Sildenafil exposure and hemodynamic effect after stage II single-ventricle surgery

OBJECTIVES

To determine sildenafil exposure and hemodynamic effect in children after stage II single-ventricle surgery.

DESIGN

Prospective, dose escalation trial.

SETTING

Single-center, pediatric catheterization laboratory.

PATIENTS

Twelve children poststage II single-ventricle surgical palliation and undergoing elective cardiac catheterization: median age 1.9 years (range, 0.8, 4.0), weight 11 kg (8, 13), nine females, and 10 with a single right ventricle.

INTERVENTIONS

Catheterization and echocardiography performed before and immediately after single-dose IV sildenafil (0.125, 0.25, 0.35, or 0.45 mg/kg over 20 min).

MEASUREMENTS

Peak sildenafil and desmethyl sildenafil concentration, change in hemodynamic parameters measured by cardiac catheterization and echocardiography including indexed pulmonary vascular resistance, and myocardial performance.

MAIN RESULTS

Maximum sildenafil concentrations ranged from 92 to 775 ng/mL and were above the in vitro threshold needed for 77% phosphodiesterase type 5 (PDE-5) inhibition in 80% of subjects and 90% inhibition in 80% of subjects with doses ≥0.35 mg/kg. Sildenafil lowered pulmonary vascular resistance index in all 12 subjects (median pulmonary vascular resistance index 2.2 [range, 1.6, 7.9]; decreased to 1.7 [1.2, 5.4] WU × m; p < 0.01) with no dose-response effect. Sildenafil improved pulmonary blood flow (+8% [0, 20], p = 0.04) and saturations (+2% [0, 16], p = 0.04) in those with baseline pulmonary vascular resistance index ≥ 2 WU × m (n = 7). Change in saturations correlated inversely with change in pulmonary vascular resistance index (r = 0.74, p < 0.01). Sildenafil also lowered mean blood pressure (-12% [-20, +10]; p = 0.04). There was no change in cardiac index and no effect on myocardial performance. There were no adverse events.

CONCLUSIONS

Sildenafil demonstrated nonlinear exposure with high interindividual variability but was well tolerated and effectively lowered pulmonary vascular resistance index in all subjects. Sildenafil did not acutely improve myocardial performance or increase cardiac index.

Pharmacological resolution of a multiloculated Candida spp. liver abscess in a preterm neonate

We report the case of a 31-week gestational age neonate with Candida albicans sepsis and a hepatic abscess. Diagnosis relied on clinical and radiological signs of sepsis, liver function impairment and culture isolation of Candida spp. from sterile sites. Liver ultrasound documented the presence of a multiloculated abscess. Treatment with micafungin (3 mg/kg/day) resulted in normalization of liver function and inflammatory laboratory values and improvement of clinical condition. After 30 days of treatment, the liver abscess resolved and at the 8-month follow up the infant is doing well. Prompt diagnosis and antifungal treatment avoided surgical drainage and liver surgery in this high-risk neonate.

Candida pneumonia in a term infant after prolonged use of inhaled corticosteroids for bronchopulmonary dysplasia (BPD)

Candida spp. frequently cause invasive fungal disease in neonates, and many organs or apparatus can be involved through bloodstream dissemination. Though Candida spp. can heavily colonize the upper and lower respiratory tract, an end-organ localization to the lung is not frequent and acquisition via descending/respiratory route is a questioned entity. Here we report the case of a young infant affected by bronchopulmonary dysplasia (BPD) and treated with inhaled steroids who developed Candida pneumonia likely acquired through descending route.

Old and new: appropriate dosing for neonatal antifungal drugs in the nursery

Candida infections are a source of significant mortality and morbidity in the neonatal intensive care unit. Treatment strategies continue to change as additional antifungals become available and studies in neonates are performed. Amphotericin B deoxycholate has been favored for many years, but fluconazole has the most data supporting its use in neonatal Candida infections and is often employed for prophylaxis as well as treatment. Voriconazole and posaconazole have limited utility in the nursery and are rarely used. The echinocandins are increasingly administered for invasive Candida infections, although higher doses are required in neonates than in older children and adults.

