0950 Effects of Sodium Oxybate (SXB) on Body Mass Index (BMI) in Pediatric Patients With Narcolepsy

Introduction

Obesity is a common comorbidity of pediatric narcolepsy. SXB is a standard of care for cataplexy and excessive daytime sleepiness in narcolepsy. BMI decreases have been observed with SXB treatment. We examined BMI changes by BMI percentile category at study entry in pediatric participants.

Methods

Participants were aged 7-17 years with narcolepsy with cataplexy. SXB-naive participants were titrated to an optimal SXB dose, then entered a 2-week stable-dose period; participants taking SXB at study entry entered a 3-week stable-dose period. After a 2-week, placebo-controlled, double-blind, randomized-withdrawal period, all participants entered an open-label safety period (total study duration: ≤1 year). Weight categories were defined using BMI percentiles at study entry based on growth charts from the Centers for Disease Control. BMI percentile was categorized as: underweight (<5%ile), normal (≥5%ile to <85%ile), overweight (≥85%ile to<95%ile), obese (≥95%ile).

Results

Among SXB-naive participants, median (Q1, Q3) BMI percentile decreased with SXB treatment in participants who were categorized as normal-weight and overweight/obese at baseline (normal-weight, n=16: 76.5 [57.8, 82.4] at baseline, 35.0 [20.5, 62.6] at week 52; overweight/obese, n=35: 97.6 [93.6, 99.1] at baseline, 86.7 [72.5, 97.9] at week 52). Of participants who were normal-weight at baseline, 15/16 remained normal-weight at week 52. Of participants who were overweight at baseline, 9/10 were normal-weight at week 52. Of participants who were obese at baseline, 7/25 were normal-weight, 3/25 were overweight, and 15/25 remained obese at week 52. Among participants taking SXB at study entry, BMI percentile decreased, but to a lesser degree. Decreased weight or weight loss was reported as an adverse event in 13 participants (11 SXB-naive; 1 participant withdrew). Four participants became underweight during the study but returned to normal-weight by study end.

Conclusion

Decreases in BMI percentile and category were observed with SXB treatment in pediatric participants with narcolepsy.

Support

Jazz Pharmaceuticals

Pathophysiology of the vascular wall and its relevance for cerebrovascular disorders in aged rodents

Chronic hypertension and cerebral amyloid angiopathy (CAA) are the main pathologies which can induce the rupture of cerebral vessels and intracerebral hemorrhages, as a result of degenerative changes in the vascular wall. A lot of progress has been made in this direction since the successful creation of the first mouse model for the study of Alzheimer's disease (AD), as the spectrum of AD pathology includes a plethora of changes found in pure cerebrovascular diseases. We describe here some of these mouse models having important vascular changes that parallel human AD pathology, and more importantly, we show how these models have helped us understand more about the mechanisms that lead to CAA formation. An important cellular event associated with reduced structural and functional recovery after stroke in aged animals is the early formation of a scar in the infarcted region that impairs subsequent neural recovery and repair. We review recent evidence showing that the rapid formation of the glial scar following stroke in aged rats is associated with premature cellular proliferation that originates primarily from the walls of capillaries in the corpus callosum adjacent to the infarcted region. After stroke several vascular mechanisms are turned-on immediately to protect the brain from further damage and help subsequent neuroregeneration and functional recovery. Although does occur after stroke, vasculogenesis is overshadowed in its protective/restorative role by the angiogenesis and arteriogenesis. Understanding the basic mechanisms underlying functional recovery after cerebral stroke in aging subjects is likely to yield new insights into the treatment of brain injury in the clinic.

Outcome analysis of preoperative embolization in cranial base surgery

OBJECTIVE

Management of cranial base tumors requires an interdisciplinary approach. Supraselective angiography and embolization is an important adjunct to cranial base surgery. Though successful embolization facilitates resection, the morbidity of this procedure remains poorly defined. Therefore, we set out to define the morbidity associated with embolization of skull base meningiomas, thus allowing for informed decision making when considering this adjunct to tumor resection.

METHODS

A retrospective analysis was performed on our experience with embolization of 167 cranial base meningiomas. Cranial base meningiomas were defined as tumors originating from the olfactory groove, tuberculum sella, medial sphenoid wing, petro-clival region or foramen magnum.

RESULTS

280 feeding vessels were embolized with an average of 1.7 vessels per lesion. In 91% of patients embolized, good to excellent embolization was achieved without permanent neurological sequelae. In 20 patients no embolization was attempted due to the risk of new neurologic deficits or lack of an appropriate vessel for embolization. Twenty-one patients (12.6%) had transient worsening of their neurologic exam or a medical complication requiring hospitalization. Fifteen patients (9%) experienced permanent neurologic deficits or medical morbidity as a result of embolization. Four of the patients who experienced major complications had a decline in previously compromised cranial nerve function.

CONCLUSIONS

Embolization of cranial base tumors is an important part of the therapeutic armamentarium for the treatment of cranial base lesions. Recognition of the morbidity of this procedure will allow for the most appropriate use of this powerful adjunct to cranial base surgery.

The diagnosis of lower extremity deep venous thrombosis

The diagnosis of lower extremity deep venous thrombosis (DVT) is critical to emergency physicians because of the risk of pulmonary embolism. This article reviews the diagnostic modalities available for patients with suspected lower extremity DVT. The use of compression ultrasonography and the recent advances in the D-dimer assays are emphasized. A clinical algorithm that utilizes a non invasive approach to this potentially life threatening disease is presented.

