Anatomia y fisiologia de la obstruccion de via aerea superior
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Este documento describe la anatomía y fisiología de la obstrucción de la vía aérea superior, incluidos los músculos dilatadores, la presión intraluminal negativa, y las propiedades de la faringe. Explica los factores estáticos y dinámicos que influyen en la vía aérea faríngea, como la resistencia nasal y faríngea, el efecto Bernoulli, y la activación de los músculos faríngeos. También analiza las diferencias anatómicas en pacientes con apnea del sueño, como el t
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Anatomia y fisiologia de la obstruccion de via aerea superior
- 1. ANATOMÍA Y FISIOLOGÍA DE LA OBSTRUCCIÓN DE VIA AEREA SUPERIOR UNIVERSIDAD AUTONOMA DE SINALOA HOSPITAL CIVIL DE CULIACAN CENTRO DE INVESTIGACIÓN Y DOCENCIA EN CIENCIAS DE LA SALUD OTORRINOLARINGOLOGÍA Y CIRUGÍA DE CABEZA Y CUELLO DR. ANGEL CASTRO URQUIZO R1 ORL CULIACAN SINALOA FEBRERO 2017
- 4. Anatomía vía aérea superior normal Cav. nasal Nasofaringe • Retropalatina (RP) • Retroglosa (RG) Orofaringe Hipofaringe
- 6. Anatomía vía aérea superior normal Pared anterior: • Paladar blando • Lengua Pared Posterior: • Mc. constrictores Pared Lateral: • Musculos: Hiogloso, estilogloso, estilohioideo, estilofaringeo, palatofaringeo, palatogloso, Mm. Constrictores. • Tej. Linfoide • Grasa parafaringea
- 7. Anatomía vía aérea superior normal
- 9. Propiedades normales de la vía aérea faríngea Faringe en ausencia de actividad muscular faríngea (condición pasiva). Relación entre área transversa aérea y presión transmural. Ptm = PI - Pti > Ptm = > A
- 10. Propiedades normales de la vía aérea faríngea
- 11. Propiedades normales de la vía aérea faríngea
- 12. Factores estáticos que influyen en la vía aérea faríngea Fuerzas adhesivas superficiales (FAS) Respiración nasal con boca cerrada FAS mantienen el paladar blando en contacto con base de lengua y promueve contacto de lengua con mucosa de cavidad oral. Abrir la boca libera las uniones. Reducción de estas fuerzas con Surfactante moderada reducción del colapso durante el sueño.
- 13. Factores estáticos que influyen en la vía aérea faríngea Posición mandibular y de cuello Flexión –> cierran VA Extensión–> abren VA Apertura mandibular Aumenta tamaño Faríngeo
- 14. Factores estáticos que influyen en la vía aérea faríngea Posición mandibular y de cuello Apertura progresiva Movimiento posterior del tubérculo geniano. Tubérculo mueve cerca de la pared faríngea posterior Lengua y hiodes hacia atrás Cierre de VA.
