Retinopathy of prematurity. Risk factors in a five-year cohort of critically ill premature neonates

Effects of Healthcare-Associated Infections on Length of PICU Stay and Mortality

OBJECTIVES

To identify the effects of healthcare-associated infections on length of PICU stay and mortality.

DESIGN

Retrospective, single-center, observational study.

SETTING

PICU of a tertiary children's hospital.

PATIENTS

Consecutive patients who stayed greater than 48 hours in the PICU between January 2013 and December 2017.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data were retrospectively collected from medical records. We identified occurrences of common healthcare-associated infections, including bloodstream infection, pneumonia, and urinary tract infection, defined according to the 2008 definitions of the Centers for Disease Control and Prevention and National Healthcare Safety Network. We assessed the effects of each healthcare-associated infection on length of PICU stay and PICU mortality using multivariable analysis. Among 1,622 admissions with a PICU stay greater than 48 hours, the median age was 299 days and male patients comprised 51% of admissions. The primary diagnostic categories were cardiovascular (58% of admissions), respiratory (21%), gastrointestinal (8%), and neurologic/muscular (6%). The median length of PICU stay was 6 days, and the PICU mortality rate was 2.5%. A total of 167 healthcare-associated infections were identified, including 67 bloodstream infections (40%), 43 pneumonias (26%), and 57 urinary tract infections (34%). There were 152 admissions with at least one healthcare-associated infection (9.4% of admissions with a stay > 48 hr). On multivariable analysis, although each healthcare-associated infection was not significantly associated with mortality, bloodstream infection was associated with an extra length of PICU stay of 10.2 days (95% CI, 7.9-12.6 d), pneumonia 14.2 days (11.3-17.2 d), and urinary tract infection 6.5 days (4.0-9.0 d). Accordingly, 9.7% of patient-days were due to these three healthcare-associated infections among patients with a stay greater than 48 hours.

CONCLUSIONS

Although healthcare-associated infections were not associated with PICU mortality, they were associated with extra length of PICU stay. As 9.7% of patient-days were due to healthcare-associated infections, robust prevention efforts are warranted.

Retinopathy of prematurity: a review of risk factors and their clinical significance

Retinopathy of prematurity (ROP) is a retinal vasoproliferative disease that affects premature infants. Despite improvements in neonatal care and management guidelines, ROP remains a leading cause of childhood blindness worldwide. Current screening guidelines are primarily based on two risk factors: birth weight and gestational age; however, many investigators have suggested other risk factors, including maternal factors, prenatal and perinatal factors, demographics, medical interventions, comorbidities of prematurity, nutrition, and genetic factors. We review the existing literature addressing various possible ROP risk factors. Although there have been contradictory reports, and the risk may vary between different populations, understanding ROP risk factors is essential to develop predictive models, to gain insights into pathophysiology of retinal vascular diseases and diseases of prematurity, and to determine future directions in management of and research in ROP.

Retinopathy of prematurity in very low birth weight infants and the potential protective role of indomethacin

BACKGROUND AND OBJECTIVE

To describe clinical features of very low birth weight (VLBW) infants and examine the effect of indomethacin on the incidence of retinopathy of prematurity (ROP).

PATIENTS AND METHODS

Medical records of all VLBW infants over a 4-year period were reviewed. Data regarding systemic and ophthalmic examinations were analyzed.

RESULTS

Forty-seven infants with ROP were evaluated. Most infants had bilateral stage 1 or 2 disease extending 5 clock hours. Infants with ROP had younger mean gestational age, had lower gestational weight, and demonstrated higher incidence of diseases of prematurity. These infants were exposed to increased doses of surfactant and higher oxygen concentration for a prolonged duration given their immature pulmonary status. Independent predictors of ROP susceptibility also included length of hospitalization and Apgar score at 5 minutes. Patent ductus arteriosus was more common among infants with ROP. Approximately half of the infants who received one or two doses of indomethacin had ROP, but the ROP rate was decreased in infants who received three doses.

CONCLUSION

Premature infants with younger gestational age, lower gestational weight, and severe morbidities were found to have an increased prevalence of ROP. Indomethacin treatment for patent ductus arteriosus may have a protective role in the development of severe ROP.