Ultrasonography by emergency physicians in patients with suspected cholecystitis

This article investigates the use of bedside abdominal ultrasonography (BAU) performed by emergency physicians (EPs) to screen patients for cholelithiasis and cholecystitis. In this prospective study EPs performed BAU on 116 patients. Agreement between BAU and formal abdominal ultrasound (FUS) performed in the radiology department for detecting cholelithiasis and cholecystitis was determined using Kappa statistics. Test characteristics of BAU for detecting cholelithiasis and acute cholecystitis were calculated. Agreement between BAU and FUS was 0.71 for cholelithiasis and 0.46 for acute cholecystitis. Test characteristics of BAU for cholelithiasis were sensitivity 92%, specificity 78%, positive predictive value (PPV) 86%, negative predictive value (NPV) 88%. Test characteristics of BAU for acute cholecystitis compared with clinical follow-up were sensitivity 91%, specificity 66%, PPV 70%, NPV 90%. BAU may be used to exclude cholelithiasis and is sensitive for cholecystitis. However, when EPs with limited experience identify cholecystitis a confirmatory test is warranted before cholecystectomy.

Treatment of sleep-disordered breathing in children with myelomeningocele

The prevalence of moderate to severe sleep-disordered breathing (SDB) in patients with myelomeningocele may be as high as 20%, but little information is available regarding treatment of these patients. To assess the efficacy and complications of treatments for these children, we collected data on 73 patients from seven pediatric sleep laboratories. Obstructive sleep apnea (OSA, n = 30) and central apnea (n = 25) occurred more frequently than central hypoventilation (n = 12). We also describe a sleep-exacerbated restrictive lung disease type of SDB in 6 patients who had hypoxemia during sleep without apnea or central hypoventilation. For each type of SDB, effective treatments were identified in a stepwise process, moving towards more complex and invasive therapies. For OSA, adenotonsillectomy was often ineffective (10/14), whereas nasal continuous positive airway pressure (CPAP) was usually successful (18/21). For central apnea, methylxanthines and/or supplemental oxygen proved sufficient in 2 of 9 and 3 of 6, respectively, but noninvasive positive pressure ventilation was required in 7 children. For central hypoventilation, supplemental oxygen (alone or with methylxanthines), noninvasive positive pressure ventilation, and tracheostomy with positive pressure ventilation were effective in 3, 2, and 2 patients, respectively. Sleep-exacerbated restrictive lung disease always required supplemental oxygen treatment, but in 2 cases also required noninvasive positive pressure ventilation; nutritional and orthopedic procedures also were helpful. Posterior fossa decompression was used for the first three types of SDB, but data were insufficient to delineate specific recommendations for or against its use. In summary, evaluation by an experienced, multidisciplinary team can establish an effective treatment regime for a child with myelomeningocele and SDB.

Primary angiitis of the central nervous system as a first presentation in Hodgkin's disease: a case report and review of the literature

OBJECTIVE AND IMPORTANCE

Granulomatous angiitis of the central nervous system is a rare cause of neurological deterioration. It is often diagnosed posthumously, and a high index of suspicion is necessary to make the correct diagnosis on a timely basis.

CLINICAL PRESENTATION

A 27-year-old woman presented to the emergency room with complaints of worsening headache, nausea, and vomiting for 10 days, which were preceded by swelling of her tongue. At the examination, she had mild ocular tenderness, but no cranial nerve abnormalities. Radiographic examination revealed a right temporal lobe area with edema, and mild contrast enhancement was noted on computed tomography and magnetic resonance imaging. A similar but smaller region was present in the left frontal lobe.

INTERVENTION

Stereotactic biopsy of the left temporal lobe revealed granulomatous angiitis. Further workup revealed Hodgkin's disease in the mediastinum. Dexamethasone as well as chemotherapy for Hodgkin's disease was initiated. The patient's symptoms resolved, and she returned to work with her disease in remission.

CONCLUSION

Previous reports of central nervous system angiitis have shown an association with Sjogren's syndrome, herpes zoster infection, human immunodeficiency virus, and Hodgkin's disease. A review of the literature revealed a total of 12 patients with central nervous system angiitis and Hodgkin's disease. As a group, these patients had very poor outcomes. However, of six patients who presented with central nervous system angiitis and concurrent Hodgkin's disease and who underwent aggressive treatment for both conditions, three had a full recovery, two had a partial recovery, and one died.

Use of intra-aortic balloon pump counterpulsation for refractory symptomatic vasospasm

Delayed neurologic deficits secondary to vasospasm remain a vexing problem. Current treatments include: hypertensive hypervolemic hemodilution (Triple-H) therapy, angioplasty, and intra-arterial papaverine administration. Significant morbidity and mortality still result from vasospasm despite these therapies. We present two patients with symptomatic vasospasm who received intra-aortic balloon pump counterpulsation (IABP) to improve cerebral blood flow when they were unable to tolerate Triple-H therapy. One patient (L.T.) developed vasospasm after resection of a meningioma that encased the carotid and middle cerebral artery. The other patient (D.F.) suffered a subarachnoid hemorrhage (Fisher Grade III, Hunt/Hess Grade III) from a basilar tip aneurysm. Postoperatively, both patients developed vasospasm. Treatment with Triple-H therapy, angioplasty, and papaverine yielded modest results. When they experienced cardiac ischemia, Triple-H therapy was stopped, but their neurologic condition deteriorated markedly. Because of this, IABP was started. Both patients had an immediate improvement in cardiac function. IABP was able to reverse some of the neurologic deficits, and was weaned off after several days of support. Both patients had a substantial improvement in function, and are now capable of caring for themselves. We conclude that IABP may play an important role for improving cerebral blood flow in patients with vasospasm. It may be particularly useful in those patients with limited cardiac reserve.

Early predictors of myoglobinuria and acute renal failure following electrical injury

Myoglobinuria-induced acute renal failure (ARF) is a potentially lethal consequence of electrical injury. We describe clinical variables that can predict the risk of myoglobinuria and ARF following electrical injury. This was a retrospective multivariate analysis of risk factors among electrically injured patients over a 26-year period. Urine myoglobin status was documented in 162 patients; 14% had myoglobinuria. No patient developed ARF. Multivariate modeling revealed that high-voltage exposure, prehospital cardiac arrest, full-thickness burns, and compartment syndrome were associated with myoglobinuria. Using a prediction rule defined as positive when a patient had > or = 2 risk factors yielded a sensitivity of 96% and negative predictive value of 99%. Electrical injury patients with myoglobinuria have little risk of developing ARF. A prediction rule can be used to screen out patients at low risk for myoglobinuria and identify high-risk patients who warrant early aggressive treatment and a more definitive myoglobin test.