10 x '20 Progress--development of new drugs active against gram-negative bacilli: an update from the Infectious Diseases Society of America

Infections caused by antibiotic-resistant bacteria, especially the "ESKAPE" pathogens, continue to increase in frequency and cause significant morbidity and mortality. New antimicrobial agents are greatly needed to treat infections caused by gram-negative bacilli (GNB) resistant to currently available agents. The Infectious Diseases Society of America (IDSA) continues to propose legislative, regulatory, and funding solutions to this continuing crisis. The current report updates the status of development and approval of systemic antibiotics in the United States as of early 2013. Only 2 new antibiotics have been approved since IDSA's 2009 pipeline status report, and the number of new antibiotics annually approved for marketing in the United States continues to decline. We identified 7 drugs in clinical development for treatment of infections caused by resistant GNB. None of these agents was included in our 2009 list of antibacterial compounds in phase 2 or later development, but unfortunately none addresses the entire spectrum of clinically relevant GNB resistance. Our survey demonstrates some progress in development of new antibacterial drugs that target infections caused by resistant GNB, but progress remains alarmingly elusive. IDSA stresses our conviction that the antibiotic pipeline problem can be solved by the collaboration of global leaders to develop creative incentives that will stimulate new antibacterial research and development. Our aim is the creation of a sustainable global antibacterial drug research and development enterprise with the power in the short term to develop 10 new, safe, and efficacious systemically administered antibiotics by 2020 as called for in IDSA's "10 × '20 Initiative."

Early sepsis does not increase the risk of late sepsis in very low birth weight neonates

OBJECTIVE

To examine whether preterm very low birth weight (VLBW) infants have an increased risk of late-onset sepsis (LOS) following early-onset sepsis (EOS).

STUDY DESIGN

Retrospective analysis of VLBW infants (401-1500 g) born September 1998 through December 2009 who survived >72 hours and were cared for within the National Institute of Child Health and Human Development Neonatal Research Network. Sepsis was defined by growth of bacteria or fungi in a blood culture obtained ≤ 72 hours of birth (EOS) or >72 hours (LOS) and antimicrobial therapy for ≥ 5 days or death <5 days while receiving therapy. Regression models were used to assess risk of death or LOS by 120 days and LOS by 120 days among survivors to discharge or 120 days, adjusting for gestational age and other covariates.

RESULTS

Of 34,396 infants studied, 504 (1.5%) had EOS. After adjustment, risk of death or LOS by 120 days did not differ overall for infants with EOS compared with those without EOS [risk ratio (RR): 0.99 (0.89-1.09)] but was reduced in infants born at <25 weeks gestation [RR: 0.87 (0.76-0.99), P = .048]. Among survivors, no difference in LOS risk was found overall for infants with versus without EOS [RR: 0.88 (0.75-1.02)], but LOS risk was reduced in infants with birth weight 401-750 g who had EOS [RR: 0.80 (0.64-0.99), P = .047].

CONCLUSIONS

Risk of LOS after EOS was not increased in VLBW infants. Surprisingly, risk of LOS following EOS appeared to be reduced in the smallest, most premature infants, underscoring the need for age-specific analyses of immune function.

Medical regulation and health outcomes: the effect of the physician examination requirement

This article investigates the effect on health outcomes of the regulation prohibiting physicians from prescribing drugs without a prior physical examination. This requirement could improve health by reducing illegal access to prescription drugs. However, it reduces access to health care by making it more difficult for patients and physicians to use many forms of telemedicine. Thus, this regulation generates a trade-off between access and safety. Using matching techniques, we find that the physician examination requirement leads to an increase of 1% in mortality rates from disease, the equivalent of 8.5 more deaths per 100,000 people, and a decrease of 6.7% in injury mortality, the equivalent of 2.5 deaths per 100,000 people. The magnitude of these effects is larger in rural areas and in areas with low physician density and is accompanied by an 18% increase in the number of days lost each month to illness.

Fluconazole pharmacokinetics and safety in premature infants

Invasive candidiasis (IC) in the premature infant population is a common infection that results in substantial morbidity and mortality. For these patients, fluconazole is among the first line therapies to treat and prevent IC, and yet few prospective studies investigating its pharmacokinetics (PK) and safety have been performed in this vulnerable population. We review five phase I studies examining the PK of fluconazole in premature infants, which demonstrate markedly differing kinetics compared to adults. Based on these data, a treatment dose of 12 mg/kg/day, with the potential need of a loading dose of 25 mg/kg to achieve rapid steady state concentrations, achieves surrogate pharmacodynamic targets. Additionally, fluconazole appears to be safe to use in this population, with only minimal reversible hepatobiliary effects.