- 15. Factores estáticos que influyen en la vía aérea faríngea Fuerzas axiales Mayor volumen pulmonar incremento área faríngea, vía aérea mas rígida Mayor vol. Pulmonar desplazamiento caudal traqueal Tensión axial en paredes faríngeas apertura faríngea 4 mecanismos
- 17. Factores estáticos que influyen en la vía aérea faríngea Gravedad
- 18. Factores dinámicos que influyen en la vía aérea faríngea Resistencia vía aérea nasal Incremento de resistencia > presión negativa intraluminal Disminución del área faríngea
- 19. Factores dinámicos que influyen en la vía aérea faríngea Resistencia vía aérea faríngea > resistencia > presión negativa intraluminal Estrechamiento en región retropalatina disminuye presión intraluminal inspiratoria caudalmente Aumenta cierre en región retroglosa e hipofaringe
- 20. Factores dinámicos que influyen en la vía aérea faríngea Efecto Bernoulli Fenómenos promueven una reducción en la presión intraluminal a medida que el aire pasa por el tubo. Contribuye a disminuir presión intraluminal inspiratoria estrecha faringe durante inspiración. Disminución de lumen faríngeo velocidad de flujo aumenta Aumento de energía cinética disminución en presión de distención estrechamiento
- 21. Factores dinámicos que influyen en la vía aérea faríngea Inicio de espiración: Presión positiva Aumento del calibre Fin de espiración: Reducción de la presión disminuye calibre. OSA: Final de espiración y en inspiración
- 23. Músculos faríngeos: Activación Mas de 20 músculos Se activan en la inspiración Dilatan las vías respiratorias
- 24. Efectos positivos Tensor paladar paladar hacia adelante Geniogloso Lengua hacia adelante Mm pared faríngea anterior hioides hacia adelante Palatofaringeo y glosofaríngeo Apertura retropalatina Efectos antagónicos • Levator palatini y constrictor superior Cierre retropalatino. • Extrínsecos linguales Protruyen y retraen lengua
- 26. Músculos faríngeos: Factores que modulan la activación • Alcohol • Privación del sueño • Anestesia • Sedantes - hipnóticos Suprimen activación m. faríngeos • Estado de alerta • Modulación sensorial de músculos faríngeos • Estímulos químicos Otros factores
- 28. Músculos faríngeos: Factores que modulan la activación Cambios en el estado Resistencia supraglotica en OSA Alta en la vigilia Aun mas alta en el sueño > Resistencia supraglotica 4 a 5 veces Durante el sueño from 1 to 2 cm H2O/L/sec during wakefulness to 5 to 10 cm H2O/L/sec during sleep Modificación neuromuscular en el sueño < Actividad geniogloso > Resistencia supraglotica
- 29. Músculos faríngeos: Factores que modulan la activación Modulación sensorial de músculos faríngeos Feedback neurosensorial torácico y faringeo Tráquea superior y laringe (NLS) Glosofaríngeo y trigémino Mecanismo de defensa durante el sueño -Neuropatía -Anormalidades sensoriales
- 30. Músculos faríngeos: Factores que modulan la activación Estímulos químicos Neuronas hacia los músculos torácicos tienen umbrales de CO2 mas bajos que los músculos faríngeos. > Co2 Actividad inicia en nervio frénico
- 31. Diferencias anatómicas de vía aérea en pacientes con apnea del sueño Área transversal faríngea mas pequeña en OSA Secundaria ampliación de tej. Blandos circundantes, cambios craneofaciales Retrognatia Hioides inferior Retropalatino Edema, >peso, lesión, genero, genética
- 34. Diferencias anatómicas de vía aérea en pacientes con apnea del sueño: Edema Presión negativa durante cierre de VA o trauma por eventos de apnea Edema Principalmente paladar blando Edema en geniogloso, úvula Asociado en IC, IR
- 35. Diferencias anatómicas de vía aérea en pacientes con apnea del sueño: Distribución grasa y peso corporal Tamaño de cuello >IMC - > % de grasa lengua, úvula Hipertrofia muscular
- 39. Diferencias anatómicas de vía aérea en pacientes con apnea del sueño: Miopatía de vía aérea superior Hipótesis En OSA miopatía que contribuye a ampliación de VRA. Mayor cantidad de fibras tipo II en geniogloso(Pacientes con OSA) Fibras tipo II son mas fatigables ¿Causa o consecuencia?
- 40. Diferencias anatómicas de vía aérea en pacientes con apnea del sueño: Sexo VA faríngea mas pequeña en mujeres. Circunferencia de cuello es mas pequeña en mujeres. Estructuras blandas mas pequeñas en mujeres. Grasa en cuello mayor en hombres Tamaño de lengua, paladar blando, etc mayor en hombres.
- 41. Diferencias anatómicas de vía aérea en pacientes con apnea del sueño: Genética Rol importante Macroglosia Trisomía 21 Características craneofaciales ApoE4
- 44. Efectos en el tratamiento de OSA: perdida de peso 5-10% Disminuye colapso Dism. Grasa cuello Disminuye tamaño de tejidos blandos Aumento de VA
- 45. Efectos en el tratamiento de OSA: CPAP Suprime actividad muscular en VA superior > presión transmural positiva faríngea > calibre Antes se creía que aumentaba el calibre desplazando lengua y paladar blando Aumento progresivo de CPAP (15-20 cm H2O) incremento de calibre VA Dimensiones laterales >volumen vía aérea > área retropalatina y retroglosa.