Proposed grading system to predict the extent of resection and outcomes for cranial base meningiomas

OBJECTIVE

This investigation was performed to construct a grading system for cranial base meningiomas that augments the current system of topographic labeling. This new system classifies cranial base meningiomas based on predicted surgical resection and patient outcomes.

METHODS

Two hundred thirty-two consecutive patients with cranial base meningiomas were surgically treated by the two senior authors between April 1993 and August 1997. Using standard statistical tests, a large number of preoperative, intraoperative, and follow-up findings were analyzed for correlation with the extent of resection. These included the presence of previous radiotherapy, Cranial Nerve III, V, and VI palsies, multiple fossa involvement, and vessel encasement.

RESULTS

Analysis revealed that each variable tested was independently and inversely correlated with total tumor resection (P < 0.002). We were able to construct a grading system based on these variables; when more variables are present, the grade is higher. With the grading system, lower-grade tumors were correlated with increased probabilities of total resection (r2 = 0.9947) and better patient outcomes, as measured by Karnofsky performance scale scores (r = 0.9291). We also found that, as a group, patients who underwent subtotal resection exhibited worse Karnofsky performance scale scores and had longer hospital stays.

CONCLUSION

The current system of classifying cranial base meningiomas provides no information regarding the tumor except location and no information concerning patient prognosis. We present a more useful system to categorize these tumors. Our scheme must be tested at other centers to corroborate our findings. This new grading system should serve to guide surgical treatment, inform patients, and improve communication among surgeons.

Clinical features of obstructive sleep apnea hypoventilation syndrome in otherwise healthy children

Obstructive sleep apnea hypoventilation syndrome (OSAHS) is an important public health problem. However, major gaps exist in our knowledge about the clinical features of this disorder in the pediatric age group. The purpose of this study was to examine clinical features of OSAHS diagnosed by polysomnography in otherwise healthy children. In this cross-sectional study, 326 children without underlying medical conditions (5.8+/-3.0 years, range 1-12 years; 56% male) were recruited from patients referred by primary care and otorhinolaryngology physicians for evaluation of snoring and difficulty breathing. Ethnic group distribution was African-American (38%), Caucasian (30%), and Hispanic (31%). Complaints of daytime tiredness or sleepiness were reported in 29% of the children. All children underwent overnight polysomnography (N = 330 studies). OSAHS was diagnosed in 59% of the children, based on polysomnographic criteria. The remaining children had either primary snoring (25%); no snoring (10%), or upper airway resistance syndrome (6%). Neither male gender nor obesity increased the likelihood for the diagnosis of OSAHS. However, the incidence of obesity in the study population (28%) was more than twice that of the general pediatric population. African-American children had a greater likelihood for OSAHS diagnosis compared to Hispanic or Caucasian children. Daytime complaints of sleepiness or tiredness were not more common in children diagnosed with OSAHS than in the children without OSAHS. As expected, tonsillar hypertrophy increased the likelihood of OSAHS diagnosis. In summary, many of the clinical features of childhood OSAHS are in marked contrast to those in adults.

Evaluation of the patient with blunt chest trauma: an evidence based approach

The patient who has sustained blunt trauma to the chest can present a diagnostic challenge to the emergency physician. There are several diagnostic modalities available for treating life-threatening injuries to these patients. The authors review published studies to support the use of these tests in diagnosing injuries from blunt thoracic trauma. The article focuses chiefly on two current areas of controversy, the diagnosis of blunt aortic and blunt myocardial injury. Finally, the authors make recommendations for the use of various tests based on the available evidence.

Ultrasonography by emergency physicians in patients with suspected ureteral colic

We performed a prospective study of patients with suspected ureteral colic to evaluate the test characteristics of bedside renal ultrasonography (US) performed by emergency physicians (EPs) for detecting hydronephrosis, and to evaluate how US can be used to predict the likelihood of nephrolithiasis. Thirteen EPs performed US, recorded the presence of hydronephrosis, and made an assessment of the likelihood of nephrolithiasis. All patients underwent i.v. pyelography (IVP) or unenhanced helical computed tomography (CT). There were 126 patients in the study: 84 underwent IVP; 42 underwent helical CT. Test characteristics of bedside US for detecting hydronephrosis were: sensitivity 72%, specificity 73%, positive predictive value (PPV) 85%, negative predictive value (NPV) 54%, accuracy 72%. The PPV and NPV for the ability of the EP to predict nephrolithiasis after performing US were 86% and 75%, respectively. We conclude that bedside US performed by EPs may be used to detect hydronephrosis and help predict the presence of nephrolithiasis.

Sleep disorders in infancy, childhood, and adolescence

Sleep disorders cause substantial problems during infancy, toddlerhood, preschool ages, school ages, and adolescence. They represent the most common behavioral problems facing most parents, as well as some of the most unusual and fascinating disorders known to medicine. Sleep disorders can result from pulmonary problems, neurologic problems, family problems, or psychologic or psychiatric problems. The majority of these disorders can be diagnosed by a comprehensive sleep and medical assessment, but special studies such as polysomnography, multiple sleep latency testing, or video electroencephalographic monitoring are necessary for certain diagnoses. Pediatric sleep disorders represent a true interdisciplinary and developmental field, richly connected with many aspects of health care and medical science. Physicians and other pediatric care providers must become increasingly knowledgeable about sleep disorders to offer the best care to their patients.