Risk factors for healthcare-associated infection in a pediatric intensive care unit

OBJECTIVE

Identify risk factors for first-onset healthcare-associated infection (HAI) in a pediatric intensive care unit (PICU).

DESIGN

Prospective cohort study.

SETTING

Medical-surgical PICU in a hospital for patients in the public healthcare system.

PATIENTS

From January 2005 to June 2006, daily surveillance was carried out on 870 patients ages 0 to 18 yrs during their stay in the PICU through to 48 hrs after discharge (5773 patient-days).

MEASUREMENTS AND MAIN RESULTS

In 256 admissions, there were 363 episodes of HAI, with a cumulative incidence of 41.7% and a density of 62.9 of 1000 patient-days. Intrinsic and extrinsic factors were investigated and measured until occurrence of first-onset HAI (diagnosed according to Nosocomial Infection Surveillance System criteria) or until discharge or death. In the multivariate logistic regression analysis, risk factors for first-onset HAI in the PICU (controlled for length of stay) were as follows: age under 2 years (odds ratio [OR]), 1.80; 95% confidence interval [CI]), 1.30-2.49); days on ventilator duration (OR, 1.16; 95% CI, 1.08-1.25); transfused blood products (OR, 1.49; 95% CI, 1.08-2.06), glucocorticoids (OR, 1.45; 95% CI, 1.04-2.02) and H2 blockers (OR, 1.47; 95% CI, 1.05-2.06).

CONCLUSIONS

Efforts toward a reduction in the exposure to extrinsic risk factors should be made, as each of these factors separately explains 30% of the risk of HAI. Interventions directed at processes related to the use of a ventilator and limitations on its duration of use should be a priority in HAI control strategies, as each day of ventilator use increases the risk of HAI.

Retinopathy of prematurity

This article briefly reviews the history of ROP followed by a discussion of the pathogenesis of this complex disorder. We describe the International Classification System for ROP and identify risk factors and screening recommendations. Finally, we discuss some of the measures that have been used in an attempt to both prevent and treat ROP.

Retinopathy of prematurity--risk factors

OBJECTIVE

Improved survival of low birth weight, premature babies have increased the incidence of retinopathy of prematurity. This hospital-based, prospective, study was undertaken to determine its incidence and risk factors in our neonatal unit.

METHODS

Neonates with gestational age < or = 35 weeks and/or birth weight < or = 1500 gm born over a one-year period were examined by indirect ophthalmoscopy between 2 to 4 weeks after birth, and followed up till retinal vascularisation was complete. Maternal and neonatal risk factors were noted and data analyzed by statistical package SPSS-10.0.

RESULTS

Sixty babies were thus examined. The incidence of retinopathy was 21.7% in the cohort, 33.3% in babies < or = 32 weeks gestation and 36.4% in babies weighing < or = 1250 gm. Oxygen (p=0.01), sepsis (p=0.04) and apnoea (p=0.02) were independent risk factors. Retinopathy was significantly more severe in babies with hyaline membrane disease (p=0.02) and lower birth weight (p=0.02). Severe disease was never seen before 6.5 weeks of age.

CONCLUSION

Indirect ophthalmoscopy should be performed at 4 weeks of post natal age in all preterm babies with birth weight < or = 1500 gm, and intensified in the presence of risk factors like oxygen administration, apnoea and septicemia.

Linezolid versus vancomycin for treatment of resistant Gram-positive infections in children

BACKGROUND

Pediatric infections caused by resistant Gram-positive infections are an increasing concern with limited treatment options. Linezolid, a new oxazolidinone, is active against staphylococci, streptococci and enterococci.

OBJECTIVE

To assess clinical efficacy and safety of linezolid vs.vancomycin in antibiotic-resistant Gram-positive infections in children. DESIGN Hospitalized children (birth to 12 years of age) with nosocomial pneumonia, complicated skin/skin structure infections, catheter-related bacteremia, bacteremia of unknown source or other infections caused by Gram-positive bacteria were randomized 2:1 to receive linezolid intravenously followed by oral linezolid or vancomycin and then by an appropriate oral agent. Treatment duration was 10 to 28 days.