- 47. Efectos en el tratamiento de OSA: aparatos orales Aparatos de avance mandibular. Aumentan calibre en área retroglosa. Aumenta mas en dimensiones laterales Mecanismo no completamente entendido.
- 48. Efectos en el tratamiento de OSA: UPPP Qx mas común en OSA Tonsil, uvula, margen distal paladar blando, tej. Faringeo excesivo Pacientes con obstrucción retropalatina con mejores resultados Tasa éxito 50% Estrechamiento persistente
- 50. Principles and Practice of Sleep Medicine, 5th Edition, by Meir H. Kryger, MD, FRCPC, Thomas Roth, PhD, and William C. Dement, MD
Notas del editor
- Kryger 1153
- Pharyngeal airway patency is maintained by a balance of forces between the activity of the upper airway muscles that dilate and stiffen the airway and negative intraluminal pressure. However, this balance can be disturbed by abnormalities in upper airway anatomy and neural control. Abnormal upper airway anatomy and possibly abnormal neural control during sleep can lead to pharyngeal airway collapse in patients with OSA
- The upper airway includes the extrathoracic trachea, larynx, pharynx, and nose. This chapter focuses on the pharynx because it is the site of upper airway narrowing and closure during sleep in patients with obstructive sleep apnea (OSA). Normally, the pharynx remains open at all times, except during momentary closures associated with swallowing, regurgitation, eructation, and speech. Pharyngeal patency during wakefulness, with integration and coordination of its various physiologic functions, is in large part attributable to continual neuromuscular control by the central nervous. The sleep state is associated with a decrease in neuromotor output to pharyngeal muscles. When this occurs against the background of anatomic abnormalities of the upper airway, the pharyngeal airway can become severely narrowed or can close.
- Retropalatino: margen posterior del paladar duro al margen caudal del paladar blando Retrogloso: margen caugal del paladar blando a la base de epiglotis. Hipofaringe de base de lengua y epiglotis hasta laringe
- Figure 101-1 A, Midsagittal magnetic resonance image (MRI) in a normal subject highlighting the four upper airway regions: the nasopharynx, which is defined from the nasal turbinates to the hard palate; the retropalatal (RP) oropharynx, extending from the hard palate to the caudal margin of the soft palate; the retroglossal (RG) region from the caudal margin of the soft palate to the base of the epiglottis; and the hypopharynx, which is defined from the base of the tongue to the larynx. B, This diagram demonstrates important midsagittal upper airway, soft tissue, and bone structures. Themajority of patients with OSA manifest upper airway narrowing and closure during sleep in the retropalatal region, the retroglossal region, or both.1,2
- The mandibular rami bound all the structures that form the lateral pharyngeal walls
- Axial MRI in a normal subject in the retropalatal region. The tongue, soft palate, parapharyngeal fat pads (fat is white on MRI), lateral parapharyngeal walls (muscles betweenthe airway and lateral parapharyngeal fat pads) and mandibular rami can all be visualized on this axial MRI.
- Figure 101-3 Midsagittal MRI in a normal subject depicting the midretropalatal (RP) and midretroglossal (RG) regions.
- Transmural es la diferencia entre intraluminal y presión de tejidos. The concept of transmural pressure (Ptm) and a tube law of the pharynx are schematized. Ptm is defined as intraluminal pressure (P1) minus surrounding tissue pressure (Pti) An increase in transmural pressure, caused either by morepositive intraluminal pressure or more-negative tissue pressure, distends and enlarges the airway area. Conversely, a decrease in transmural pressure, caused either by more-negative intraluminal pressure or more-positive tissue pressure, narrows the airway.
