Antenatal Neuroprotective Magnesium Sulfate in Very Preterm Infants and Its Association With Feeding Intolerance.

INTRODUCTION/OBJECTIVE: Magnesium sulfate (MgSO 4 ) treatment is widely used for fetal neuroprotection despite the controversy concerning the side effects. There is limited data regarding the impact of various cumulative maternal doses and neonatal serum magnesium (Mg) levels on short-term neonatal morbidity and mortality. We opted to carry out a study to determine the impact of neonatal serum Mg levels on neonatal outcomes. METHOD: We conducted this prospective observational study between 2017 and 2021. Antenatal MgSO 4 was used for neuroprotective purpose only during the study period. Inborn preterm infants delivered between 23 and 31 6/7 weeks of gestation were enrolled consecutively. Babies who underwent advanced resuscitation in the delivery room, inotropic treatment due to hemodynamic instability in the first 7 days of life, >12 hours since the discontinuation of maternal MgSO 4 treatment, severe anemia, and major congenital/chromosomal anomalies were excluded from the study. The subgroup of babies with serum Mg level at the 6th hour of life underwent an analysis. A neonatal Mg concentration of 2.5 mg/dL was used to classify MgSO 4 -exposed patients into 2 groups (<2.5 mg/dL and ≥2.5 mg/dL). Another analysis was performed between babies whose mothers were exposed to MgSO 4 and those not exposed. Finally, the groups' neonatal outcomes were compared. RESULTS: Of the 584 babies, 310 received antenatal MgSO 4 . The birth weights were significantly lower in the MgSO 4 exposed group (1113 ± 361 g vs 1202 ± 388 g, P = 0.005). Antenatal corticosteroid usage and intrauterine growth restriction were also noted to be higher. The MgSO 4 group was more likely to have bronchopulmonary dysplasia, prolonged invasive ventilation, necrotizing enterocolitis, delayed enteral nutrition, and feeding intolerance ( P < 0.05). MgSO 4 treatment was shown as an independent risk factor for feeding intolerance when corrected for confounders (odds ratio 2.13, 95% confidence interval: 1.4-3.1, P = 0.001). Furthermore, serum Mg level significantly correlated with feeding intolerance ( r = 0.21, P = 0.002). CONCLUSION: This study highlighted the effect of MgSO 4 treatment and the potential superiority of serum Mg level as a predictor of immediate neonatal outcomes, particularly delayed enteral nutrition and feeding intolerance. Further studies are warranted to ascertain the optimal serum Mg concentration of preterm infants in early life to provide maximum benefit with minimal side effects.

Increasing the dose of ibuprofen with postnatal age to close a hemodynamically significant patent ductus arteriosus in very preterm infants.