RESULTS

There were 321 patients enrolled (linezolid 219, vancomycin 102). Clinical cure rates were 79% vs.74% (P = 0.36) and 89% vs.85% (P = 0.31) for linezolid and vancomycin in intent-to-treat and clinically evaluable patients, respectively. Cure rates were similar by age and infection diagnosis. Pathogen eradication rates in microbiologically evaluable patients were high for linezolid and vancomycin, respectively, for methicillin-susceptible S. aureus (95% vs.94%; P = 0.82), methicillin-resistant S. aureus (88% vs.90%; P = 0.89) and methicillin-resistant coagulase-negative staphylococci (85% vs.83%, P = 0.87). In clinically evaluable patients, linezolid-treated patients required significantly fewer days of intravenous therapy compared with vancomycin-treated patients (8.0 +/- 4.8; 10.9 +/- 5.8 days, respectively; P < 0.001). In addition significantly fewer linezolid-treated patients had drug-related adverse events than did vancomycin-treated patients (19% vs.34%, respectively; P = 0.003). Hematologic events were uncommon and similar between treatment groups.

CONCLUSIONS

Linezolid was well-tolerated and as effective as vancomycin in treating serious Gram-positive infections in children.

Retinopathy of prematurity: causation

The incidence of ROP is birth weight dependent and restricting therapeutic oxygen levels has dramatically reduced the incidence of ROP in infants of birth weight >1000 g. However, the incidence of ROP has remained high in very low birth weight (VLBW) infants and this appears to be related to these babies being more ill. Several risk factors have been identified in this group, however oxygen variability, rather than high levels, has been correlated with severity of disease in recent clinical and animal studies. Difficulties in defining 'normal' oxygen in this group has meant the optimal range of oxygen therapy has not yet been defined. Clinical studies are now underway using even lower oxygen therapy ranges. The impact this may have on ROP, neurological and respiratory outcomes will require further study.

Nosocomial infections in pediatric intensive care units

Nosocomial infections are a significant problem in pediatric intensive care units. While Indian estimates are not available, western PICUs report incidence of 6-8%. The common nosocomial infections in PICU are bloodstream infections (20-30% of all infections), lower respiratory tract infections (20-35%), and urinary tract infections (15-20%); there may be some differences in their incidence in different PICUs. The risk of nosocomial infections depends on the host characteristics, the number of interventions, invasive procedures, asepsis of techniques, the duration of stay in the PICU and inappropriate use of antimicrobials. Most often the child had endogenous flora, which may be altered because of hospitalization, are responsible for the infections. The common pathogens involved are Staphylococcus aureus, coagulase negative staphylococci, E. coli Pseudomonas aeruginosa, Klebsiella, enterococci, and candida. Nosocomial pneumonias predominantly occur in mechanically ventilated children. There is no consensus on the optimal approach for their diagnosis. Bloodstream infections are usually attributable to the use of central venous lines; use of TPN and use of femoral site for insertion increase the risk. Urinary tract infections occur mostly after catheterization and can lead to secondary bacteremia. The diagnostic criteria have been discussed in the review. With proper preventive strategies, the nosocomial infection rates can be reduced by up to 50%; handwashing, judicious use of interventions, and proper asepsis during procedures remain the most important practices.

Is the partial pressure of carbon dioxide in the blood related to the development of retinopathy of prematurity?

AIMS

To determine the role of carbon dioxide in the development of retinopathy of prematurity (ROP).

METHODS

This was a retrospective cohort study of 25 consecutive infants admitted to the neonatal unit with continuously recorded physiological data. The daily mean and standard deviation (SD) of transcutaneous carbon dioxide partial pressure (tcPCO(2)) was compared between infants who had stage 1 or 2 ROP and stage 3 ROP. The time spent hypocarbic (<3 kPa) and/or hypercarbic (>10 kPa and >12 kPa) was also compared between these groups. Intermittent arterial carbon dioxide tension was also measured and compared with the simultaneous tcPCO(2) data.

RESULTS

There were no significant differences in carbon dioxide variability or time spent hypocarbic and/or hypercarbic between the ROP groups on any day. 86% of transcutaneous values were within 1.5 kPa of the simultaneous arterial value.