- An increase in Ptm results in an increase in the cross-sectional area (A) in accordance with a tube law of the pharynx. The slope of the tube law represents compliance of the pharynx. Pclose, closing pressure; Pti, tissue pressure. This relationship is referred to as the tube law and describes the dependence of cross-sectional area on transmural pressure. The closing pressure (Pclose) is the transmural pressure when cross-sectional airway area reaches zero (i.e., complete obstruction), and the point at which the curve reaches a plateau is the maximum airway area. The slope of the line at any point in the relationship (ΔA/ΔPtm) is the effective compliance at that particular transmural pressure. A number of mechanical factors (Box 101-1) influence the upper airway to cause it to be fully open, narrowed, or closed
- number of mechanical factors (Box 101-1) influence the upper airway to cause it to be fully open, narrowed, or closed. These factors, classified as static and dynamic, interact with the tube law of the pharynx to determine, at any time, the crosssectional area of the airway.
- Neck flexion The retropalatal and retroglossal regions of the pharyngeal airway are narrowed as the neck is flexed. Opening the jaw slightly can actually increase the size of the pharynx by providing more room in the oral cavity for the tongue.
- Figure 101-5 Jaw opening results in a posterior and caudal displacement of the genial tubercle of the mandible, as well as the floating hyoid bone, through the many hyomandibular attachments. As a result, the anterior pharyngeal wall structures such as the tongue and epiglottis move in a posterior direction, decreasing pharyngeal airway size. Neck flexion would have a similar effect on the hyoid, tongue, and epiglottis even without a change in the relationship between the mandible and the maxilla. This posterior movement of the genial tubercle of the mandible with mouth opening causes the tongue and hyoid apparatus to move posteriorly, and thereby narrows the pharyngeal airway.
- Aumento – tiron traqueal Increases in lung volume are thought to increase pharyngeal cross-sectional area, reduce closing pressure stiffen the upper airway.8,9 This action may be exerted through axial forces in the trachea, called tracheal tug. Increasing lung volume airway. The resulting passive axial tension in the pharyngeal wall tends to open the pharynx. There are at least four mechanisms by which caudal traction on the upper airway may improve airway patency
- Possible mechanisms that can explain how tracheal traction on the upper airway protects upper airway patency. As the upper airway is pulled toward the thorax, folding may be reduced in the walls of both the larynx and oropharynx. Second, stretching should stiffen the upper airway and make it more resistant to collapse. Caudal displacement of fat and other structures surrounding the pharynx can reduce extrinsic compression of the airway. Finally, caudal traction can improve airway patency through its mechanical effect on the hyoid apparatus.
- Gravity also has an important influence on pharyngeal airway patency and it is common for patients with OSA to have a higher apnea-hypopnea index in the supine than in the nonsupine position. When the patient is supine, gravity can help to narrow the pharyngeal airway by pulling the tongue and soft palate in a posterior direction.11
- This driving pressure for inspiratory airflow is generated by reduction in nasopharyngeal pressure secondary to active contraction of the diaphragm and other inspiratory pump muscles. flow pattern is turbulent, characteristics that are enhanced when the nasal airway is narrowed by such conditions as mucosal congestion, nasal polyps, and turbinate hypertrophy. These factors increase nasal airway resistance during inspiration. The extent to which the lumen narrows depends on regional airway compliance, that is, the relative compliance of each segment.
- As is the case with nasal resistance, a high resistance within the pharynx is associated with a more-negative intraluminal pressure in more caudal (more downstream) segments during inspiration. In other words, a narrowing at the retropalatal region is associated with a further decline in intraluminal pressure during inspiration at sites caudal to the retropalatal region, thereby increasing the tendency for closure in the retroglossal region and hypopharynx.
- the conversión of energy from static to kinetic caused by an increase in the velocity of airflow when cross-sectional airway area Decreases. The first phenomenon relates to upstream resistance to airflow. Whenever gas flows through a resistance, potential energy is dissipated in overcoming friction and, consequently, intraluminal pressure decreases. The second phenomenon relates to acceleration of gas as it flows through a narrowed segment of a tube. Both phenomena contribute to decreasing pharyngeal intraluminal pressure during inspiration; therefore, both tend to narrow the pharynx during inspiration. If the cross-sectional area of the pharyngeal lumen decreases in some regions, the velocity of airflow is elevated in these regions
- In early expiration (positive airway pressure due to chest wall recoil), airway caliber increases, and toward the end of expiration (reduction in positive airway pressure and the upper airway dilator muscles remain inactive), the airway narrows.1 Patients with OSA are at risk for airway closure at the end of expiration and in inspiration
- Figure 101-13 Diagram of the changes in upper airway area as a function of tidal volume during the respiratory cycle. Airway caliber is relatively constant in inspiration (phases 1 and 2), whereas airway size increases in early expiration (phase 3) and decreases in late expiration (phase 4). The finding that upper airway caliber is smallest at the end of expiration may have important implications with regard to the timing of sleep-induced upper airway closure.
