Upper airway obstruction-What is on the airway obstruction?
Upper airway obstruction (UAO) is severely hampered by a variety of reasons due to upper airway airflow medical emergency, its clinical manifestations are not specific, confused easy with bronchial asthma and obstructive pulmonary disease, and other diseases. The disease is more common in children and rare in adults. There is no specific clinical manifestations of upper airway obstruction, manifested as irritating dry cough, shortness of breath and difficulty breathing; mainly dyspnea breathing difficulties, activities can cause breathing difficulties increased significantly, and often occur due to changes in posture array onset seizures.
Upper airway obstruction - Description
Upper airway obstruction - DescriptionAirway obstruction in the upper airway obstruction (upperairwayobstruction, UAO) is severely hampered by a variety of reasons due to upper airway airflow medical emergency, its clinical manifestations are not specific, easy with bronchial asthma and obstructive pulmonary disease and other diseases confused. Clinically, the disease is more common in children is relatively rare in adults. Upper airway obstruction caused by many reasons, which derived foreign matter other than those caused by the most common, and the rest of the more common laryngeal movement disorders, infections, tumors, trauma, and iatrogenic. Timely understanding and treatment of upper airway obstruction has extremely important clinical implications, since the majority of patients with previously healthy, can be fully recovered by the effective treatment.Upper airway obstruction - symptoms and signs
Airway obstruction in the upper airway obstruction early general without any performance, often start blocking more serious symptoms. Acute upper airway obstruction abrupt onset, severe illness, and even lead to suffocation and death, often obvious signs and symptoms. There is no specific clinical manifestations of upper airway obstruction, manifested as irritating dry cough, shortness of breath and difficulty breathing; mainly dyspnea breathing difficulties, activities can cause breathing difficulties increased significantly, and often occur due to changes in posture array onset seizures. A small number of patients with snoring at night, awakened several times and dyspnea, manifested as sleep apnea syndrome. Caused by inhalation of foreign bodies, choking history, often obvious respiratory distress, looked very painful, from time to time scratching throat. Occasionally chronic upper airway obstruction caused by pulmonary edema and recurrent pulmonary edema performance. The symptoms and signs of upper airway obstruction and the extent and nature of the obstruction. The majority of upper airway obstruction seen in clinical incomplete obstruction. The main signs of inspiratory stridor, significantly more than in the neck, the lungs can also be heard and but weak, sniff can cause wheezing significantly increased. Stridor prompted more serious obstruction, airway diameter is often less than 5 mm. The inspiratory stridor multi prompted extrathoracic upper airway obstruction, more common on the vocal cords or vocal parts; biphasic stridor prompted obstruction breath of song's intensity changes and more tips in the subglottic trachea; curved neck obstruction occurred The thorax the entrance. Children are barking cough, especially at night appear more tips as bronchitis, throat, salivation, difficulty swallowing, fever but no cough is more common in severe epiglottitis. Some patients, there may be a change in sound, location and nature of its changing characteristics and disease, such as unilateral vocal cord paralysis hoarseness; bilateral vocal cord paralysis sound normal, but the wheezing; the glottis over parts lesions often appear low voice , but no hoarseness; the oral abscess contents like sound.
Upper airway obstruction - disease etiologyClinical, upper airway obstruction, although relatively rare, but may be caused by a variety of diseases, such main reasons include: ① airway cicatricial stenosis: multi-intubation or incision treatment; ② airway wall lesions: such as inflammation of the soft tissue of the throat, pharyngeal abscess, enlarged tonsils, vocal cord paralysis, laryngeal or tracheal tumor, tracheomalacia, recurrent polychondritis go far; ③ airway cavity lesions: airway foreign body is more common, and with pedicle endotracheal polyps or tumors and inflammatory granuloma; ④ airway the external oppression: around the airway space-occupying lesions such as thyroid cancer, abscess, hematoma or gas compression; ⑤ airway secretions retention: respiratory tract bleeding or a large number of sputum failed to cough up the large number of inhalation of gastric contents. The cause common cause of upper airway obstruction in adults and children of different anatomical sites, are summarized in Table 1, for reference in clinical diagnosis. A handful of cases, the functional vocal cord abnormalities or psychological factors, may also cause upper airway obstruction.