CONCLUSION

TcPCO(2) measurement can be a very useful management technique. However, in this cohort neither variable blood carbon dioxide tension nor duration of hypercarbia or hypocarbia in the first 2 weeks of life was associated with the development or severity of ROP.

The costs associated with nosocomial bloodstream infections in the pediatric intensive care unit

OBJECTIVE: To assess the operational and subsidiary costs and length of stay (LOS) attributable to nosocomial bloodstream infections (BSI) in a pediatric intensive care unit (PICU). DESIGN: Matched case-control study. SETTING: Sixteen bed PICU in a 250-bed tertiary-care pediatric hospital. PATIENTS: Cases with BSI were prospectively identified from PICU patients who developed a nosocomial BSI from August 1996 to July 1998. Controls were PICU patients who were matched for age, severity of illness, diagnosis, and admission date who did not develop a nosocomial BSI. RESULTS: A total of 38 cases and 38 controls form the basis for this study. The cases and controls were similar with respect to the matching criteria. In addition, the cases and controls did not differ with respect to demographic characteristics or PICU survival. There was a trend toward increased hospital mortality among cases (23.7% vs. 10.5%, p =.084). Significant differences were encountered in the utilization of PICU therapeutic modalities. Cases were significantly less likely to be managed care plan enrollees (36.8% vs. 60.5%, p =.043). Total operational and subsidiary costs for radiology, pharmacy, and laboratory services were significantly higher for cases than controls ($78,272 vs. $35,005, $3,622 vs. $1,432, $8,635 vs. $4,630, and $8,648 vs. $3,971, respectively; all p <.001). The PICU and hospital LOS were significantly higher for cases than controls (19.3 vs. 4.6 days for PICU and 46.7 vs. 24.4 days for hospital; both p <.001). The operational costs attributable to nosocomial infection were $46,133. Radiology, pharmacy, and laboratory costs attributable to nosocomial infection were $2,364, $4,691, and $5,156, respectively. The PICU and hospital LOS attributable to a nosocomial BSI were 14.6 days and 21.1 days, respectively. The attributable mortality rate was 13.1%. CONCLUSIONS: The costs and LOS associated with nosocomial BSI in patients admitted to the PICU were significantly higher than controls.

The role of gown and glove isolation and strict handwashing in the reduction of nosocomial infection in children with solid organ transplantation

OBJECTIVE

Nosocomial infection is an important contributor to morbidity and mortality in pediatric solid organ transplantation. The relative effect of protective gown and glove isolation was compared with strict handwashing in pediatric intensive care unit (PICU) patients with solid organ transplantation.

DESIGN/SETTING

A prospective, randomized design was used; children in a 23-bed PICU with solid organ transplantation were enrolled into a gown and glove protective isolation protocol or a strict handwashing protocol.

PATIENTS

All children admitted to the PICU immediately after solid organ transplantation, excluding renal transplantation, and at subsequent readmissions to the PICU were eligible for the study. Children with current infection or known exposure to varicella were excluded from the study initially or at readmission.

INTERVENTIONS

By using a block randomization design based on organ transplanted, age, and initial admission vs. readmission, each patient was randomized to either strict handwashing or protective gown and glove isolation intervention groups.

MEASUREMENTS

We analyzed demographics, infection outcomes (defined according to Centers for Disease Control criteria), and monitoring of patient contacts in compliance with protocols.

RESULTS

The infection rate in the overall PICU population did not change significantly from the year before the study compared with during the study (2.1 per 100 vs. 1.95 per 100 patient days; p =.4) The infection rate in the gown and glove group (2.3 per 100 patient days) was reduced significantly compared with the prestudy infection rate in the transplant population (4.9 per 100 patient days; p =.0008). Strict handwashing also significantly reduced the infection rate in the transplant population (3.0 per 100 patient days; p =.008). Compliance with gowning and gloving was 82% and compliance with handwashing was 76% (compared with 22% before study [p <.0001] and 52% after the study [p <.0001]). Despite an increased mean length of stay in the PICU in the gown and glove group (p =.014), there was a trend toward reduction in the incidence of infection (Fisher's exact test, p =.07; odds ratio,.76) in the gown and glove group.

