Pathophysiology of Chronic Hypercapnic Respiratory Failure.

Chronic hypercapnic respiratory failure occurs in several conditions associated with hypoventilation. The mechanisms underlying the development of chronic hypercapnia include a combination of processes that increase metabolic CO2 production, reduce minute ventilation (V'e), or increase dead space fraction (Vd/Vt). Fundamental to the pathophysiology is a mismatch between increased load and a reduction in the capacity of the respiratory pump to compensate. Though neural respiratory drive may be decreased in a subset of central hypoventilation disorders, it is more commonly increased in attempting to maintain the load-capacity homeostatic balance.

Autism spectrum disorder in young patients with congenital central hypoventilation syndrome: role of the autonomic nervous system dysfunction.

BACKGROUND: Congenital central hypoventilation syndrome (CCHS) is a rare condition characterized by alveolar hypoventilation and autonomic nervous system (ANS) dysfunction requiring long-term ventilation. CCHS could constitute a risk factor of autism spectrum disorder (ASD) due to birth injury related to respiratory failure, which remains to be determined. ANS dysfunction has also been described in ASD and there are indications for altered contribution of ANS-central nervous system interaction in processing of social information; thus, CCHS could be a risk factor for ASD based on pathophysiological background also. Our study aimed to determine the prevalence of ASD among CCHS patients, identify risk factors, and explore the relationship between the ANS, evaluated by heart rate variability indices, and adaptative functioning. RESULTS: Our retrospective study, based on the analysis of records of a French national center of patients with CCHS under 20 years of age, determined that the prevalence of ASD (diagnosed by a psychiatrist, following the criteria of DSM-4 or DSM-5) was 6/69 patients, 8.7% (95% confidence interval: 3.3-18.0%). In a case (CCHS with ASD, n = 6) - control (CCHS without ASD, n = 12) study with matching on sex, longer neonatal hospitalization stay and glycemic dysfunction were associated with ASD. Adaptative functioning was assessed using Vineland Adaptative behavioral scales (VABS) and heart rate variability indices (including daytime RMSSD as an index of parasympathetic modulation) were obtained from ECG Holter performed the same day. In 19 young subjects with CCHS who had both ECG Holter and VABS, significant positive correlations were observed between RMSSD and three of four sub-domains of the VABS (communication: R = 0.50, p = 0.028; daily living skills: R = 0.60, p = 0.006; socialization: R = 0.52, p = 0.021). CONCLUSION: Our study suggests a high prevalence of ASD in patients with CCHS. Glycemic dysfunction and longer initial hospitalization stays were associated with ASD development. A defect in parasympathetic modulation was associated with worse adaptative functioning.

Congenital Central Hypoventilation Syndrome and Disorders of Control of Ventilation.

Congenital disorders of ventilatory control typically manifest as central apneas, periodic breathing, and hypoventilation in the neonatal period, but some may present at a later age. Obstructive apneas may be the initial presentation, and some may have associated autonomic nervous system dysfunction. Individuals with these disorders can have absent or impaired ventilatory and arousal responses to hypoxemia and hypercapnia. This article discusses the presentation, pathophysiology, evaluation, and management of congenital central hypoventilation syndrome, rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD) syndrome, Prader-Willi syndrome, and myelomeningocele.

Brief apnea with hypoventilation reduces seizure duration and shifts seizure location for several hours in a model of severe traumatic brain injury.

OBJECTIVE: Seizures can be difficult to control in infants and toddlers. Seizures with periods of apnea and hypoventilation are common following severe traumatic brain injury (TBI). We previously observed that brief apnea with hypoventilation (A&H) in our severe TBI model acutely interrupted seizures. The current study is designed to determine the effect of A&H on subsequent seizures and whether A&H has potential therapeutic implications. METHODS: Piglets (1 week or 1 month old) received multifactorial injuries: cortical impact, mass effect, subdural hematoma, subarachnoid hemorrhage, and seizures induced with kainic acid. A&H (1 min apnea, 10 min hypoventilation) was induced either before or after seizure induction, or control piglets received subdural/subarachnoid hematoma and seizure without A&H. In an intensive care unit, piglets were sedated, intubated, and mechanically ventilated, and epidural electroencephalogram was recorded for an average of 18 h after seizure induction. RESULTS: In our severe TBI model, A&H after seizure reduced ipsilateral seizure burden by 80% compared to the same injuries without A&H. In the A&H before seizure induction group, more piglets had exclusively contralateral seizures, although most piglets in all groups had seizures that shifted location throughout the several hours of seizure. After 8-10 h, seizures transitioned to interictal epileptiform discharges regardless of A&H or timing of A&H. SIGNIFICANCE: Even brief A&H may alter traumatic seizures. In our preclinical model, we will address the possibility of hypercapnia with normoxia, with controlled intracranial pressure, as a therapeutic option for children with status epilepticus after hemorrhagic TBI.