Patent ductus arteriosus (PDA) is associated with neonatal morbidities in high-risk preterm infants. Early neonatal treatment by ibuprofen induces the ductus arteriosus (DA) closure in approximatively 60% of infants. Dose escalation of ibuprofen according to postnatal age has been suggested for improving the DA closure rate. The aim of this study was to assess the efficacy and tolerance of an increasing dose regimen of ibuprofen. This single-center retrospective cohort study involved infants hospitalized from 2014 to 2019 in our neonatal unit. Selection criteria were gestational age < 30 weeks, birth weight < 1000 g, and treatment by ibuprofen. Three dose levels were used and consisted of a daily intravenous injection of ibuprofen-tris-hydroxymethyl-aminomethane (ibuprofen-THAM) for three consecutive days: (i) 10 -5 -5 mg/kg before the 70th h of life (H70) (dose level 1), (ii) 14 -7 -7 mg/kg between H70 and H108 (dose level 2), (iii) 18 -9 -9 mg/kg after H108 (dose level 3). The ibuprofen-induced DA closure was compared between ibuprofen schedules, and the Cox proportional-hazard regression was performed to identify factors associated with the ibuprofen efficacy. Tolerance was assessed through renal function, acidosis, and platelet count. One hundred forty-three infants met the inclusion criteria. The ibuprofen-induced DA closure was observed in 67 infants (46.8%). One course of ibuprofen at dose level 1 was more efficient in closing the DA than other schedules (dose level 1, one course (n = 70): 71%, dose level 2 or 3, one course (n = 20): 45%, two-course schedules (n = 53): 15%, p < 0.0001). Independent factors associated with ibuprofen-induced DA closure were a complete antenatal schedule of steroids (p = 0.001), a lower CRIB II score (p = 0.009), and a lower and earlier exposure to ibuprofen (p < 0.0001 and p = 0.002). No severe side effects were observed. Neonatal mortality and morbidities were similar regardless of the infant's response to ibuprofen.  Conclusion: Increasing ibuprofen doses with postnatal age failed to reach an efficacy similar to earlier treatment. Although the infant response to ibuprofen was likely to depend on multiple factors, the optimal use of ibuprofen included its early initiation. What is Known: • Ibuprofen is the current first-line treatment for patent ductus arteriosus during the early neonatal period in very preterm infants. • However, the ibuprofen efficacy rapidly declined with postnatal age during the first week of life. A dose escalation of ibuprofen according to postnatal age has been suggested to improve the ibuprofen-induced ductus arteriosus closure. What is New: • The rapid drop of ibuprofen's ability to close hemodynamically significant patent ductus arteriosus persisted beyond the postnatal day 2 despite the dose adjustment arguing for an early initiation to optimize its efficacy. • The early selection of patients who will suffer from patent ductus arteriosus-related morbidities and who will positively respond to ibuprofen is an issue that could determine the future place of ibuprofen in the patent ductus arteriosus management.

Early Empirical Antibiotics and Adverse Clinical Outcomes in Infants Born Very Preterm: A Population-Based Cohort.

OBJECTIVE: The objective of this study was to evaluate the association between empirical antibiotic therapy in the first postnatal week in uninfected infants born very preterm and the risk of adverse outcomes until discharge. STUDY DESIGN: Population-based, nationwide registry study in Norway including all live-born infants with a gestational age <32 weeks surviving first postnatal week without sepsis, intestinal perforation, or necrotizing enterocolitis (NEC) between 2009 and 2018. Primary outcomes were severe NEC, death after the first postnatal week, and/or a composite outcome of severe morbidity (severe NEC, severe bronchopulmonary dysplasia [BPD], severe retinopathy of prematurity, late-onset sepsis, or cystic periventricular leukomalacia). The association between empirical antibiotics and adverse outcomes was assessed using multivariable logistic regression models, adjusting for known confounders. RESULTS: Of 5296 live-born infants born very preterm, 4932 (93%) were included. Antibiotics were started in first postnatal week in 3790 of 4932 (77%) infants and were associated with higher aOR of death (aOR 9.33; 95% CI: 1.10-79.5, P = .041), severe morbidity (aOR 1.88; 95% CI: 1.16-3.05, P = .01), and severe BPD (aOR 2.17; 95% CI: 1.18-3.98; P = .012), compared with those not exposed. Antibiotics ≥ 5 days were associated with higher odds of severe NEC (aOR 2.27; 95% CI: 1.02-5.06; P = .045). Each additional day of antibiotics was associated with 14% higher aOR of death or severe morbidity and severe BPD. CONCLUSIONS: Early and prolonged antibiotic exposure within the first postnatal week was associated with severe NEC, severe BPD, and death after the first postnatal week.

Caffeine: Some of the Evidence behind Its Use and Abuse in the Preterm Infant.

Apnea of prematurity is a developmental disorder affecting most extremely preterm infants. The consequences of apnea of prematurity on neurodevelopment are not well established, but several reports suggest that apnea and hypoxemia episodes may be associated with worse neurological outcome. Caffeine is the only FDA-approved drug for the prevention and treatment of apnea of prematurity. Besides its clear effectiveness to reduce apnea, the use of caffeine appears to have a wide margin of safety and has been associated with possible beneficial effects on later neurodevelopmental outcome. At the same time, there are also many studies in experimental animals and some in preterm infants suggesting potential serious adverse effects from caffeine administration, especially when using higher doses. Because of these uncertainties, there is a wide variation in caffeine use across institutions. This review summarizes some of the available evidence on caffeine use in this population, its indications and best timing of initiation and discontinuation, appropriate dosing, and some of the possible adverse effects of caffeine administration. Because of the many gaps in knowledge, especially as it relates to efficacy and safety, we encourage further basic and clinical studies to provide stronger evidence, not only on its potential beneficial effects but also its side effects.