Risk factors for invasive candidiasis in infants >1500 g birth weight

BACKGROUND

We describe the incidence, risk factors and outcomes of invasive candidiasis in infants >1500 g birth weight.

METHODS

We conducted a retrospective cohort study of infants >1500 g birth weight discharged from 305 neonatal intensive care units in the Pediatrix Medical Group from 2001 to 2010. Using multivariable logistic regression, we identified risk factors for invasive candidiasis.

RESULTS

Invasive candidiasis occurred in 330 of the 530,162 (0.06%) infants. These were documented from positive cultures from ≥1 of these sources: blood (n = 323), cerebrospinal fluid (n = 6) or urine from catheterization (n = 19). Risk factors included day of life >7 (odds ratio [OR]: 25.2; 95% confidence interval: 14.6-43.3), vaginal birth (OR: 1.6 [1.2-2.3]), exposure to broad-spectrum antibiotics (OR: 1.6 [1.1-2.4]), central venous line (OR: 1.8 [1.3-2.6]) and platelet count <50,000/mm (OR: 3.7 [2.1-6.7]). All risk factors had poor sensitivities, low positive likelihood ratios and low positive predictive values. The combination of broad-spectrum antibiotics and low platelet count had the highest positive likelihood ratio (46.2), but the sensitivity of this combination was only 4%. Infants with invasive candidiasis had increased mortality (OR: 2.2 [1.3-3.6]).

CONCLUSIONS

Invasive candidiasis is uncommon in infants >1500 g birth weight. Infants at greatest risk are those exposed to broad-spectrum antibiotics and with platelet counts of <50,000/mm(3).

Echinocandins for the nursery: an update

As the incidence rates of neonatal invasive fungal infection (IFI) have been increasing over the last years, research efforts have been addressed towards identifying both effective preventative strategies, and efficacious and well-tolerated antifungal drugs. Historically, the first options in treatment of neonatal IFI have been -and currently are- fluconazole and amphotericin B. However, these two drugs carry limitations both in efficacy and in putative toxicity. Recently, new therapeutic alternatives have drawn the neonatologists' attention. Echinocandins are a new class of antifungal drugs with characteristics that might better meet the needs of this particular population of patients. Caspofungin, Micafungin and Anidulafungin have inherent good activities both against biofilms, and against natively fluconazole-resistent strains of Candida spp, thus overcoming two of the major weaknesses of the commonly used antifungal drugs in nurseries. Caspofungin and Micafungin have been recently studied in neonatal populations. The kinetics and appropriate dosing of this agent in premature and term infants have been described, but ongoing further studies are needed to better address this area. Extrapolation of data from randomized trials conducted in pediatric and adult patients showed through a subgroup analysis that both Caspofungin and Micafungin are effective and well tolerated also in neonates. Further studies properly designed for neonatal populations will better address long-term safety and echological issues related to Echinocandin use in neonates.

Triazole use in the nursery: fluconazole, voriconazole, posaconazole, and ravuconazole

Invasive fungal infections in infants admitted to the neonatal intensive care unit are common and often fatal. The mainstay of therapy against invasive fungal infections is antifungal agents. Over the last two decades, the development and approval of these drugs evolved tremendously, and the azole class emerged as important agents in the treatment and prevention of invasive fungal infections. Among the azoles, fluconazole has been used extensively due to its favorable pharmacokinetics, excellent activity against Candida spp, and safety profile. This drug has been well studied in children, but data for its use in infants are largely limited to Candida prophylaxis studies. Voriconazole, a second generation triazole, has excellent activity against Candida and Aspergillus spp. However, data on its use in neonates are extremely limited. Posaconazole and ravuconazole are the newest agents of the triazole family. The antimicrobial spectrum of posaconazole is similar to voriconazole, but with additional activity against zygomycetes. Experience with posaconazole in children is very limited, and there are no reports of its use in infants. Ravuconazole is not approved for use by the FDA, but studies in animals and humans show that it is often fungicidal and has favorable pharmacokinetics. In conclusion, the management of invasive fungal infections has progressed greatly over the last two decades with the azole antifungals playing a significant role. Related to this class, future research is needed in order to better assess dosing, safety, schedules and areas of use of these agents in infants admitted to the neonatal intensive care unit.

