Newborn hearing screening: tobramycin and vancomycin are not risk factors for hearing loss

Furosemide Safety in Preterm Infants at Risk for Bronchopulmonary Dysplasia: A Randomized Clinical Trial

OBJECTIVE

To evaluate the safety of furosemide in preterm infants at the risk of developing bronchopulmonary dysplasia (BPD).

STUDY DESIGN

This multicenter, randomized, dose-escalating, placebo-controlled trial enrolled infants born <29 weeks gestational age at 7-28 days postnatal age and at risk for BPD. Infants were randomized 3:1 (furosemide:placebo) into 2 cohorts with escalating doses of furosemide to a maximum of 1 mg/kg intravenous (IV; or 2 mg/kg enteral) every 24 hours (cohort 1; n = 40) or 1 mg/kg IV (or 2 mg/kg enteral) every 6 hours (cohort 2; n = 40) for 28 days. Effects of furosemide on total adverse events (AEs; primary outcome), BPD, death, hearing loss, serum electrolyte AEs, and nephrocalcinosis were estimated using logistic regression adjusted for gestational age.

RESULTS

We found 293 AEs in 74 of 80 (93%) infants, including 223 AEs among 56 of 61 (92%) infants who received furosemide and 70 AEs among 18 of 19 (95%) infants who received placebo (P > .99). Adjusted analysis among all groups showed no difference in the odds of having moderate-to-severe BPD or death at 36 weeks post-menstrual age (P = .32), hearing loss (P = .78), or nephrocalcinosis (P = .39). For serum electrolyte AE, OR (furosemide vs placebo) was 4.46 (95% CI, 1.06-21.70; P = .048) for cohort 1 and 7.89 (95% CI, 1.50-61.91; P = .023) for cohort 2.

CONCLUSIONS

In preterm infants, furosemide did not increase the overall incidence of AEs, hearing loss, or nephrocalcinosis, but did increase the incidence of electrolyte abnormalities. Furosemide given for 28 consecutive days was not associated with a difference in moderate-to-severe BPD or death at 36 weeks postmenstrual age.

CLINICALTRIALS

GOV: NCT02527798.

Cumulative risk factors contributing to hearing loss in preterm infants

OBJECTIVE

To investigate individual and concomitant risk factors for hearing loss during neonatal care.

DESIGN

Case-control study.

SETTING

Community.

POPULATION

237 children born <32 weeks of gestation; 57 with hearing loss and 180 with normal hearing born between 2009 and 2013, matched for sex, gestation and year of birth.

MAIN OUTCOME MEASURES

Data were abstracted from clinical records for overall risk factors daily for the first 14 days and then weekly until discharge from neonatal care. All infants were screened for the presence of m.1555A>G mutation.

RESULTS

Children with hearing loss had lower birth weight for gestational age, more severe neonatal illness, with increased exposure to inotrope, steroid, gentamicin, vancomycin and furosemide, and more frequent physiological risk, elevated bilirubin and creatinine levels and acidosis, but no index child was found to have the m.1555A>G mutation, compared with one among controls. The duration of gentamicin, vancomycin or furosemide administration in the first 14 days was associated with impaired hearing (OR per dose: 1.25; 95% CI 1.14 to 1.38). Multivariate analyses revealed independent risks for hearing loss for each day when there was physiological risk (OR per day 1.15 (1.05 to 1.27)) and each day of medication exposure (OR 1.23 (1.1 to 1.37)).

CONCLUSION

Although the relative contribution of underlying illness and medication cannot be identified by this study, cumulative use of ototoxic medication and the presence of physiologic risk factors independently increased the likelihood of hearing loss, warranting close monitoring of coincident therapy throughout neonatal critical care.

Individualized vancomycin dosing in infants: prospective evaluation of an online dose calculator

BACKGROUND

Empiric vancomycin dosing regimens fail to achieve recommended target trough concentrations of 10-20 mg/L in the majority of infants. This study assessed the performance of a model-based dosing calculator (Vanc App) in achieving target vancomycin concentrations at first steady-state level.

METHODS

This was a multicenter prospective study in four tertiary pediatric hospitals over an 18-month period. Infants aged 0-90 days with suspected Gram-positive sepsis requiring empiric vancomycin treatment were included if they did not meet any of the exclusion criteria: post-menstrual age (PMA) <25 weeks, weight <500 g, glycopeptide allergy, receiving extracorporeal membrane oxygenation, vancomycin use within the previous 72 h, and renal impairment. The Vanc App used a published population pharmacokinetic model to generate a dose based on the infant's PMA, weight, creatinine, and target vancomycin concentration.

RESULTS

A total of 40 infants were included; 40% were female, median (range) weight was 2505 (700-4460) g and median (range) PMA was 37.4 (25.7-49.0) weeks. The median (range) vancomycin dose was 45 (24-79) mg/kg/day. All infants had trough vancomycin concentrations measured at steady-state (24-<48 hours) and 30 (75%) infants achieved target concentrations. Five infants had supratherapeutic (median 25, range 21-38 mg/L) and five had subtherapeutic (median 6, range <5-9 mg/L) concentrations. An area under the concentration-time curve (AUC_0-24) of 400-650 mg/L.h was achieved in 33 (83%) infants. There were no infusion-related reactions or nephrotoxicity.

CONCLUSION

Individualized intermittent vancomycin dosing using a model-based online calculator resulted in 75% and 83% of infants achieving target trough and AUC_0-24, respectively, at first steady-state level. There were no vancomycin-related nephrotoxicity or infusion-related reactions.

Vancomycin Use in Children and Neonates across Three Decades: A Bibliometric Analysis of the Top-Cited Articles

Vancomycin is frequently prescribed in pediatrics, especially in intensive care unit settings, to treat Gram-positive bacterial infections. This work aims to collect the top-cited articles of pediatric and infectious diseases areas to gather the current evidence and gaps of knowledge on the use of vancomycin in these populations. The most relevant journals reported in the "pediatrics" and "infectious diseases" categories of the 2019 edition of Journal Citation Reports were browsed. Articles with more than 30 citations and published over the last three decades were collected. A bibliometric analysis was performed and 115 articles were retrieved. They were published in 21 journals, with a median impact factor of 4.6 (IQR 2.9-5.4). Sixty-eight of them (59.1%) belonged to "infectious diseases" journals. The most relevant topic was "bloodstream/complicated/invasive infections", followed by "antibiotic resistance/MRSA treatment". As for population distribution, 27 articles were on children only and 27 on neonates, most of which were from intensive care unit (ICU) settings. The current literature mainly deals with vancomycin as a treatment for severe infections and antibiotic resistance, especially in neonatal ICU settings. Lately, attention to new dosing strategies in the neonatal and pediatric population has become a sensible topic.

Vancomycin-induced ototoxicity in very-low-birthweight infants

BACKGROUND

Vancomycin is an extensively used anti-infective drug in neonatal ICUs. However, exposure-toxicity relationships have not been clearly defined.

OBJECTIVES

To evaluate the risk profile for hearing deficits in vancomycin-exposed very-low-birthweight infants (VLBWI).

METHODS

In a large cohort study of the German Neonatal Network (GNN; n = 16 967 VLBWI) we assessed the association of vancomycin treatment and pathological hearing tests at discharge and at 5 year follow-up. We performed audits on vancomycin exposure, drug levels, dose adjustments and exposure to other ototoxic drugs in a subgroup of 1042 vancomycin-treated VLBWI.

