Apnea events in neonatal age: A case report and literature review.

BACKGROUND: Among the most common autonomic signs visible in preterm neonates, apnea can represent the first sign of several neurologic and non-neurologic disorders, and seizure is a relatively infrequent cause. Herein authors present a case of neonatal autonomic apnea, discussing the polygraphic video-EEG features of this pathological entity and the differential diagnosis with central apnea and autonomic apnea. CASE REPORT: A female preterm Caucasian infant (29 + 4 weeks' gestational age (GA)), first twin of a twin pregnancy, at birth was intubated and surfactant administration was performed. She was ventilated via invasive ventilation for three days, with subsequent weaning with non-invasive ventilation for other two days, when she stopped requiring any ventilator support. After one week the ventilation weaning, the child presented episodes of cyanosis associated with sudden oxygen desaturation, skin pallor, apnea, and bradycardia. Therefore, the child underwent a continuous video-eeg recording with polygraphic study. The exam showed the presence of apneic episodes with an abrupt and clear start, associated with oxygen desaturation at 70%, with minimal thoracic effort at onset, and then evolving into central apnea. Central apnea lasted about 16 s and presented clear start- and end-points. These episodes were also associated with suppression of the EEG trace in frequency and amplitude, and after about 10 s of central apnea an abrupt decrease of the child's heart rate (more than 50% variation, from 160 bpm to 65 bpm) was recorded. In the suspect of epileptic apneas of autonomic origin, a therapy with oral Levetiracetam, at a starting dose of 10 mg/Kg/day, then increased up to 40 mg/Kg/day, was initiated, and after about 48 h the first administration of the anticonvulsant therapy, no new episodes of cyanosis or electrical apneas were recorded. HYPOTHESIS: Herein the authors suggest to consider the diagnosis of autonomic seizures in those neonates with apneic events associated with EEG suppression. Considering that apnea events are not only present in preterm infants but also in term neonates, it is mandatory to diagnose in this context neonatal seizures for a correct diagnosis and a proper therapeutic choice.

A new simple efficient classification technique for severity of sleep apnea with mathematical model and interpretation.

BACKGROUND: Obstructive Sleep Apnea (OSA) is the cessation of breathing during sleep due to the collapse of the upper airway. Polysomnographic recording is a conventional method for detection of OSA. Although it provides reliable results, it is expensive and cumbersome. Thus, an advanced non-invasive heart rate variability (HRV) signal processing technique other than the standard spectral analysis, which also has efficiency limitations, is needed for identification of OSA and classification of apnea levels. OBJECTIVE: The main purpose of this work was to predict the severity of sleep apnea using an efficient method based on the combination of time-domain and frequency-domain analysis of the HRV to classify sleep apnea into three different levels (mild, moderate, and severe) according to its severity and to distinguish them from normal subjects. METHODS: The statistical signal characterization of the FFT-based spectrum of the RRI data is used in this work in order to rank patients to full polysomnography. Data of 20 normal subjects, 20 patients with mild apnea, 20 patients with moderate apnea and 20 patients with severe apnea were used in this study. RESULTS: Accuracy result of 100% was obtained between severe and normal subjects, 100% between mild and normal subjects, and 100% between apnea (mild, moderate, severe) and normal subjects. This perfect accuracy is obtained using the parameter mean (mt). The physiological interpretation of the SSC parameters has been derived using a mathematical model system. CONCLUSIONS: An efficient method for screening of sleep apnea with 100% efficiency in classification of sleep apnea levels, is investigated in this work.

Apnoea and hypopnoea scoring for people with spinal cord injury: new thresholds for sleep disordered breathing diagnosis and severity classification.