Upper airway obstruction - pathophysiologicalUpper airway obstruction airway anatomy: the conducting airways of the respiratory system, including the nose, throat, trachea, main bronchus, lobe bronchus and segmental bronchi, bronchioles until the terminal bronchioles part. Different mechanics and other respiratory physiological functions around the small airways and central airways of the respiratory tract is generally divided into three parts: (1) the small airways, airway diameter less than 2mm; ② large airways refers to Long protruding below to 2mm diameter airway; ③ The upper airway, from the nose to carina period of the respiratory tract, including the nose, pharynx, larynx and trachea. Usually pleural entrance or sternum notch is bounded by the upper extrathoracic upper airway and intrathoracic airway is divided into two parts of the upper airway. The extrathoracic on airway mandibular inferior vena (including a region of Ludwig angina), the retropharyngeal chamber (including the produce area retropharyngeal abscess) and throat. Generalized throat to the base of the tongue, down to the trachea, can be divided into the supraglottic larynx (epiglottis, aryepiglottic fold and false vocal cords), glottis (including the the arytenoid vocal cords plane structure) and subglottic area (about 1.5 ~ 2.0cm, cricoid surrounding the airways). The total length of the trachea for l0 ~ 13cm, wherein a length of about 6 intrathoracic ~~ 9cm. The extrathoracic tracheal length of about 2 ~ 4cm, the entrance to the chest from the lower edge of the cricoid, front chest about above the suprasternal notch 1 to 3cm. Normal endotracheal coronal diameter, male the l3 ~ 25mm, 10 ~ 21mm female. Cause tracheal diameter narrowing factors are the following: (1) Saber sheath trachea; ② amyloidosis; ③ recurrent polychondritis; ④ Wegener granulomatosis; the ⑤ tracheobronchial flat osteochondral angioplasty; of ⑥ rhinoscleroma disease; ⑦ complete cricoid ; ⑧ Down syndrome. Pathophysiology of upper airway obstruction: Under normal circumstances, when breathing, respiratory muscle contraction intrathoracic pressure lower airway pressure below atmospheric pressure, the gas from the outside world into the lungs; Instead, breath, respiratory muscle relaxation chest The increased pressure within the gas excreted by the lungs. Acute upper airway obstruction can directly affect the ventilation function of the body, the oxygen of the outside world can not be inhaled into the lungs, the carbon dioxide produced by the metabolism can not be eliminated from the body, causing acute respiratory failure, such as failure to obtain timely medical treatment, every serious shortage oxygen and carbon dioxide retention leads to death. Chest part of the upper airway at atmospheric pressure under the intrathoracic part in the pleural cavity under pressure role. The trachea both sides of the inside and outside pressure difference for the cross-wall pressure. Pleural cavity pressure greater than the outside pressure when the trachea, cross-wall positive pressure airway tend to close; pressure is greater than when the transmural pressure is negative, endotracheal the tracheal outside pressure, tracheal smooth. Upper airway obstruction affecting the patient's ventilatory function, due to the decrease in alveolar ventilation, airway obstruction can be produced in the patient's movement on Health hypoxemia, but its mostly normal dispersion function. Upper airway obstruction location, extent, nature (fixed or variable type) and expiratory or inspiratory pressure changes caused by patients with different pathophysiological changes produce inspiratory airflow limitation, expiratory airflow limitation, or both limited. Clinically, depending on the respiratory airflow obstruction of upper airway obstruction is divided into the following three kinds: variable extrathoracic airway obstruction, of variable intrathoracic upper airway obstruction and a fixed upper airway obstruction.A variable extrathoracic upper airway obstruction variable blocking the tracheal lumen of the size of the site of obstruction may be due to the tracheal changes in the internal and external pressures and changes in the upper airway obstruction. Variable extrathoracic upper airway obstruction found in patients suffering from diseases such as tracheomalacia and vocal cord paralysis. Under normal circumstances, the chest on the outer periphery of the airway pressure throughout the respiratory cycle are under atmospheric pressure, the inspiratory airway pressure decreases, causing the cross-wall pressure increases, and its direction of action grounds tube outward tube, causing chest on the gas Road tend to shrink. Variable extrathoracic upper airway obstruction in patients, sniff, the result of the Venturi effect and turbulence the obstruction distal airway pressure was significantly reduced, significantly increased transmural pressure caused by the obstruction site of airway caliber further narrow The inspiratory airflow serious disruption; contrary, when its forced expiratory endotracheal pressure increased, due to the cross-wall pressure decreases, the extent of blocking eased. Therefore, in this patient dynamic flow - volume loop tracings showed inspiratory flow limitation and showed inspiratory and expiratory flow limitation lighter does not appear platform, or even render normal graphics.Variable intrathoracic upper airway obstruction variable intrathoracic upper airway obstruction, seen in intrathoracic