RESULTS

In the GNN cohort, 28% (n = 4739) were exposed to IV vancomycin therapy. In multivariable logistic regression analysis, vancomycin exposure proved to be independently associated with pathological hearing test at discharge (OR 1.18, 95% CI 1.03-1.34, P = 0.016). Among vancomycin-treated infants, a cumulative vancomycin dose above the upper quartile (>314 mg/kg bodyweight) was associated with pathological hearing test at discharge (OR 2.1, 95% CI 1.21-3.64, P = 0.009), whereas a vancomycin cumulative dose below the upper quartile was associated with a reduced risk of pathological tone audiometry results at 5 years of age (OR 0.29, 95% CI 0.1-0.8, P = 0.02, n = 147).

CONCLUSIONS

Vancomycin exposure in VLBWI is associated with an increased, dose-dependent risk of pathological hearing test results at discharge and at 5 years of age. Prospective studies on long-term hearing impairment are needed.

Association between Hyperbilirubinemia and Hearing Screen Failure in the Neonatal Intensive Care Unit in Infants Born Preterm

OBJECTIVE

To characterize the association between hyperbilirubinemia and a failed newborn hearing screen in infants born at 22-32 weeks of gestation.

STUDY DESIGN

We included infants with gestational ages of 22-32 weeks who were discharged from neonatal intensive care units in the US from 2002 to 2017 with available newborn hearing screen results obtained after 34 weeks postmenstrual age. We excluded infants with severe birth asphyxia or craniofacial abnormalities. We identified 95 672 infants from 313 neonatal intensive care units. We used multivariable logistic regression to examine the association between maximum total bilirubin at <21 days postnatal age with failed hearing screen, adjusting for important demographic and clinical risk factors.

RESULTS

The median gestational age and birth weight were 30 weeks (IQR, 28-32 weeks) and 1330 g (IQR, 1010-1630 g), respectively. The median maximum total bilirubin was 8.3 mg/dL (IQR, 6.7-10.0 mg/dL), and 5275 infants (6%) failed their newborn hearing screen. On adjusted analysis, each 1 mg/dL increase in maximum total bilirubin was associated with a small, but significant, increase in odds of a failed hearing screen (OR, 1.03; 95% CI, 1.02-1.04).

CONCLUSIONS

An increased maximum total bilirubin level was independently associated with hearing screen failure. Further prospective studies are needed to understand whether this increased risk of hearing screen failure translates to increased risk of hearing loss.

Ototoxicity of Non-aminoglycoside Antibiotics

It is well-known that aminoglycoside antibiotics can cause significant hearing loss and vestibular deficits that have been described in animal studies and in clinical reports. The purpose of this review is to summarize relevant preclinical and clinical publications that discuss the ototoxicity of non-aminoglycoside antibiotics. The major classes of antibiotics other than aminoglycosides that have been associated with hearing loss in animal studies and in patients are discussed in this report. These antibiotics include: capreomycin, a polypeptide antibiotic that has been used to treat patients with drug-resistant tuberculosis, particularly in developing nations; the macrolides, including erythromycin, azithromycin and clarithromycin; and vancomycin. These antibiotics have been associated with ototoxicity, particularly in neonates. It is critical to be aware of the ototoxic potential of these antibiotics since so much attention has been given to the ototoxicity of aminoglycoside antibiotics in the literature.

Treatment for hypotension in the first 24 postnatal hours and the risk of hearing loss among extremely low birth weight infants

OBJECTIVE

To evaluate whether treated hypotension in the first 24 postnatal hours is associated with hearing loss in extremely low birth weight (ELBW) infants.

STUDY DESIGN

In a cohort of 735 ELBW infants, we identified 25 with sensorineural hearing loss (SNHL) at 12-24 months adjusted age. For each case, we selected three controls with normal hearing. Logistic regression models were used to adjust for confounding variables.

RESULTS

Sixty percent of cases and 25% of controls were treated for hypotension. After adjusting for confounding variables (gestational age, antenatal glucocorticoids, 5 min Apgar < 6, insertion of an umbilical catheter, treatment with high frequency ventilation, and major cranial ultrasound abnormality), treated hypotension was associated with an increased risk of SNHL (adjusted odds ratio: 3.6; 95% confidence interval: 1.3-9.7).

CONCLUSIONS

Treated hypotension in ELBW infants in the first 24 h of life is associated with an increased risk of SNHL.

Hearing in Schoolchildren After Neonatal Exposure to a High-Dose Gentamicin Regimen

OBJECTIVE

To assess the association between gentamicin exposure in the neonatal period and hearing in school age.

METHODS

This study included children exposed to a high-dose (6 mg/kg) gentamicin regimen as neonates (2004-2012), invited for follow-up at school age, and a healthy age-matched control group. We assessed hearing with pure tone audiometry including the extended high-frequency (EHF) range. Outcomes were average hearing thresholds in the midfrequencies (0.5-4 kHz) and the EHFs (9-16 kHz). The measures of gentamicin exposure were cumulative dose and highest trough plasma concentration. We used linear regression models to assess the impact of gentamicin exposure, and other peri- and postnatal morbidities, on hearing thresholds.

RESULTS

A total of 219 gentamicin-exposed and 33 healthy-control children were included in the audiological analysis. In the gentamicin cohort, 39 (17%) had a birth weight <1500 g. Median cumulative doses and trough plasma concentrations were 30 (interquartile range 24-42) mg/kg and 1.0 (interquartile range 0.7-1.2) mg/L, respectively. Median hearing thresholds for the midfrequencies and the EHFs were 2.5 (0 to 6.3) dB hearing level and -1.7 (-5.0 to 5.0) dB hearing level, both of which were within the normal range. In an adjusted analysis, increasing hearing thresholds were associated with lower birth weight and postnatal middle-ear disease but not level of gentamicin exposure. After adjusting for birth weight, there was no difference in hearing threshold between the gentamicin-exposed cohort and healthy controls.

CONCLUSIONS

Exposure to a high-dose gentamicin regimen in the neonatal period was not associated with an increase in hearing thresholds in schoolchildren being able to complete audiometry.

Ototoxicity and Nephrotoxicity With Elevated Serum Concentrations Following Vancomycin Overdose: A Retrospective Case Series

Although a high vancomycin serum concentration is known to be associated with nephrotoxicity, its association with ototoxicity is not well known. The purpose of our study was to examine the latter association in pediatric patients, especially in cases of accidental overdose. Pediatric patients who received vancomycin at our facility between March 2010 and December 2015 with a serum trough concentration > 30 mg/L were enrolled. Age, sex, neonatal hearing screening results, estimated peak vancomycin serum concentration, duration of drug exposure, renal function, and hearing test results were collected. The estimated duration of concentrations above 30 or 80 mg/L were simulated with the Sawchuk-Zaske method. We defined a "high concentration" and "toxic concentration" of vancomycin as 30 to 80 mg/L and > 80 mg/L, respectively. Ototoxicity was assessed based on the auditory brain stem response. We identified 4 females and 2 males with normal hearing at birth. Four of the 6 patients were ≤ 3 months old. All the patients reached an estimated peak serum concentration of > 80 mg/L, and 5 exceeded 150 mg/L. The estimated duration of exposure to a high concentration and toxic concentration of vancomycin was 15 to 62 hours and 8 to 43 hours, respectively. All the patients experienced transient renal dysfunction. Although transient ototoxicity was found in 1 patient, prolonged ototoxicity was not observed in any of the patients. All the patients had received an accidental overdose of vancomycin. Prolonged hearing loss due to a high vancomycin serum concentration was not found in any of the subjects in the present report.