STUDY DESIGN: Descriptive study. OBJECTIVES: To determine the effect of respiratory event rule-set changes on the apnoea hypopnoea index, and diagnostic and severity thresholds in people with acute and chronic spinal cord injury. SETTING: Eleven acute spinal cord injury inpatient hospitals across Australia, New Zealand, Canada and England; community dwelling chronic spinal cord injury patients in their own homes. METHODS: Polysomnography of people with acute (n = 24) and chronic (n = 78) tetraplegia were reanalysed from 1999 American Academy of Sleep Medicine (AASM) respiratory scoring, to 2007 AASM 'alternative' and 2012 AASM respectively. Equivalent cut points for published 1999 AASM sleep disordered breathing severity ranges were calculated using receiver operator curves, and results presented alongside analyses from the able-bodied. RESULTS: In people with tetraplegia, shift from 1999 AASM to 2007 AASM 'alternative' resulted in a 22% lower apnoea hypopnoea index, and to 2012 AASM a 17% lower index. In people with tetraplegia, equivalent cut-points for 1999 AASM severities of 5,15 and 30 were calculated at 2.4, 8.1 and 16.3 for 2007 AASM 'alternative' and 3.2, 10.0 and 21.2 for 2012 AASM. CONCLUSION: Interpreting research, prevalence and clinical polysomnography results conducted over different periods requires knowledge of the relationship between different rule-sets, and appropriate thresholds for diagnosis of disease. SPONSORSHIP: This project was proudly supported by the Traffic Accident Commission (Program grant) and the National Health and Medical Research Council (PhD stipend 616605).

Classifying Apnea of Prematurity by Transcutaneous Electromyography of the Diaphragm.

BACKGROUND: Treatment of apnea is highly dependent on the type of apnea. Chest impedance (CI) has inaccuracies in monitoring respiration, which compromises accurate apnea classification. Electrical activity of the diaphragm measured by transcutaneous electromyography (EMG) is feasible in preterm infants and might improve the accuracy of apnea classification. OBJECTIVES: To compare the accuracy of apnea classification based on diaphragmatic EMG (dEMG) and CI tracings in preterm infants. METHODS: Fifteen cases of central apnea, 5 of obstructive apnea, and 10 of mixed apnea were selected from recordings containing synchronized continuous tracings of respiratory inductive plethysmography (RIP), airway flow, heart rate (HR), oxygen saturation (SpO2), and breathing activity measured by dEMG and CI. Twenty-two assessors (neonatologists, pediatricians-in-training, and nurses) classified each apnea twice; once based on dEMG, HR, and SpO2 tracings, and once based on CI, HR, and SpO2. The assessors were blinded to the type of respiratory tracing (dEMG or CI) and to the RIP and flow tracings. RESULTS: In total 1,320 assessments were performed, and in 71.1% the apnea was classified correctly. Subgroup analysis based on respiratory tracing showed that 74.8% of the dEMG tracings were classified correctly compared to 67.3% of the CI tracings (p < 0.001). This improved apnea classification based on dEMG was present for central (86.7 vs. 80.3%, p < 0.02) and obstructive (56.4 vs. 32.7%, p < 0.001) apnea. The improved apnea classification based on dEMG tracing was independent of the type of assessor. CONCLUSION: Transcutaneous dEMG improves the accuracy of apnea classification when compared to CI in preterm infants, making this technique a promising candidate for future monitoring systems.

Does the Kushida morphometric model predict outcomes following maxillomandibular advancement surgery for obstructive sleep apnoea?

OBJECTIVE: The primary aim of this study was to explore the predictive potential of the preoperative Kushida index score and subsequent outcome following maxillomandibular advancement surgery (MMA). Secondarily we looked at how well the Kushida values of our OSA patients matched the morphometric models diagnostic thresholds. METHODS: We performed a retrospective analysis of patients who underwent MMA for OSA at our institution. Kushida morphometric scores were calculated using the described formula: P + (Mx - Mn) + 3 × OJ + 3 × [Max (BMI - 25)] × (NC ÷ BMI). Regression analysis was performed to explore the possible association between Kushida index score and outcome variables of postoperative apnoea/hypopnea indices (AHI) and Epworth Sleepiness Scores (ESS). RESULTS: We identified 28 patients with complete data available for analysis. The mean age was 45 years (SD 6) with mean BMI of 28 (SD 3). All, but one patient underwent bi-maxillary procedure with or without genioplasty, with a mean advancement of 8.5 mm (SD 2). The mean Kushida index score in our sample was 79 (SD 14). 89% of patients had postoperative AHI <15 in keeping with surgical success. We found no statistically significant relationship with Kushida morphometric model variables and overall score with either of our outcome variables. CONCLUSION: The mean Kushida index score in our patients was in the range consistent with the morphometric models diagnostic cut-off for OSA. Kushida's morphometric model does not appear to be a good predictor of postoperative success in individuals following MMA. The morphometric model represents a clinical adjunct in the initial diagnostic work-up of OSA patients referred for surgery.