airway of tracheomalacia and tumor patients. Intrathoracic airway pressure around the pleural cavity pressure close to the external pressure (pleural cavity pressure) intraluminal pressure compared to the negative pressure in the lumen, the direction of action of the cross-wall pressure from the lumen to the extraluminal intrathoracic airway, leading to tend to expand. When patients with forced expiratory Venturi effect and turbulence of the obstruction proximal airway pressure reduces, further narrowing the airway caliber also cause obstruction site, but expiratory flow severely hampered. This patient dynamic flow - volume loops tracings, performance render breath platform expiratory flow limitation, inspiratory flow limitation lighter.Fixed upper airway obstruction fixed upper airway obstruction refers stiff upper airway obstructive lesion fixed, breathing changes in airway caliber cross-wall pressure change can not be caused by the obstruction was found in tracheal stenosis, and thyroid cancer patients . These patients, their inspiratory and expiratory airflow were limited and a similar level of dynamic flow - volume loop inspiratory flow and expiratory flow showed a platform. Most scholars believe that expiratory flow rate and inspiratory flow than 50% of vital capacity (FEF50% / FIF50%) is equal to 1 is the characteristics of the fixed upper airway obstruction. But variable type obstruction and airway obstructive lesions adjacent normal FEF50% / FIF50% certain, should be noted.Upper airway obstruction - diagnostic testsDiagnosis of upper airway obstruction: diagnosis of upper airway obstruction, the key is to take into account the possibility of upper airway obstruction. Clinical, should be timely and relevant examination: ① mainly shortness of breath, difficulty breathing, activity significantly worse, sometimes symptoms aggravated with postural after bronchodilator therapy invalid; ② exist on gas tract inflammation, injury, and in particular the history of endotracheal intubation and tracheostomy; the ③ pulmonary function tests showing maximal expiratory flow, maximal voluntary ventilation sexual decline unchanged FVC, FEV1 was not changed significantly, with the decline in maximum voluntary ventilation fails proportion; or FEV1 decreased but closing volume normal.Laboratory tests: upper airway obstruction is more common infections, such as infection, blood leukocytes may be elevated.Other laboratory examinations:Pulmonary function tests peak expiratory flow (speed) - volume curve (Central) is the preferred method of examination for the diagnosis of upper airway obstruction. Upper airway obstruction, the flow - volume curve exhibits a distinct change of diagnostic value. As mentioned earlier, can be determined according to the change of the flow - volume curve shape different upper airway obstruction. ① variable extrathoracic on, airway obstruction, its flow - volume curve showed inspiratory flow significantly restricted presented inspiratory and expiratory flow is basically normal, the therefore FEF50% / FIF50%> 1; the ② variable intrathoracic upper airway obstruction, its flow - volume curve showed expiratory flow significantly restricted render breath platform, FEF50% / FIF50%, <1; (3) fixed upper airway obstruction, its flow - volume curve showed inspiratory expiratory flow were significantly decreased, and a considerable degree of rendered as a rectangle, FEF50% / FIF50% = 1. Other indicators of lung function, such as FEV0.5, FEV1.0 reduced, PEFR, MVV progressive decline FIF50% ≤ 100L/min FEV1.0/PEFR ≥ 10 ml / (L? Min) FEVl.0/FEV0.5 ≥ 1.5. Closed volume vital capacity VC and CV normal, suggesting that the presence of upper airway obstruction. Pulmonary function tests can not be performed in patients with acute respiratory distress, and high sensitivity to upper airway obstruction.2 radiographic examination(1) plain films of the neck: plain film of the trachea, upper airway obstruction of exudative tracheitis, airway foreign body and innominate artery compression due to higher sensitivity, but on the larynx or trachea softening sensitive poor. Inspiratory neck plain film laryngotracheitis and epiglottitis has differential value. The laryngotracheitis the typical signs for the "steeple" sign. The subglottic stenosis more common in patients with laryngotracheitis, but can also be found epiglottitis. The epiglottitis the neck lateral radiographs can show swelling of the epiglottis and hypopharynx expansion. Airway plain film diagnosis of upper airway obstruction may provide important information, but less accurate, the judge should be combined with medical history and symptoms.The size and morphology of upper airway obstruction (2) Chest CT Scan: CT scan of the airway can learn obstructive lesions, the degree of airway narrowing and airway wall, as well as the situation of the lesion surrounding tissue. The enhanced scan still helps clear lesions blood supply.