Renal ultrasonography

Renal US is one of several imaging modalities available to the emergency physician in the evaluation of patients with acute urologic disorders. It offers excellent anatomic detail without exposure to radiation or contrast agents but does not assess renal function. It is particularly useful in the evaluation of renal colic, although its role here may decrease with increasing availability of helical CT. It also has an important role in excluding bilateral renal obstruction as the cause of acute renal failure. Doppler renal US is likely to take on a more prominent role in the evaluation of renal trauma and is the diagnostic study of choice to rule out renal vein thrombosis. Bedside emergency renal US performed and interpreted by emergency physicians with limited training and experience is gaining in use and acceptance. Its role at present is primarily to identify unilateral hydronephrosis in patients with suspected renal colic. This role is likely to expand in the future as emergency US use grows and technology advances. Bedside emergency renal US may eventually be used in the evaluation of patients with acute renal failure, suspected renal vein thrombosis, and renal trauma.

Mechanisms of pediatric electrical injury. New implications for product safety and injury prevention

OBJECTIVES

To determine age-specific mechanisms of electrical injury in children, to examine product safety regulation of the major sources of electrical injury hazard, and to assess the adequacy of current prevention strategies.

DESIGN

Case series of 144 pediatric and adolescent electrical injuries in patients seen in the specialized burn center and tertiary care hospital between 1970 and 1995, examination of Consumer Product Safety Commission product recall reports for electrical injury hazards between 1973 and 1995, and review of the National Electric Code.

RESULTS

Eighty-six cases of electrical injuries resulted from low-voltage (< 1000-V) exposures, all occurring within the home. In children aged 12 years and younger, household appliance electrical cords and extension cords caused more than 64 (63%) of 102 injuries, whereas wall outlets were responsible for only 14 (15%) of injuries. Fifty-eight cases resulted from high-voltage exposures, accounting for 38 (90%) of 42 injuries in children older than 12 years. No federal safety regulations for electrical cords exist, although voluntary standards have been adopted by many manufacturers. Among 383 consumer products identified by the Consumer Product Safety Commission to be electrical injury hazards, 119 were appliance cords, extension cords, or holiday stringed light sets. Several products numbered more than 1.5 million units in US household distribution prior to the investigation by the Consumer Product Safety Commission.

CONCLUSIONS

Household electrical cords are the major electrocution hazard for children younger than 12 years, yet no federal safety mandates exist. Despite voluntary standards, noncompliant manufacturers can introduce vast numbers of unsafe cords onto the US household market every year. Conversion of existing voluntary safety guidelines into federally legislated standards may be the most effective intervention against pediatric electrocutions.

Blind nasotracheal intubation in the presence of facial trauma

Blind nasotracheal intubation (BNTI) is an effective procedure for the intubation of trauma patients. The presence of major facial trauma has been considered a relative contraindication due to the perceived risk of intracranial placement. The purpose of the present study was to assess the risk of intracranial placement in patients with facial fractures who undergo BNTI. The records of 311 patients with facial fractures were reviewed for methods of intubation and complications. Eighty-two patients underwent BNTI. There were no cases of intracranial placement, significant epistaxis requiring nasal packing, esophageal intubation, or osteomyelitis. Three patients (4%) developed sinusitis and eight (10%) developed aspiration pneumonia. We conclude that the presence of facial trauma does not appear to be a contraindication to BNTI.

Rhinovirus infection associated with serious lower respiratory illness in patients with bronchopulmonary dysplasia

OBJECTIVE

To determine the characteristics of rhinovirus infection in patients with bronchopulmonary dysplasia.

SUBJECTS AND METHODS

Between July 1, 1993, and July 1, 1995, 40 patients with bronchopulmonary dysplasia were identified. Viral cultures were obtained in ambulatory patients presenting with an acute respiratory illness requiring hospitalization or in hospitalized patients with a respiratory deterioration. When rhinovirus was isolated epidemiologic data were collected, and the characteristics of the illness, its severity and outcome were noted. Key features of rhinovirus and respiratory syncytial virus (RSV) bronchiolitis were compared.

RESULTS

There were 8 cases of lower respiratory tract illness associated with rhinovirus infection in 6 infants (mean age, 7.1 +/- 4.1 months) and 1 child (age, 40 months), an incidence of 0.15 infection/patient year. The mean gestational age and birth weight of these patients were 27.3 (+/- 2.75) weeks and 853 (+/-341) g, respectively. There were 5 males. Four patients needed intensive care unit admission and 1 required mechanical ventilation. By comparison there were 13 cases of RSV bronchiolitis, an incidence of 0.25 infection/patient year. The 2 groups were similar epidemiologically and an equal proportion of patients with rhinovirus and RSV needed intensive care unit admission. A greater percentage of patients with RSV required mechanical ventilation (50% vs. 14%), but this difference was not statistically significant. Three cases of rhinovirus were nosocomial, and 1 infant had a second infection. Four patients required 5 hospitalizations caused by rhinovirus infection, and the mean duration of hospital stay was 11 days. All children had sustained worsening in their respiratory status after rhinoviral illness requiring additional therapy.

CONCLUSIONS

Rhinovirus is a common and potentially serious lower respiratory pathogen in bronchopulmonary dysplasia patients. Rhinovirus infection has lasting pulmonary sequelae in these children.

The efficacy of intravenous droperidol in the prehospital setting

Droperidol is used for sedating combative patients in the emergency department (ED). We performed a randomized, prospective, double-blind study to evaluate the efficacy of droperidol in the management of combative patients in the prehospital setting. Forty-six patients intravenously received the contents of 2-cc vials of saline or droperidol (5 mg). Paramedics used a 5-point scale to quantify agitation levels prior to and 5 and 10 min after administration of the vials. Twenty-three patients received droperidol and 23 received saline. At 5 min, patients in the droperidol group were significantly less agitated than were patients in the saline group. At 10 min, this difference was highly significant. Eleven patients in the saline group (48%) required more sedation after arrival in the ED versus 3 patients (13%) in the droperidol group. We conclude that droperidol is effective in sedating combative patients in the prehospital setting.