A unique cerebellar pattern of microglia activation in a mouse model of encephalopathy of prematurity.

Preterm infants often show pathologies of the cerebellum, which are associated with impaired motor performance, lower IQ and poor language skills at school ages. Using a mouse model of inflammation-induced encephalopathy of prematurity driven by systemic administration of pro-inflammatory IL-1ß, we sought to uncover causes of cerebellar damage. In this model, IL-1ß is administered between postnatal day (P) 1 to day 5, a timing equivalent to the last trimester for brain development in humans. Structural MRI analysis revealed that systemic IL-1ß treatment induced specific reductions in gray and white matter volumes of the mouse cerebellar lobules I and II (5% false discovery rate [FDR]) from P15 onwards. Preceding these MRI-detectable cerebellar volume changes, we observed damage to oligodendroglia, with reduced proliferation of OLIG2+ cells at P10 and reduced levels of the myelin proteins myelin basic protein (MBP) and myelin-associated glycoprotein (MAG) at P10 and P15. Increased density of IBA1+ cerebellar microglia were observed both at P5 and P45, with evidence for increased microglial proliferation at P5 and P10. Comparison of the transcriptome of microglia isolated from P5 cerebellums and cerebrums revealed significant enrichment of pro-inflammatory markers in microglia from both regions, but cerebellar microglia displayed a unique type I interferon signaling dysregulation. Collectively, these data suggest that perinatal inflammation driven by systemic IL-1ß leads to specific cerebellar volume deficits, which likely reflect oligodendrocyte pathology downstream of microglial activation. Further studies are now required to confirm the potential of protective strategies aimed at preventing sustained type I interferon signaling driven by cerebellar microglia as an important therapeutic target.

Early initiation of broad-spectrum antibiotics in premature infants.

BACKGROUND: Neonatal sepsis remains one of the main reasons for mortality among premature infants, and the early initiation of empirical broad-spectrum antibiotics could increase the risk of complications, including late-onset sepsis. This study aimed to investigate the complications related to the use of empirical broad-spectrum antibiotics in the first week of life. METHODS: A retrospective study of 365 neonates with gestational age ≤32 weeks and birth weight <1500 g who survived and had no confirmed sepsis in the first week of life from July 2015 to June 2018 was performed in a large tertiary Neonatal Intensive Care Unit. The primary outcome of this study was the incidence of a composite outcome consisting of late-onset sepsis, necrotizing enterocolitis, and mortality. The secondary outcomes were the incidences of late-onset sepsis, necrotizing enterocolitis, bronchopulmonary dysplasia, and infant mortality. RESULTS: Of the 365 premature infants, 75 (20.5%) received broad-spectrum antibiotics. Multivariate regression analysis revealed that administration of broad-spectrum antibiotics in infants was independently associated with adverse outcomes. The composite outcome (late-onset sepsis, necrotizing enterocolitis, and death) had an odds ratio of 3.03 with 95% confidence interval of 1.41-6.49. CONCLUSIONS: Administration of empirical broad-spectrum antibiotics in the first week of life is associated with severe adverse outcomes. Thus, the restricted use of broad-spectrum antibiotics in the first week of life is recommended.

The Risk of Necrotizing Enterocolitis following the Administration of Hyperosmolar Enteral Medications to Extremely Preterm Infants.