Prolonged furosemide exposure and risk of abnormal newborn hearing screen in premature infants

BACKGROUND

At very high doses, furosemide is linked to ototoxicity in adults, but little is known about the risk of hearing loss in premature infants exposed to furosemide.

AIMS

Evaluate the association between prolonged furosemide exposure and abnormal hearing screening in premature infants.

STUDY DESIGN

Using propensity scoring, infants with prolonged (≥28 days) exposure to furosemide were matched to infants never exposed. The matched sample was used to estimate the impact of prolonged furosemide exposure on the probability of an abnormal hearing screen prior to hospital discharge.

SUBJECTS

A cohort of infants 501-1250 g birth weight and 23-29 weeks gestational age discharged home from 210 neonatal intensive care units in the United States (2004-2013).

OUTCOME MEASURES

We defined abnormal hearing screen as a result of either "fail" or "refer" for either ear.

RESULTS

Altogether, 1020 infants exposed to furosemide for ≥28 days were matched to 790 unique infants never exposed, yielding a total of 1042 matches due to sampling with replacement and propensity score ties. Matching resulted in a population similar in baseline characteristics. After adjusting for covariates, the proportion of infants with an abnormal hearing screen in the furosemide-exposed group was not significantly higher than the never-exposed group (absolute difference 3.0% [95% CI -0.2-6.2%], P = 0.07).

CONCLUSIONS

Prolonged furosemide exposure was associated with a positive, but not statistically significant, difference in abnormal hearing screening in premature infants. Additional studies with post-hospital discharge audiology follow-up are needed to further evaluate the safety of furosemide in this population.

Normal neonatal hearing screening did not preclude sensorineural hearing loss in two-year-old very preterm infants

AIM

Very preterm infants are at risk of neonatal hearing loss. However, it is unknown whether infants with a normal neonatal hearing screening result risk sensorineural hearing loss (SNHL) at a later age.

METHODS

This cohort study was conducted at the Erasmus Medical University Center Rotterdam, the Netherlands, on 77 very preterm infants born between October 2005 and September 2008. All infants underwent auditory brainstem response audiometry during neonatal hearing screening and at two years of corrected age. The frequency of SNHL in infants with a normal neonatal hearing screening was analysed and the risk factors associated with newly diagnosed SNHL in these infants were examined.

RESULTS

We found that 3.9% (3/77) of the very preterm infants showed permanent hearing loss during their neonatal hearing screening. In addition, a relatively high prevalence of newly diagnosed SNHL (4.3%) was found in three of the 70 infants followed up at the age of two. The total prevalence rate of permanent hearing loss in the cohort was approximately 8%.

CONCLUSION

A normal outcome of neonatal hearing screening did not guarantee normal hearing at two years of age in this very preterm cohort and paediatricians should be alert to the possibility of late-onset SNHL.

Evaluating the ototoxicity of an anti-MRSA peptide KR-12-a2

INTRODUCTION

Methicillin-resistant staphylococcus aureus is an emerging problem for the treatment of chronic suppurative otitis media, and also for pediatric tympanostomy tube otorrhea. To date, there are no effective topical antibiotic drugs to treat methicillin-resistant staphylococcus aureus otorrhea.

OBJECTIVE

In this study, we evaluated the ototoxicity of topical KR-12-a2 solution on the cochlea when it is applied topically in the middle ear of guinea pigs.

METHODS

The antimicrobial activity of KR-12-a2 against methicillin-resistant staphylococcus aureus strains was examined by using the inhibition zone test. Topical application of KR-12-a2 solution, gentamicin and phosphate buffered saline were applied in the middle ear of the guinea pigs after inserting ventilation tubes. Ototoxicity was assessed by auditory brainstem evoked response and scanning electron microscope examination.

RESULTS

KR-12-a2 produced an inhibition zone against methicillin-resistant staphylococcus aureus from 6.25 μg. Hearing threshold in the KR-12-a2 and PBS groups were similar to that before ventilation tube insertion. However, the gentamicin group showed elevation of the hearing threshold and there were statistically significant differences compared to the phosphate buffered saline or the KR-12-a2 group. In the scanning electron microscope findings, the KR-12-a2 group showed intact outer hair cells. However, the gentamicin group showed total loss of outer hair cells. In our experiment, topically applied KR-12-a2 solution did not cause hearing loss or cochlear damage in guinea pigs.

CONCLUSION

In our experiment, topically applied KR-12-a2 solution did not cause hearing loss or cochlear damage in guinea pigs. The KR-12-a2 solution can be used as ototopical drops for treating methicillin-resistant staphylococcus aureus otorrhea; however, further evaluations, such as the definition of optimal concentration and combination, are necessary.

Coagulase negative staphylococcal sepsis in neonates: do we need to adapt vancomycin dose or target?

Background

Despite differences in types of infection and causative organisms, pharmacokinetic-pharmacodynamic (PKPD) targets of vancomycin therapy derived from adult studies are suggested for neonates. We aimed to identify doses needed for the attainment of AUC/MIC > 400 and AUC/MIC > 300 in neonates with sepsis and correlate these targets with recommended doses and treatment outcome.

Methods

Neonates who had Vancomycin therapeutic drug monitoring (TDM) performed between January 1, 2010 and December 31, 2012 were studied. Clinical characteristics, episodes of Gram-positive sepsis with outcomes and all neonatal blood culture isolates in hospital were collected from medical records. To estimate probability of target attainment of AUC/MIC >400 and AUC/MIC >300 a 1000-subject Monte Carlo simulation was performed by calculating AUC using Anderson’s (Anderson et al. 2006) and TDM trough concentrations (C_trough) based population PK models.

Results

Final dataset included 76 patients; 57 with confirmed Gram-positive sepsis. TDM was taken after the 1^st to 44^th dose. 84.1% of C_trough were within the range 5–15 mg/L. Currently recommended doses achieved probability of the targets (PTA) of AUC/MIC >400 and AUC/MIC >300 in less than 25% and 40% of cases, respectively. Doses required for 80% PTA of AUC/MIC > 400 for MIC ≥2 mg/L resulted in C_trough values ≥14 mg/L. Mean AUC/MIC values were similar in treatment failure and success groups.

Conclusion

With currently recommended vancomycin dosing the therapeutic target of AUC/MIC > 400 is achieved only by 25% of neonates. Appropriate PKPD targets and respective dosing regimens need to be defined in prospective clinical studies in this population.

Newborn hearing screening programme in Belgium: a consensus recommendation on risk factors

Background

Understanding the risk factors for hearing loss is essential for designing the Belgian newborn hearing screening programme. Accordingly, they needed to be updated in accordance with current scientific knowledge. This study aimed to update the recommendations for the clinical management and follow-up of newborns with neonatal risk factors of hearing loss for the newborn screening programme in Belgium.