Obstructive sleep apnea syndrome (OSAS) in children: diagnostic challenges

Obstructive sleep apnea syndrome (OSAS) is increasingly recognized in the pediatric population. It is characterized by a combination of partial upper airway obstruction and intermittent obstructive apnea that disrupts normal ventilation and sleep. It is estimated to occur in 1-3% of children with a peak age of 2 to 5 years. Common symptoms include habitual snoring, difficulty breathing during sleep, restlessness, and witnessed apnea. Adenotonsillar hypertrophy is the most common associated condition in otherwise normal children, but cranialfacial abnormalities, neuromuscular diseases, and obesity are also predisposing factors. Severe OSAS can have serious neurobehavioral and cardiorespiratory consequences including excessive daytime sleepiness, growth failure, school failure, behavioral problems, cor pulmonale, or even death. Diagnosis is based on data from the history, physical exam, and laboratory studies that confirm the presence and severity of the upper airway obstruction. Polysomnography has been the diagnostic tool of choice. Treatment depends on the severity of symptoms and the underlying anatomic and physiologic abnormalities. Since childhood OSAS is usually associated with adenotonsillar hypertrophy, the majority of cases are amenable to surgical treatment. However, there is increasing pediatric experience with CPAP therapy when tonsillectomy and adenoidectomy are either unsuccessful or inappropriate.

Use of nasal continuous positive airway pressure as treatment of childhood obstructive sleep apnea

OBJECTIVE

To determine the safety and efficacy of nasal continuous positive airway pressure (CPAP) for obstructive sleep apnea (OSA) during childhood and the effects of growth and maturation on CPAP requirements.

DESIGN

Retrospective study with use of a written questionnaire administered to pediatric practitioners treating sleep disorders.

SETTING

Nine academic pediatric sleep disorders centers.

RESULTS

Data were obtained for 94 patients. Three percent of patients receiving CPAP were less than 1 year, 29% were 1 to 5 years, 36% were 6 to 12 years, and 32% were 13 to 19 years of age; 64% were boys. The longest duration of CPAP use was 4 years. Indications for CPAP included OSA associated with obesity (27%), craniofacial anomalies (25%), idiopathic OSA persisting after adenoidectomy and tonsillectomy (17%), and trisomy 21 (13%). Continuous positive airway pressure was effective in 81 patients (86%), in one patient it was unsuccessful, and in 12 patients compliance was inadequate. The median pressure required was 8 cm H2O (range, 4 to 20 cm H2O); pressure requirements were independent of age or diagnosis. Twenty-two percent of patients eventually required a modification of CPAP levels. Complications of CPAP were minor. Sixty-four percent of centers reported difficulty in obtaining funding for CPAP.

CONCLUSIONS

Continuous positive airway pressure is safe, effective, and well tolerated by children and adolescents with OSA. Experience in infants is limited. As pressure requirements change with patient growth, we recommend that CPAP requirements be regularly reevaluated over time. The marked center-to-center variability in CPAP use suggests that specific indications for this therapy require clarification.

Cloning of neurotrimin defines a new subfamily of differentially expressed neural cell adhesion molecules

Previous studies in the laboratory indicated that glycosylphosphatidylinositol (GPI)-anchored proteins may generate diversity of the cell surface of different neuronal populations (Rosen et al., 1992). In this study, we have extended these findings and surveyed the expression of GPI-anchored proteins in the developing rat CNS. In addition to several well characterized GPI-anchored cell adhesion molecules (CAMs), we detected an unidentified broad band of 65 kDa that is the earliest and most abundantly expressed GPI-anchored species in the rat CNS. Purification of this protein band revealed that it is comprised of several related proteins that define a novel subfamily of immunoglobulin-like (Ig) CAMs. One of these proteins is the opiate binding-cell adhesion molecule (OBCAM). We have isolated a cDNA encoding a second member of this family, that we have termed neurotrimin, and present evidence for the existence of additional family members. Like OBCAM, with which it shares extensive sequence identity, neurotrimin contains three immunoglobulin-like domains. Both proteins are encoded by distinct genes that may be clustered on the proximal end of mouse chromosome 9. Characterization of the expression of neurotrimin and OBCAM in the developing CNS by in situ hybridization reveals that these proteins are differentially expressed during development. Neurotrimin is expressed at high levels in several developing projection systems: in neurons of the thalamus, subplate, and lower cortical laminae in the forebrain and in the pontine nucleus, cerebellar granule cells, and Purkinje cells in the hindbrain. Neurotrimin is also expressed at high levels in the olfactory bulb, neural retina, dorsal root ganglia, spinal cord, and in a graded distribution in the basal ganglia and hippocampus. OBCAM has a much more restricted distribution, being expressed at high levels principally in the cortical plate and hippocampus. These results suggest that these proteins, together with other members of this family, provide diversity to the surfaces of different neuronal populations that could be important in the specification of neuronal connectivity.

