Evidence-based methylxanthine use in the NICU

Development and validation of a predictive tool for adverse drug reactions in neonates under intensive care

AIMS

Neonates hospitalized in neonatal intensive care units (NICUs) commonly experience adverse drug reactions (ADRs). Thus, we aimed to develop and validate a tool for predicting ADRs in neonates hospitalized in NICUs.

METHODS

A nested case-control study in an open cohort with neonates admitted to the NICU of a maternity hospital in Natal, Brazil was conducted from January 2019 to January 2022 [Correction added on 4 December 2023, after first online publication: 2023 has been changed to 2019 in the preceding sentence.]. Neonates with ADR were randomly paired with 2 controls. For the development of the tool, a multivariate logistic regression was applied on 2/3 of the sample (cases with respective controls). The model's fit was evaluated using the Hosmer-Lemeshow test for calibration and the Brier score for performance assessment. Validation of the tool was performed by determining the area under the receiver operating characteristic curve with bootstrap adjusted c-statistics.

RESULTS

In all, 450 neonates (150 cases and 300 controls) were included in the study. We identified 5 independent risk factors for ADR, 4 related to the neonate (current mechanical ventilation, heart rate ≥178 beats/min, intravenous medications, ≥5 prescription medications) and 1 to the mother (gestational hypertension). The tool had a classification cut-off point of ≥15, and its total score ranged from 0 to 34. In validation, the tool had an area under the receiver operating characteristic curve of 0.74 (95% confidence interval [CI] 0.66-0.81) with sensitivity of 52.02% (95% CI 47.40-56.64) and specificity of 81.35% (95% CI 77.75-84.95).

CONCLUSION

The tool demonstrated adequate discriminative ability and utilized 5 commonly monitored variables in the NICU.

Doxapram for the prevention and treatment of apnea in preterm infants

BACKGROUND

Apnea of prematurity is a common problem in preterm infants that may have significant consequences on their development. Methylxanthines (aminophylline, theophylline, and caffeine) are effective in the treatment of apnea of prematurity. Doxapram is used as a respiratory stimulant in cases refractory to the methylxanthine treatment.