Methods

A literature review was performed, and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system assessment method was used to determine the level of evidence quality and strength of the recommendation for each risk factor. The state of scientific knowledge, levels of evidence quality, and graded recommendations were subsequently assessed using a three-round Delphi consensus process (two online questionnaires and one face-to-face meeting).

Results

Congenital infections (i.e., cytomegalovirus, toxoplasmosis, and syphilis), a family history of hearing loss, consanguinity in (grand)parents, malformation syndromes, and foetal alcohol syndrome presented a ‘high’ level of evidence quality as neonatal risk factors for hearing loss. Because of the sensitivity of auditory function to bilirubin toxicity, hyperbilirubinaemia was assessed at a ‘moderate’ level of evidence quality. In contrast, a very low birth weight, low Apgar score, and hospitalisation in the neonatal intensive care unit ranged from ‘very low’ to ‘low’ levels, and ototoxic drugs were evidenced as ‘very low’. Possible explanations for these ‘very low’ and ‘low’ levels include the improved management of these health conditions or treatments, and methodological weaknesses such as confounding effects, which make it difficult to conclude on individual risk factors. In the recommendation statements, the experts emphasised avoiding unidentified neonatal hearing loss and opted to include risk factors for hearing loss even in cases with weak evidence. The panel also highlighted the cumulative effect of risk factors for hearing loss.

Conclusions

We revised the recommendations for the clinical management and follow-up of newborns exhibiting neonatal risk factors for hearing loss on the basis of the aforementioned evidence-based approach and clinical experience from experts. The next step is the implementation of these findings in the Belgian screening programme.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-015-0479-4) contains supplementary material, which is available to authorized users.

How to use vancomycin optimally in neonates: remaining questions

In neonates, vancomycin, a narrow-spectrum antibiotic, is the first choice of treatment of late-onset sepsis predominantly caused by Gram-positive bacteria (coagulase-negative staphylococci and enterococci). Although it has been used for >50 years, prescribing the right dose and dosing regimen remains a challenge in neonatal intensive care units for many reasons including high pharmacokinetic variability, increase in the minimal inhibition concentration against staphylococci, lack of consensus on dosing regimen and way of administration (continuous or intermittent), duration of treatment, use of therapeutic drug monitoring, limited data on short- and long-term toxicity, risk of mutant selection and errors of administration linked to concentrated formulations. This article highlights and discusses future research directions, with specific attention given to dosing optimization of vancomycin, including the advantages of modeling and simulation approaches.

Optimization of vancomycin dosing in very low-birth-weight preterm neonates

OBJECTIVE

To compare vancomycin serum trough concentrations and 24-hour area under the serum concentration-versus-time curve (AUC24) among very low-birth-weight (VLBW) premature infants before and after implementation of an institution-wide increase in neonatal vancomycin dosing.

STUDY DESIGN

We performed a retrospective analysis of vancomycin concentrations among preterm VLBW neonates before (2007-2010) and after (2010-2013) implementation of a new vancomycin dosing protocol consisting of increased vancomycin daily dose and frequency of administration.

RESULTS

Neonates weighing < 1,500 g and receiving the new vancomycin dosing regimen had lower rates of undetectable trough concentrations (24 vs. 50%, p = 0.04), higher median trough concentrations (10.8 vs. 5.9 µg/mL, p = 0.003), a higher proportion of goal trough concentrations of 10 to 20 µg/mL (35 vs. 4%, p = 0.005), and a significantly higher vancomycin AUC24 (438 vs. 320 mg·h/L, p = 0.004) compared with historical controls.

CONCLUSION

Increasing the vancomycin daily dose and dosing frequency led to an increase in vancomycin trough concentrations and AUC24, and a decrease in the proportion of undetectable (< 5.0 µg/mL) troughs, without an increase in toxicity among VLBW premature neonates.

Assessment of initial vancomycin dosing in neonates

BACKGROUND

Vancomycin is recommended for optimal treatment of late-onset sepsis caused by coagulase-negative Staphylococcus in neonates.

OBJECTIVES

To assess the performance of an empirical vancomycin dosing regimen in achieving target trough levels, and to revise this regimen if needed.

METHODS

Data regarding doses and levels were collected and pharmacokinetic parameters were calculated, where possible, for neonates receiving vancomcyin in a neonatal intensive care unit. The primary measure was the percentage of neonates with initial prevancomycin levels of <10 mg/L, 10 mg/L to 20 mg/L and >20 mg/L. Secondary measures included the percentage of neonates with extrapolated trough levels in these ranges, total daily doses that achieved target levels (10 mg/L to 20 mg/L) and total daily doses/dosing intervals that were pharmacokinetically predicted to achieve trough levels of 15 mg/L.

RESULTS

Of 153 infants started on the empirical regimen (15 mg/kg/day to 45 mg/kg/day, depending on postnatal age and weight), 34.2% initially achieved target trough levels (mean 8.7 mg/L). Analysis of actual doses and pharmacokinetically predicted doses required to reach target levels suggested increasing the empirical dosing for all neonatal age groups. The revised regimen used in the present study (20 mg/kg/day to 40 mg/kg/day, depending on postmenstrual age and postnatal age) was predicted to result in 72% of infants achieving initial target trough levels (mean 15.4 mg/L).

CONCLUSIONS

A revised empirical vancomycin dosage regimen for neonates was required based on poor achievement of target trough levels (10 mg/L to 20 mg/L) using the previous regimen. The modified regimen is predicted to reach target trough levels more often and increase the mean initial trough levels achieved. This regimen requires clinical validation in an independent cohort in the future.

The risk factor profile of children covered by the Polish universal neonatal hearing screening program and its impact on hearing loss incidence

OBJECTIVE

The high frequency of risk factors detected within the newborn population increases the total number of children that should receive regular follow-ups. However, in some circumstances, this could be beyond the capacity of the health system. Therefore, careful interpretation and selection of risk factors, and in particular of those factors not strictly defined, should be carried out during screening. The aim of the study was to analyse the risk factor profile of children covered by the national universal neonatal hearing screening program and to correlate it with hearing loss incidence.

PATIENTS AND METHODS

The analysis of records in the program database collected from 472 neonatal and well-baby units over a period of 10 years (2002-2012), focused on children with at least one risk factor. The analysis was subdivided into distribution of risk factors as well as to risk factors and hearing loss correlation.

RESULTS

In the studied cohort of n=137,432 children (4% of the total number of screened children) single risk factors were most frequently detected, accounting for 71% of records. The association of two or more risk factors appeared in 659 configurations (29%), with a mean of 3.1 coexisting risk factors and a maximum of 9. Hearing loss was dependent on the number of risk factors in a child, but reached its maximum with the association of 6 factors.

CONCLUSIONS

The detection of postnatal hearing loss should be continued in order to increase our understanding of hearing incidence and the role of environmental factors. To optimize screening, discussions between specialists (mostly related to the issue of risk factors detected and registered in the earliest stage of screening programs) would be beneficial.

Aminoglycoside toxicity in neonates: something to worry about?

Toxicity has limited the use of aminoglycosides and adult studies report high rates of both ototoxicity and nephrotoxicity. Conversely paediatric studies have shown lower rates and extended interval dosing may have reduced toxicity further. We review the animal and human evidence for aminoglycoside toxicity in neonates including mechanisms, measurement and rates of toxicity; and differences between aminoglycosides and dosing regimens. We discuss genetic susceptibility and the impact of other synergistic effects.