An unusual ophthalmologic finding in a patient with congenital central hypoventilation syndrome.

INTRODUCTION: Congenital Central Hypoventilation Syndrome (CCHS) is a rare disease due to a severely impaired central control of breathing and dysfunction of the autonomic nervous system. Ophthalmologic abnormalities are common in patients with CCHS and include horizontal strabismus, pupil and iris abnormalities and ptosis. We report a unique case of CCHS in association with monocular elevation deficit (MED) in a boy diagnosed with CCHS at birth. CASE DESCRIPTION: We report a case of a boy with a confirmed diagnosis of CCHS (complete sequencing of the paired-like homeobox 2b (PHOX2B) gene) after presenting little respiratory effort and cyanosis at birth. The ophthalmological examination shows an impaired elevation of the left eye, both in adduction and abduction, associated with mild and variable left ptosis. His mother has observed that the left eyelid elevates when the child feeds. A deviation in the primary gaze position or a chin-up position are not present. The funduscopic examination is normal. Given that deviation is limited to upgaze, the ptosis is mild and the patient's age, observation is decided. CONCLUSIONS: Ophthalmologic abnormalities are common in patients with CCHS and include horizontal strabismus, pupil and iris abnormalities and ptosis. To the best of our knowledge, this is the first report of MED in association with CCHS. Further studies are needed to determine if an association between MED and CCHS exists or is just a casual finding in this case.

Trastorno de hipoventilación central del sueño en pediatría: causas poco frecuentes / Central hypoventilation disorders sleep-related in pediatrics: unusual causes

Congenital central hypoventilation syndrome (CCHS) and rapid-onset obesity syndrome with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD) are rare causes of hypoventilation during sleep in the pediatric population. This group of disorders are characterized by the absence or decrease in the automatic control of ventilation, decreased sensitivity of chemoreceptors to CO2, causing hypoventilation during sleep and even in wakefulness, in the most severe cases. For these reasons it is important to diagnose and treat them promptly. The objective of this review is to provide current and complete literature, to be able to identify, treat and refer this group of children early, and thus reduce the complications and/or associated comorbidities in the short and long term, improving their quality of life.

El síndrome de hipoventilación central congénita (CCHS) y síndrome de obesidad de inicio rápido con disfunción hipotalámica, hipoventilación y desregulación autonómica (ROHHAD), son causas poco comunes de hipoventilación durante el sueño en la población pediátrica. Este grupo de trastornos se caracterizan por ausencia o disminución en el control automático de la ventilación, sensibilidad disminuida de los quimioreceptores al CO2, provocando hipoventilación durante el sueño e incluso en vigilia, en los casos más severos. Por estas razones es importante diagnosticarlos y tratarlos oportunamente. El objetivo de esta revisión es proporcionar literatura actual y completa, para poder identificar, tratar y referir a éste grupo de niños tempranamente, y así disminuir las complicaciones y/o comorbilidades asociadas a corto y largo plazo, mejorando su calidad de vida.

Utilidad de la monitorización transcutánea de CO2 durante el registro polisomnográfico en una unidad de sueño / The usefulness of transcutaneous monitoring of CO2 during a sleep study in the sleep disorder unit