Sports medicine and ethics

Physicians working in the world of competitive sports face unique ethical challenges, many of which center around conflicts of interest. Team-employed physicians have obligations to act in the club's best interest while caring for the individual athlete. As such, they must balance issues like protecting versus sharing health information, as well as issues regarding autonomous informed consent versus paternalistic decision making in determining whether an athlete may compete safely. Moreover, the physician has to deal with an athlete's decisions about performance enhancement and return to play, pursuit of which may not be in the athlete's long-term best interests but may benefit the athlete and team in the short term. These difficult tasks are complicated by the lack of evidence-based standards in a field influenced by the lure of financial gains for multiple parties involved. In this article, we review ethical issues in sports medicine with specific attention paid to American professional football.

Treatment and prophylaxis of invasive candidiasis

Invasive candidiasis (IC) is a leading cause of morbidity and mortality in preterm infants. Even if successfully treated, IC can cause significant neurodevelopmental impairment. Preterm infants are at increased risk for hematogenous Candida meningoencephalitis owing to increased permeability of the blood-brain barrier, so antifungal treatment should have adequate central nervous system penetration. Amphotericin B deoxycholate, lipid preparations of amphotericin B, fluconazole, and micafungin are first-line treatments of IC. Fluconazole prophylaxis reduces the incidence of IC in extremely premature infants, but its safety has not been established for this indication, and as yet, the product has not been shown to reduce mortality in neonates. Targeted prophylaxis may have a role in reducing the burden of disease in this vulnerable population.

Very low birth weight neonates who survive early-onset sepsis do not have an increased risk of developing late-onset sepsis

BACKGROUND

Very low birth weight neonates (≤ 1500 g, VLBWs) have a high rate of infection and distinct baseline immune function compared with more mature populations. In critically ill children and adults, sepsis increases subsequent infection risk. It is unknown whether sepsis modifies the risk of subsequent infection in VLBWs.

METHODS

We conducted a retrospective cohort study of VLBWs≤32weeks of gestation at birth cared for in 312 neonatal intensive care units in the United States from 1997 to 2011 (n=103,376). Early-onset sepsis (EOS, culture-positive only) and late-onset sepsis (LOS, culture-positive or clinical) cases were identified. Cox proportional hazard models were used to control for clinical variables between neonates with and without EOS to determine if EOS modified risk of LOS, necrotizing enterocolitis (NEC), or death.

RESULTS

LOS occurred in 12,112/102,317 (11.8%) neonates without EOS and in 133/1059 (12.6%) of those with EOS. After adjustment for clinical variables, the risk of LOS was not different between neonates with or without a history of EOS (hazard ratio [HR]=0.92; 95% confidence interval [CI] 0.74, 1.16). EOS increased the risk of 120-day mortality (HR=1.78; 95% CI 1.49, 2.13).

CONCLUSIONS

In contrast to findings in children and adults, EOS was not associated with an increased risk of LOS in this cohort. Age-specific investigations are needed to determine if post-sepsis immunologic alterations are present.

Safety and effectiveness of meropenem in infants with suspected or complicated intra-abdominal infections

BACKGROUND

Intra-abdominal infections are common in young infants and lead to significant morbidity and mortality. Meropenem is a broad-spectrum antimicrobial with excellent activity against pathogens associated with intra-abdominal infections. The purpose of this study was to determine the safety and effectiveness of meropenem in young infants with suspected or complicated intra-abdominal infections.

METHODS

Preterm and term infants <91 days of age with suspected or confirmed intra-abdominal infections hospitalized in 24 neonatal intensive care units were studied in an open-label, multiple-dose study. Adverse events and serious adverse events were collected through 3 and 30 days following the last meropenem dose, respectively. Effectiveness was assessed by 3 criteria: death, bacterial cultures, and presumptive clinical cure score.

RESULTS

Of 200 subjects enrolled in the study, 99 (50%) experienced an adverse event, and 34 (17%) had serious adverse events; no adverse events were probably or definitely related to meropenem. The most commonly reported adverse events were sepsis (6%), seizures (5%), elevated conjugated bilirubin (5%), and hypokalemia (5%). Only 2 of the serious adverse events were determined to be possibly related to meropenem (isolated ileal perforation and an episode of fungal sepsis). Effectiveness was evaluable in 192 (96%) subjects, and overall treatment success was 84%.

CONCLUSIONS

Meropenem was well tolerated in this cohort of critically ill infants, and the majority of infants treated with meropenem met the definition of therapeutic success.

CLINICAL TRIALS REGISTRATION

NCT00621192.

Candida virulence properties and adverse clinical outcomes in neonatal candidiasis

OBJECTIVE

To determine whether premature infants with invasive Candida infection caused by strains with increased virulence properties have worse clinical outcomes than those infected with less virulent strains.