CONCLUSIONS

Increased compliance with handwashing was associated with a reduction in nosocomial infections, and gown and glove isolation appeared to have an additional protective effect. Some nosocomial infections may be preventable in the pediatric solid organ transplantation population.

Nosocomial pneumonia in the pediatric trauma patient: a single center's experience

OBJECTIVES

To evaluate a single center's experience with the frequency rate, patterns of occurrence, and impact on outcome of nosocomial pneumonia in the critically injured child.

DESIGN

Retrospective review of prospectively collected data.

SETTING

Level I university trauma center with a pediatric trauma intensive care unit.

PATIENTS

A total of 523 consecutive critically injured children admitted to the pediatric intensive care unit during an 80-month interval.

MEASUREMENTS AND RESULTS

Thirty-five episodes of nosocomial pneumonia were identified in 29 children (frequency rate of 5.5%). The mean age of the children was 9.2 yrs, and the mean Injury Severity Score was 27 +/- 9. In 91% of patients (26 children), nosocomial pneumonia was associated with mechanical ventilation. This represented a 13% frequency rate in injured children who were ventilated during the study period. The most common organisms recovered were Staphylococcus aureus (21%), Haemophilus influenzae (19%), Pseudomonas (11%), and Enterobacter (11%). Early pneumonia (diagnosed < or = 7 days after injury) was predominantly caused by Haemophilus species. In contrast, Enterobacter and/or Pseudomonas were isolated primarily in late pneumonia (diagnosed >7 days after injury). Staphylococcus was prominent throughout the hospitalization. Overall, children with nosocomial pneumonia were more severely injured (Injury Severity Score 27 vs. 17, p < .001) and had a longer hospital stay (26 vs. 7 days, p < .001). Despite this, mortality (6.9% vs. 7.9%, p = NS) was not significantly different from injured children without pneumonia.

CONCLUSIONS

In this study of a single pediatric trauma center, nosocomial pneumonia occurred in a small but significant percentage of injured children. The frequency rate increased two- to three-fold with mechanical ventilation. Microbiology varied with day of onset. In contrast to the adult, mortality did not seem to be significantly altered by this complication. Analysis of additional pediatric trauma centers is encouraged to confirm these characteristics of nosocomial pneumonia in the injured child.

Retinopathy of prematurity: evaluation of risk factors

OBJECTIVES

The purpose of this study was to determine what risk factors play a role in the development of retinopathy of prematurity (ROP).

STUDY DESIGN

Data were collected on 157 infants born and cared for in one institution between January 1991 and July 1994. Initially we evaluated all children enrolled in the study to determine potential risk factors for the development of ROP. We subsequently compared multiple variables for ROP positive singletons with ROP positive twins to determine ROP risk factors for each group and to determine if one group was more susceptible to a given risk factor.

RESULTS

Of the 157 infants examined, 72 infants (46%) developed ROP. Infants who developed ROP had a lower gestational age, a lower birth weight, a higher number of days on oxygen/ventilator, more days in the intensive care unit (ICU), a greater need for steroids and a higher incidence of sepsis when compared to infants who did not develop ROP. There was no significant difference noted between singleton and twin gestation infants that developed ROP when comparing gestational age, weight, ventilator time or length of ICU stay. Total number of days on oxygen therapy was higher in the singleton group and this difference did reach statistical significance.

CONCLUSIONS

Several risk factors are associated with a higher incidence of ROP. These variables may not be independent risk factors but may be a sign of the increased severity of illness associated with those infants who are born earlier with a lower birth weight. Multiple gestational births do not appear to increase the risk of developing ROP when compared to a similar group of singleton birth infants.

The decreasing incidence and severity of retinopathy of prematurity

PURPOSE

We sought to determine whether the incidence of retinopathy of prematurity (ROP) at our institution has changed since the Cryo-ROP recruitment period 10 years ago.

METHODS

We determined the incidences of threshold ROP, prethreshold ROP, less-than-prethreshold ROP, and no disease for each of 3 birth weight classes (<750 g, 750 to 999 g, and 1000 to 1250 g) of infants born between July 1, 1995, and June 30, 1996, and cared for in the Vanderbilt Neonatal Intensive Care Unit. We then compared these with the rates from our institution during the Cryo-ROP study recruitment period (January 1, 1986, to November 30, 1987).