Severe hypoxemia in children with upper airway obstruction during sleep does not lead to significant changes in heart rate

Life-threatening cardiac arrhythmias, including bradyarrhythmias, are well-known sequelae of obstructive sleep apnea syndrome (OSAS) in adults and are associated with apnea and severe hypoxemia. Since the clinical expression of OSAS in children is different, we questioned whether arrhythmias are a common feature of pediatric OSAS. Therefore, we analyzed R-R interval patterns from 12 subjects (age 8 months to 14 years) with OSAS in detail. The diagnosis of pediatric OSAS is based on clinical signs of loud snoring and paradoxical respiratory efforts, as well as elevated end-tidal carbon dioxide tension (PETCO2) and major phasic decreases of oxyhemoglobin saturation (SaO2). Two hundred and nine episodes of severe hypoxemia, defined as SaO2 values < or = 85% lasting > or = 30 seconds, were identified. Only 29 (14%) of these episodes were associated with obstructive apneas. The R-R intervals were analyzed before and during each desaturation. Compared to baseline, mean and minimum R-R intervals (RRmean, RRmin) decreased during the desaturation episodes (P < 0.05), while maximum R-R interval (RRmax) increased (P < 0.05). Although the absolute changes in all parameters were significantly different from baseline, the magnitude of these changes was small, with a mean of -5.3%, -12.2%, and 10.4% for RRmean, RRmin, and RRmax, respectively. No child had life-threatening arrhythmias. Although severe hypoxemia existed in these children, the magnitude of the R-R interval changes was modest, and profound bradycardia as described in adults, was rare.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of acute hypoxia on metabolism and ventilation in awake piglets

We studied the effect of acute sustained hypoxia on ventilation (VE) and oxygen consumption (VO2) over one hour during quiet wakefulness in young (6 days) and older (6 weeks) piglets in thermoneutral conditions during baseline, moderate hypoxia (PaO2 approximately 45 mmHg), and severe hypoxia (PaO2 approximately 30 mmHg). During severe hypoxia, ventilation and pH increased while PaCO2 decreased in both age groups. Blood gas changes (decreases PACO2, increases pH), but not ventilatory changes, were greater in the older piglets (P < 0.05). VO2 decreased similarly (-30%) while VE/VO2 rose over 160% in both age groups. During moderate hypoxia, changes in blood gas, VE, and VO2 were in a similar direction, but smaller in magnitude. We conclude that: (1) changes in blood gases and VO2 are amplified by maturation and severity of hypoxia and (2) blood gas changes are greater in older vs young piglets despite similar ventilatory responses suggesting maturational differences in CO2 production or dead space ventilation.

Klippel-Feil sequence and sleep-disordered breathing in two children

We report two children with severe sleep-disordered breathing associated with Klippel-Feil sequence. In both patients, minor vertebral anomalies were associated with a major hindbrain anomaly. In one child, the Klippel-Feil sequence had been diagnosed previously, but the hindbrain anomaly was not recognized. Two years later, this child developed fatal obstructive sleep apnea. In the other child, neither the Klippel-Feil sequence nor hindbrain anomaly had been identified before the child's presentation with sleep-disordered breathing characterized by bradypnea and stridor. Because many of the complications of hindbrain anomalies may be amenable to neurosurgical treatment, we recommend that patients with Klippel-Feil sequence be followed for the development of sleep-disordered breathing. Sleep complaints need prompt evaluation with polysomnography, whereas neurologic signs require imaging with attention to the cervicomedullary junction. Unsuspected CNS disorders must be considered in children who present with stridor or serious respiratory disturbances during sleep.

Adult criteria for obstructive sleep apnea do not identify children with serious obstruction

Although obstructive sleep apnea (OSA) occurs in the pediatric population, diagnostic criteria have not been established. Since criteria for adult OSA are well established, we asked whether commonly used adult criteria, such as the apnea index (based on the number of obstructive apnea [OA] events per hour), would identify children with serious sleep-related upper airway obstruction. Polysomnographic data were analyzed from 20 children (ages 8 months to 16 yr) with clinical evidence of upper airway obstruction during sleep (loud snoring and labored breathing) and who had cyclic oscillations of oxyhemoglobin saturation (SaO2) during sleep. The overnight studies included sleep state (EEG, EOG, and EMG), SaO2, ECG, nasal (end-tidal CO2) and oral (thermistor) airflow, chest and abdominal movement (inductance plethysmography), and video camera and behavioral observations. Measurements included the number of obstructive events > or = 10 s, the number of desaturations (> or = 5% decrease lasting > or = 5 s), the number of desaturation episodes to < 90%, < 85%, and < 80% lasting > 5 s, and the percentage of sleep time with SaO2 values < 90%. Gas exchange was impaired as evidenced by cyclic decreases in SaO2 and elevated PETCO2 values (maximum value 58 +/- 6 mm Hg). The children experienced 175 +/- 168 (range 6 to 609) episodes of decreased SaO2 > 5%, with an average minimum SaO2 of 66 +/- 13% (range 30 to 85%). The average number of apnea events was only 1.9 +/- 3.2 events/h (range 0 to 10.4).(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of unique sets of GPI-linked proteins by different primary neurons in vitro

We have surveyed the proteins expressed at the surface of different primary neurons as a first step in elucidating how axons regulate their ensheathment by glial cells. We characterized the surface proteins of dorsal root ganglion neurons, superior cervical ganglion neurons, and cerebellar granule cells which are myelinated, ensheathed but unmyelinated, and unensheathed, respectively. We found that the most abundant proteins are common to all three types of neurons. Reproducible differences in the composition of the integral membrane proteins (enriched by partitioning into a Triton X-114 detergent phase) were detected. These differences were most striking when the expression of glycosylphosphatidyl-inositol (GPI)-anchored membrane proteins by these different neurons was compared. Variations in the relative abundance and degree of glycosylation of several well known GPI- anchored proteins, including Thy-1, F3/F11, and the 120-kD form of the neural cell adhesion molecule (N-CAM), and an abundant 60-kD GPI-linked protein were observed. In addition, we have identified several potentially novel GPI-anchored glycoproteins on each class of neurons. These include a protein that is present only on superior cervical ganglion neurons and is 90 kD; an abundant protein of 69 kD that is essentially restricted in its expression to dorsal root ganglion neurons; and proteins of 38 and 31 kD that are expressed only on granule cell neurons. Finally, the relative abundance of the three major isoforms of N-CAM was found to vary significantly between these different primary neurons. These results are the first demonstration that nerve fibers with diverse ensheathment fates differ significantly in the composition of their surface proteins and suggest an important role for GPI-anchored proteins in generating diversity of the neuronal cell surface.