OBJECTIVES

To evaluate the benefits and harms of doxapram administration on the incidence of apnea and other short-term and longer-term clinical outcomes in preterm infants.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was March 2023.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) assessing the role of doxapram in prevention and treatment of apnea of prematurity and prevention of reintubation in preterm infants (less than 37 weeks' gestation). We included studies comparing doxapram with either placebo or methylxanthines as a control group, or when doxapram was used as an adjunct to methylxanthines and compared to methylxanthines alone as a control group. We included studies of doxapram at any dose and route.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were clinical apnea, need for positive pressure ventilation after initiation of treatment, failed apnea reduction after two to seven days, and failed extubation (defined as unable to wean from invasive intermittent positive pressure ventilation [IPPV] and extubate or reintubation for IPPV within one week). We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We included eight RCTs enrolling 248 infants. Seven studies (214 participants) provided data for meta-analysis. Five studied doxapram for treatment of apnea in preterm infants. Three studied doxapram to prevent reintubation in preterm infants. None studied doxapram in preventing apnea in preterm infants. All studies administered doxapram intravenously as continuous infusions. Two studies used doxapram as an adjunct to aminophylline compared to aminophylline alone and one study as an adjunct to caffeine compared to caffeine alone. When used to treat apnea, compared to no treatment, doxapram may result in a slight reduction in failed apnea reduction (risk ratio [RR] 0.45, 95% confidence interval [CI] 0.20 to 1.05; 1 study, 21 participants; low-certainty evidence). The evidence is very uncertain about the effect of doxapram on need for positive pressure ventilation after initiation of treatment (RR 0.31, 95% CI 0.01 to 6.74; 1 study, 21 participants; very low-certainty evidence). Doxapram may result in little to no difference in side effects causing cessation of therapy (0 events in both groups; risk difference [RD] 0.00, 95% CI -0.17 to 0.17; 1 study, 21 participants; low-certainty evidence). Compared to alternative treatment, the evidence is very uncertain about the effect of doxapram on failed apnea reduction (RR 1.35, 95% CI 0.53 to 3.45; 4 studies, 84 participants; very low-certainty evidence). The evidence is very uncertain about the effect of doxapram on need for positive pressure ventilation after initiation of treatment (RR 2.40, 95% CI 0.11 to 51.32; 2 studies, 37 participants; very-low certainty evidence; note 1 study recorded 0 events in both groups. Thus, the RR and CIs were calculated from 1 study rather than 2). Doxapram may result in little to no difference in side effects causing cessation of therapy (0 events in all groups; RD 0.00, 95% CI -0.15 to 0.15; 37 participants; 2 studies; low-certainty evidence). As adjunct therapy to methylxanthine, the evidence is very uncertain about the effect of doxapram on failed apnea reduction after two to seven days (RR 0.08, 95% CI 0.01 to 1.17; 1 study, 10 participants; very low-certainty evidence). No studies reported on clinical apnea, chronic lung disease at 36 weeks' postmenstrual age (PMA), death at any time during initial hospitalization, long-term neurodevelopmental outcomes in the three comparisons, and need for positive pressure ventilation and side effects when used as adjunct therapy to methylxanthine. In studies to prevent reintubation, when compared to alternative treatment, the evidence is very uncertain about the effect of doxapram on failed extubation (RR 0.43, 95% CI 0.10 to 1.83; 1 study, 25 participants; very low-certainty evidence). As adjunct therapy to methylxanthine, doxapram may result in a slight reduction in 'clinical apnea' after initiation of treatment (RR 0.36, 95% CI 0.13 to 0.98; 1 study, 56 participants; low-certainty evidence). Doxapram may result in little to no difference in failed extubation (RR 0.92, 95% CI 0.52 to 1.62; 1 study, 56 participants; low-certainty evidence). The evidence is very uncertain about the effect of doxapram on side effects causing cessation of therapy (RR 6.42, 95% CI 0.80 to 51.26; 2 studies, 85 participants; very low-certainty evidence). No studies reported need for positive pressure ventilation, chronic lung disease at 36 weeks' PMA, long-term neurodevelopmental outcomes in the three comparisons; failed extubation when compared to no treatment; and clinical apnea, death at any time during initial hospitalization, and side effects when compared to no treatment or alternative treatment. We identified two ongoing studies, one conducted in Germany and one in multiple centers in the Netherlands and Belgium.

AUTHORS' CONCLUSIONS

In treating apnea of prematurity, doxapram may slightly reduce failure in apnea reduction when compared to no treatment and there may be little to no difference in side effects against both no treatment and alternative treatment. The evidence is very uncertain about the need for positive pressure ventilation when compared to no treatment or alternative treatment and about failed apnea reduction when used as alternative or adjunct therapy to methylxanthine. For use to prevent reintubation, doxapram may reduce apnea episodes when administered in adjunct to methylxanthine, but with little to no difference in failed extubation. The evidence is very uncertain about doxapram's effect on death when used as adjunct therapy to methylxanthine and about failed extubation when used as alternative or adjunct therapy to methylxanthine. There is a knowledge gap about the use of doxapram as a therapy to prevent apnea. More studies are needed to clarify the role of doxapram in the treatment of apnea of prematurity, addressing concerns about long-term outcomes. The ongoing studies may provide useful data.

Challenges in respiratory management during therapeutic hypothermia for neonatal encephalopathy

Neonatal encephalopathy (NE) is a serious condition with devastating neurological outcomes that can impact oxygenation and ventilation. The currently recommended therapeutic hypothermia (TH) for these infants may also has several respiratory implications. It decreases metabolic rate and oxygen demands; however, it increases oxygen solubility in the blood and impacts its release to peripheral tissue including the brain. Respiratory management of infants treated with TH should aim for minimizing exposure to hypocapnia or hyperoxia. Inspiratory gas should be heated to 37 °C and humidified to prevent airway and alveolar injury. Blood gas values should be corrected to the core temperature during TH and the use of alkaline buffers is discouraged. While mild sedation/analgesia may ameliorate the discomfort related to cooling, paralytic agents/heavy sedation should be used with caution considering their side effects. Finally, the use of caffeine still needs careful investigation in this population.