- Endurecen las paredes Aumenta P transmural, aumenta area
- Figure 101-7 A, Schematic diagram of upper airway anatomy. The tensor palatini moves the soft palate ventrally. The genioglossus acts to displace the tongue ventrally. Coactivation of the muscles in the anterior pharyngeal wall such as the geniohyoid and sternohoid act on the hyoid bone to move it ventrally. B, Schematic diagram of upper airway muscles. Among the many upper airway muscles attaching to the floating hyoid bone are the genioglossus, geniohyoid, hyoglossus, middle pharyngeal constrictor, sternohyoid, and digastric. Similarly, the extrinsic tongue muscles can have antagonistic effects; namely, the genioglossus and geniohyoid protrude the tongue and the hyoglossus and styloglossus retract it. --The hyoid bone in humans, unlike that in other mammals, does not articulate with any other bony or cartilaginous structure. The position of the hyoid bone is determined by the muscle attachments to this floating bony structure. Muscles inserting on the hyoid include the geniohyoid and genioglossus. Contraction of these muscles pulls the hyoid in a rostral and anterior direction. Strap muscles originating from the sternum (sternohyoid) and thyroid cartilage (thyrohyoid) also insert on the hyoid and pull it in a caudal direction. With simultaneous contraction of all four muscles, the resultant force vector acting on the hyoid is directed caudally and anteriorly. This combined effect moves the anterior pharyngeal wall outward, can stiffen the lateral pharyngeal walls, and promotes upper airway patency. Another example of coactivation of muscles and upper airway patency involves the tongue. Evidence indicates that simultaneous activation of the antagonistic protrudor and retractor tongue muscles, as occurs under hypercapnic and hypoxic conditions, has a synergistic effect in promoting upper airway patency.16
- Curva donde se ven cambios en presion mscular,, en estado pasivo, al activarse se obstiene mayor area por aumento de la presion transmural Figure 101-8 Airway area under passive conditions (i.e., no muscle activation) can be increased by a rise in transmural pressure (Ptm). Such a change occurs with the application of a positive intraluminal pressure, such as with nasal continuous positive airway pressure (CPAP). Contraction of pharyngeal dilators shifts the passive curve up and to the left. The muscle contraction increases Ptm, and (P2-P1) now represents Pmus (muscle pressure). The effect of pharyngeal dilator muscle activation on the tube law of the pharynx is shown in Figure 101-8. Under active conditions, the pressure–area relationship is shifted upward and to the left. At any given transmural pressure, muscle activation increases airway area and stiffens the airway, that is, decreases effective compliance. The effect of muscle activation on the tube law is quantified by the term Pmus, the effective pressure exerted by muscle activation, equivalent to the change in transmural pressure required to yield the equivalent change in area on the passive curve
- Figure 101-9 Balance of forces that sustain upper airway patency. The two major forces are airway suction pressure and upper airway muscle tone that dilates and stiffens the airway. These in turn are influenced by other factors. Additional factors that modulate respiratory-related activity of pharyngeal airway motoneurons include changes in state, proprioceptive feedback, and chemical drive (Fig. 101-9).
- Aumenta la Resistencia de 4 a 5 veces durante el sueño That modification of neuromuscular factors (e.g., decrease in genioglossus activity) by sleep is a normal physiologic phenomenon can be inferred from measurements of supraglottic resistance, the airflow resistance extending from the nares to the region above the glottis in normal subjects in whom supraglottic resistance increases fourfold to fivefold with sleep onset. EMG recordings of pharyngeal muscles, such as the genioglossus and tensor palatini, confirm this decrease in pharyngeal muscle activity during the transition from wakefulness to sleep.23,24 An even more pronounced reduction in motor output to pharyngeal muscles occurs in rapid eye movement (REM) sleep, particularly in phasic REM.