Los trastornos respiratorios del sueño son frecuentes en la población general y generan un alto consumo de recursos por ingresos, consultas y uso crónico de las terapias ventilatorias. La medición de CO2 transcutánea (tcCO2 ) ha mostrado buena correlación con la presión arterial de CO2 (PCO2 ) y es superior al pulsioxímetro para detectar hipoventilación. Su uso está poco extendido en nuestro medio. Nuestro objetivo fue valorar su utilidad en estudios de sueño basales y en titulaciones de CPAP y BIPAP, aplicadas a pacientes con síndrome de apneas del sueño (SAHS) y síndrome de obesidad-hipoventilación (SOH). Usamos el medidor tcCO2 en polisomnografías (PSG) basales de pacientes con sospecha de patología respiratoria del sueño y en titulaciones de CPAP o BIPAP de pacientes ya diagnosticados. Se realizaron 102 estudios a 89 pacientes. Hubo 45 estudios basales, 21 titulaciones de CPAP y 34 de BIPAP. La patología más frecuente fue el SAHS. La presión media de las titulaciones de CPAP fue de 9,6 cmH2 O. En las titulaciones de BIPAP la IPAP media fue de 15,7 y la EPAP media de 7,4. El índice de desaturación (IDH) medio fue de 27. La SpO2 media fue de 91,8% y el CT90 del 22,9%. La tcCO2 media fue de 45,6 y la máxima de 49,2. No hubo efectos secundarios a la monitorización tcCO2 . Conclusiones: observamos hipercapnia latente en muchos pacientes y el medidor fue bien tolerado. Creemos que la monitorización tcCO2 puede ser útil como método no invasivo para detectar hipoventilación, aun con cifras normales de SpO2

The transcutaneous CO2 (tcCO2 ) monitoring has demonstrated a good correlation with the arterial CO2 value, and is better than pulsioxymeter for to detect hypoventilation episodes. The tcCO2 monitoring is not routine in our environment. The aim of our study was to evaluate the utility of tcCO2 monitoring in our sleep unit, in basal studies and in non invasive ventilation settings. We performed a prospective study. We measured the tcCO2 values in basal polisomnografies (PSG) and in CPAP or BIPAP settings in patients with diagnosis of OSAS, obesity-hypoventilation Syndrome and COPD. We included 102 studies in 89 patients. There were 45 basal studies, 21 CPAP settings and 34 BIPAP settings. The most frequent pathology was OSAS. The mean pressure in CPAP settings was 9.6 H2 Ocm, while in BIPAP settings the mean IPAP was 15.7 and the mean EPAP was 7.4. The mean desaturation index was 27, the mean peripheral O2 value was 91.8%, and the mean cumuled time under 90% (CT90) of O2 peripheral saturation was 22.9%. The mean tcCO2 was 45.6 and the maximum was 49.2. Conclusions: tcCO2 monitoring is a non invasive method for to detect hypoventilation episodes in patients with sleep pathology and in non invasive ventilation settings, although the peripheral oxygen saturation remains in normal values

Aplicaciones de la ventilación mecánica no invasiva en Anestesiología y Reanimación / Applications of noninvasive ventilation in anesthesiology and postanesthesia recovery care

La ventilación mecánica no invasiva (VMNI) puederesultar una técnica muy útil para el anestesiólogo tantosi su trabajo transcurre en la Unidad de CuidadosCríticos, en la Unidad de Recuperación Postanestésica(URPA), en el quirófano e incluso fuera del áreaquirúrgica. Puede ayudar a tratar situaciones en las quese presente una insuficiencia respiratoria aguda (IRA) opuede prevenir que ésta aparezca en pacientes de riesgosometidos a intervenciones con anestesia loco-regional oen determinadas pruebas diagnóstico-terapéuticas querequieren sedación. La correcta utilización de la VMNIdepende de una adecuada formación del personalsanitario y de una acertada elección del material(interfases, respiradores, etc.) para su realización encada uno de los ámbitos de nuestro trabajo en los quepuede ser útil su puesta en práctica(AU)

Noninvasive ventilation (NIV) can be useful toanesthesiologists working in critical care units,postanesthesia recovery units, operating theaters, orother settings. NIV can help in situations of acuterespiratory failure or serve as a preventive measure inpatients undergoing interventions under local-regionalanesthesia or diagnostic or therapeutic proceduresrequiring sedation. Successful NIV depends onadequately trained health personnel and the properchoice of material (interfaces, respirators, etc.) for eachsetting where this modality is used(AU)

Estudio de los trastornos respiratorios del sueño en pacientes con enfermedades neuromusculares / Study of sleep respiratory disorders in patients with neuromuscular diseases

El presente capitulo aborda aspectos fisiopatológicos de los trastornos respiratorios del sueño (TRS) y los métodos diagnósticos disponibles para su pesquisa precoz en pacientes neuromusculares, en riesgo de hipoventilación nocturna, con objeto de ayudar en la decisión de cuando iniciar ventilación mecánica no invasiva (VNI).