RESULTS

The current incidence and severity of ROP have decreased substantially overall and for each weight group compared with the 1986-87 incidence (P < .001, Cochran-Mantel-Haenszel test). The incidence of "any ROP" decreased by 27% for infants with birth weights less than 750 g, by 51% for infants 750 to 999 g, and by 71% for infants 1000 to 1250 g. The incidence of "prethreshold or greater ROP" decreased by 70% for the 750 to 999 g and 77% for the 1000 to 1250 g weight groups. Although the decrease in "prethreshold or greater ROP" was not as dramatic (25%) for the infants less than 750 g, only 1 infant (10%) progressed to threshold disease in this group, whereas 7 (47%) did in 1986-87. The incidence of threshold ROP decreased by 84% for infants less than 750 g and by 66% for infants 750 to 999 g. No infant with birthweight greater than 999 g progressed to threshold ROP.

CONCLUSIONS

The incidence of all levels of ROP has decreased substantially for all infants with birth weights less than 1251 g at Vanderbilt University Medical Center during the past decade. Putative factors responsible for this decrease may include surfactant use, continuous pulse oximetry, aggressive use of antenatal steroids, and improved neonatal nutritional support.

Nosocomial infection following cardiovascular surgery: comparison of two periods, 1987 vs. 1992

OBJECTIVE

To evaluate whether changes have occurred at our center in the rate of nosocomial infections and in the infectious organisms consequent to changes in policy and procedure as of 1987.

SETTING

Multidisciplinary pediatric intensive care unit (PICU) in a major tertiary care center.

DESIGN

Prospective comparative study.

PATIENTS

Four-hundred and fifty-five consecutive patients who underwent cardiac surgery within a 10-month period.

INTERVENTIONS

Changes related to antibiotic use and invasive device management were introduced after the 1987 survey. To determine the effect of these changes, all patients undergoing cardiac surgery between July 1991 and April 1992 were followed daily from PICU admission to 2 months after hospital discharge for signs of infection. Each infectious episode was reviewed by the nosocomial infection control committee. A weighted scoring system was used to determine risk.

MEASUREMENTS AND MAIN RESULTS

In the 1987 study, 40 of 310 patients had 78 infections for a nosocomial infection ratio (NIR) of 25.2. Of the 455 patients surveyed in 1992, 72 had 91 episodes of infection. The nosocomially infected patient rate was 15.8 and the NIR was 20. The frequency of wound infection decreased from 7% in 1987 to 4.3% in this study, and no episode of mediastinitis was observed. In the bacteriological spectrum, the absence of candidal infection was significant, and there was a decrease in the proportional frequency of pseudomonas infection from 21% to 15%.

CONCLUSION

The comparison between the two time periods demonstrates that an aggressive approach to managing intravascular catheters and urinary catheters and limiting the use of antibiotics probably affects the spectrum of nosocomial infections.

The effect of carbon dioxide on oxygen-induced retinopathy in the neonatal rat

PURPOSE

Hypercarbia has been suggested as a risk factor for retinopathy of prematurity. We investigated the effect of raised inspired carbon dioxide on oxygen-induced retinopathy in the neonatal rat.

METHODS

Newborn rats raised in expanded litters (n = 25 each) were exposed to cycles of hyperoxia (80% O2) and hypoxia (10% O2 for 7 days, followed by room air recovery for 5 days. During cyclic oxygen exposure, 3 litters (n = 75) were exposed to 10% CO2 (PaCO2 78 mm Hg +/- 6; mean +/- SD) and 3 litters (n = 75) were exposed to 0.2% CO2 (PaCO2 45 mm Hg +/- 7). Animals were sacrificed on day 13 and retinae were analyzed using fluorescein perfusion and ADPase staining techniques.

RESULTS

Neovascularization occurred in 85% of rats exposed to high CO2 compared to 52% of rats exposed to low CO2 (p = 0.001). The severity of neovascularization, in clock hours, was also greater in the rats exposed to high CO2 (p < 0.001).