Apneas e infecciones en lactantes / Apnea and infections in infants

Infections are a frequent cause of apnea in infants, involving both respiratory and extrarrespiratory systems. In the first group we find upper respiratory infections and lower respiratory infections caused by virus or bacteria such as Respiratory Syncytial Virus, Parainfluenza and Bordetella pertussis; in the second group urinary tract infections and severe infections such as meningitis and sepsis are of importance. In this article we analyze different causes of infections attributed to apnea, taking into account existing literature at the time.

Las infecciones son una frecuente causa de apneas en lactantes, pudiendo involucrar tanto el sistema respiratorio como extrarrespiratorio. En el primero encontramos las infecciones respiratorias altas y/o bajas producidas tanto por virus como bacterias, donde destacan Virus Respiratorio Sincicial, Parainfluenza y Bordetella Pertussis; en el segundo grupo son de importancia la infección urinaria e infecciones graves como meningitis y sepsis. En este artículo se analizan estas distintas causas infecciosas atribuidas a eventos de apneas en lactantes, en consideración a la literatura actualmente existente.

Neonatal apnoea.

Premature infants have immature respiratory control that predisposes them to apnoea, haemoglobin oxygen desaturation and bradycardia. Apnoeas are loosely classified, according to the presence or absence of respiratory effort, into central, obstructive or mixed. There are a variety of conditions, in the perioperative period, that predispose an infant to apnoea, including: central nervous system (CNS) lesions, infections and sepsis, ambient temperature fluctuations, cardiac abnormalities, metabolic derangements, anaemia, upper airway structural abnormalities, necrotising enterocolitis, drug administration (including opiates and general anaesthetics) and possibly gastro-oesophageal reflux. Various monitoring techniques are discussed; the mainstay are pulse oximetry and abdominal-pressure transduction. There is some evidence of both short- and long-term complications of repeated apnoeas in the neonatal period, but the causal relationship is difficult to establish. Continuous positive airway pressure and caffeine therapy (up to 10 mg kg(-1)) are the most common treatments of neonatal apnoea. The less soluble volatile agents and regional anaesthetic techniques (without concurrent sedation) are associated with a lower incident of postoperative apnoea.

Mallampati class is not useful in the clinical assessment of sleep clinic patients.

STUDY OBJECTIVES: To assess the utility of Mallampati class, a simple grade of oropharyngeal appearance used to assess difficulty of intubation, to predict severe obstructive sleep apnea and absence of OSA (rule in severe OSA and rule out OSA). METHOD: Retrospective review of consecutive patients undergoing diagnostic polysomnography in a tertiary referral sleep disorders center. Modified Mallampati class and other simple patient characteristics (age, gender, body mass index) were compared to apnea-hypopnea index (AHI). The sensitivity, specificity, and the positive and negative likelihood ratios (LR+ and LR-) were calculated for Mallampati class IV to detect an AHI > 30 (rule in severe OSA) and Mallampati class I to detect an AHI < 5 (rule out OSA). RESULTS: A total of 953 consecutive patients (619 male) undergoing diagnostic polysomnography were included. The age of the cohort was 50.0 ± 6.4 years, with a BMI of 33.8 ± 8.6 kg/m² and AHI of 26.1 ± 25.1 /h (95% CI 1.4-78.8). Mallampati class was significantly associated with AHI (r = 0.13, p < 0.001), but there were no differences in AHI between Mallampati classes. A Mallampati class IV had a sensitivity of 40%, specificity of 67%, LR+ of 1.21, and LR- of 0.90 for an AHI > 30. A Mallampati class I was only 13% sensitive but 92% specific for an AHI < 5, with LR+ of 1.63 and LR- 0.90. CONCLUSIONS: Mallampati class is associated with AHI but does not significantly modify likelihood of severe OSA or absence of OSA. As such, it is of limited use to "rule in" severe OSA or "rule out OSA" in the sleep clinic population.

