Síndrome de apnea obstructiva del sueño y sus consecuencias cardiovasculares / sleep apnea and its cardiovascular consequences

El sueño es fundamental para una serie de funciones corporales, incluyendo el metabolismo de radicales libres, secreción hormonal y fijación de la memoria. Existen evidencias crecientes de que la simple restricción en el número de horas de sueño puede ser perjudicial para el sistema cardiovascular. Por ejemplo, estudios de cohorte sugieren que dormir menos de 5 horas/noche puede aumentar el riesgo de desarrollar hipertensión arterial sistémica (HAS), infarto agudo del miocardio (IAM) y accidente vascular cerebral (AVC). Otro creciente foco de interés en la medicina actual son los trastornos respiratorios del sueño. En este artículo, nos enfocaremos a los trastornos respiratorios del sueño de mayor interés para el cardiólogo, el síndrome apnea obstructiva del sueño (SAOS) y la apnea central asociada a la respiración de Cheyne-Stokes. Además de extremadamente comunes, existen evidencias de que estos trastornos respiratorios del sueño, una vez presentes, pueden contribuir al desarrollo o empeoramiento de las enfermedades cardiovasculares

Sleep is essential for several physiological functions, including free radical metabolism, hormone secretion, and memory. There is growing evidence that restricting the number of hours of sleep can be harmful to the cardiovascular system. For example, cohort studies suggest that sleeping less than 5 hours/night may increase the risk of developing systemic arterial hypertension, acute myocardial infarction and strokes. Another growing focus of interest in current medicine is sleep respiratory disturbances. In this article, we will focus on the respiratory sleep disorders of greatest interest to the cardiologist, obstructive sleep apnea syndrome and central Cheyne-Stokes respiration-associated apnea. In addition, there is evidence that breathing sleep disorders are extremely common and once present can contribute to the development or worsening of cardiovascular disease

Respiración de Cheyne-Stokes en una adolescente con insuficiencia cardíaca secundaria a miocardiopatía dilatada que requirió trasplante cardíaco / Cheyne-Stokes respiration in an adolescent with heart failure secondary to dilated cardiomyopathy requiring heart transplantation

La respiración de Cheyne-Stokes es una variante cíclica o tipo de apnea central del sueño poco frecuente en la población pediátrica. Se describe a una paciente de 12 años con insuficiencia cardíaca grave relacionada con miocardiopatía dilatada que demostró trastornos del sueño con características de respiración de Cheyne-Stokes, que se resolvieron completamente después del trasplante cardíaco.

Cheyne-Stokes respiration is a cyclic variant or type of central sleep apnea rare in pediatric population. We describe a 12-year-old female patient with severe heart failure related to dilated cardiomyopathy who demonstrated sleep disorders with Cheyne-Stokes breathing features, which completely resolved following cardiac transplantation.

Factors Associated with Cheyne-Stokes Respiration in Acute Ischemic Stroke

BACKGROUND AND PURPOSE: Cheyne-Stokes respiration (CSR) is frequently observed in patients with acute stroke. There have been conflicting opinions about the associations of CSR with the location and size of the lesion. We aimed to better define the clinical relevance and pathogenesis of CSR in acute stroke. METHODS: We investigated patients who had been admitted with acute ischemic stroke and received an overnight sleep apnea test. We collected data on demographics, risk factors, etiologic subtypes, initial vital signs, clinical course of the stroke, and parameters associated with respiratory events during the sleep apnea test. We performed a multivariate logistic regression analysis to determine the factors associated with CSR. RESULTS: Among 182 patients, 35 patients showed CSR in sleep apnea testing. Large-artery atherosclerosis or cardioembolism, bilateral hemispheric involvement, atrial fibrillation, low left-ventricle ejection fraction (LVEF), and left atrium (LA) enlargement were all associated with the presence of CSR. Multivariate analysis revealed that the previous modified Rankin Scale (mRS) score, bilateral hemispheric involvement, low LVEF, and LA enlargement were significantly associated with CSR. Subgroup analysis with large-artery atherosclerosis without cardiac disease revealed that the previous mRS score is the only independent factor associated with CSR. CONCLUSIONS: CSR frequently occurs in strokes involving large arteries or due to cardioembolism, regardless of the location and severity of the stroke. Predisposing conditions such as preexisting neurologic disability, low LVEF, and LA enlargement are associated with CSR in acute stroke.