Myelin formation following transplantation of normal fetal glia into myelin-deficient rat spinal cord

Structurally normal myelin sheaths develop in the spinal cord of juvenile myelin-deficient rats (mdr) 11 days after transplantation of normal fetal spinal cord fragments or cultured cells that do not yet express galactocerebroside. Cultures result in more extensive myelin formation, and in both cases the myelin that forms is located primarily at or near the site of transplantation. Myelin formation also occurs after transplantation of postnatal donor tissue, but the extent diminishes with donor age, and none was seen after transplantation of adult donor tissue over the two-week period studied. Injection of killed tissue, tissue derived from mouse donors or an extract of myelin also did not lead to myelin formation. The results imply that myelin formed in the host following transplantation was generated by oligodendrocytes newly differentiated from donor precursor cells rather than by donor oligodendrocytes that were already mature at the time of transplantation or by host oligodendrocytes that took up components of the injected material. We conclude that exogenous fetal glial cell precursors are able to survive, differentiate and form myelin in the environment of the juvenile mdr spinal cord.

Type 1 astrocytes inhibit myelination by adult rat oligodendrocytes in vitro

We have determined the effect of Type 1 astrocytes on the myelination of dorsal root ganglion cell axons by oligodendrocytes obtained from adult animals. Experiments were initiated by the addition of oligodendrocytes [purified either by density gradient centrifugation and treatment in culture with 5-fluorodeoxyuridine (FdU) or by fluorescence-activated cell sorting after immunostaining with antigalactocerebroside antibody] to cultures of purified neurons. In control conditions, the added oligodendrocytes proliferate and, after 4 weeks, accomplish substantial myelination of the sensory axons. Type 1 astrocytes (purified from cultures of dissociated newborn rat cerebral cortex by vigorous shaking to remove less adherent cells) or fibroblasts (purified from cultures of cranial periosteum by serial replating) were added to some of these cultures after the oligodendrocytes had attached and started to proliferate. We observed that the added Type 1 astrocytes, but not the added fibroblasts, strongly inhibited myelination and caused decreased oligodendrocyte proliferation or survival. These effects of added Type 1 astrocytes were reproduced with Type 1 astrocyte-conditioned medium. We conclude that Type 1 astrocytes can release soluble factors that inhibit oligodendrocyte myelination.

Effect of enkephalins on cardiac output and regional blood flow in conscious dogs

Page H1656: C. L. Rosen, A. Cote, and G. G. Haddad. “Effect of enkephalins on cardiac output and regional blood flow in conscious dogs.” Figures 5 and 6 should appear as follows.

(See PDF)

Effect of enkephalins on cardiac output and regional blood flow in conscious dogs

Page H1656: C. L. Rosen, A. Cote, and G. G. Haddad. “Effect of enkephalins on cardiac output and regional blood flow in conscious dogs.” Figures 5 and 6 should appear as follows.

(See PDF)

Plasma beta-casomorphin-7 immunoreactive peptide increases after milk intake in newborn but not in adult dogs

To determine the relation between milk intake and plasma levels of beta-casomorphins as a function of age, we studied the levels of beta-casomorphin-7 immunoreactive material (BCMIR) in 2- and 4-wk-old beagle neonates and adult dogs following milk intake. We used three kinds of milk: 1) bovine casein-based milk formula; 2) canine bitch's milk, and 3) soy protein-based (noncasein) formula. Using a new extraction technique, BCMIR was isolated from plasma and assayed by radioimmunoassay at 0, 2, 4, and 6 h after feeding. We found that BCMIR increased significantly in both 2- and 4-wk-old puppies post bovine and canine milk feeding, but not after soy protein formula. Base-line values were about 80-120 fmol/ml and increased to 100-120% 2 h after bovine casein intake in the older puppies and by 4 h in the younger group. BCMIR levels were undetectable in adult dogs before or after bovine milk feeding. Beta-casomorphin-7 added to plasma was rapidly degraded whereas BCMIR was stable. Chromatographic profiles demonstrated that the BCMIR moiety is larger than beta-casomorphin-7. Our data suggest that the appearance of BCMIR in the plasma of neonatal dogs is a result of beta-casein degradation along a permeable gastrointestinal mucosa. We speculate that morphiceptin and beta-casomorphins can be cleaved from BCMIR and may have important physiologic effects.

Effect of enkephalins on cardiac output and regional blood flow in conscious dogs

To investigate the effects of enkephalins on cardiac output and regional blood flow, we administered D-Ala-D-Leu-enkephalin (DADLE) intracisternally (ic) to 14 chronically instrumented unanesthetized dogs. Measurements were made at base line, 20, 45, and 75 min after DADLE (25 or 125 micrograms/kg) and 15 min after naloxone (5 micrograms/kg ic). After 125 micrograms/kg DADLE, all animals developed hypoventilation, bradycardia, and decreased O2 consumption without hypotension. Cardiac output decreased (-34%), but brain blood flow increased (+110%). Blood flow decreased to the diaphragm (-38%), heart (-21%), skeletal muscle (-40%), skin (-67%), pancreas (-79%), and gastrointestinal tract (-26%). After 25 micrograms/kg DADLE, there were no consistent changes in cardiac output or regional blood flow. Four additional animals (without DADLE) were exposed to altered inspired gases to reproduce the blood gas changes after DADLE. These animals developed hyperventilation without bradycardia and increased brain (+114%) and diaphragm (+649%) blood flow. We conclude that centrally administered enkephalins produce 1) a parallel decrease in ventilation, heart rate, O2 consumption, and cardiac output and 2) a major blood flow redistribution, primarily dictated by the effects of opioids on ventilation, heart rate, and metabolism.

