The use of DCEEG to estimate functional and metabolic state of nervous tissue of the brain at hyper- and hypoventilation

A pilot study has been made of the simultaneous DC potential and total slow electrical activity changes during modeling various metabolic and functional states of the human brain. The multi-electrode DCEEG recordings have been performed during the hyperventilation (frequent deep one-minute long breathing motions) and the hypoventilation (voluntary breath holding). It has been shown that the ischemic state occurring in hyperventilation is accompanied by the negative shift of DC potential and increase in the EEG rhythms amplitude. A distention of brain vessels during hypoventilation (voluntary breath-hold) and an improvement of blood supply and thus improvement of vital and functional state of neurons gave rise to an increase in the EEG rhythm amplitude too, though against a background of a positive DC-potential shift. Obtained results are considered with context the generation of the qualitatively different functional states of brain cells during hyper- and hypoventilation which is reflected in their resting potential and activity. The conducted study show the prospects for DCEEG and the method we used for DCEEG data processing to understand the character of functional and metabolic changes in the nervous tissue.

Risk factors and management countermeasures for obstructive sleep apnea hypoventilation syndrome in children

BACKGROUND Obstructive sleep apnea hypoventilation syndrome(OSAHS)in children is a sleep respiratory disorder characterized by a series of pathophysiologic changes.Statistics in recent years have demonstrated an increasing yearly incidence.AIM To investigate the risk factors for OSAHS in children and propose appropriate management measures.METHODS This study had a case–control study design.Altogether,85 children with OSAHS comprised the case group,and healthy children of the same age and sex were matched at 1:1 as the control group.Basic information,including age,sex,height,weight and family history,and medical history data of all study participants were collected.Polysomnography was used to detect at least 8 h of nocturnal sleep.All participants were clinically examined for the presence of adenoids,enlarged tonsils,sinusitis,and rhinitis.RESULTS The analysis of variance revealed that the case group had a higher proportion of factors such as adenoid grading,tonsil indexing,sinusitis,and rhinitis than the control group.CONCLUSION A regression model was established,and glandular pattern grading,tonsil indexing,sinusitis,and pharyngitis were identified as independent risk factors affecting OSAHS development.

Pulmonary hypertension and chronic hypoventilation in ROHHAD syndrome treated with average-volume assured pressure support

Introduction:Rapid-onset obesity with hypothalamic dysfunction,hypoventilation,and autonomic dysregulation(ROHHAD)syndrome is an exceptionally rare clinical entity with significant morbidity and high mortality with challenging-to-treat hypoventilation.Case presentation:An 11-year-old morbidly obese Chinese female presented with a putative diagnosis of ROHHAD associated with a left psoas ganglioneuroma.Initial polysomnography showed severe obstructive sleep apnea and hypoventilation.She was not adherent to prescribed non-invasive positive pressure ventilation(NIPPV).Echocardiography demonstrated evidence of pulmonary hypertension,likely secondary to chronic hypoventilation.With behavioral modification and trial of average volume-assured pressure support(AVAPS),adherence improved with eventual improvement of her pulmonary hypertension.Conclusion:AVAPS may improve ventilation and NIPPV adherence in central hypoventilation disorders such as ROHHAD,reducing risk of morbidity and mortality.

Noninvasive ventilation in a young infant with congenital central hypoventilation and 7-year follow-up

Introduction:Congenital central hypoventilation syndrome(CCHS)is a rare disorder characterized by alveolar hypoventilation and autonomic system dysregulation secondary to mutations of the PHOX2B gene.Treatment consists of assisted ventilation using positive-pressure ventilators via tracheostomy,bi-level positive airway pressure(BPAP)via a noninvasive interface,negative-pressure ventilators,or diaphragm pacing.The long-term use of BPAP in younger children at home has been less frequently reported.Case presentation:We present a case of a 2-month-old infant with CCHS who was successfully managed by BPAP without the need for tracheostomy and followed up for 7 years.Conclusion:CCHS is a rare disease that manifests as nocturnal desaturation and carbon dioxide retention in early life.Noninvasive ventilation can be successfully used in young infants via an appropriate mask.

Polycythemia, Ablepsia, and Obesity Hypoventilation Syndrome： A Case Report

Obesity hypoventilation syndrome （OHS） is defined as obesity （body mass index, 〉30 kg/m^2） with daytime hypoventilation （PCO2, 〉45 mmHg） that is not secondary to cardiopulmonary or neurologic disease. Around 80-90% of the patients with OHS have obstructive sleep apnea and severe arterial oxygen desaturation. Obstructive sleep apnea has been found to be associated with a variety of eye diseases, including floppy eyelid syndrome, glaucoma, papilledema, nonarteritic anterior ischemic optic neuropathy, and retinal vein occlusion （RVO）. While the association between OHS and ophthalmologic disorders is not well-known, our case report sheds light on this association.