A Case of Continuous Positive Airway Pressure Therapy in a Patient with Central Sleep Apnea and Heart Failure / 수면정신생리

Central sleep apnea (CSA) is a highly prevalent comorbidity in patients with heart failure and may present in 25 to 40 percent of heart failure patients. Continuous positive airway pressure (CPAP) is the primary therapeutic option and effective in treatment of obstructive sleep apnea (OSA). In heart failure patients with CSA, several trials of CPAP showed a number of positive effects in heart failure treatment. A 58-year-old male visited the hospital because of dyspnea and he was diagnosed as heart failure with ischemic heart disease. He underwent coronary angiography and received percutaneous coronary intervention due to stenosis at the middle of left anterior descending coronary artery. However, dyspnea was not completely improved after treatment with percutaneous coronary intervention. The patient also experienced snoring and sleep apnea which worsened with symptom of dyspnea in the recent year. We suspected CSA and the patient underwent polysomnography to confirm whether sleep apnea was present. During the polysomnography, CSA with Cheyne-Stokes respiration (CSR) was observed and apnea-hypopnea index was 45.9/hr. The patient was treated with CPAP. After CPAP treatment, hypoxemia and CSA were resolved and dyspnea was improved with reducing NYHA class. We report a case successfully treated with clinical improvement by presuming CSA in a patient with heart failure.

Circulatory sleep apnea: Preliminary report of clinical observation on sleep apnea in patients with chronic heart failure / 中国应用生理学杂志

<p><b>OBJECTIVE</b>The aim of this study is to investigate the occurrence and mechanism of Cheyne-Stokes breathing pattern in patients with heart failure.</p><p><b>METHODS</b>Fifty-six patients who performed polusomnography sleep testing at National Center of Cardiovascular Diseases Fuwai Hospital from March to May in 2015. We divided them into chronic heart failure (CHF) group and non-CHF group.</p><p><b>RESULTS</b>The occurrences of sleep apnea in two groups were high. In CHF group (n = 11) , there were 10 patients with apnea hypopnea index (AHI) > 5; and their AHI was 23.93 ±14.63. In non-CHF group (n = 45), there were 33 patients whose AHI > 5; and their AHI was 16.20 ± 18.76. The ratio of center sleep apnea to all gross sleep apnea ratio in CHF group was higher than that in non-CHF group (80.21% ± 30.55% vs 27.16% ± 35.71%, P < 0.01 ).</p><p><b>CONCLUSION</b>Based upon the new theory of holistic integrative physiology and medicine, we explain the mechanism of circulatory dysfunction induce the oscillation breathing in patients with CHF. The sleep apnea and C-S respiration in CHF should be called circulatory sleep apnea, rather than central sleep apnea.</p>

Respiración de Cheyne-Stokes y bruxismo severo documentada por polisomnografía que mejora con la administración de oxígeno a 1 L/min / Cheyne-Stokes respiration and severe bruxism documented by polysomnography that improves with administration of oxygen at 1 L/min

Se presenta el caso de una mujer de 59 años con diagnóstico de encefalopatía anoxicoisquémica, quien se encuentra en estado vegetativo persistente y epilepsia secundaria de difícil control, quien en el transcurso de su evolución clínica desarrolla apnea central del sueño con índice de apnea hipopnea (IAH) de 87.86/h con patrón de respiración de Cheyne-Stokes (RCS) y bruxismo severo documentado mediante polisomnografía, alteraciones que mejoraron tras la administración de oxígeno por cánula nasal a 1 L/min. La asociación de bruxismo con respiración de Cheyne-Stokes y la respuesta simultánea y completa de las dos alteraciones a la administración de oxígeno suplementario no ha sido reportada previamente.