Prophylactic versus therapeutic caffeine for apnea of prematurity: a randomized controlled trial

BACKGROUND

Therapeutic initiation of methyxanthines for treatment of apnea in preterm infants was the standard policy. Caffeine therapy is beneficial for various outcomes of preterm infants.

AIM

To evaluate the efficacy of early prophylactic compared to routine therapeutic caffeine therapy on duration of oxygen support and other outcomes of preterm infants.

METHODS

In a randomized controlled trial including preterm infants < 32 weeks' gestation, prophylactic (in the first 72 h of life) versus therapeutic (only if apnea exists or infant requires mechanical ventilation) decision of caffeine was compared. The primary outcome was the duration of oxygen therapy. Secondary outcomes included duration of respiratory support modalities; bronchoplumonary dysplasia (BPD); necrotizing enterocolitis; intra-ventricular hemorrhage; retinopathy of prematurity; length of hospital stay (LOS); neonatal mortality; and caffeine side effects.

RESULTS

We enrolled 90 infants in the prophylactic and 91 infants in therapeutic groups respectively. Prophylactic caffeine decreased the duration of oxygen therapy [median and IQR of 28 (18-36) days versus 34 (23-51) days, p = .005 respectively]. Prophylactic caffeine significantly decreased the durations of respiratory support modalities, LOS, and incidences of mild to moderate BPD without reported effects on the incidence of severe BPD or other clinical outcomes compared to therapeutic caffeine. A significantly higher proportion of infants in the prophylactic caffeine group did not require mechanical ventilation during their NICU admission and a significant lower proportion required late mechanical ventilation compared to the prophylactic caffeine group.

CONCLUSION

Prophylactic caffeine decreased the duration of oxygen therapy, invasive and noninvasive ventilation, incidences of mild to moderate BPD, and LOS in preterm infants.

Effects of Preinjury and Postinjury Exposure to Caffeine in a Rat Model of Traumatic Brain Injury

Background: Lethal apnea is a significant cause of acute mortality following a severe traumatic brain injury (TBI). TBI is associated with a surge of adenosine, which also suppresses respiratory function in the brainstem. Methods and Materials: This study examined the acute and chronic effects of caffeine, an adenosine receptor antagonist, on acute mortality and morbidity after fluid percussion injury. Results: We demonstrate that, regardless of preinjury caffeine exposure, an acute bolus of caffeine given immediately following the injury dosedependently prevented lethal apnea and has no detrimental effects on motor performance following sublethal injuries. Finally, we demonstrate that chronic caffeine treatment after injury, but not caffeine withdrawal, impairs recovery of motor function. Conclusions: Preexposure of the injured brain to caffeine does not have a major impact on acute and delayed outcome parameters; more importantly, a single acute dose of caffeine after the injury can prevent lethal apnea regardless of chronic caffeine preexposure.

Monitoring of Infants Discharged Home with Medical Devices

Preterm infants and term infants with complex medical conditions are often discharged home with technological support. There is a scarcity of evidence-based guidelines for post-discharge management of these infants at high risk. Common diagnoses necessitating the need for respiratory support and/or monitoring devices include apnea of prematurity and bronchopulmonary dysplasia for preterm infants, and upper airway anomalies, central nervous system disorders, and neuromuscular disorders for term infants. Some infants who are unable to receive complete oral feeds for various reasons are sometimes discharged home with nasogastric or gastrostomy tube feeds. For safe patient care at home and reduction of emergency department visits, there should be proper transition of care from hospital to primary care provider, and appropriate instruction of caregivers for care of the infant including teaching about medications, feeding, and management of medical devices. Primary care providers should be aware of these common supportive devices and their complications to provide timely intervention if needed. [Pediatr Ann. 2020;49(2):e88-e92.].