PHOX2B mutations in three Chinese patients with congenital central hypoventilation syndrome

Congenital central hypoventilation syndrome （CCHS, OMIM #209880） is a rare autosomal dominant disorder of the autonomic nervous system （ANS） characterized by an abnormal autonomic ventilatory response to progressive hypercarbia and sustained hypoxemia. Patients typically present in the newborn period with hypoventilation or apnea asleep, awake, or both, without any associated cardiac, pulmonary, neuromuscular or brainstem lesions. Rarely, some patients may present at a later age and are diagnosed to have late onset central hypoventilation syndrome （LOCHS）.1 Other features of ANS dysfunction such as feeding difficulty due to oesophageal dysmotility, severe constipation in the absence of Hirschsprung disease, poor regulation of basal body temperature, episodes of profuse sweating, pupillary and ocular abnormalities, decreased beat-to-beat variability of heart rate, attenuated response of heart rate to exercise, abnormal fluctuation of blood pressure, decreased perception to pain, and decreased perception to anxiety may be variably present but not essential for diagnosis Furthermore, this central hypoventilation can occur as an isolated feature or in association with a number of neurocristopathies, notably Hirschsprung disease （Haddad syndrome, OMIM #209880） and tumours of the sympathetic nervous system particularly neuroblastoma, ganglioneuro- blastoma, and ganglioneuroma, which were found in 20% and 5%--10% of CCHS patients, respectively.2 Studies of genes pertinent to the early embryologic development of the neural crest cells, specifically the endothelin and the RET-GDNF signaling pathways, have recently led to the identification of PHOX2B as the major disease causing gene for CCHS.2-6 PHOX2B was mapped to chromosome 4p12 and consists of 3 exons. It encodes a highly conserved paired-like homeobox transcription factor of 314 amino acids linked to the RET-GDNF signaling

Pyloric Stenosis and Nonbilious Vomiting in Infants: Negative Base Excess and Hypercapnia—Two Opposing Points of One Scale a Comparative Case Series

Background: Blood pH and bicarbonate estimations are basal acid-base laboratory tests that are performed in infants with infantile hypertrophic pyloric stenosis (IHPS). This study aimed to define the clinical value of pCO2 and BE in infants suspected to have IHPS. Methods: We collected data from 80 “surgical” infants younger than 100 days with prolonged nonbilious vomiting who were suspected to have IHPS. In 65 infants, pyloric stenosis was confirmed, and 15 infants had nonsurgical conditions. Capillary blood was tested for standard acid-base parameters and lactate. The two groups were compared. Results: Eighty-eight percent of the IHPS infants had elevated standard bicarbonate levels (st bicarb) > 25 mmol/l, and 60% had BE > 3.5 mmol/l;12% of the infants showed hypercapnia (pCO2 ≥ 50 mmHg) associated with markedly increased standard bicarbonate and BE. Infants with nonsurgical vomiting were older at admission (p = 0.002), had a longer duration of vomiting (p < 0.001), were older (p = 0.002) and weighted more at admission (p = 0.004), had lower pCO2 (p = 0.021), lower st bicarb (p < 0.001) and lower BE (p = 0.001). In addition, nonsurgical infants showed a trend to anemia (p = 0.002). Conclusions: In infants with IHPS/nonbilious vomiting, acid-base analysis (ABA) is equivocal or inconclusive. These findings may be misleading and could result in a false clinical decision. Nonsurgical vomiting is associated with a lower degree of alkalosis, normocapnia to slight hypercapnia and a base deficit. However, even infants with IHPS may present with a negative BE. In infants with IHPS and severe alkalosis, hypercapnia carries a risk for respiratory depression. Monitoring the infant’s respiration allows for the early detection of respiratory deterioration.

气管切开术在头颈肿瘤困难气道患者围手术期的临床应用价值

头颈肿瘤手术往往与鼻咽、口咽、喉咽、气管等解剖结构关系密切,部分患者在围手术期即可发生呼吸困难,通气无法正常维持,短时间内就可因缺氧导致心跳骤停,大脑损害,甚至死亡。本文就我科2009年1月～2011年1月共22例头颈肿瘤困难气道患者采用气管切开术的临床应用体会。

Validation of Novel Completely Sealed Nasal Positive Airway Pressure Device: SuperNO₂VA™EtCO₂Measurement and Pressure Test Performance