The case of a 59 year old female diagnosed with anoxic-ischemic encephalopathy, who is in a persistent vegetative state and secondary epilepsy difficult to control, who in the course of her clinical evolution develops central sleep apnea with apnea hypopnea index (AHI) of 87.86 / h with Cheyne-Stokes pattern and severe bruxism documented by polysomnography, alterations that improved after administration of oxygen by nasal cannula at 1 L / min., is presented. The association of bruxism with Cheyne-Stokes respiration and the simultaneous and complete response of the two alterations to the administration of supplemental oxygen has not been reported previously.

Apneia do sono e insuficiência cardíaca / Sleep apnea and congestive heart failure

Os distúrbios respiratórios do sono, incluindo a apneia obstrutiva do sono e a respiração de Cheyne-Stokes, são extremamente comuns em pacientes com insuficiência cardíaca congestiva, com prevalência estimada de 50 por cento. Ambos os distúrbios estão associados à piora da qualidade de vida e ao aumento da mortalidade em pacientes com insuficiência cardíaca congestiva. Nesta revisão abordaremos tanto a etiologia da respiração de Cheyne-Stokes em pacientes com insuficiência cardíaca congestiva, suas consequências e seu tratamento, como o impacto cardiovascular da apneia obstrutiva do sono nos pacientes com insuficiência cardíaca congestiva.

Impacto da etiologia da cardiopatia nos distúrbios respiratórios do sono: comparação entre pacientes com valvopatias versus insuficiência cardíaca com disfunção sistólica / Impact of etiology of cardiopathy on sleep disordered breathing: comparison between patients with valve diseases and systolic congestive heart failure

Introdução: A apnéia central do sono e a apnéia obstrutiva do sono (ACS e AOS, respectivamente) são comuns em pacientes com insuficiência cardíaca com disfunção sistólica (ICC). No entanto, vários fatores que levam a instabilidade respiratória incluindo baixo débito cardíaco, congestão pulmonar e hipocapnia coexistem nestes pacientes. Pacientes com valvopatias (VAL) com alta pressão de capilar pulmonar (PCP) e com fração de ejeção (FE) de ventrículo esquerdo normal representam um modelo adequado para elucidar a gênese da apnéia do sono. Objetivos: Comparar as características dos distúrbios respiratórios do sono em pacientes com VAL e pacientes com ICC. Métodos: Pacientes com VAL com PCP > 12 mmHg e pacientes com ICC foram avaliados por, gasometria arterial, ecocardiograma e polissonografia. Resultados: Pacientes com VAL (n=17, PCP 24 ± 9 mmHg e FE 61 ± 6 %) e ICC (n=17, FE 31 ± 10 %) eram semelhantes quanto as características demográficas e gases arteriais (idade: 46 ± 10 versus 47 ± 9, sexo feminino: 11 em ambos os grupos, índice de massa corporal: 26 ± 5 vs 26 ± 6 Kg/m2, PaCO2: 34 ± 3 vs 35 ± 4 mmHg, respectivamente). Pacientes com VAL apresentaram índice de apnéia-hipopnéia (IAH) significativamente menor do que pacientes com ICC (10 ± 8 e 26 ± 25 eventos/hora, p=0,0179) e uma menor prevalência de apnéia do sono (IAH > 15 eventos/hora, 29% e 53%, p=0,0009). Dentre os pacientes com apnéia do sono, os pacientes com VAL apresentaram predominantemente AOS (60%) enquanto os pacientes com ICC apresentaram predominantemente ACS (89%, p < 0,0001). Conclusões: Pacientes com VAL e alta PCP e FE normal apresentam apnéia do sono menos grave e com excesso de eventos de origem obstrutiva quando comparados com pacientes com ICC. Congestão pulmonar e hipocapnia não explicam completamente a presença de ACS em pacientes com doenças cardíacas.