High-dose gentamicin in newborn infants: is it safe?

Dosing regimens often recommend lower gentamicin doses in neonates (3-5 mg/kg) than in older children (7 mg/kg or more) despite the higher volume of distribution in neonates. We studied an extended-interval high-dose (6 mg/kg) gentamicin regimen in a single tertiary neonatal unit from 2004-2012. During the first week of life, dosing interval was 24 h for term infants, 36 h for preterm infants with gestational age (GA) 29-36 weeks and 48 h for preterm infants with GA <29 weeks. After the first week of life, dosing interval was 24 h if corrected age (GA + postnatal age) ≥29 weeks and 36 h if corrected age <29 weeks. Outcome measures were trough plasma concentration (TPC), ototoxicity and prescription errors. In 546 treatment episodes, TPC was measured prior to the third gentamicin dose. There were 37 episodes (6.7 %) of prescription errors, mainly a too long dosing interval. We included 509 treatment episodes (440 infants) in the final analysis. Mean (standard deviation) gentamicin TPC during the first week of life was 1.1 (0.5) mg/L and after the first week of life 0.8 (0.6) mg/L. In 31 (6 %) episodes, TPC was ≥2.0 mg/L, predominantly among term infants with renal impairment. Thirty-eight patients failed the neonatal hearing screening, but only four of these 38 had permanent hearing loss. All four had a TPC <2.0 mg/L. Conclusions: This extended-interval high-dose gentamicin regimen was associated with low numbers of elevated TPCs, low numbers of prescription errors and no evidence for ototoxicity.

Antibiotics and Antifungals in Neonatal Intensive Care Units: A Review

The incidence of infections is higher in the neonatal period than at any time of life. The basic treatment of infants with infection has not changed substantially over the last years. Antibiotics (with or without supportive care) are one of the most valuable resources in managing sick newborn babies. Early-onset (ascending or transplacental) or late-onset (hospital acquired) infections present different chronology, epidemiology, physiology and outcome. Some classes of antibiotics are frequently used in the neonatal period: penicillins, cephalosporins, aminoglycosides, glycopeptides, monobactams, carbapenems. Other classes of antibiotics (chloramphenicol, cotrimoxazole, macrolides, clindamycin, rifampicin and metronidazole) are rarely used. Due to emergence of resistant bacterial strains in Neonatal Intensive Care Units (NICU), other classes of antibiotics such as quinolones and linezolid will probably increase their therapeutic role in the future. Although new formulations have been developed for treatment of fungal infections in infants, amphotericin B remains first-line treatment for systemic Candida infection. Prophylactic antibiotic therapy is almost always undesirable. Challenges from pathogens and antibiotic resistance in the NICU may warrant modification of traditional antibiotic regimens. Knowledge of local flora and practical application of different antibiotic characteristics are key to an effective and safe utilization of antibiotics and antifungals in critical newborns admitted to the NICU, and especially in very low birth weight infants.

Educational paper: do we need neonatal clinical pharmacologists?

Effective and safe drug administration in young infants should be based on integrated knowledge concerning the evolving physiological characteristics of the infant who will receive the drug and the pharmacokinetic and pharmacodynamic characteristics of a given drug. Consequently, clinical pharmacology in neonates is as dynamic and diverse as the neonates we are entitled to take care of. Even more than median estimates, covariates of variability within the population are of clinical relevance. We aim to illustrate the complexity and the need for neonatal clinical pharmacology based on the gap between current and likely best clinical practice for two commonly administered compounds (aminoglycosides for infection and ibuprofen for patent ductus arteriosus) and one new compound (bevacizumab, to treat threshold retinopathy of prematurity). Progression has been made to render pharmacokinetic studies child size, e.g., low volume samples, optimal study design, and population pharmacokinetics. Challenges to further improve clinical pharmacology in neonates include, when appropriate, the validation of off-patent drug dosing regimens and of infant-tailored formulations. Knowledge integration, i.e., the use of available data to improve current drug use and to predict pharmacokinetics/pharmacodynamics for similar compounds is needed. Development of clinical research networks is helpful to achieve these goals.

Use of antibacterial agents in the neonate: 50 years of experience with vancomycin administration

Neonatal sepsis, classified as either early or late onset, has specific pathogen distribution and infection rates in the different neonatal age groups. It is a major cause of mortality and morbidity and administration of antibiotics is urgently required for suspected or proven infection. Vancomycin is the first choice treatment of late onset sepsis due to resistant staphylococci. Although it has been used for more than 50 years, prescription remains a challenge in neonatal intensive care units for many reasons, including: high pharmacokinetic variability, numerous presentations, lack of consensus on dosing regimen and therapeutic drug monitoring. In addition, recent concerns about the increase in minimal inhibition concentration and other more generic problems have prompted reappraisal of the rational use of vancomycin. This article highlights the goal of optimising vancomycin therapy in the neonate and discusses future research directions. Specific attention is given to dosing optimisation of vancomycin to avoid resistance and maximise the likelihood of achieving the therapeutic target. Modelling and simulation approaches have clear advantages in dosing optimisation of antimicrobial agents in the neonate. Neonatologists and paediatric pharmacologists should work closely together to achieve this goal.

Therapeutic drug monitoring--the appropriate use of drug level measurement in the care of the neonate

Neonates and young infants are in a unique and dynamic pharmacokinetic state, in which they undergo relatively rapid maturational changes in drug absorption, distribution, metabolism, and excretion. In addition to these maturational changes, most drug pharmacokinetic studies in neonates show wide interindividual variability despite similar gestational and postnatal ages. Therapeutic drug monitoring is a necessary tool in the neonatal intensive care unit, despite the relative lack of outcome data. This article discusses therapeutic drug monitoring for several frequently used drugs in neonates.

Evaluation of the vancomycin dosage regimen based on serum creatinine used in the neonatal intensive care unit

BACKGROUND

Vancomycin is frequently used for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections; however, determining the optimal dosage for neonates is difficult because of their immature renal function.

METHODS

Serum creatinine-based dosing was introduced in Kumamoto City Hospital Neonatal Medical Center. Serum trough concentration and therapeutic efficacy of vancomycin were evaluated before and after the introduction of the creatinine-based dosing.

RESULTS

When the therapeutic range of serum trough concentration of vancomycin at steady state was set to 5-15 µg/mL, 20 trough concentrations (48.8%) were within the therapeutic range and 21 trough concentrations were outside the therapeutic range before the introduction of the serum creatinine-based dosing. After the introduction of serum creatinine-based dosing, 18 trough concentrations (81.8%) were within the therapeutic range and 4 trough concentrations were not, and there was an increase in the number of patients with trough concentrations in the therapeutic range (P= 0.01; Fisher's exact test).

CONCLUSIONS

The serum creatinine-based dosing of vancomycin is useful in maintaining the appropriate serum level of vancomycin in neonates.

Risk factors associated with hearing loss in infants: an analysis of 5282 referred neonates

OBJECTIVE

The aim of our study was to evaluate the frequency of risk factors and their influence on - the distribution and manifestation of - hearing loss in infants. The study was conducted at the Department of Laryngology in the Upper Silesian Center for Child Health in Katowice (Poland), as part of the Polish National Universal Neonatal Hearing Screening, conducted from 2003 to 2009.