- Ramia interna del LS, Sensory information from the upper airway is also transmitted in the glossopharyngeal and trigeminal nerves. Evidence indicates that there is a sensory-neural abnormality in patients with sleep apnea with impaired upper airway sensation, which is partially reversible with continuous positive airway pressure (CPAP). Repeated episodes of snoring and vibration at night have also been thought to lead to progressive local neuropathy. 40,41 Both the upper airway sensory abnormalities and neuropathy could explain the progressive worsening of sleep apnea over time.
- The airway narrowing has been shown to be primarily in the retropalatal region. Reduction in mandibular body length, in particular, has been shown to be an important risk factor for obstructive sleep apnea. In addition to craniofacial differences, enlargement of the upper airway soft tissue structures (tongue(Mm. geniogloso), lateral pharyngeal walls, soft palate, parapharyngeal fat pads) has also been demonstrated in patients with OSA compared to normal persons.42,43 There are several possible explanations for the enlargement of the upper airway soft tissue structures in OSA patients including edema, weight gain, muscle injury, gender, and genetic factors.
- A, Midsagittal MRI of a normal subject (left) and a patient with sleep apnea (right). The upper airway is smaller and the soft palate is longer in the patient with sleep apnea. The amount of subcutaneous fat (white area at the back of the neck) is greater in the apneic than in the normal subject.
- B, Axial MRI in the retropalatal region of a normal subject (left) and a patient with sleep apnea (right). The upper airway is smaller (primarily narrowed in the lateral dimension) in the patient with sleep apnea. There is more subcutaneous fat in the patient with sleep apnea.
- pueden causar edema en el tejido blando Estructuras que rodean la vía aérea superior. Paladar blando está especialmente en riesgo de desarrollar edema Puede ser tirada caudalmente y traumatizada durante las apneas IC, IR: Sobregarga hídrica Aumento de la PVC
- *Depositos de grasa en cuello *primarily enlargement of the lateral parapharyngeal fat pads *Tamaño de cuello mejor predictor que el IMC Neck Circumference: ³17 inches(43) (male) and ³15.5 inches(40) (female); most predictive indicator of OSAS *¡hipertrofia secundario primero a obesidada o al SAOS? *predispose to OSA by increasing the size of the muscular soft tissue structures (tongue, soft palate, lateral pharyngeal walls *This hypothesis is supported by data in obese nonapneic women that show that weight loss decreases the volume of the lateral pharyngeal walls and parapharyngeal fat pads
- Volumetric reconstruction of axial MR images in a normal subject and patient with sleep apnea. The mandible is depicted in white, the tongue in red, the soft palate in blue, the lateral parapharyngeal fat pads in yellow, and the lateral-posterior pharyngeal walls in green. The airway is depicted in gray. The normal subject has a larger airway than the patient with sleep apnea. The tongue, soft palate, parapharyngeal fat pads, and lateral pharyngeal walls of the patient with sleep apnea are all larger than in the normal subject.
- A, Axial MRIs of a normal subject, before and after weight loss in the retropalatal region. Airway area and lateral airway dimensions increase with weight loss. The thickness of lateral pharyngeal walls and the size of the parapharyngeal fat pads decrease with weight loss.
- Volumetric reconstructions of the upper airway soft tissues and craniofacial tissue before and after weight loss in a normal subject: soft palate (purple), tongue (orange/rust), lateral pharyngeal walls (green), parapharyngeal fat pads (yellow), and mandible (gray). The size of the upper airway increases with weight loss. The lateral pharyngeal walls and the parapharyngeal fat pads demonstrated the largest reductions in size with weight loss. Mandibular volume did not change with weight loss.
- VRA: vías resp. Altas *cambios en las propiedades contráctiles. *Type II fibers are more likely to fatigue than type I fibers; therefore, the upper airway muscles in patients with OSA would be more susceptible to fatigue than those of normal subjects *Miopatia ¿causa o consecuentcia? *these fiber changes in the genioglossus muscle were reversed with CPAP.