Introduction: Central and obstructive sleep apnea (CSA and OSA, respectively) are common in patients with systolic congestive heart failure (ICC). However, several factors leading to respiratory instability, including low cardiac output, pulmonary congestion and hypocapnia co-exist in these patients. Patients with valvular heart disease (VAL) with high pulmonary capillary wedge pressure (PCWP) but normal resting left ventricular ejection fraction (LVEF) may provide insights into the genesis of sleep apnea. Objectives: Compare sleep disordered breathing characteristics in patients with VAL and patients with ICC. Methods: Patients with VAL and PCWP > 12 mmHg and ICC were evaluated by awake arterial blood gas analysis, echocardiogram and overnight polysomnography. Results: Patients with VAL (n=17, PCP=24 ± 9 mmHg and LVEF=61 ± 6 %) and ICC (n=17, LVEF=31 ± 10 %) were similar for demographics and blood gases (age: 46 ± 10 vs 47 ± 9, females: 11 in both groups, body mass index: 26 ± 5 Kg/m2 vs 26 ± 6, PaCO2: 34 ± 3 vs 35 ± 4 mmHg, respectively). Patients with VAL as compared to patients with ICC presented significantly lower apnea hypopnea index (10 ± 8 vs 26 ± 25 events/hour, p=0.0179), a lower prevalence of sleep apnea (apnea-hypopnea index > 15 events/hour) 29% vs 53%, p=0.0009, and among patients with sleep apnea the nature was predominantly OSA (60%) while patients with ICC had predominantly CSA (89%, p < 0.0001). Conclusion: Patients with VAL and high PCWP had a less severe sleep apnea and an excess of obstructive events when compared to patients ICC. Pulmonary congestion and hypocapnia do not completely explain CSA in patients with heart diseases.

Breathing disorders in congestive heart failure: gender, etiology and mortality

We investigated the relationship between sleep-disordered breathing (SDB) and Cheyne-Stokes respiration (CSR) while awake as well as mortality. Eighty-nine consecutive outpatients (29 females) with congestive heart failure (CHF; left ventricular ejection fraction, LVEF <45 percent) were prospectively evaluated. The presence of SDB and of CSR while awake before sleep onset was investigated by polysomnography. SDB prevalence was 81 and 56 percent, using apnea-hypopnea index cutoffs >5 and >15, respectively. CHF etiologies were similar according to the prevalence of SDB and sleep pattern. Males and females were similar in age, body mass index, and LVEF. Males presented more SDB (P = 0.01), higher apnea-hypopnea index (P = 0.04), more light sleep (stages 1 and 2; P < 0.05), and less deep sleep (P < 0.001) than females. During follow-up (25 ± 10 months), 27 percent of the population died. Non-survivors had lower LVEF (P = 0.01), worse New York Heart Association (NYHA) functional classification (P = 0.03), and higher CSR while awake (P < 0.001) than survivors. As determined by Cox proportional model, NYHA class IV (RR = 3.95, 95 percentCI = 1.37-11.38, P = 0.011) and CSR while awake with a marginal significance (RR = 2.96, 95 percentCI = 0.94-9.33, P = 0.064) were associated with mortality. In conclusion, the prevalence of SDB and sleep pattern of patients with Chagas' disease were similar to that of patients with CHF due to other etiologies. Males presented more frequent and more severe SDB and worse sleep quality than females. The presence of CSR while awake, but not during sleep, may be associated with a poor prognosis in patients with CHF.