Estudios polisomnográficos en niños / Polysomnographic study in children

La polisomnografía es un examen de gran utilidad en pediatría para el estudio de los niños roncadores con sospecha de Síndrome de Apnea-Hipopnea Obstructiva del Sueño (SAHOS). En el pasado se intentaba prevenir la aparición de secuelas cardiovasculares como el cor pulmonale, lo que se ha logrado satisfactoriamente al identificar y tratar a los pacientes claramente sintomáticos. La literatura internacional nos ha mostrado los últimos años la gran cantidad de alteraciones neurocognitivas asociadas al ronquido y SAHOS. A su vez existe una clara relación entre el SAHOS del adulto con la hipertensión arterial y patología cardiovascular.

Ventilación no invasiva en lactantes afectados de síndrome de Ondine: ¿una indicación real? / Noninvasive ventilation in infants with Ondine´s syndrome: a real indication?

El síndrome de Ondine se trata de un síndrome de hipoventilación central congénita secundaria a un trastorno en el control autonómico de la respiración en ausencia de enfermedad primaria que lo justifique. Se ha descrito la eficacia de la ventilación no invasiva (VNI) en lactantes afectados del síndrome de Ondine, evitando así la necesidad de una traqueostomía para ventilación mecánica. Se describe nuestra experiencia en VNI en lactantes con síndrome de Ondine. Se describen 2 lactantes afectados del síndrome de Ondine que son trasladados a nuestro centro para control y adecuación terapéutica. A su ingreso se inicia VNI mediante ventilador presurométrico (BiPAP vision®) con interfase nasal en modalidad S/T (espontánea/controlada) con imposibilidad de conseguir una adecuada ventilación (PCO2 > 90 mmHg). Finalmente se realiza traqueostomía reglada para ventilación mecánica continua. La aplicación de VNI en pacientes menores de 5 años con síndrome de Ondine, aunque se ha realizado con éxito en algunos casos, no parece ser la norma general de tratamiento

Ondine's syndrome is a congenital central hypoventilation syndrome due to a disorder in the autonomic control of breathing in the absence of any primary disease that would explain it. Noninvasive ventilation (NIV) has been reported to be effective in the management of these patients, thus avoiding the need for tracheotomy for prolonged mechanical ventilation. We describe our experience of NIV in infants with Ondine's syndrome. Two infants with Ondine's syndrome were transferred to our center for management and adjustment of therapy. On admission NIV (BiPAP VISION®) was started with nasal interphase in S/T (spontaneous/timed) mode, which failed to provide suitable ventilation (PCO2 > 70 mmHg). Finally, tracheotomy for continuous mechanical ventilation was performed. Although NIV has been reported to be successful in some patients with Ondine's syndrome, its application in patients younger than 5 years does not seem to be the general norm of treatment

Síndrome de hipoventilación: enfermedad de ondina: revisión de la literatura / Hypoventilation`s syndrome: ondine disease: literature review

Los síndromes de hipoventilación son múltiples y pueden deberse a causas obstructivas, siendo de origen congénito y adquirido; sin embargo, es de especial atención el llamado síndrome de hipoventilación central congénito o enfermedad de ondina por su complejidad tanto en su fisiopatología, diagnóstico y manejo

Insuficiência respiratória / Respiratory failure

A expressao "Insuficiência Respiratória" é utilizada para caracterizar condiçao clínica, na qual o aparelho respiratório é incapaz de elevar a níveis satisfatórios a oxigenaçao do sangue arterial associada (insuficiência ventilatória) ou nao à retençao de dióxido de carbono (insuficiência hipoxêmica). É freqüente estar associada à presença de doenças broncopulmonares e/ou cardíacas, ma também pode ocorrer na presença de pulmoes normais (doenças do sistema nervoso central, neuromusculares e da caixa torácica). Embora ocorram, as manifestaçoes clínicas da insuficiência respiratória sao inespecíficas e o diagnóstico depende da análise da gasometria arterial e do pH. Assim sendo, o conhecimento dos processos intrapulmonares envolvendo as trocas gasosas é essencial para o entendimento de sua fisiopatologia nas diferentes condiçoes clínicas que pode estar presente.

Hipoventilación alveolar primaria: ¿Enfermedad de monge en Bogotá?

Se presentan dos casos de hipoventilación alveolar sin enfermedad pulmonar ni apneas de sueño, secundarias a trastornos no anatómicos del sistema de control de la respiración. Se discuten los diagnósticos diferenciales y se plantea la hipótesis que su etiología es la hipoventilación crónica de la altura o enfermedad de Monge