INTRODUCTION: Necrotizing enterocolitis (NEC) is a disease predominantly affecting preterm infants. The administration of hyperosmolar solutions could lead to the development of NEC. The objective of this study was to measure the osmolality of enteral medications used in clinical practice and to assess the risk of NEC following exposure to hyperosmolar medications. METHODS: A retrospective cohort study in extremely preterm infants (gestational age <28 weeks) born between 2010 and 2016 at a tertiary neonatal intensive care unit in Sweden. 465 infants were identified via the Swedish Neonatal Quality register. Data relating to enteral administrations received during a two-week period were collected from the medical records. The osmolalities of medications were measured using an osmometer. Logistic regression was used to calculate the odds ratio of developing NEC. RESULTS: A total of 253 patients met the inclusion criteria. The osmolalities of 5 commonly used medications significantly exceeded the recommended limit of 450 mOsm/kg set by the American Academy of Paediatrics (AAP). Most patients (94%) received at least one hyperosmolar medication. No significant risk of developing NEC could be found. CONCLUSION: The medications used in clinical practice can significantly exceed the limit set by the AAP. This study does not indicate an increased risk of developing NEC in extremely preterm infants following exposure to hyperosmolar medications. Further studies in larger cohorts are needed to determine the specific cut-off level of osmolality in relation to the pathogenesis of NEC.

Necrotizing Enterocolitis in Neonates With Hyperinsulinemic Hypoglycemia Treated With Diazoxide.

The most common cause of persistent hypoglycemia in the neonatal period is hyperinsulinism. Severe, refractory hypoglycemia resulting from hyperinsulinism can lead to significant brain injury and permanent cognitive disability. Diazoxide is the first-line and only US Food and Drug Administration-approved, pharmacologic treatment for refractory hyperinsulinism. In recent years, the use of diazoxide in neonates with persistent hyperinsulinemic hypoglycemia has increased in the United States. Known adverse effects of diazoxide include fluid retention, hypertrichosis, neutropenia, thrombocytopenia, and more recently, pulmonary hypertension. It is currently unknown if diazoxide exposure is associated with an increased risk of necrotizing enterocolitis (NEC) in neonates. We reviewed the cases of 24 patients in a level IV NICU at Massachusetts General Hospital who received diazoxide over 12 years (April 2006-April 2018). All 24 patients received enteral diazoxide for refractory hyperinsulinemic hypoglycemia. A total of 5 patients developed NEC after initiation of diazoxide based on clinical and radiographic findings, corresponding to 20% of infants exposed to diazoxide. This is above our baseline incidence of NEC (1% for all inborn infants and 6% for all inborn very low birth weight infants). More research and monitoring are necessary to characterize the potential risk of NEC associated with the use of diazoxide in the neonatal period.

Antenatal magnesium sulfate treatment and risk of necrotizing enterocolitis in preterm infants born at less than 32 weeks of gestation.

Antenatal magnesium sulfate (MgSO4) treatment is widely used for fetal neuroprotection in women at risk of preterm delivery. However, some studies have recently suggested that in utero MgSO4 exposure is associated with an increased risk of necrotizing enterocolitis (NEC). This study aimed to investigate the association between antenatal MgSO4 treatment and risk of NEC. This retrospective cohort study included 756 infants born at 24‒31 weeks' gestation. Subjects were classified into three groups: period 1, when MgSO4 treatment protocol for fetal neuroprotection was not adopted (n = 267); period 2, when the protocol was adopted (n = 261); and period 3, when the protocol was withdrawn because of concern of risk of NEC (n = 228). Rates of NEC (≥ stage 2b) were analyzed according to time period and exposure to antenatal MgSO4. Significant difference in the rate of NEC was not found across the three time periods (2.6% vs. 6.5% vs. 4.8% in periods 1, 2 and 3, respectively, p = 0.103). The rate of NEC was comparable between the infants exposed and unexposed to antenatal MgSO4 (5.1% vs. 3.6%, p = 0.369). These results showed that antenatal MgSO4 treatment was not associated with risk of NEC in our study population.

Association of initial empirical antibiotic therapy with increased risk of necrotizing enterocolitis.

