with "type 1 retinopathy of prematurity" as defined by the Early Treatment for Retinopathy of Prematurity trial) had a cost-effectiveness of $6,200 per eye with severe visual impairment prevented. Analyses that considered long-term costs and outcomes found that early treatment was cost-saving. CONCLUSIONS: Early treatment of retinopathy of prematurity is both efficacious and economically desirable. Because of the high lifetime costs of severe visual impairment, the early treatment strategy provides long-term cost savings.

Nurse opinions and pulse oximeter saturation target limits for preterm infants.

OBJECTIVE: The objectives of this study were to compare pulse oximeter saturation limits targeted by nurses for extremely preterm infants during routine care with nurse opinions regarding appropriate pulse oximeter saturation limits and with policy-specified pulse oximeter saturation limits and to identify factors that influence pulse oximeter saturation limits targeted by nurses. METHODS: We surveyed nurses in US NICUs with neonatal-perinatal fellowships in 2004. Data collected included pulse oximeter saturation limits targeted by nurses and by NICU policy when present, nurses' opinions about appropriate pulse oximeter saturation limits, and NICU and nurse characteristics. Factors associated with pulse oximeter saturation limits targeted by nurses were identified with hierarchical linear modeling. RESULTS: Among those eligible, 2805 (45%) nurses in 59 (60%) NICUs responded. Forty (68%) of 59 NICUs had a policy that specified a pulse oximeter saturation target range for extremely preterm infants. Among 1957 nurses at NICUs with policies, 540 (28%) accurately identified the upper and lower limits of their NICU's policy and also targeted these values in practice. NICU-specific SDs for individual nurse target limits were less at NICUs with versus without a policy for both upper and lower limits. Hierarchical linear modeling identified presence of pulse oximeter saturation policy, NICU-specific nurse group opinion, and individual nurse opinion as factors significantly associated with individual pulse oximeter saturation target limits. For each percentage point increase in individual opinion upper limit, the individual target upper limit increased by 0.41 percentage point at NICUs with a policy compared with 0.6 percentage point at NICUs with no policy. CONCLUSIONS: Presence of policy-specified pulse oximeter saturation limits, nurse group opinion, and individual nurse opinion were independently associated with individual nurse pulse oximeter saturation target limits during routine care of extremely preterm infants. The presence of a policy reduced the influence of individual nurse opinion on targeted pulse oximeter saturation limits and reduced variation among nurse target limits within NICUs.

Growth and neurodevelopmental outcomes after early low-dose hydrocortisone treatment in extremely low birth weight infants.

BACKGROUND: Low cortisol concentrations in premature infants have been correlated with increased severity of illness, hypotension, mortality, and development of bronchopulmonary dysplasia. A total of 360 mechanically ventilated infants with a birth weight of 500 to 999 g were enrolled in a randomized, multicenter trial of prophylaxis of early adrenal insufficiency to prevent bronchopulmonary dysplasia. Mortality and bronchopulmonary dysplasia were decreased in the hydrocortisone-treated patients exposed to chorioamnionitis. We now report outcomes at 18 to 22 months' corrected age. PATIENTS AND METHODS: Surviving infants were evaluated with standardized neurologic examination and Bayley Scales of Infant Development-II. Neurodevelopmental impairment was defined as a Mental Developmental Index or Psychomotor Developmental Index of <70, cerebral palsy, blindness or deafness. RESULTS: A total of 252 (87%) of 291 survivors were evaluated. Cerebral palsy was diagnosed in 13% of hydrocortisone-treated versus 14% of placebo-treated infants. Fewer hydrocortisone-treated infants had a Mental Development Index <70, and more of the hydrocortisone-treated infants showed evidence of awareness of object permanence. Incidence of neurodevelopmental impairment was not different (39% [hydrocortisone] vs 44% [placebo]). There were no differences in physical growth measures. Chorioamnionitis-exposed infants treated with hydrocortisone were shorter and weighed less than controls but had no evidence of neurodevelopmental impairment. Among infants not exposed to chorioamnionitis, hydrocortisone-treated patients were less likely to have a Mental Development Index of <70 or to be receiving glucocorticoids at follow-up. CONCLUSIONS: Early, low-dose hydrocortisone treatment was not associated with increased cerebral palsy. Treated infants had indicators of improved developmental outcome. Together with the short-term benefit previously reported, these data support additional studies of hydrocortisone treatment of adrenal insufficiency in extremely premature infants.

Achieved versus intended pulse oximeter saturation in infants born less than 28 weeks' gestation: the AVIOx study.

OBJECTIVE: The objective of this study was to document pulse oximeter saturation levels achieved in the first 4 weeks of life in infants who were born at < 28 weeks' gestation, compared with the levels that were targeted by local policy, and examine factors that are associated with compliance with the target range. METHODS: Infants who were < 28 weeks' gestation and < or = 96 hours of age were enrolled in a prospective, multicenter cohort study. Oximetry data were collected with masked signal-extraction oximeters for a 72-hour period in each of the first 4 weeks of life. Data were compared with the pulse oximeter saturation target range prescribed by local institutional policy. Factors that were associated with intended range compliance were identified with hierarchical modeling. RESULTS: Fourteen centers from 3 countries enrolled 84 infants with mean +/- SD birth weight of 863 +/- 208 g and gestational age of 26 +/- 1.4 weeks. Oxygen saturation policy limits ranged between 83% and 92% for lower limits and 92% and 98% for upper limits. For infants who received respiratory support, median pulse oximeter saturation level achieved was 95%. Center-specific medial levels were within the intended range at 12 centers. Centers maintained infants within their intended range 16% to 64% of the time but were above range 20% to 73% of the time. In hierarchical modeling, wider target ranges, higher target range upper limits, presence of a policy of setting oximeter alarms close to the target range limits, and lower gestational age were associated with improved target range compliance. CONCLUSIONS: Success with maintaining the intended pulse oximeter saturation range varied substantially among centers, among patients within centers, and for individual patients over time. Most noncompliance was above the intended range. Methods for improving compliance and the effect of improved compliance on neonatal outcomes require additional research.