Acute hemodynamic effects of methylxanthine therapy in preterm neonates: Effect of variations in subgroups

BACKGROUND

Methylxanthines have cardiac stimulant effects. The current study aimed to compare acute hemodynamic changes between caffeine and aminophylline in ≤34 weeks' preterm neonates.

METHODS

The study was performed using information on echocardiography measurements from preterm neonates recruited for apnea of prematurity (75 of 240) and preventing extubation failure (113 of 156) studies. The neonates were randomized either to the caffeine or aminophylline groups. Neonates with no maintenance followed by loading doses with both the methylxanthines (caffeine and aminophylline) and incomplete echocardiography examination were excluded.

RESULTS

Cardiac parameters were found to be similar between groups. The heart rate was higher among the aminophylline-treated neonates (p < 0.001) than among the caffeine-treated ones. End-systolic volume was higher among both caffeine- (p < 0.001) and aminophylline-treated neonates (p = 0.001) when compared with pretreatment values. End-diastolic volume was statistically higher in both groups' neonates (p = 0.01). The odds of increase in cardiac output was higher; however, increase in ejection fraction was less in caffeine-treated small-for-gestation-age neonates.

CONCLUSION

Caffeine has similar effects on cardiac parameters as aminophylline; however, caffeine-treated small-for-gestation stratification gave rise to significant cardiac variations.

Early Caffeine Administration and Neurodevelopmental Outcomes in Preterm Infants

BACKGROUND

Although caffeine use for apnea of prematurity is well studied, the long-term safety and benefit of routine early caffeine administration has not been explored. Our objective was to determine the association between early (within 2 days of birth) versus late caffeine exposure and neurodevelopmental outcomes in preterm infants.

METHODS

Infants of <29 weeks' gestation born between April 2009 and September 2011 and admitted to Canadian Neonatal Network units and then assessed at Canadian Neonatal Follow-up Network centers were studied. Neonates who received caffeine were divided into early- (received within 2 days of birth) and late-caffeine (received after 2 days of birth) groups. The primary outcome was significant neurodevelopmental impairment, defined as cerebral palsy, or a Bayley Scales of Infant and Toddler Development, Third Edition composite score of <70 on any component, hearing aid or cochlear implant, or bilateral visual impairment at 18 to 24 months' corrected age.

RESULTS

Of 2108 neonates who were eligible, 1545 were in the early-caffeine group and 563 were in the late-caffeine group. Rates of bronchopulmonary dysplasia, patent ductus arteriosus, and severe neurologic injury were lower in the early-caffeine group than in the late-caffeine group. Significant neurodevelopmental impairment (adjusted odds ratio 0.68 [95% confidence interval 0.50-0.94]) and odds of Bayley Scales of Infant and Toddler Development, Third Edition cognitive scores of <85 (adjusted odds ratio 0.67 [95% confidence interval 0.47-0.95]) were lower in the early-caffeine group than in the late-caffeine group. Propensity score-based matched-pair analyses revealed lower odds of cerebral palsy and hearing impairment only.

CONCLUSIONS

Early caffeine therapy is associated with better neurodevelopmental outcomes compared with late caffeine therapy in preterm infants born at <29 weeks' gestation.

[Clinical effect of early or late administration of caffeine citrate in prevention and treatment of apnea in very low birth weight infants]

OBJECTIVE

To study the clinical effect of early or late administration of caffeine citrate in the prevention and treatment of apnea in very low birth weight (VLBW) infants.

METHODS

A total of 82 VLBW infants who were hospitalized and treated in the neonatal intensive care unit between June 2015 and May 2017 were enrolled. According to the age in days when caffeine citrate treatment was started, they were divided into early treatment group (<3 days) with 22 infants and late treatment group (3 - <10 days) with 60 infants. A retrospective analysis was performed for their clinical data. The two groups were compared in terms of general information during the perinatal period, treatment process, and clinical outcome.

RESULTS

Compared with the late treatment group, the early treatment group had a significantly lower birth weight (P=0.004), significantly shorter durations of mechanical ventilation and oxygen inhalation (P<0.05), and a significantly lower incidence rate of bronchopulmonary dysplasia (P=0.032). There were no significant differences in other general information, treatment process, and clinical outcome between the two groups (P>0.05).