Whether the prophylactic use of antibiotics increase the risk of necrotizing enterocolitis (NEC) remains controversial. This review aims to investigate initial empirical antibiotic therapy (IEAT) and is associated with the risk of NEC. PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched through March 1, 2020. All studies on the impacts of antibiotic exposure on NEC development were included. Thirteen studies including 7901 participants were selected. Two reviewers independently examined the extracted data and assessed the quality of the included studies. Random-effects model was used to pool the effect estimates. We found that IEAT (≥ 5 days) was associated with an increased risk of NEC in adjusted (Odds risk [OR] 1.51, 95% confidence interval [CI] 1.22-1.87) and unadjusted (OR 2.35, 95% CI 1.54-3.57) analyses. Sensitivity analysis also supported these findings.Conclusion: The evidence suggests an association between IEAT (≥ 5 days) and the risk of NEC. Further studies are needed to address whether the association with IEAT is causal.What is Known:•Necrotizing enterocolitis (NEC) is acute inflammatory necrosis of the intestinal tractin the newborn infant.•Some observational studies have associated initial empirical antibiotics with an increased risk of subsequent NEC.What is New:•Initial empirical antibiotic therapy (IEAT) (≥ 5 days) appear to increase the risk of NEC.

LPA1/3 overactivation induces neonatal posthemorrhagic hydrocephalus through ependymal loss and ciliary dysfunction.

Posthemorrhagic hydrocephalus (PHH) in premature infants is a common neurological disorder treated with invasive neurosurgical interventions. Patients with PHH lack effective therapeutic interventions and suffer chronic comorbidities. Here, we report a murine lysophosphatidic acid (LPA)-induced postnatal PHH model that maps neurodevelopmentally to premature infants, a clinically accessible high-risk population, and demonstrates ventriculomegaly with increased intracranial pressure. Administration of LPA, a blood-borne signaling lipid, acutely disrupted the ependymal cells that generate CSF flow, which was followed by cell death, phagocytosis, and ventricular surface denudation. This mechanism is distinct from a previously reported fetal model that induces PHH through developmental alterations. Analyses of LPA receptor-null mice identified LPA1 and LPA3 as key mediators of PHH. Pharmacological blockade of LPA1 prevented PHH in LPA-injected animals, supporting the medical tractability of LPA receptor antagonists in preventing PHH and negative CNS sequelae in premature infants.

Phthalate-associated hypertension in premature infants: a prospective mechanistic cohort study.

BACKGROUND: Phthalates are associated with increased blood pressure in children. Large exposures to di-(2-ethylhexyl) phthalate (DEHP) among premature infants have been a cause for concern. METHODS: We conducted a prospective observational cohort study to determine if DEHP exposures are related to systolic blood pressure (SBP) in premature infants, and if this exposure is associated with activation of the mineralocorticoid receptor (MR). Infants were monitored longitudinally for 8 months from birth. Those who developed idiopathic hypertension were compared with normotensive infants for DEHP exposures. Appearance of urinary metabolites after exposure was documented. Linear regression evaluated the relationship between DEHP exposures and SBP index and whether urinary cortisol/cortisone ratio (a surrogate marker for 11ß-HSD2 activity) mediated those relationships. Urinary exosomes were quantified for sodium transporter/channel expression and interrogated against SBP index. RESULTS: Eighteen patients met the study criteria, nine developed transient idiopathic hypertension at a postmenstrual age of 40.6 ± 3.4 weeks. The presence of urinary DEHP metabolites was associated with prior IV and respiratory tubing DEHP exposures (p < 0.05). Both IV and respiratory DEHP exposures were greater in hypertensive infants (p < 0.05). SBP index was related to DEHP exposure from IV fluid (p = 0.018), but not respiratory DEHP. Urinary cortisol/cortisone ratio was related to IV DEHP and SBP index (p < 0.05). Sodium transporter/channel expression was also related to SBP index (p < 0.05). CONCLUSIONS: Increased blood pressure and hypertension in premature infants are associated with postnatal DEHP exposure. The mechanism of action appears to be activation of the MR through inhibition of 11ß-HSD2.

Lack of Evidence for Time or Dose Relationship between Antenatal Magnesium Sulfate and Intestinal Injury in Extremely Preterm Neonates.

