Optimization of ß-Lactam Dosing Regimens in Neonatal Infections: Continuous and Extended Administration versus Intermittent Administration.

BACKGROUND AND OBJECTIVE: In neonates, ß-Lactam antibiotics are almost exclusively administered by intermittent infusion. However, continuous or prolonged infusion may be more beneficial because of the time-dependent antibacterial activity. In this pharmacokinetic/pharmacodynamic simulation study, we aimed to compare treatment with continuous, extended and intermittent infusion of ß-lactam antibiotics for neonates with infectious diseases. METHODS: We selected population pharmacokinetic models of penicillin G, amoxicillin, flucloxacillin, cefotaxime, ceftazidime and meropenem, and performed a Monte Carlo simulation with 30,000 neonates. Four different dosing regimens were simulated: intermittent infusion in 30 min, prolonged infusion in 4 h, continuous infusion, and continuous infusion with a loading dose. The primary endpoint was 90% probability of target attainment (PTA) for 100% ƒT>MIC during the first 48 h of treatment. RESULTS: For all antibiotics except cefotaxime, continuous infusion with a loading dose resulted in a higher PTA compared with other dosing regimens. Sufficient exposure (PTA >90%) using continuous infusion with a loading dose was reached for amoxicillin (90.3%), penicillin G (PTA 98.4%), flucloxacillin (PTA 94.3%), cefotaxime (PTA 100%), and ceftazidime (PTA 100%). Independent of dosing regimen, higher meropenem (PTA for continuous infusion with a loading dose of 85.5%) doses might be needed to treat severe infections in neonates. Ceftazidime and cefotaxime dose might be unnecessarily high, as even with dose reductions, a PTA > 90% was retained. CONCLUSIONS: Continuous infusion after a loading dose leads to a higher PTA compared with continuous, intermittent or prolonged infusion, and therefore has the potential to improve treatment with ß-lactam antibiotics in neonates.

[A neonate with abnormal eye movements]. / Afwijkende oogbewegingen bij een neonaat.

Few hours after birth, a neonate showed abnormal eye movements with episodes of downward gazing with a vertical nystagmus. Electrolytes were normal and CRP was low. Cerebral ultrasound and amplitude integrated electroencephalography showed no abnormalities. The abnormal eye movements resolved spontaneously. The infant was diagnosed with paroxysmal tonic downgaze of infancy.

[Developmental problems in prematures]. / Ontwikkelingsproblemen bij vroeggeborenen.

The French EPIPAGE-2 study evaluated a large group of premature born children (24-34 weeks' gestational age (GA))) at age 5.5 years. Outcome information of the whole cohort was presented after careful imputation including/using the variable socio-economic-status (SES), because participation rate improved with increasing SES. Survival improved with increasing GA. Survival without moderate or severe impairment was 20% in children born at 24-26 weeks' GA, but among the survivors 75% had no or mild impairment. Mild cognitive impairment rates were comparable and common among all GA groups (25-28%) and thus frequent in prematures. School problems were also common. In addition to prematurity, SES is an important risk factor for developmental impairment. Follow-up programs for premature infants beyond 30 weeks' GA are less common and may need extra attention in low SES families. Future studies should focus on both prevention of prematurity and programs to improve outcome.

Necrotizing enterocolitis in haemolytic disease of the newborn: a retrospective cohort study.

BACKGROUND AND OBJECTIVES: Necrotizing enterocolitis (NEC) is a common and often severe gastrointestinal emergency in newborn infants. While usually affecting (very) premature infants, an association between NEC and haemolytic disease of the foetus and newborn (HDFN) has been suggested. HDFN may be an additional risk factor to develop NEC. The objective of this study was to evaluate the occurrence of NEC in infants affected with moderate to severe HDFN in a large single centre cohort as compared to a broad population of infants without HDFN. MATERIALS AND METHODS: Retrospective cohort study of medical records of neonates with and without HDFN, with a gestational age at birth ≥30 weeks and ≤38 weeks, and admitted to the Leiden University Medical Center between January 2000 and December 2016. RESULTS: A total of 3284 patient records of infants born in the study period were reviewed and 317 cases of HDFN were identified. The incidence of NEC was significantly higher among infants with HDFN compared to infants without HDFN: 4/317 affected infants (1·3%) vs. 11/2967 affected infants (0·4%, relative risk 3·40, 95% confidence interval: 1·09-10·63). CONCLUSIONS: We observed a higher incidence of NEC in an overall late preterm to near term population of infants with moderate to severe HDFN, compared to infants born without HDFN. The clinician taking care of an HDFN-affected infant should be cautious of this higher risk.

The diagnostic value of routine antenatal ultrasound in screening for congenital uropathies.

BACKGROUND: Antenatal hydronephrosis (ANH) is characteristic for congenital obstructive abnormalities of the urinary tract (COAUT). COAUT is the most common cause of urinary tract infections (UTI's) in newborns. The prognosis of mild to moderate ANH is unclear. The aim of this study was to determine the diagnostic value of antenatal ultrasound screening for ANH in order to inform patients correctly. METHODS: A retrospective cohort study over the period 2009-2011, evaluating all structural ultrasounds and proven cases of ANH. Also, evaluation of all patients diagnosed with UTIs caused by COAUT in the same period. RESULTS: About 7003 children underwent antenatal screening. Of them, 0.7% (n = 47) were diagnosed with ANH. In the same period, 257 children without ANH had a proven UTI. Of them, 4.3% (n = 11) were diagnosed with COAUT, which was not found during antenatal screening. The predictive value of the antenatal ultrasound was higher in the third trimester than the second trimester (sensitivity 0.97 versus 0.62, respectively). CONCLUSION: Antenatal ultrasound screening is a reliable method in diagnosing ANH. Third trimester scanning is more specific for diagnosing ANH than second trimester scanning. Our findings allow collaborating gynecologists and pediatricians to inform patients more accurately in the future after the antenatal detection of COAUT.

Early postnatal calcium and phosphorus metabolism in preterm infants.

OBJECTIVES: Bone mineralisation in preterm infants is related to the supply of calcium (Ca) and phosphorus (P). We increased the amount of minerals in parenteral nutrition (PN) for preterm infants and evaluated postnatal Ca and P metabolism in relation to mineral and vitamin D (vitD) intake. METHODS: Preterm infants, included on their first day of life, received standard PN, providing a maximum Ca/P intake of 3/1.92 mmol · kg(-1) · day(-1) on day 3. Ca/P content of formula was 2.5/1.6 mmol/dL, and fortified human milk was 2.4/1.95 mmol/dL. PN supplied 80 IU · kg(-1) · day(-1) vitD. Formula and fortified human milk contained 200 IU/dL of vitD. During a 5-week period, serum concentrations and urinary excretion of Ca/P were registered and related to the intake of minerals and vitD. RESULTS: During 12 months, 79 infants (mean gestational age 29.8 ± 2.2 weeks, mean birth weight 1248 ± 371 g) were included. The recommended intake for minerals was achieved by day 5 and for vitD by 4 weeks. Infants developed hypercalcaemia, hypercalciuria, and hypophosphataemia during the first postnatal week, leading to the additional P supplementation in 49 infants. The renal tubular reabsorption of P was >95% until day 9 but decreased <70% after the second week. Alkaline phosphatase was normal at birth, increased to a maximum of 450 IU/L by day 14, and remained above the normal range for the remaining period. CONCLUSIONS: Parenteral intake of P appeared to be too low, leading to mineral imbalances in the early postnatal period, and vitD intake was also below recommendations.