Home monitor follow-up of persistent apnea and bradycardia in preterm infants

We reviewed our experience with home monitor observations of 83 preterm infants (postconceptional age, 36 to 44 weeks) who had persistent apnea, bradycardia, or cyanosis. Polygraphic recordings before discharge showed that 92% of these infants had cardiorespiratory abnormalities that included prolonged (greater than 20 s) apnea, excessive periodic breathing (greater than 15%), bradycardia (greater than 80 beats per minute), feeding hypoxemia, or elevated carbon dioxide values. At home, 70 infants had either no alarms or alarms that resolved spontaneously, while 13 (16%) had more serious episodes that required parental intervention, including mouth-to-mouth ventilation in one infant. While polygraphic studies were helpful in documenting specific cardiorespiratory abnormalities, neither these abnormalities nor the clinical characteristics of the infants identified those infants experiencing subsequent home monitor alarms requiring parental intervention. Our data suggest that some preterm infants with persistent episodes of apnea, bradycardia, and cyanosis beyond 36 weeks of postconceptional age remain at risk for future serious episodes for several months.

Home negative pressure ventilation: report of 20 years of experience in patients with neuromuscular disease

Twenty years of experience using negative pressure devices (NPD) at home to ventilate 40 patients with neuromuscular disease is presented. The purpose of the study was to determine the costs, complications, and clinical outcome of this form of respiratory support, and to ascertain the reasons for failure to institute effective negative pressure ventilation (NPV) in nine patients. Emerson tank respirators, used mainly to rest respiratory muscles at night, and intermittent positive pressure breathing machines were used by 98% of patients at an average equipment cost of +2,700 annually. Patients in whom NPV was initiated on an elective rather than emergent basis saved an average of +12,000 during their initial hospitalization. Life table analysis shows a five-year survival of 76%, and a 10-year survival of 61%. Complications were minor and occurred at an average rate of less than one per year per patient at home on NPV. Failure to achieve satisfactory NPV in nine patients was associated with age (six patients were younger than 3 years of age), or severe thoracocervical scoliosis, which prevented proper fitting of the NPD. For reasons of safety, economy, and quality of life, NPV at home is the preferred treatment for patients having neuromuscular disease who need respiratory assistance.

Hypoxemia associated with feeding in the preterm infant and full-term neonate

Polygraphic monitoring studies were performed on more than 150 older preterm infants (postconceptional ages of 36 weeks or more) and full-term neonates to evaluate unexplained or persistent apnea. During polygraphic monitoring, 16 infants were observed to have hypoxemia associated with feedings. The feeding hypoxemia was accompanied by irregular respiratory effort and preceded any associated bradycardia. A comparison group of eight infants with similar gestational and postconceptional ages, but without feeding hypoxemia, was selected retrospectively from other infants referred for evaluation of persistent or unexplained apnea. The group with feeding hypoxemia showed evidence of CNS compromise as manifested by significant elevations of the maximum end-tidal carbon dioxide pressure during sleep and abnormal computed tomograms (7/11 v 0/5 in the comparison group). There was no relationship between feeding hypoxemia and sleep apnea or gastroesophageal reflux. Clinical follow-up showed that the feeding hypoxemia resolved with maturation.

Two siblings with recurrent cardiorespiratory arrest: Munchausen syndrome by proxy or child abuse?

The terms "Munchausen syndrome by proxy" or "Polle syndrome" have been used to describe children who are victims of parentally induced or fabricated illness. This report gives case histories of two siblings (a 7-month-old girl and a 4-year-old boy) with recurrent episodes of cardiorespiratory arrest that were induced by a mother who skillfully resuscitated the children and who demonstrated model parental behavior. Polygraphic monitoring with hidden camera was used to determine that the episodes of cardiorespiratory arrest were parentally induced in the infant. The 4-year-old sibling had previously undergone multiple diagnostic and surgical procedures. After the diagnosis was made in the infant, and the mother was no longer permitted to be alone with the children, neither child had further episodes. A psychologic profile of the mother is presented, and special features of these two and other cases in the literature are reviewed. These cases represent a form of child abuse. A parentally induced illness should be considered in the differential diagnosis of unusual illnesses with bizarre features, even when the parent's behavior appears exemplary.

Infant apnea: polygraphic studies and follow-up monitoring

Twenty-six infants with unexplained and apparently life-threatening apnea were evaluated clinically, underwent eight- or 12-hour polygraphic recordings during sleep, and were then observed on home monitors. The one exception was an infant who was treated with theophylline and not monitored at home. Clinical evaluation revealed a history of vomiting in 19 infants, gastroesophageal reflux (GER) on esophagram in 19, and subtle neurologic abnormalities in ten. Polygraphic studies revealed questionable EEG abnormalities in nine infants, abnormal rapid eye movement (REM) time in four, prolonged apnea in one, and increased frequency of brief mixed (central and obstructive) and obstructive apneas in five. Of the 11 infants who underwent pH monitoring during their polygraphic sleep studies, seven had at least one recorded episode of GER, but the episodes were not accompanied by apnea or bradycardia. Thirteen infants had a subsequent episode of apnea that required stimulation, and in eight infants, cardiopulmonary resuscitation was given. There was two deaths. Two infants subsequently developed seizure disorders. Three of the five infants who underwent surgical fundoplication had recurrent apneic episodes. GER commonly occurred in these infant apnea patients but did not correlate with the clinical outcome. Although subtle abnormalities may be detected by sophisticated polygraphic monitoring studies, they are not predictive of recurrent apnea or death. Home monitoring may be useful in detecting the infant at risk for recurrent life-threatening apnea and in providing some safeguard for that infant.

An experimental study of visual perceptual training and reading achievement in first grade

To determine the effects of perceptual training upon selected measures of reading achievement in first grade, 12 experimental classrooms received a 29-day adaptation of the Frostig program for the development of visual perception while 13 control classrooms added comparable time to regular reading instruction. Analysis of the data revealed significant differences between treatment groups in certain post-training perceptual capabilities without concomitant effects on dependent measures. Additional findings strongly suggest need for further research.