BACKGROUND: Recent studies reported conflicting results on the relationship between antenatal magnesium sulfate (MgSO4) exposure and neonatal intestinal injury. Most studies have not assessed MgSO4 exposure quantitatively and none reported the exposure timing. OBJECTIVES: The aim of this work was to assess whether there is a temporal or dose-dependent relationship between antenatal MgSO4 exposure and intestinal injury in extremely preterm neonates. METHODS: A retrospective study was made of inborn neonates with gestational age ≤28 weeks and/or birth weights ≤1,000 g. Primary outcomes included necrotizing enterocolitis (NEC), spontaneous intestinal perforation (SIP), and/or death prior to discharge or in the first 2 weeks of life. Outcome comparisons were made based on the timing of MgSO4 exposure, within 7 days (Mg7D) or within 3 days (Mg3D) of birth. Total cumulative doses for the Mg3D group were also computed. RESULTS: A total of 302 neonates were included, 210 in the Mg7D group, out of whom 179 (85.2%) constituted the Mg3D group. There were no differences noted when comparing MgSO4 exposure timing and the likelihood of NEC, SIP, and/or death. This remained the same for subgroup analysis of neonates < 26 weeks' gestation. Each 10-g increase in MgSO4 cumulative dose correlated with a decrease in SIP/NEC/death by 18.9% prior to discharge and by 21.9% in the first 2 weeks of life. Small for gestational age (SGA) was a potential effect modifier by a likelihood ratio test with p = 0.07. CONCLUSIONS: Antenatal MgSO4 exposure in extremely preterm neonates was not associated with an increased risk of intestinal injury or death, and might have reduced these complications in a dose-dependent manner in our study. This protective effect was more noticeable in SGA neonates.

The contribution of morphine sulfate to the development of necrotizing enterocolitis in preterm infants: a matched casecontrol study.

Zvizdic Z, Milisic E, Jonuzi A, Terzic S, Zvizdic D. The contribution of morphine sulfate to the development of necrotizing enterocolitis in preterm infants: a matched case-control study. Turk J Pediatr 2019; 61: 513-519. The aim of the study was to determine whether morphine sulfate administration is associated with an increased risk of necrotizing enterocolitis (NEC) in preterm infants supported by mechanical ventilation due to respiratory failure. The matched case-control retrospective study was carried out at the Neonatal Intensive Care Unit (NICU) of the University Clinical Center Sarajevo, on 122 preterm infants classified into total NEC group and control group. The total NEC group was further divided into medical NEC and surgical NEC subgroups. The association between the use and duration of morphine sulfate infusion and the development of NEC was evaluated in both unadjusted and adjusted analysis. Preterm infants who developed NEC were on mechanical ventilation more frequently compared to premature infants without signs of NEC (Mann- Whitney U test; p=0.0031). A positive correlation between the frequency of receiving morphine sulfate and the development of NEC was observed (Chi square test of independence; p=0.0001). The risk of NEC in preterm infants was increased by the use of morphine sulfate. Validation of this observation in other populations is warranted.

[Prolonged initial empirical antibiotic treatment and the risk of morbidity and mortality in very low birthweight infants]. / Tratamiento antibiótico empírico inicial prolongado y riesgo de morbimortalidad en recién nacidos de muy bajo peso al nacer.

INTRODUCTION: The objective of this study is to evaluate the association between the duration of ini tial empirical antibiotic treatment and the subsequent development of late-onset sepsis, necrotizing enterocolitis (NEC) and death in very low birth weight (VLBW) infants. PATIENTS AND METHODS: Quantitative, cross-sectional, analytical study of VLBW infants admitted to the neonatal ICU were included over a period of five years. Initial empirical antibiotic therapy was that which started immediately after birth, without knowing the results of blood cultures. It was considered prolonged antibiotic therapy when the treatment duration was > 5 days. Perinatal variables, as well as the inci dence of late-onset sepsis, confirmed NEC and mortality were analyzed. RESULTS: 266 VLBW infants were studied, with an average gestational age and birth weight of 28.8 ± 2.5 weeks and 1.127 ± 264 g respectively. 213 infants received initial empiric antibiotic therapy (80.0%), which was prolonged in 67.6% of cases. All infants received two different antibiotics. 136 episodes of late-onset sepsis were described. The most common pathogens were coagulase-negative Staphylococcus and Staphylococcus aureus. Among the newborns with prolonged antibiotic therapy, there were 20 cases of confirmed NEC and 15 of the studied infants died (10.4%). When comparing the use of antibiotic therapy during > 5 days versus treatment less than 5 days duration, a statistically significant association was observed between prolonged antibiotic therapy and late-onset sepsis (p = 0.03) and confirmed NEC (p = 0.03), but not of mortality (p = 0.12). CONCLUSION: The use of empirical antibiotic therapy for five days or more was associated with an increased risk of late-onset sepsis and NEC, but not of mortality in VLBW infants.