CONCLUSIONS

Early administration of caffeine citrate can improve the prognosis of VLBW infants.

Drug-induced renal damage in preterm neonates: state of the art and methods for early detection

Only a small fraction of drugs widely used in neonatal intensive care units (NICU) are specifically authorized for this population. Even if unlicensed or off-label use is necessary, it is associated with increased adverse drug reactions, which must be carefully weighed against expected benefits. In particular, renal damage is frequent among preterm babies, and is considered a predisposing factor for the development of chronic kidney disease in adulthood. Apart from specific conditions affecting premature neonates (e.g. respiratory distress syndrome, perinatal asphyxia), drugs play an important role in impairing renal function because of well-known nephrotoxicity and/or interaction with renal developmental factors. From a review of the available studies on drug use in NICU patients, we identified and described the most commonly administered drugs that are correlated to renal damage. Early detection of kidney injury is becoming an essential aspects for clinicians because of the limited number of biomarkers applicable in the neonatal population. Postnatal changes of biochemical processes that influence pharmacokinetic and pharmacodynamic aspects need to be further investigated in order to better understand the mechanisms of drug toxicity in this population. The most promising strategies for dose adjustment and therapeutic schemes are discussed. The purpose of this review was to describe current knowledge on drug use among premature babies and their implication in kidney injury development, as well as to highlight available strategies for early detection of renal damage.

Inhibitory respiratory responses to progesterone and allopregnanolone in newborn rats chronically treated with caffeine

KEY POINTS

In premature newborns, recurrent apnoea is systematically treated with caffeine to prevent long-term neurocognitive disorders, but a substantial percentage of apnoea persists particularly in neonates born before 28 weeks of gestation. Progesterone has been proposed as a respiratory stimulant potentially suitable for the treatment of newborn apnoea persistent to caffeine. Accordingly we asked whether acute progesterone administration reduces apnoea frequency in newborn rats treated with caffeine. Surprisingly our results show that in newborn rats treated with caffeine, administration of progesterone inhibits breathing and increases apnoea frequency. Additional experiments showed an enhanced GABAergic inhibitory drive on breathing after caffeine treatment, and that progesterone is converted to allopregnanolone (an allosteric modulator of GABAA receptors) to inhibit breathing. We conclude that combining progesterone and chronic caffeine is not an option in preterm neonates, unless the effects of allopregnanolone can be counteracted.

ABSTRACT

Caffeine is the main treatment for apnoea in preterm neonates, but its interactions with other respiratory stimulants like progesterone are unknown. We tested the hypothesis that the addition of progesterone to caffeine treatments further stimulates ventilation. Newborn rats were treated with water (control) or caffeine (15 mg kg(-1)) by daily gavage between postnatal day (P)3 and P12. At P4 and P12, we measured apnoea frequency, ventilatory responses and metabolic parameters under both normoxia and hypoxia (12% O2, 20 min) following an acute administration of either saline or progesterone (4 mg kg(-1); i.p.). Progesterone injection increased the serum levels of both progesterone and its neuroactive metabolite allopregnanolone. Progesterone had no effect on ventilation in control rats under normoxia. Progesterone depressed ventilation in P12 caffeine-treated rats under normoxia and hypoxia and increased apnoea frequency in both P4 and P12 rats. Because allopregnanolone is an allosteric modulator of GABAA receptors and caffeine may enhance GABAergic inhibition in newborns, we studied the effects of the GABAA receptor antagonist bicuculline at 0, 1, 2 and 3 mg kg(-1) doses and allopregnanolone (10 mg kg(-1) dose) in P12 rats. In caffeine-treated rats, bicuculline enhanced ventilation, while allopregnanolone decreased ventilation and increased total apnoea time. Progesterone had no effect on ventilation and apnoea frequency in caffeine-treated rats injected with finasteride, which blocks the conversion of progesterone to allopregnanolone. We conclude that combining progesterone and chronic caffeine therapy is not an option for the treatment of persistent apnoea in preterm neonates, unless the effects of allopregnanolone can be counteracted.