Sleep-disordered breathing and cardiovascular disease: an outcome-based definition of hypopneas.

RATIONALE: Epidemiologic studies on the consequences of sleep-disordered breathing invariably use the apnea-hypopnea index as the primary measure of disease severity. Although hypopneas constitute a majority of disordered breathing events, significant controversy remains about the best criteria used to define these events. OBJECTIVES: The current investigation sought to assess the most appropriate definition for hypopneas that would be best correlated with cardiovascular disease. METHODS: A community sample of middle-aged and older adults was recruited as part of the Sleep Heart Health Study. Full-montage polysomnography was conducted and hypopneas were defined using different thresholds of oxyhemoglobin desaturation with and without arousals. Prevalent cardiovascular disease was assessed based on self-report. Logistic regression analysis was used to characterize the independent association between the hypopnea index and prevalent cardiovascular disease. MEASUREMENTS AND MAIN RESULTS: Using a sample of 6,106 adults with complete data on cardiovascular disease status and polysomnography, the current study found that hypopneas associated with an oxyhemoglobin desaturation of 4% or more were associated with prevalent cardiovascular disease independent of confounding covariates. The adjusted prevalent odds ratios for quartiles of the hypopnea index using a 4% desaturation criterion were as follows: 1.00 (<1.10 events/h), 1.10 (1.01-3.20 events/h), 1.33 (3.21-7.69 events/h), and 1.41 (>7.69 events/h). Hypopnea measures based on less than 4% oxyhemoglobin desaturation or presence of arousals showed no association with cardiovascular disease. CONCLUSIONS: Hypopneas comprise a significant component of sleep-disordered breathing in the general community. By varying the criteria for defining hypopneas, this study demonstrates that hypopneas with a desaturation of at least 4% are independently associated with cardiovascular disease. In contrast, no association was observed between cardiovascular disease and hypopneas associated with milder desaturations or arousals.

Automatic classification of activity and apneas using whole body plethysmography in newborn mice.

An increasing number of studies in newborn mice are being performed to determine the mechanisms of sleep apnea, which is the hallmark of early breathing disorders. Whole body plethysmography is the method of choice, as it does not require immobilization, which affects behavioral states and breathing. However, activity inside the plethysmograph may disturb the respiratory signal. Visual classification of the respiratory signal into ventilatory activity, activity-related disturbances, or apneas is so time-consuming as to considerably hamper the phenotyping of large pup samples. We propose an automatic classification of activity based on respiratory disturbances and of apneas based on spectral analysis. This method was validated in newborn mice on the day of birth and on postnatal days 2, 5, and 10, under normoxic and hypoxic (5% O(2)) conditions. For both activity and apneas, visual and automatic scores showed high Pearson's correlation coefficients (0.92 and 0.98, respectively) and high intraclass correlation coefficients (0.96-0.99), supporting strong agreement between the two methods. The present results suggest that breathing disturbances may provide a valid indirect index of activity in freely moving newborn mice and that automatic apnea classification based on spectral analysis may be efficient in terms of precision and of time saved.

Classification and definition of respiratory disorders during sleep.

Growing interest in sleep disorders has led to increased research in this direction. Increasingly sophisticated instrumental tests have disclosed new breathing patterns and complex syndromes. The initial identification of obstructive apneas was followed by studies characterizing snoring, hypopneas, respiratory effort-related arousal and flow limitation events. Since Pickwickian syndrome, an historical term currently deemed obsolete and confusing, sleep investigations have differentiated secondary hypoventilation, central hypoventilation and syndromes resulting from narrowing of the upper airways (snoring, upper airway resistance syndrome, obstructive sleep apnea-hypopnea syndrome). Inevitably, this has given rise to some confusion in the classification of events and syndromes which recent studies have attempted to clarify.