MATERIALS AND METHODS

The selected population included every newborn that twice tested positive on the transient evoked otoacoustic emission (TEOAE) screening test, as well as all neonates with one or more risk factors as defined by the Joint Committee of Infant Hearing in 2000 (JCIH). The following procedures were used with each neonate: otolaryngological examination (with otoscopy), tympanometry, automated otoacoustic emission (AOAE), and auditory brainstem response (ABR). A total of 5282 infants were examined. Subjects were categorized into two groups: the first group consisted of 2986 (56.53%) neonates with risk factors of hearing loss, while the second group included 2296 (43.47%) neonates without any known risk factors, but who twice tested positive on the TEOAE screening.

RESULTS

Among all infants examined (5282), sensorineural hearing loss (SNHL) was identified in 240 cases (4.54%), and conductive hearing loss (CHL) in 40 cases (0.76%), while normal hearing (NH) appeared in 5002 cases (94.70%). In the first group, SNHL was identified in 128 neonates (4.29%), and CHL in 28 (0.94%), while NH appeared in 2830 (94.78%). The largest percentage of SNHL (15.52%) appeared in children with identified or suspected syndromes associated with hearing loss. The next highest frequency of SNHL was comprised of children subjected to mechanical ventilation for a period in excess of 5 days (11.45%). Only a small percentage (2.86%) of SNHL appeared to be due to the use of ototoxic medications, despite the fact that this factor is the most prevalent (33.13%) of all analyzed risk factors of hearing impairment. After ototoxic medications, the frequencies of risk factors are as follows: premature birth (16.21%); low birth weight (12.04%); intensive care in excess of 7 days (10.64%). Furthermore, as the number of coexisting risk factors increases, the probability of SNHL in infants is seen to also increase. For children with one to four coexisting risk factors, the probability of SNHL ranges from 3.15% to 5.56%; for five or more risk factors the probability nearly doubles.

CONCLUSION

Our results indicate that syndromes associated with hearing loss and mechanical ventilation for more than 5 days were statistically significant risk factors in the occurrence of hearing loss. The most common risk factors are ototoxic medications, premature birth, low birth weight, and intensive care in excess of 7 days. As the number of risk factors an infant is exposed to grows, the probability of hearing impairment increases. The large percentage of children with sensorineural hearing loss in the absence of any known risk factors demonstrates the necessity of hearing examinations in all neonates.

Risk factors for auditory neuropathy spectrum disorder in NICU infants compared to normal-hearing NICU controls

OBJECTIVES

To evaluate independent etiologic factors associated with auditory neuropathy spectrum disorder (ANSD) in infants who have been admitted to the neonatal intensive care unit (NICU) compared to normal-hearing controls.

STUDY DESIGN

Case-control study.

METHODS

We included all infants (n = 9) with the ANSD profile admitted to the NICU of Sophia Children's Hospital between 2004 and 2009. Each patient was matched with four normal-hearing controls of the same gender and postconceptional age. The following possible risk factors were studied: birth weight, dysmorphic features, APGAR scores (at 1, 5, and 10 minutes), respiratory distress (IRDS), cytomegalovirus (CMV) infection, sepsis, meningitis, cerebral bleeding, hyperbilirubinemia requiring phototherapy, peak total bilirubin level, furosemide, dexamethason, vancomycin, gentamycin, and tobramycin administration.

RESULTS

Nine infants met the ANSD criteria in one or both ears. IRDS (P = .02), meningitis (P = .04), and vancomycin administration (P = .009) were significantly increased in infants with ANSD compared to controls.

CONCLUSIONS

In high-risk NICU infants IRDS, meningitis and vancomycin administration are associated with auditory neuropathy spectrum disorder.

Accuracy of Empiric Gentamicin Dosing Guidelines in Neonates

OBJECTIVE

To evaluate the accuracy of a neonatal gentamicin nomogram to achieve therapeutic gentamicin serum concentrations without further adjustment, allowing for decreased serum drug monitoring

METHODS

Retrospective single center review of all gentamicin pharmacokinetic evaluations in patients ≤ 30 days of life from July 2005 – June 2007. Patients were evaluated for postnatal age, gestational age, weight, serum creatinine, dose/interval, serum drug peaks and troughs, results of discharge hearing test and recent use of indomethacin. Logistic regression was utilized to determine potential factors impacting overall dosing accuracy, potentially allowing for decreased therapeutic drug monitoring. Factors found to be significant were incorporated into new guidelines which were evaluated through pharmacokinetic modeling.

RESULTS

Overall accuracy rate was 84% when empiric dosing guidelines were utilized; 16% of all doses were changed due to supratherapeutic troughs and 1% were changed due to subtherapeutic peaks. Variables found to impact the necessity for dose changes incuded gestational age (p≤0.001), weight (p≤0.001), indomethacin use (p≤0.001), number of indomethacin doses used (p≤0.001 and p=0.009 for 1–3 and 4–6 doses, respectively), and SCr in patients ≥ 7 days old (p=0.028); however, only gestational age remained a significant predictor when all other factors were considered (p=0.008). The current guidelines were changed to account for increased troughs in patients ≤ 28 weeks gestation and examined through pharmacokinetic modeling. Pharmacokinetic modeling of the new guidelines predicted an overall accuracy of 94%.

CONCLUSIONS

From the data gathered regarding the accuracy in patients ≥ 35 weeks gestation, we recommend to decrease therapeutic drug monitoring within this cohort. Utilizing the results of regression analysis, the current guidelines have been adjusted to allow for increased clearance in patients ≤ 28 weeks gestation, although they still need to be prospectively evaluated.

Therapeutic drug monitoring of aminoglycosides in neonates

The efficacy and toxicity of aminoglycosides show a strong direct positive relationship with blood drug concentrations, therefore, therapy with aminoglycosides in adults is usually guided by therapeutic drug monitoring. Dosing regimens in adults have evolved from multiple daily dosing to extended-interval dosing. This evolution has also taken place in neonates. Neonates, however, display large interindividual differences in the pharmacokinetics of aminoglycosides due to developmental differences early in life. The volume of distribution of aminoglycosides shows a strong relationship with bodyweight, which tends to be larger (corrected for bodyweight) in more premature infants and those with sepsis. Renal clearance of aminoglycosides increases with gestational age and accelerates immediately after birth. Because of these developmental influences, there is great inter- and intraindividual variability in the volume of distribution and clearance of these drugs, and investigators have established aminoglycoside dosing regimens based on bodyweight and/or gestational age. Widely practised dosing regimens comprise 4-5 mg/kg bodyweight of gentamicin every 24-48 hours as a first dose, followed by dose adjustment based on therapeutic drug monitoring. Although formal toxicity studies are scarce, there is no evidence that aminoglycoside toxicity in neonates differs from that in adults. Monitoring of blood drug concentrations and intelligent reconstruction of individual pharmacokinetic behaviour using a population pharmacokinetic model, optimally chosen blood sampling times and appropriate pharmacokinetic software, help clinicians to quickly optimize aminoglycoside dosing regimens to maximize the clinical effect and minimize the toxicity of these drugs.