Sleep Disturbances and Behavioral Disturbances in Children and Adolescents

Sleep deprivation and sleep disorders are commonly seen in children and adolescents. They are often undiagnosed and undertreated. A balance of circadian rhythm and homeostatic drive determine sleep quality, quantity, and timing, which changes across the developmental years. Environmental and lifestyle factors can affect sleep quality and quantity and lead to sleep deprivation. A comprehensive assessment of sleep disorders includes parental report, children's self-report, and school functioning. Diagnostic tools are used in diagnosing and treating sleep disorders.

International survey on periextubation practices in extremely preterm infants

OBJECTIVE

To determine periextubation practices in extremely preterm infants (<28 weeks gestation).

DESIGN

A survey consisting of 13 questions related to weaning from mechanical ventilation, assessment of extubation readiness and postextubation respiratory support was developed and sent to clinical directors of level III NICUs in Australia, Canada, Ireland, New Zealand and USA. A descriptive analysis of the results was performed.

RESULTS

112/162 (69%) units responded; 36% reported having a guideline (31%) or written protocol (5%) for ventilator weaning. Extubation readiness was assessed based on ventilatory settings (98%), blood gases (92%) and the presence of clinical stability (86%). Only 54% ensured that infants received caffeine ≤24 h prior to extubation. 16% of units systematically extubated infants on the premise that they passed a Spontaneous Breathing Test with a duration ranging from 3 min (25%) to more than 10 min (35%). Nasal continuous positive airway pressure was the most common type of respiratory support used (84%) followed by nasal intermittent positive pressure ventilation (55%) and high-flow nasal cannula (33%). Reintubation was mainly based on clinical judgement of the responsible physician (88%). There was a lack of consensus on the time frame for definition of extubation failure (EF), the majority proposing a period between 24 and 72 h; 43% believed that EF is an independent risk factor for increased mortality and morbidity.

CONCLUSIONS

Periextubation practices vary considerably; decisions are frequently physician dependent and not evidence based. The definition of EF is variable and well-defined criteria for reintubation are rarely used. High-quality trials are required to inform guidelines and standardise periextubation practices.

Metyrapone alleviates deleterious effects of maternal food restriction on lung development and growth of rat offspring

Maternal food restriction (MFR) causes intrauterine growth restriction, a known risk factor for developing chronic lung disease. However, it is unknown whether this negative outcome is gender specific or preventable by blocking the MFR-induced hyperglucocorticoidism. Using a well-established rat model, we used metyrapone (MTP), an inhibitor of glucocorticoid synthesis, to study the MFR-induced lung changes on postnatal day (p) 21 in a gender-specific manner. From embryonic day 10 until delivery, pregnant dams were fed either an ad libitum diet or a 50% caloric restricted diet with or without MTP supplementation. Postnatally, the offspring were fed ad libitum from healthy dams until p21. Morphometric, Western blot, and immunohistochemical analysis of the lungs demonstrated that MTP mitigated the MFR-mediated decrease in alveolar count, decrease in adipogenic protein peroxisome proliferator-activated receptor γ, increase in myogenic proteins (fibronectin, α-smooth muscle actin, and calponin), increase in Wnt signaling intermediates (lymphoid enhancer-binding factor 1 and β-catenin), and increase in glucocorticoid receptor (GR) levels. The MFR-induced lung phenotype and the effects of MTP were similar in both genders. To elucidate the mechanism of MFR-induced shift of the adipogenic-to-myogenic phenotype, lung fibroblasts were used to independently study the effects of (1) nutrient restriction and (2) excess steroid exposure. Nutrient deprivation increased myogenic proteins, Wnt signaling intermediates, and GR, all changes blocked by protein supplementation. MTP also blocked, likely by normalizing nicotinamide adenine dinucleotide phosphate levels, the corticosterone-induced increase in myogenic proteins, but had no effect on GR levels. In summary, protein restriction and increased glucocorticoid levels appear to be the key players in MFR-induced lung disease, affecting both genders.