Ventilação periódica durante vigília prediz a respiração de Cheyne-Stokes durante o sono em pacientes com insuficiência cardíaca / Awake periodic breathing predicts Cheyne-Stokes respiration during sleep in patients with heart failure

Introdução: Os distúrbios respiratórios do sono na forma de apnéia central associada à respiração de Cheyne-Stokes (RCS) e apnéia obstrutiva do sono (AOS), são comuns nos pacientes com insuficiência cardíaca (IC) e podem contribuir para morbimortalidade. A RCS é uma forma exagerada de ventilação periódica (VP) na qual apnéias centrais alternam com períodos de hiperventilação. Em contraste, a AOS resulta em um colapso completo ou parcial da via aérea superior recorrente durante o sono. Objetivo: Fizemos à hipótese que VP durante vigília prediz a RCS durante o sono em pacientes com IC. Métodos: Estudamos pacientes do ambulatório de Cardiopatia Geral, do Instituto do Coração (InCor), recrutados no período de 2001 a 2003, submetidos a avaliação clínica e ecocardiográfica. Os pacientes foram submetidos à monitoração do padrão respiratório em posição supina, com luz acesa por 10 minutos, imediatamente antes do início de registro do sono por polissonografia noturna. Na manhã seguinte, o padrão respiratório foi monitorado por 10 minutos em repouso, os pacientes permaneciam sentados, seguido por teste de exercício cardiopulmonar em bicicleta ergométrica, com medida de fração expirada de CO2 e relação ventilação/CO2 (VE/VCO2). A presença dos distúrbios respiratórios do sono foi determinada através de polissonografia (índice de apnéia-hipopnéia 15 eventos/hora), os pacientes foram divididos nos grupos sem Distúrbio Respiratório do Sono (sem DRS), RCS e AOS. Os resultados estão apresentados como média ± desvio padrão. Resultados: Foram incluídos no estudo 47 pacientes, 5 foram excluídos por falta de coordenação motora e incapacidade de realizar o teste de exercício em bicicleta. O grupo final se constituiu de 42 pacientes (67% masculino, idade = 62±9 anos, fração de ejeção ventricular esquerda = 35±6%), sendo 22 do grupo sem DRS, 11 do grupo RCS e 9 do grupo AOS. Não houve diferenças significativas nos grupos nos parâmetros antropométricos e fração de ejeção...

Introduction: Sleep disordered breathing in the form of central sleep apnea and Cheyne-Stokes respiration (CSR) and obstructive sleep apnea (OSA) are common among heart failure (HF) patients and can independently contribute to morbimortality. CSR is an exaggerated form of periodic breathing (PB) in which central apneas alternate with periods of hyperventilation. In contrast, OSA results from recurrent collapse of upper airway during sleep. Objective: We hypothesize that PB while awake predicts CSR during sleep in patients with HF. Methods: Patients were recruited from one outpatient heart failure clinic (Instituto do Coração, InCor) in the period 2001 until 2003. All patients were submitted respiratory monitoring, for 10 minutes while awake in supine position immediately before overnight polysomnography. In the next morning, the patients were monitored for 10 minutes while sitting in a comfortable chair at rest, followed by cardiopulmonary exercise tests (electromagnetic-braked cycle). The presence of sleep disordered breathing was determined through polysomnography (apnea-hypopnea index 15 events/hour). The patients were divided according to the respiratory pattern during sleep in no-Sleep Disordered Breathing (no-SDB), CSR and OSA. Results: Forty seven patients were included in the study, 5 were excluded because of inability to perform exercise. The final group consisted of 42 patients (67% males, age: 62±9 yr, left ventricular ejection fraction: 35±6%). There were 22 in the no-SDB group, 11 in the CSR group and 9 in the OSA group. There were no significant differences among groups regarding anthropometric measurements and left ventricular ejection fraction. The CSR group presented a significantly increased proportion of NYHA functional class III-IV (p=0.03), lower PETCO2 (p=0.01) and increased VE/VCO2 slope (p=0.03) than no-SDB and OSA groups. PB while awake was present 19%, 31% e 36% before and during exercise and before sleep, respectively...