- Hombres acumulan mas grasa arriba, mujeres abajo *However, two studies have examined gender-related differences in upper airway soft tissue structures in normal subjects with MRI,69,76 and while both showed that the size of the tongue, soft palate, and total soft tissue were greater in normal men than women,69, *
- *Genetic factors play an important role in determining the size of the upper airway soft tissue structures. Family aggregation of craniofacial anatomy (reduction in posterior airway space, increase in mandibular to hyoid distance, inferior hyoid placement) has been shown in patients with OSA. DISTINCIONES SE HEREDAN
- A typical tracing derived from a patient with obstructive sleep hypopnea. A submental electromyogram (EMG) indicates rhythmical bursting of pharyngeal inspiratory muscles. SaO2 reveals stable mild hypoxemia. Airflow demonstrates flow limitation during inspiration. Despite a progressively larger driving pressure during an inspiratory effort (time between dashed vertical lines), flow remains constant, which indicates increasing resistance during inspiration, presumably resulting from progressive narrowing of the pharyngeal lumen. The thickened tracing at this time results from high-frequency oscillation in airflow caused by snoring. EEG, electroencephalogram; EOG, electrooculogram; MIC, microphone; Peso, esophageal pressure; RESPabd, abdominal motion; SaO2, arterial oxygen saturation; V, volume; V, airflow.
- MRI in the retropalatal region of a normal subject during wakefulness and sleep. Airway area is smaller during sleep in this normal subject. The state-dependent change in airway caliber is a result of decreases in the lateral and anterior–posterior airway dimensions. Thickening of the lateral pharyngeal walls is demonstrated during sleep
- The following sections review data on the effect of weight loss, CPAP, oral appliances, and surgery on upper airway size and the surrounding soft tissue and craniofacial structure. The purpose of this section is to illustrate how these therapeutic interventions influence upper airway pathophysiology. However, the mechanism by which weight loss improves OSA, increases the size of the upper airway, and changes the size and configuration of the upper airway soft-tissue structures (soft palate, tongue, parapharyngeal fat pads, lateral pharyngeal walls) is not known It has been hypothesized that weight loss decreases the volume of the parapharyngeal fat pads, which, in turn, could increase the size of the upper airway. Alternatively, weight loss might decrease the size of the tongue or other upper airway soft tissue structures.
- Progressive increases in CPAP (up to 15 cm H2O) not only increase airway caliber in the lateral dimension but also significantly increase airway volume (threefold increase) and airway area in the retropalatal and retroglossal regions
- A, Volumetric reconstruction of the upper airway with progressively greater continuous positive airway pressure (CPAP) (0 to 15 cm H2O) settings in a normal subject. There are significant increases in upper airway volume in the retropalatal and retroglossal regions with higher levels of CPAP. B, Axial MRI in a normal subject at two levels of CPAP (0 and 15 cm H2O) in the retropalatal region. Airway area is significantly greater at 15 cm H2O. The airway enlargement is predominantly in the lateral dimension. Airway enlargement with CPAP results in thinning of the lateral pharyngeal walls, although the parapharyngeal fat pads are not displaced.
- Adelantan mandibula y tiran lengua hacia delante Mas en retrofgloso que en retropalatino
- Mejores resultados con obst. Retropalatina que retroglosa Extio no tan aceptable. Morefavorable results with UPPP have been demonstrated if the surgery reduces the critical closing pressure.102 Thus far, the biomechanical changes in the upper airway soft tissue structures that underlie the efficacy, or lack of efficacy, of UPPP have not been identified.1,49,103. Persistent upper airway narrowing in the nonresected portion of the soft palate after UPPP might explain why UPPP has not been more successful in treating patients with OSA.
- A, Midsagittal MRI in a patient with sleep apnea before and after an uvulopalatopharyngoplasty. The uvula is shorter after the uvulopalatopharyngoplasty. However, the airway remains narrow in the region where the soft palate is not resected. B, Axial MRI before and after uvulopalatopharyngoplasty in the region where the uvula was resected. Airway caliber increases substantially after the uvulopalatopharyngoplasty in this region of the airway