Tratamiento antibiótico empírico inicial prolongado y riesgo de morbimortalidad en recién nacidos de muy bajo peso al nacer / Prolonged initial empirical antibiotic treatment and the risk of morbidity and mortality in very low birthweight infants

Resumen: Introducción: El objetivo de este estudio es evaluar la asociación entre la duración del tratamien to antibiótico empírico inicial y el desarrollo posterior de sepsis tardía, enterocolitis necrotizante (NEC) y muerte en recién nacidos de muy bajo peso al nacer (RNMBP). Pacientes y Método: Estudio cuantitativo, transversal analítico, en RNMBP ingresados a UCI neonatal durante un período de 5 años. Se consideró antibioterapia empírica inicial aquella que comenzó desde el nacimiento, sin conocer resultado de hemocultivos. Antibioterapia prolongada se estimó cuando la duración del tratamiento fue > 5 días. Se analizaron variables perinatales, e incidencia de sepsis tardía, NEC confirmada y mortalidad. Resultados: Se estudiaron un total de 266 RNMBP, con edad gestacional y peso de nacimiento promedios de 28,8 ± 2,5 semanas y 1.127 ± 264 g respec tivamente. Recibieron antibioterapia empírica inicial 213 (80,0%), siendo ésta prolongada en el 67,6%. Todos recibieron antibioterapia biasociada. Se pesquisaron 136 episodios de sepsis tardía, siendo los gérmenes más frecuentes el Staphylococcus coagulasa negativo y el Staphylococcus au reus. Del total de RN con antibioterapia empírica prolongada, hubo 20 casos de NEC confirmada y 15 fallecidos (10,4%) en el grupo analizado. Al comparar el uso de antibioterapia > 5 días ver sus tratamiento menor de 5 días, se observó una asociación estadísticamente significativa entre la antibioterapia prolongada y sepsis tardía (p = 0,03) y además de NEC confirmada (p = 0,03), pero no de mortalidad (p = 0,12). Conclusión: El uso de antibioterapia empírica inicial por 5 días o más se asoció a un riesgo aumentado de sepsis tardía y de NEC, pero no de la mortalidad en RNMBPN.

Abstract: Introduction: The objective of this study is to evaluate the association between the duration of ini tial empirical antibiotic treatment and the subsequent development of late-onset sepsis, necrotizing enterocolitis (NEC) and death in very low birth weight (VLBW) infants. Patients and Methods: Quantitative, cross-sectional, analytical study of VLBW infants admitted to the neonatal ICU were included over a period of five years. Initial empirical antibiotic therapy was that which started im mediately after birth, without knowing the results of blood cultures. It was considered prolonged antibiotic therapy when the treatment duration was > 5 days. Perinatal variables, as well as the inci dence of late-onset sepsis, confirmed NEC and mortality were analyzed. Results: 266 VLBW infants were studied, with an average gestational age and birth weight of 28.8 ± 2.5 weeks and 1.127 ± 264 g respectively. 213 infants received initial empiric antibiotic therapy (80.0%), which was prolonged in 67.6% of cases. All infants received two different antibiotics. 136 episodes of late-onset sepsis were described. The most common pathogens were coagulase-negative Staphylococcus and Staphylococcus aureus. Among the newborns with prolonged antibiotic therapy, there were 20 cases of confirmed NEC and 15 of the studied infants died (10.4%). When comparing the use of antibiotic therapy during > 5 days versus treatment less than 5 days duration, a statistically significant association was observed between prolonged antibiotic therapy and late-onset sepsis (p = 0.03) and confirmed NEC (p = 0.03), but not of mortality (p = 0.12). Conclusion: The use of empirical antibiotic therapy for five days or more was associated with an increased risk of late-onset sepsis and NEC, but not of mortality in VLBW infants.