Efficacy of adaptive servoventilation in patients with congestive heart failure and Cheyne-Stokes respiration / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Congestive heart failure (CHF) is associated with Cheyne-Stokes respiration (CSR), which may hasten CHF. Adaptive servoventilation (ASV) is a novel method of ventilatory support designed for removal of CSF in CHF patients. This study compares the efficacy of ASV in patients with CHF and CSR with the efficacy of oxygen therapy.</p><p><b>METHODS</b>Fourteen patients with CHF and CSR were recruited. During sleep, nasal oxygen therapy and ASV treatment were each performed for two weeks. Comparison before and after each treatment was made for the following items: a) parameters of sleep respiration, sleep structure and quality; b) left ventricle ejection fraction (LVEF) and 6-minute walk distance.</p><p><b>RESULTS</b>Compared with the baseline levels of apnoea hypopnoea index of 34.5 +/- 6.1 before treatment, the apnoea hypopnoea index significantly decreased following oxygen therapy to 27.8 +/- 8.2, P < 0.05 and further reduced following ASV treatment to 6.5 +/- 0.8, P < 0.01. The minimal pulse oxygen saturation markedly increased following oxygen therapy from a baseline of (84.3 +/- 2.6)% to (88.6 +/- 3.7)%, P < 0.05 and further increased following ASV treatment (92.1 +/- 4.9)%, P < 0.01. Stages I + II sleep as percentage of total sleep time decreased from (81.9 +/- 7.1)% to (78.4 +/- 6.7)% following oxygen therapy and further to (72.4 +/- 5.0)% following ASV treatment. Stages III + IV sleep as percentage of total sleep time decreased from (8.4 +/- 5.5)% to (6.0 +/- 3.0)% following oxygen therapy and but increased to (11.9 +/- 5.4)% following ASV treatment. The arousal index of 30.4 +/- 8.1 before treatment significantly decreased following oxygen therapy to 25.6 +/- 5.7, P < 0.05 and further declined following ASV treatment to 18.2 +/- 6.1, P < 0.01. No significant difference was shown in above percentages between day 14 of oxygen therapy and before treatment (P > 0.05). LVEF was significantly higher on day 14 of ASV treatment (37.2 +/- 4.1)% than on day 14 of oxygen therapy (33.2 +/- 5.1)% and before treatment (30.2 +/- 4.6)% (all P < 0.05). Six-minute walk distance was the shortest before treatment (226 +/- 28) m, longer on day 14 of oxygen therapy (289 +/- 26) m, and the longest on day 14 of ASV treatment (341 +/- 27) m (all P < 0.01).</p><p><b>CONCLUSION</b>ASV treatment is of better efficacy and greater clinical significance in improvement of CHF by eliminating CSR than oxygen therapy.</p>

Cheyne-Stokes respiration in patients with congestive heart failure: causes and consequences

A respiração de Cheyne-Stokes é uma forma de respiração periódica na qual apnéias e hipopnéias se alternam com períodos de hiperpnéias que apresentam um padrão crescendo e decrescendo de volume corrente. Esta revisão enfoca as causa e conseqüências da respiração de Cheyne- Stokes em pacientes com insuficiência cardíaca congestiva na qual a prevalência é extremamente alta e varia entre 30 a 50%. Vários fatores foram implicados na gênese da respiração de Cheyne-Stokes, incluindo baixo debito cardíaco e hipoxia recorrente. Hiperventilacão e baixos níveis de CO2 arterial (PaCO2), que quando abaixo do limiar de apnéia desencadeiam apnéia central são os mecanismos fisiopatológicos chave na gênese da respiração de Cheyne-Stokes. Hiperventilação está associada com congestão pulmonar, e a respiração de Cheyne-Stokes tem uma tendência maior de ocorrer durante o sono, quando o centro respiratório é dependente principalmente do controle químico. A respiração de Cheyne-Stokes está associada a quedas recorrentes da saturação de oxigênio e ao despertar do sono, com oscilações recorrentes na freqüência cardíaca, pressão arterial, aumento da atividade simpática e risco aumentado de taquicardia ventricular. A respiração de Cheyne-Stokes é um marcador independente de mau prognostico e provavelmente participa de um ciclo vicioso que contribui para a deterioração cardíaca.