Background: SuperNO2VA™ Et Nasal Mask (Vyaire Medical, Inc., United States) is a new nasal mask with an integrated sampling hood to capture exhaled gases and enable accurate measurements of end tidal carbon dioxide (EtCO2). The authors hypothesized that the SuperNO2VA Et design would measure EtCO2 more accurately than a predicate EtCO2 sampling line, the Smart CapnoLine® Plus, Adult/Intermediate CO2 Oral-Nasal Set (Medtronic, United States). Methods: A simulated patient setup enabled comparison of the accuracy of CO2 measurements within the SuperNO2VA Et and a predicate device for eight condition combinations of input CO2;breath rate and tidal volume (VT);and O2 flow rates. These tests were repeated with simulating Nasal Breathing and Oral Breathing. Results: Testing demonstrated that measurements of 1% and 5% input CO2 within the SuperNO2VA Et were accurate for a range of respiratory rates, VT, O2 flows, and CO2 concentrations. CO2 measurement errors were significantly larger for the Oral-Nasal Set compared to the SuperNO2VA Et for both 1% Input CO2 (-0.12%vol vs. -0.01%vol, p = 0.0005) and 5% Input CO2 (-0.93%vol vs. -0.08%vol, p < 0.0001). At 5% Input CO2, eight of the 12 trials for the Oral-Nasal Set failed to meet the ISO accuracy specification, while all SuperNO2VA Et measurements met the specification. The accuracy of CO2 measurement within the SuperNO2VA were not different for Oral and Nasal Breathing trials for both CO2 concentration (1%: p = 0.33, 5%: p = 0.064). With the Oral-Nasal Set, CO2 measurements were lower during Oral compared to Nasal Breathing (1%: p = 0.0005, 5%: p = 0.0091). Conclusions: Based on performance outcomes, use of the SuperNO2VA Et offers significantly more accurate measurement of EtCO2 than the predicate EtCO2 sampling line. Measurements of EtCO2 within the SuperNO2VA Et are accurate over a range of CO2, breathing rates, tidal volumes, and O2 flows, as well as for nasal and oral breathing.

Relationship between metabolic syndrome and hypercapnia among obese patients with sleep apnea Relationship between metabolic syndrome and hypercapnia among obese patients with sleep apnea

BACKGROUND In the obese patient population,some patients have severe obstructive sleep apnea(OSA)with daytime hypoventilation.Such patients are generally identified on the basis of the presence or absence of daytime hypercapnia,and the condition is called obesity hypoventilation syndrome.However,mechanisms for such daytime hypoventilation remain unclear.AIM To investigate metabolic syndrome and daytime hypercapnia association based on hypercapnia prevalence in obese OSA patients in a nested case-control study.METHODS Consecutive obese patients(body mass index≥30 kg/m2)who underwent polysomnography due to suspected OSA were included.Among them,patients with severe OSA(apnea hypopnea index≥30/h)were divided into two groups according to the presence or absence of hypercapnia during wakefulness(arterial partial pressure of carbon dioxide≥or<45 Torr,respectively).The characteristics and clinical features of these two groups were compared.RESULTS Among 97 eligible patients,25 patients(25.8%)had daytime hypercapnia.There were no significant differences in age,gender,body mass index,apnea-hypopnea index,and Epworth Sleepiness Scale scores between the two groups.However,patients with hypercapnia had a significantly lower arterial partial pressure of oxygen level(75.8±8.2 torr vs 79.9±8.7 torr,P=0.042)and higher arterial partial pressure of carbon dioxide level(46.6±2.5 torr vs 41.0±2.9 torr,P<0.001).Additionally,patients with hypercapnia were more likely to have metabolic syndrome(72.0%vs 48.6%,P=0.043)and a higher metabolic score(the number of satisfied criteria of metabolic syndrome).In multivariate logistic regression analysis,the presence of metabolic syndrome was associated with the presence of hypercapnia(OR=2.85,95%CI:1.04-7.84,P=0.042).CONCLUSION Among obese patients with severe OSA,26%of patients had hypercapnia during wakefulness.The presence of metabolic syndrome was independently correlated with the presence of daytime hypercapnia.

微动敏感床垫睡眠监测系统在OSAHS诊断中的应用

阻塞性睡眠呼吸暂停低通气综合征（OSAHS）是一种比较常见的睡眠疾病,由于可以引发多种全身性疾病,尤其使中重度患者心脑血管并发症的危险性及死亡率均显著提高,是目前睡眠障碍的研究热点[1,2]。对于该疾病的诊断主要依靠睡眠过程中的多道睡眠监测（PSG）和食管压力测定2种方法。

低通气综合征与无创正压通气治疗

PaCO2超过45 mm Hg(1 mm Hg=0.133 kPa)即表示存在肺泡低通气,当PaCO2达到50～70 mm Hg可产生相应的病理生理改变和临床症状,称为低通气综合征(hypoventilation syndromes).动脉血气分析和肺功能检查可明确诊断及病因.应用无创正压通气(NPPV)治疗可改善患者的通气状况,取得良好效果.