STUDY DESIGN

Clinical isolates were studied from 2 populations of premature infants, those colonized with Candida spp (commensal; n = 27) and those with invasive candidiasis (n = 81). Individual isolates of C albicans and C parapsilosis were tested for virulence in 3 assays: phenotypic switching, adhesion, and cytotoxicity. Invasive isolates were considered to have enhanced virulence if detected at a level >1 SD above the mean for the commensal isolates in at least one assay. Outcomes of patients with invasive isolates with enhanced virulence were compared with those with invasive isolates lacking enhanced virulence characteristics.

RESULTS

Enhanced virulence was detected in 61% of invasive isolates of C albicans and 42% of invasive isolates of C parapsilosis. All C albicans cerebrospinal fluid isolates (n = 6) and 90% of urine isolates (n = 10) had enhanced virulence, compared with 48% of blood isolates (n = 40). Infants with more virulent isolates were younger at the time of positive culture and had higher serum creatinine levels.

CONCLUSION

Individual isolates of Candida species vary in their virulence properties. Strains with higher virulence are associated with certain clinical outcomes.

Evidence-based guidelines for pediatric clinical trials: focus on StaR Child Health

Clinical trials in children are challenging and filled with important ethical considerations that differ from adults. Given difficulties associated with pediatric clinical trials, off-label prescribing is a common practice in pediatrics, which can lead to adverse safety events and efficacy failures. To overcome these consequences, in the past 15 years, legislation in the USA and Europe has provided incentives to industry and increased government funding to conduct pediatric trials. Pediatric trial networks have also been formed to decrease the knowledge gap. However, challenges to performing pediatric trials and lack of standardization and guidelines regarding studies in children still exist. Standards for Research (StaR) in Child Health, begun in 2009, aims to improve the design, conduct and reporting of pediatric trials. This organization uses a consensus guideline approach involving academic, government and industry stakeholders to identify and disseminate best practices for pediatric trials. Six out of 11 planned standards are currently published.

Effect of sex and race on outcome in patients undergoing congenital heart surgery: an analysis of the society of thoracic surgeons congenital heart surgery database

BACKGROUND

Previous studies on the impact of race and sex on outcome in children undergoing cardiac operations were based on analyses of administrative claims data. This study uses clinical registry data to examine potential associations of sex and race with outcomes in congenital cardiac operations, including in-hospital mortality, postoperative length of stay (LOS), and complications.

METHODS

The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) was queried for patients younger than 18 years undergoing cardiac operations from 2007 to 2009. Preoperative, operative, and outcome data were collected on 20,399 patients from 49 centers. In multivariable analysis, the association of race and sex with outcome was examined, adjusting for patient characteristics, operative risk (Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery [STAT] mortality category), and operating center.

RESULTS

Median age at operation was 0.4 years (interquartile range 0.1-3.4 years), and 54.4% of patients were boys. Race/ethnicity included 54.9% white, 17.1% black, 16.4% Hispanic, and 11.7% "other." In adjusted analysis, black patients had significantly higher in-hospital mortality (odds ratio [OR], 1.67; 95% confidence interval [CI], 1.37-2.04; p<0.001) and complication rate (OR, 1.15; 95% CI, 1.04-1.26; p<0.01) in comparison with white patients. There was no significant difference in mortality or complications by sex. Girls had a shorter LOS than boys (-0.8 days; p<0.001), whereas black (+2.4 days; p<0.001) and Hispanic patients (0.9 days; p<0.01) had longer a LOS compared with white patients.

CONCLUSIONS

These data suggest that black children have higher mortality, a longer LOS, and an increased complication rate. Girls had outcomes similar to those of boys but with a shorter LOS of almost a day. Further study of potential causes underlying these race and sex differences is warranted.

Neonatal fungal infections: when to treat?

Candida infections are a major cause of morbidity and mortality in neonatal intensive care units. Mortality following Candida bloodstream infections is as high as 40%, and neurodevelopmental impairment is common among survivors. Because invasive fungal infections are common and extremely difficult to diagnose, empirical treatment with antifungal therapy should be considered in high-risk, low-birth-weight infants who fail to quickly respond to empirical antibacterial treatment. Risk factors to consider when deciding to administer empirical antifungal therapy include: prior exposure to third-generation cephalosporins, extreme prematurity, and presence of central venous catheters.