Distúrbios do sono / Sleeping disorders

Os autores inicialmente apresentam as bases diagnósticas e terapêuticas dos distúrbios respiratórios do sono (DRS), caracterizados basicamente pela apnéia obstrutiva e os roncos. Säo também discutidos aspectos da síndrome da apnéia-hipopnéia obstrutiva do sono (SAHOS), da síndrome da apnéia-hipopnéia central do sono (SAHCS), da síndrome da respiraçäo Cheyne-Stokes (SRCS) e da síndrome da hipoventilaçäo do sono (SHS). A seguir os autores apresentam as características clínicas da hipersônia primária e da narcolepsia, bem como o tratamento sintomático(estimulantes e narcóticos). Relatam também as características clínicas e terapêuticas da síndrome das pernas inquietas (SPI) e dos movimentos periódicos dos membros em sono (SMPMS). Finalizando, discutem as bases clínicas para o diagnóstico e a terapêutica das insônias (farmacoterapia e terapia cognitiva comportamental-TCC), das parassônias e dos distúrbios do ritmo circadiano.(au)

The mouse as an experimental model for tityus serrulatus scorpion envenoming

The scorpion toxin induces a number of physiological parameters alterations, as disturbance of cardiac rhythm, heart failure, shock, pancreatic hypersecretion, abortion, respiratory arrhytmias and pulmonary edema. As the purification of the venom fractions is a laborious process, one alternative for this would be the utilization of small animals. We utilized in the o present study thity-six mice that received progressive doses of scorpion toxin TsTX), i.p. or i.v., and were observed for three hours or sacrificed, and the pulmonary alterations were determined by the lung-body index and by histological analysis of the lungs in order to determine if the mouse can be an esperimental model for scorpion envenomation. The data were analyzed by One Way analysis of variance with p<0,05 indicating significance. These experiments showed no differences in clinical signs of scorpion envenomation between mice and other mammalians, the effects were dose-dependent and the i.v. administration needed less quantity to produce the same changings. In the pulmonary histology we observed septal but not alveolar edema, and we presumed that these differences are due to species-specific variations.

Fisiología y patología respiratorias durante el sueño en pediatría (1ra. parte) / Respiratory pathophysiology during sleep in pediatrics

Los mecanismos del control respiratorio sufren grandes modificaciones con el pasaje de la vigilia al sueño. A su vez en el sujeto dormido se observan diferencias en el funcionamiento respiratorio según el estadio de sueño en que se halle (REM o No REM). La diferenciación inicial entre estos estadios del sueño es muy precoz y su maduración se completa durante el primer año de vida. En este lapso se producen también importantes cambios en la anatomía y fisiología del aparato respiratorio. Las variaciones neurofisiológicas que se producen en el sueño (REM) originan una mayor labilidad de la mecánica respiratoria, que se exagera aún más en el niño pequeño por su inmadurez anatómica. En el sueño No REM el control respiratorio depende preponderantemente de los mecanismos autonómicos centrales. Estas particularidades se reflejan en el agravamiento durante el sueño de pacientes con diferentes desórdenes respiratorios y originan igualmente patologías de presentación exclusivamente asociadas al sueño, sin manifestaciones respiratorias durante la vigilia. Estos trastornos pueden tener múltiples consecuencias sobre la maduración, el desarrollo y el funcionamiento neurológico y cardiopulmonar. Se describen estas patologías agrupadas en tres categorías: 1) trastornos secundarios a la obstrucción de las vías aéreas superiores durante el sueño; 2) trastornos secundarios a la patología torácica; 3) trastornos del control respiratorio durante el sueño. Se discuten la clínica, fisiopatología, y terapéutica de estas entidades. Se discute igualmente la metodología diagnóstica, basada en el registro simultáneo de múltiples variables fisiológicas durante el sueño. Se excluyen de esta actualización los aspectos relacionados con la fisiología y patología del recién nacido pretérmino