Cerebrospinal fluid compartmental pharmacokinetics of amikacin in neonates

To describe and investigate the covariate effects of cerebrospinal fluid (CSF) amikacin pharmacokinetics in neonates, CSF samples were prospectively collected from neonates in whom amikacin had been initiated before a diagnostic lumbar puncture was performed. CSF analysis (amikacin concentration, white blood count [WBC], glucose content, and protein concentration) and amikacin therapeutic drug monitoring results (peak and trough concentrations) in serum were recorded. Correlations (Spearman rank) between the CSF amikacin concentration and the CSF WBC and glucose and protein concentration were investigated. There were 44 CSF amikacin concentrations and 83 serum samples available from 43 neonates (mean postmenstrual age, 36 weeks [range, 26 to 41 weeks]; mean weight, 2.43 kg [range, 0.87 to 3.86 kg]). The median time interval between initiation of amikacin administration and CSF sampling was 25 h (range, 2.5 to 93.7 h). The median amikacin concentration in the CSF was 1.08 mg/liter (range, 0.34 to 2.65 mg/liter), and the mean trough and peak amikacin concentrations in serum were 3.8 +/- 2.5 mg/liter and 35.7 +/- 5.9 mg/liter, respectively. A correlation between CSF amikacin and CSF protein contents (P < 0.01, r = 0.41, 95% confidence interval = 0.13 to 0.63) but not between CSF WBC and CSF glucose was documented. A two-compartment (central and CSF) linear disposition model was used to estimate population pharmacokinetics. The half time for equilibration (T(eq)) between serum and CSF compartments was used as a measure of blood-brain barrier permeability. The T(eq) was 7.58 h (coefficient of variation [CV] = 49.1%) with a partition coefficient of 0.103 (CV = 26.4%). There was no relationship between the T(eq) and CSF WBC, CSF glucose content, or CSF protein content.

Extremely low birth weight infants are at high risk for auditory neuropathy

Auditory neuropathy (AN) is a condition in which transmission of sound to the brain is abnormal. This is reflected as an electrophysiologic profile of normal otoacoustic emissions (OAE), with abnormal auditory brainstem evoked responses (ABR). Functionally speech perception is impaired and management strategies remain controversial. AN can be missed if high-risk newborns are screened for hearing loss with only OAE testing. The rate of sensorineural hearing loss (SNHL) in high-risk nursery infants is 10 times greater compared with normal term newborns. Therefore, we hypothesize that infants from the neonatal intensive care unit (NICU) are at significantly higher risk for AN than normal term infants.

OBJECTIVE

The objective of this study is to establish a prevalence rate and characterize risk factors for NICU graduates who demonstrate the AN electrophysiologic profile.

STUDY DESIGN

This retrospective study examined infants admitted to the NICU at Kapi'olani Medical Center for Women and Children in Honolulu, HI from 1999 through 2003. Infants were screened with automated ABR. Diagnostic testing and OAE were performed before discharge if the ABR was abnormal. Hospital courses of 24 AN, 71 SNHL and 95 gestational age (GA)-matched control infants with normal hearing were reviewed.

RESULT

With a SNHL prevalence of 16.7/1000, the rate for AN was 5.6/1000 NICU infants. Compared to infants with SNHL, infants with AN were significantly younger (GA 28.3+/-4.8 AN vs 32.9+/-5.2 weeks SNHL, P<0.0001) and smaller (BW 1318+/-894 AN vs 1968+/-1006 g SNHL). Nearly two-thirds of the AN infants were ELBW and had significantly longer hospital stays compared to SNHL infants of the same birth weight group. Exposure to furosemide, aminoglycosides, vancomycin or dexamethasone was associated with increased AN but not SNHL. Peak bilirubin level correlated with SNHL but not AN.

CONCLUSION

Low birth weight NICU infants are at significant risk for AN. ELBW infants are at significantly higher risk for both AN and SNHL. Infants admitted to the NICU should be routinely screened by automated ABR and if abnormal, further evaluation should be started before hospital discharge. Early identification of AN will result in better understanding of this disorder and lead to the development of appropriate intervention strategies.

Determination of extended-interval gentamicin dosing for neonatal patients in developing countries

BACKGROUND

Infectious diseases account for an estimated 36% of neonatal deaths globally. The purpose of this study was to determine safe, effective, simplified dosing regimens of gentamicin for treatment of neonatal sepsis in developing countries.

METHODS

Neonates with suspected sepsis in the neonatal intensive care unit (NICU) at Christian Medical College and Hospital (CMC), Vellore, India (n = 49), and Dhaka Shishu Hospital (DSH), Bangladesh (n = 59), were administered gentamicin intravenously according to the following regimens: (1) 10 mg every 48 hours for neonates <2000 g; (2) 10 mg every 24 hours for neonates 2000-2249 g; and (3) 13.5 mg every 24 hours for neonates > or =2500 g. Serum gentamicin concentration (SGC) at steady state and pharmacokinetic indices were determined. Renal function was followed while under treatment and hearing was examined 6 weeks to 3 months after discharge.

RESULTS

All neonates, except 1 weighing 2000-2249 g at DSH, had a peak SGC >4 microg/mL. Overall, 5 (10%) and 17 (29%) infants had a peak SGC level > or =12 microg/mL from CMC and DSH, respectively, and 10 (20%) and 4 (7%) cases from CMC and DSH, respectively, had a trough SGC level > or =2 microg/mL. However, no infant <2000 g had a trough SGC level > or =2 microg/mL. We found no evidence of gentamicin nephrotoxicity or ototoxicity.

CONCLUSION

Safe, therapeutic gentamicin dosing regimens were identified for treatment of neonatal sepsis in developing country settings. Administration of these doses could be simplified through use of Uniject, a prefilled, single injection device designed to make injections safe and easy to deliver in developing country settings.

Altered cardiovascular control in preterm infants with bronchopulmonary dysplasia

Vestibulo-mediated cardiovascular control in hazardous situations is important. Our hypothesis is that the prerequisite for sudden infant death syndrome (SIDS) is impaired vestibulo-mediated cardiovascular control. Prematurity is a risk factor for SIDS, and postnatal intermittent hypoxia may contribute to this risk. We studied heart rate (HR) and blood pressure (BP) responses in 10 infants with bronchopulmonary dysplasia (BPD) who were born at 27 +/- 2.4 (23-30) wk of gestation. Twenty healthy term infants served as controls. Cardiovascular tests were performed under polysomnographic control during slow-wave sleep (SWS) at a corrected age of 12 +/- 3.5 (7-19) wk. Control infants showed biphasic HR and BP responses to side motion with an immediate increase followed by a modest decrease and return to baseline. Compared with the controls, half of the BPD infants had altered BP responses (p < 0.005) without an early increase, followed by a more prominent decrease in BP. BPD infants also presented with a greater variability in BP responses to head-up tilts than did the controls (p < 0.001). In conclusion, these findings suggest that some BPD infants have impaired vestibular sympathoreflex-mediated cardiovascular control. This dysfunction may become critical in life-threatening situations.

Ototoxic drugs and sensorineural hearing loss following severe neonatal respiratory failure

AIM

To determine relationships between ototoxic drugs and 4-y sensorineural hearing loss (SNHL) in near-term and term survivors of severe neonatal respiratory failure.