A pulmonary score for assessing the severity of neonatal chronic lung disease.

BACKGROUND: Limited data are available to describe the spectrum of severity of neonatal chronic lung disease. In the multicenter Supplemental Therapeutic Oxygen for Prethreshold Retinopathy of Prematurity trial, all infants had some degree of pulmonary dysfunction, because eligibility required a median oxygen saturation of < or =94% with room air. Infants randomized to the supplemental oxygen group (oxygen saturation target of 96-99%) had more pulmonary morbidity than did those in the conventional group (oxygen saturation target of 88-94%). This prompted the retrospective development of a pulmonary severity score to compare the baseline status of the 2 groups. OBJECTIVES: To describe a pulmonary score that reflects the severity of neonatal lung disease and to evaluate the association of the score and its components with subsequent pulmonary morbidity through 3 months of corrected age. DESIGN AND METHODS: A pulmonary score was developed empirically by a consensus panel of 3 neonatologists and was defined as the fraction of inspired oxygen (Fio2) x (support) + (medications), where Fio2 is the actual or "effective" (for nasal cannula) Fio2; support is 2.5 for a ventilator, 1.5 for nasal continuous positive airway pressure, or 1.0 for nasal cannula or hood oxygen; and medications is 0.20 for systemic steroids for bronchopulmonary dysplasia, 0.10 each for regular diuretics or inhaled steroids, and 0.05 each for methylxanthines or intermittent diuretics. The scores could range from 0.21 to 2.95. Pulmonary morbidity was defined as any of the following occurring from randomization at a mean of 35.4 weeks' postmenstrual age through 3 months of corrected age: death or rehospitalization with a pulmonary cause; an episode of pneumonia/sepsis/exacerbation of chronic lung disease; or continued hospitalization, supplemental oxygen therapy, diuretic treatment, or systemic steroid therapy at 3 months. Between-group differences were tested with the Kruskal-Wallis or chi2 test. RESULTS: Data through death or the 3-month corrected age examination were available for 588 infants. Enrolled infants represented a wide spectrum of severity of chronic lung disease, with baseline pulmonary scores at randomization ranging from 0.21 to 2.6. The median pulmonary score at enrollment did not differ between the conventional and supplemental groups (0.42 and 0.45, respectively). However, higher baseline pulmonary scores were observed for infants who did versus did not develop subsequent pulmonary morbidity (0.48 vs 0.38). The pulmonary score was associated with subsequent pulmonary morbidity. Regression analyses adjusting for Supplemental Therapeutic Oxygen for Prethreshold Retinopathy of Prematurity group assignment, gestational age at birth, race, gender, and postmenstrual age at randomization revealed that the score was a significant independent predictor of subsequent pulmonary morbidity (odds ratio: 7.2; 95% confidence interval: 3.6-14.4). CONCLUSIONS: The pulmonary score, calculated near term, reflects a wide spectrum of bronchopulmonary dysplasia severity and is associated with subsequent pulmonary morbidity through corrected age of 3 months. This simple score could prove useful in clinical and research settings. Validation of the score requires additional study.

Prophylaxis of early adrenal insufficiency to prevent bronchopulmonary dysplasia: a multicenter trial.

BACKGROUND: Infants developing bronchopulmonary dysplasia (BPD) show decreased cortisol response to adrenocorticotropic hormone. A pilot study of low-dose hydrocortisone therapy for prophylaxis of early adrenal insufficiency showed improved survival without BPD at 36 weeks' postmenstrual age, particularly in infants exposed to histologic chorioamnionitis. METHODS: Mechanically ventilated infants with birth weights of 500 to 999 g were enrolled into this multicenter, randomized, masked trial between 12 and 48 hours of life. Patients received placebo or hydrocortisone, 1 mg/kg per day for 12 days, then 0.5 mg/kg per day for 3 days. BPD at 36 weeks' postmenstrual age was defined clinically (receiving supplemental oxygen) and physiologically (supplemental oxygen required for O2 saturation > or =90%). RESULTS: Patient enrollment was stopped at 360 patients because of an increase in spontaneous gastrointestinal perforation in the hydrocortisone-treated group. Survival without BPD was similar, defined clinically or physiologically, as were mortality, head circumference, and weight at 36 weeks. For patients exposed to histologic chorioamnionitis (n = 149), hydrocortisone treatment significantly decreased mortality and increased survival without BPD, defined clinically or physiologically. After treatment, cortisol values and response to adrenocorticotropic hormone were similar between groups. Hydrocortisone-treated infants receiving indomethacin had more gastrointestinal perforations than placebo-treated infants receiving indomethacin, suggesting an interactive effect. CONCLUSIONS: Prophylaxis of early adrenal insufficiency did not improve survival without BPD in the overall study population; however, treatment of chorioamnionitis-exposed infants significantly decreased mortality and improved survival without BPD. Low-dose hydrocortisone therapy did not suppress adrenal function or compromise short-term growth. The combination of indomethacin and hydrocortisone should be avoided.