CONCLUSIONS

Exposure to high CO2 results in an increased incidence and severity of neovascularization in a rat model for oxygen-induced retinopathy. Our results support the suggestion that hypercarbia may be a risk factor for retinopathy of prematurity.

Ambient light, ophthalmic artery blood flow velocities and retinopathy of prematurity

Exposure to bright light was recently proposed as a possible risk factor for the development of retinopathy of prematurity. A semi-longitudinal Doppler ultrasound study was conducted of ophthalmic artery flow velocities at normal and increased ambient light in 22 preterm infants, at post-menstrual ages from 28 to 37 weeks. The aim of this study was to obtain relationships between ophthalmic artery blood flow velocities at various post-menstrual ages and lighting conditions and the occurrence of retinopathy of prematurity. A gradual increase in average blood flow velocities was seen between 28 and 37 weeks. A stepwise increase in flow velocity was seen in all cases when ambient light was increased from moderate to intense. Five of the 22 infants developed retinopathy. No association could be established between ophthalmic artery flow velocities or light-induced changes in flow velocity and the occurrence of retinopathy.

Ocular findings in prematurely born children at 5 years of age

Fifty-eight prematurely born children (gestational age < or = 32 weeks) were studied at the age of 5 years. The ophthalmological examination was part of an extensive neurodevelopmental evaluation. The eye study revealed significant hyperopia (> or = + 2.0) in 22.4%, myopia (> or = -1.0 D) in 8.6%, astigmatism (> or = 1.0 D) in 12.1%, and anisometropia (> or = 1.0 D) in 12.1%. The myopic refractive error was high in all of the cases: from -6.0 to -14.0 D. Manifest strabismus was found in 24.2% and significant visual impairment or blindness in 6.9%. Optic atrophy and cicatricial retinopathy of prematurity were the main causes for severe visual defects. In the randomly selected full-term children of the same age, significant hyperopia was seen in 14.3%, astigmatism in 5.4% and strabismus in 1.8%. The pattern of the eye findings was different in the preterm children compared with those born at term.

The premature retina: a model for the in vivo study of molecular genetics?

Retinopathy of prematurity is a disease of developing blood vessels. Although it is seen predominantly in premature infants requiring life support systems to survive, it does occur in full-term infants, infants with hypoxia, cyanotic heart disease and in stillborn infants. Although oxygen has been considered to be the prime aetiologic agent, evidence for this, particularly in recent years, is not compelling. The timing of the occurrence of the disease is closely related to the conceptional age of the infant rather than weeks post birth, birth weight, gestational age at birth. In addition, the case to case similarity of the disease, as well as the diverse cell types produced in unfavourable outcomes (cicatricial ROP), point to the possibility of an in utero insult to the clone of cells giving rise to the vascular endothelium providing blood supply to the neural retina.

Optic nerve hypoplasia, encephalopathy, and neurodevelopmental handicap

Abnormalities of the central nervous system are frequently described in optic nerve hypoplasia. In a longitudinal study of 46 consecutive children (32 term, 14 preterm) with bilateral optic nerve hypoplasia 32 (69.5%) had associated neurodevelopmental handicap. Of these, 90% had structural central nervous system abnormalities on computed tomographic brain scans. Neurodevelopmental handicap occurred in 62.5% of the term and 86% of the preterm infants respectively. Term infants had a greater incidence of ventral developmental midline defects and proportionately fewer maternal and/or neonatal complications throughout pregnancy, while encephaloclastic lesions were commoner among the premature infants. An association of optic nerve hypoplasia with the twin transfusion syndrome and prenatal vascular encephalopathies is described.

Retinopathy of prematurity: the relationship with intraventricular hemorrhage and bronchopulmonary dysplasia

We studied prospectively a cohort of 326 neonates weighing 500-1250 gm at birth. These babies were all born at Magee-Womens Hospital during 1986 and 1987. Sixty-five percent survived and were discharged from the hospital, and 197 of the survivors (93%) had at least one ophthalmological exam before their discharge. Of the patients who were examined, 34% had retinopathy of prematurity (ROP) and 12% had stage 3 or 4 ROP in at least one eye. There were six neonates with at least one blind eye, giving an estimated prevalence of blindness caused by ROP of 301 per million live births. By univariate analysis there was a strong association of ROP with birthweight, oxygen exposure, respirator treatment, and intraventricular hemorrhage (IVH). By multivariate analysis, only the respirator treatment was significantly associated with ROP. When birthweight, oxygen exposure, and IVH were controlled, a baby requiring more than 28 days of ventilator treatment was 4.07 times more likely to have stage 3 or 4 ROP than a baby with less ventilator exposure. These data confirm the strong association of ROP with bronchopulmonary dysplasia (BPD), low birth-weight, and IVH, and suggest that the key component among these interrelated variables may be time spent on a ventilator.