Mechanisms of sudden unexpected death in epilepsy: the pathway to prevention

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in patients with refractory epilepsy, with an estimated 35% lifetime risk in this patient population. There is a surprising lack of awareness among patients and physicians of this increased risk of sudden death: in a recent survey, only 33% of Canadian paediatricians who treated patients with epilepsy knew the term SUDEP. Controversy prevails over whether cardiac arrhythmia or respiratory arrest is more important as the primary cause of death. Effective preventive strategies in high-risk patients will rely on definition of the mechanisms that lead from seizures to death. Here, we summarize evidence for the mechanisms that cause cardiac, respiratory and arousal abnormalities during the ictal and postictal period. We highlight potential cellular mechanisms underlying these abnormalities, such as a defect in the serotonergic system, ictal adenosine release, and changes in autonomic output. We discuss genetic mutations that cause Dravet and long QT syndromes, both of which are linked with increased risk of sudden death. We then highlight possible preventive interventions that are likely to decrease SUDEP incidence, including respiratory monitoring in epilepsy monitoring units and overnight supervision. Finally, we discuss treatments, such as selective serotonin reuptake inhibitors, that might be personalized to a specific genetic or pathological defect.

Decaffeination and measurement of caffeine content by addicted Escherichia coli with a refactored N-demethylation operon from Pseudomonas putida CBB5

The widespread use of caffeine (1,3,7-trimethylxanthine) and other methylxanthines in beverages and pharmaceuticals has led to significant environmental pollution. We have developed a portable caffeine degradation operon by refactoring the alkylxanthine degradation (Alx) gene cluster from Pseudomonas putida CBB5 to function in Escherichia coli. In the process, we discovered that adding a glutathione S-transferase from Janthinobacterium sp. Marseille was necessary to achieve N 7 -demethylation activity. E. coli cells with the synthetic operon degrade caffeine to the guanine precursor, xanthine. Cells deficient in de novo guanine biosynthesis that contain the refactored operon are ″addicted″ to caffeine: their growth density is limited by the availability of caffeine or other xanthines. We show that the addicted strain can be used as a biosensor to measure the caffeine content of common beverages. The synthetic N-demethylation operon could be useful for reclaiming nutrient-rich byproducts of coffee bean processing and for the cost-effective bioproduction of methylxanthine drugs.

Treatment of dyssomnias and parasomnias in childhood

OPINION STATEMENT

Dyssomnias are sleep disorders associated with complaints of insomnia or hypersomnia. The daytime sleepiness of narcolepsy is treated by a combination of planned daytime naps, regular exercise medications such as modafinil, or salts of methylphenidate, or amphetamine. Cataplexy that accompanies narcolepsy is treated with anticholinergic agents, selective serotonin reuptake inhibitors, or sodium oxybate. Children with neurodevelopmental disabilities such as autism have sleep initiation and maintenance difficulties on a multifactorial basis, with favorable response to melatonin in some patients. Childhood onset restless legs syndrome is often familial, associated with systemic iron deficiency, and responsive to iron supplementation and gabapentin. Parasomnias are episodic phenomena events which occur at the sleep -- wake transition or by intrusion on to sleep. Arousal parasomnias such as confusional arousals and sleep walking can sometimes be confused with seizures. A scheme for differentiating arousal parasomnias from nocturnal seizures is provided. Since arousal parasomnias are often triggered by sleep apnea, restless legs syndrome, or acid reflux, treatment measures directed specifically at these disorders often helps in resolution. Clonazepam provided in a low dose at bedtime can also alleviate sleep walking and confusional arousals. Obstructive sleep apnea affects about 2 percent of children. Adeno-tonsillar hypertrophy, cranio-facial anomalies, and obesity are common predisposing factors. Mild obstructive sleep apnea can be treated using a combination of nasal corticosteroids and a leukotriene antagonist. Moderate to severe obstructive sleep apnea are treated with adeno-tonsillectomy, positive airway pressure breathing devices, or weight reduction as indicated. This paper provides an overview of the topic, with an emphasis on management steps. Where possible, the level of evidence for treatment recommendations is indicated.