Apnea, sudden infant death syndrome, and home monitoring.

More than 25 years have elapsed since continuous cardiorespiratory monitoring at home was suggested to decrease the risk of sudden infant death syndrome (SIDS). In the ensuing interval, multiple studies have been unable to establish the alleged efficacy of its use. In this statement, the most recent research information concerning extreme limits for a prolonged course of apnea of prematurity is reviewed. Recommendations regarding the appropriate use of home cardiorespiratory monitoring after hospital discharge emphasize limiting use to specific clinical indications for a predetermined period, using only monitors equipped with an event recorder, and counseling parents that monitor use does not prevent sudden, unexpected death in all circumstances. The continued implementation of proven SIDS prevention measures is encouraged.

[SIDS and polygraphy]. / SIDS und Polygraphie.

The description of an association between central apneas and the sudden infant death syndrome (SIDS) by Steinschneider et al. in 1972 was followed by a sharp rise of polygraphic studies. The hope to use these as a screening method for an increased risk of SIDS could subsequently not be confirmed by prospective studies. Pathological alterations, such as obstructive apneas and hypoxemias, however, seem to have prognostical relevance. They thus represent a focus of current research even though being unable as well to reliably predict a predisposition to SIDS for an individual subject. Instead of being used as a diagnostic tool for SIDS, polygraphic studies have nowadays acquired an accepted role in the investigation of certain physical symptoms and signs such as unexplained 'apparent life threatening events' (ALTE) or cyanotic attacks. Basic technical requirements for a polygraphic laboratory include facilities to record thoracic/abdominal respiration, nasal air flow, ECG/heart rate, oxygen saturation, and to classify different stages of sleep. Registration of additional parameters (EEG, breath sounds, video etc.) is optional, but may prove helpful to arrive at an appropriate diagnosis. Recently, Austrian and German centres have been trying in cooperation to standardize performance conditions and evaluation criteria for polygraphic measurements in pediatric patients under the guidance of the German Association for Sleep Medicine, Pediatric Workgroup. Their aim is to establish common guidelines for the diagnosis and treatment of sleep and arousal disorders in infancy and childhood.

Diagnóstico del síndrome de apnea obstructiva del sueño

El síndrome de Apnea Obstructiva del Sueño (SAOS) constituye la causa más frecuente de excesiva somnolencia diurna. Es necesario un diagnóstico de sospecha precoz basado en la sintomatología clínica, para derivar al paciente a una Unidad de Sueño especializada. En dicha unidad se le realizará una valoración clínica y, en el caso de que esté indicado, una polisomnografía nocturna completa. La polisomnografía nocturna es la prueba más sensible y específica para el diagnóstico del SAOS (AU)

Cephalometric characteristics of nonobese patients with severe OSA.

The purpose of this study was to determine the facial characteristics of nonobese patients with obstructive sleep apnea (OSA). Observational data on a cohort of patients was analyzed retrospectively. The subjects were classified into four groups: nonobese mild, obese mild, nonobese severe, and obese severe. The nonobese mild group included patients with a body mass index (BMI = kilogram/meter2) <25 and an apnea-hypopnea index (AHI) >5 and <15; the obese mild patients had a BMI >35 and an AHI >5 and <15; the nonobese severe patients had a BMI <25 and an AHI >40; the obese severe group had a BMI >35 and AHI >40. Thirty-three male patients referred for overnight polysomnography and lateral cephalometry who met the selection criteria were included. Between-group differences were examined pairwise by analysis of variance (ANOVA) with Bonferroni correction. Only two variables--lower facial height and overbite--were significantly different at p<0.05 between the nonobese severe group and the obese mild group. A discriminant analysis on the cephalometric measurements revealed that patients in the nonobese severe group could be distinguished from patients in other groups by their facial characteristics. OSA patients do not have a homogenous bony structure of the face. In particular, OSA severity in nonobese severe patients may be associated with a vertical skeletal disharmony.