Retinopathy of prematurity: screening and optimal use of the ophthalmologist's time

In recent years it has been standard practice to recommend that indirect ophthalmoscopy be carried out between six and nine weeks of age in very low birthweight infants to screen for the presence of retinopathy of prematurity (ROP). Following this recommendation we examined 85 infants over a two-year period. Acute ROP occurred in 29 (34%), and two (2.4%) developed cicatricial disease. One-third of infants were initially examined slightly earlier or later than the strict six to nine week limits, but all except three infants were examined between 35 and 42 weeks gestation. One infant born at 26 weeks gestation, was examined 'too late' in that she had stage 4 disease when first seen at 11 weeks of age. Recent information on the natural history of ROP, and confirmation of the efficacy of treatment with cyotherapy, suggested that the timing of an initial screening examination for ROP needed reassessment. From our experience and a review of the literature we recommended that infants of less than 1000 g birthweight or less than 28 weeks gestation have an initial examination at six weeks of age; for infants of 1000 to 1250 g birthweight or 28 to 30 weeks gestation examination continue to be at six to nine weeks of age; and for infants of more than 1250 g birthweight or 31 weeks gestation screening at six to nine weeks of age is only necessary if the infant has had an unstable course or prolonged oxygen requirements. Such a protocol would not place too great a burden on ophthalmological services and would direct efforts towards the group of infants most at risk of severe visual handicap.

Retinopathy of prematurity in infants of 24-30 weeks' gestational age

Over the 10-year period from January 1, 1977 to December 31, 1986, 1114 infants with gestational ages of 24 to 30 completed weeks were cared for on a long-term basis in our nursery; 757 (68%) infants survived. As expected, both the mortality rate and the prevalence of stage-3 or stage-4 retinopathy of prematurity among survivors fell with increasing maturity at birth (P less than 0.0001). Adjusting for gestational age, and excluding infants with lethal malformations, the mortality rate decreased significantly (P = 0.018) over time by an estimated 11.5%; also the survival rate of infants with at least stage-3 retinopathy of prematurity increased significantly (P = 0.005) by an estimated 6.8%. In other words, for every 10 additional survivors over the decade, six survivors would have been expected to show at least stage-3 retinopathy of prematurity in either eye. Although the prevalence of advanced stages of retinopathy of prematurity increased in immature survivors, it was not in epidemic proportions; however, it was more likely to be related to the survival of the increasing numbers of at-risk immature infants who, in earlier times, would have died.

Premature graduates of the newborn intensive care unit: a guide to followup

Approximately 40,000 infants weighing less than 1500 grams are born in the United States each year. Caring for these infants after their discharge from the newborn intensive care unit is complex and difficult. The survival, growth, routine health care maintenance, neurologic and developmental outcome and assessment, and long-term medical complications are reviewed.

Retinopathy of prematurity

ROP is a challenging disease of the decade of the 1980s. Answers, even partial answers, to many of its questions may provide information bearing on those same questions in other blinding vascular retinopathies, such as diabetes and sickle cell disease. Answers more clearly defining the role of oxygen, ventilation, antioxidants, blood transfusions, and a host of diseases of the premature infant will lead to better care of that infant. I have tried in this article to present the boundaries of the problem, a theory of its genesis and progression, and a review of the major issues to be confronted by the pediatric, ophthalmologic, and basic science communities through its recurrence today. I have tried to make it clear to the reader when I was so doing. I have used information liberally from studies both under way and in the planning stages to make the reader aware of what is being done, even if these have not yet reached fruition, for the field is a rapidly growing one. Finally, I have tried to point out directions that I believe clinical and experimental work should take on certain critical issues.