METHODS

All 81 survivors of the Canadian arm of the Neonatal Inhaled Nitric Oxide Study (mortality 32, loss to follow-up 9) received loop diuretics, aminoglycosides, and neuromuscular blockers (NMB), and 50 received vancomycin as neonates. Prospective, longitudinal secondary outcome using audiological tests diagnosed late-onset, progressive SNHL in 43 (53%); not flat (sloping) in 29, flat (severe to profound) in 14. Risk for SNHL was determined.

RESULTS

A combination of duration of diuretic use of >14 d and average NMB dose of >0.96 mg/kg/d contributed to SNHL among survivors (odds ratio 5.2; 95% CI 1.6, 16.7). Markers of illness severity did not contribute. Dosage or duration of aminoglycosides use did not relate to SNHL. Cumulative dosages and duration of use of diuretics; NMB; use of vancomycin; and overlap of diuretics with NMB, aminoglycosides, and vancomycin individually linked to SNHL (p<0.001).

CONCLUSION

Overuse of loop diuretics and/or NMB contributes to SNHL after neonatal respiratory failure; markers of illness severity or the appropriate administration of aminoglycosides do not.

Newborn hearing screening in the NICU: profile of failed auditory brainstem response/passed otoacoustic emission

OBJECTIVE

Incidence of a specific pattern of auditory responses, absent auditory brainstem responses (ABRs) and present otoacoustic emissions (OAEs), in newborn hearing screening in a regional perinatal center neonatal intensive care unit (NICU) is described. This profile, labeled auditory neuropathy or auditory dyssynchrony (AN/AD), is a dysfunction in neural/brainstem transmission that occurs in individuals whose outer hairs cells are functioning normally. Although the AN/AD profile has been associated with various risk factors, incidence and prediction are unknown.

METHOD

Analysis of electrophysiologic measures and medical record reviews of the first 22 months of the universal newborn hearing-screening program was conducted. Association of the AN/AD profile was evaluated with the following factors: gender, gestational age, ototoxic drug regimen, low birth weight, hyperbilirubinemia, hydrocephalus, low Apgar score, anoxia, respiratory distress syndrome, pulmonary hypertension, intraventricular hemorrhage, multiple birth, seizure activity, and family history.

RESULTS

One hundred fifteen (24.1%) of the 477 infants failed the ABR in 1 or both ears and passed OAEs bilaterally. Comparisons of infants fitting the AN/AD profile with those not fitting the AN/AD profile were negative with 3 exceptions: those with hyperbilirubinemia and those who were administered vancomycin or furosemide. A logistic-regression analysis model failed to predict which infants would be at risk for the AN/AD profile either unilaterally or bilaterally.

CONCLUSIONS

Screening of NICU infants should be conducted with ABR first, followed by OAE after failure on ABR. Because the incidence of the AN/AD profile was found to be 24% in this at-risk population, additional study is warranted.

New dosing strategies for antibacterial agents in the neonate

Dosing of antibiotics in neonates requires finding a delicate balance between maximal efficacy and minimal toxicity. There is a lack of data on efficacy of currently used antibiotics in neonates, and rational dosing therefore needs to be based on gestational- and postnatal-age-dependent pharmacokinetics in combination with surrogate markers. These surrogate markers are: (i) the area-under-the serum concentration time curve to minimum inhibitory concentration ratio (AUC/MIC); (ii) peak concentration to MIC ratio (Cmax/MIC); and (iii) the time the concentration remains above the MIC (T>MIC). Whereas the efficacy of beta-lactam antibiotics (including carbapenems) depends on T>MIC, the efficacy of most other antimicrobials (including aminoglycosides and fluoroquinolones) is related to AUC/MIC and Cmax/MIC. Most modern dosing regimens are adequate when these concentration effect relationships are taken into account. Dosing adjustments in neonates are suggested, based on these relationships. Several antimicrobial combinations for treatment of meningitis and necrotizing enterocolitis exist. Empiric treatment should be based on efficacy, concerns about resistance as well as information from institutional microbiological surveillance.

Medical management of childhood hearing loss

Hearing loss in children is common. Advances in the identification of infectious diseases at birth or in utero, genetic testing, and diagnostic imaging now permit many infants and children to be identified and treated sooner. Treatment and rehabilitation should be instituted early so that the effects of hearing loss on communication are minimized and the child's social and academic skills maximized. CHL can usually be managed medically or surgically with subsequent return to normal or near normal hearing. Children with SNHL, and their future hearing will benefit from new antiviral agents, less antibiotics, ototoxic more focused chemotherapy, and possibly genetic therapy. Digital and programmable hearing aids, more accessible FM systems, cochlear implants, and bone-anchored hearing aids provide significant rehabilitation potential for children with even very significant hearing losses. Early identification and prevention, however, remain the best strategies to combat hearing loss in children.

[Universal hearing screening in newborns. Recommendations for organizing and conducting universal hearing screening for congenital hearing loss in Germany]

The Interdisciplinary Consensus Conference for Newborn Hearing Screening (IKKNHS) has worked out joint recommendations for universal hearing screening of newborns. In the consensus paper, 11 professional associations and scientific societies in the fields of gynecology and obstetrics, ENT, pediatrics, and phoniatrics and pedaudiology came to an agreement on how to implement newborn hearing screening in Germany. The paper deals with the following topics: goals of universal newborn hearing screening, target group of hearing screening, schedule for screening, personnel involved in the screening program, technologies and framework conditions of hearing screening, documentation, continuous quality control of screening, confirmation diagnostics for conspicuous test subjects, motivation to take part in screening, information on newborn hearing screening, tracking, various infrastructural situations in urban and rural regions, follow-up care, in-patient vs. out-patient screening, cost factors of screening, reporting children with permanent hearing loss to the German Central Registry for hearing loss in children.

Antibacterial agents in pediatrics

Antibiotics are among the most widely prescribed therapeutic agents in children. Several new trends in antibiotic usage for pediatric care have emerged. New mechanisms of antibacterial resistance have required a broader repertoire of antibiotic usage, including new agents directed at multidrug resistance. After promotion of judicious antibiotic use, there has been a decline in the number of pediatric prescriptions for antibiotics. Recent legislation addresses the necessity for pediatric clinical drug trials, ensuring development of further antibacterial agents for use in pediatric patients.

Strategic use of antibiotics in the neonatal intensive care unit

Infection is one of the most common causes of infant morbidity and mortality in the neonatal intensive care unit, despite the availability of various therapeutic medical interventions, such as mechanical ventilation, that allow premature infants a better chance of survival. In fact, many of these therapeutic interventions violate the natural protective barriers for infection. Fortunately, maternal and neonatal risk factors have been identified for early- and late-onset sepsis and the prevalence of highly suspected pathogens for each type of infection influences the empiric selection of antibiotics. In many institutions, the common pathogens have developed resistance to antibiotics. In others, the predominance of pathogens has shifted. Both challenges may warrant modification of traditional antibiotic regimens. Continual monitoring of pathogen shifts within an individual neonatal intensive care unit and application of various antibiotic characteristics are key elements of strategic, safe, and effective use of antibiotics in this patient population. Development of a protocol incorporating infection control measures and guidelines for judicious use of antibiotics can minimize the threat of antibiotic resistance.