(3) chest MRI examination: has a good ability to distinguish, can be expected that the extent and length of the airway occlusion, as well as evaluating the mediastinal case.3 the acoustic check breathing audio spectrum analysis found that normal human peak frequency and frequency spectrum are mainly located below 200Hz.Airway obstruction in patients with chest appearance, a significant increase in the peak frequency of breath sounds, mostly three times greater than the baseline, the frequency spectrum of the group widened and moved towards the area of high-frequency greater than 200Hz. The above-mentioned changes in the inspiratory phase is greater than the expiratory phase, and the signal strength of the neck to the chest. The blocking variable thoracic breathing sound spectrum changes as compared to the expiratory than inspiratory chest signal stronger. Therefore, breathing audio spectrum analysis to determine airway obstruction has better clinical value.Endoscopy fiberoptic laryngoscope or fiberoptic bronchoscopy can directly observe the upper airway, to understand the dynamic characteristics of the lesions in the vocal cords, trachea ring the changes as well as the respiratory process, and can be collected living tissue for pathological examination, so the diagnosis decisive role. Suspected obstruction of the upper airway, should be considered for endoscopy. But the severe breathing difficulties should not be checked for biopsy and non-vascular diseases.Upper airway obstruction - Differential DiagnosisCerebrovascular accident, seizures, sleeping pill overdose, heart attack, acute laryngospasm and laryngeal edema as well as other causes of airway obstruction phase identification.Upper airway obstruction - treatment optionsUpper airway obstruction due to reasons caused by upper airway obstruction more, the choice of treatment should be determined according to its etiology and severity. Severe upper airway obstruction should take urgent measures to relieve airway obstruction, to save the lives of patients. Some type of upper airway obstruction, changes in position can make the symptoms can be alleviated; caused by infectious diseases, such as epiglottitis, pharyngeal abscess, antibiotic treatment should be timely. Acute upper airway obstruction often occurs outside the hospital can not receive timely diagnosis and treatment, lead to the death of patients. Upper airway obstruction can not allow clinical comparative study, the treatment measures are based on limited clinical observation data, and there is a big controversy.Treatment of an upper airway foreign body obstructionFirst aid techniques: (1) inhalation of foreign bodies and the first to use the dental pad or openings to open the mouth, and to clear a foreign body in the mouth; stimulate the throat with a tongue depressor or index finger, at the same time the rapid increase in patients on abdominal abdominal pressure Heimlich techniques, can be ruled out some airway foreign body; patients awake upright rescuer from the patient behind clinging to the upper abdomen, right fist, thumb pointing below the xiphoid, left hand pressed right fist rapidly up the weight several times inward; rescuer facing the patient supine patients kneeling its legs on both sides of the upper body leaning forward, right fist placed below the xiphoid, the left hand is placed on top of the right hand, rapid downward move within the weight on abdomen.(2) removal of foreign body bronchoscopy: foreign body removed by the above techniques can not remove the foreign body, or inappropriate practices such as fishbone should laryngoscope or bronchoscope peep removal of foreign body.2. Drug treatment for laryngeal or tracheal spasms caused by upper airway obstruction, and some inflammatory diseases caused by mucosal edema due to upper airway obstruction, drug therapy has a certain value. Effective drugs mainly epinephrine and glucocorticoids, these drugs poor epiglottitis treatment effect, and even lead to adverse reactions should not use this kind of upper airway obstruction.(1) adrenaline: excitable alpha adrenergic receptors causes vasoconstriction, reducing mucosal edema, throat bronchitis has good therapeutic effect, can also be used to treat laryngeal edema. Use, the use of inhalation or intratracheal instillation, each ~~ 2mg rapid onset of action, but to maintain a short time, should be repeated drug.Upper airway obstruction (2) glucocorticoids: a role in the elimination of edema, reduce local inflammation, can be used for a variety of reasons, such as endotracheal intubation edema. Viral throat bronchitis, inhaled corticosteroid effect. Durward given budesonide (budesonide) inhalation therapy, can significantly reduce the intubation rate. Hormone therapy on upper airway scar or tumor stenosis caused by invalid.3. Endotracheal intubation or tracheostomy intubation or incision can create artificial airway to keep the airway and maintain an effective respiratory conditions. Especially need referral for treatment, the intubation can significantly reduce the mortality rate of patients. Laryngeal edema, laryngospasm, functional vocal cord dysfunction, inhalation injury, angina, epiglottitis, laryngeal and tracheal tumors, etc., can be considered for endotracheal intubation or incision. Minimum nasotracheal intubation injury, the most security. But it should be marked with the meaning of airway obstruction, endotracheal intubation or incision itself can also cause upper airway obstruction, and therefore should be closely observed for patients receiving such treatment.4 mixed gas of the helium - the oxygen mixed gas of helium (80%) and oxygen (20%), its density is only 1/3 of the density of air, can reduce the resistance of the airway of turbulence to increase the gas flow rate, to improve the upper airway obstruction in patients with hypoxia. Helium - oxygen gas mixture in part, airway obstruction, such as tracheal stenosis or possession of foreign oppression, severe asthma and angioedema patients achieved a certain effect. However, this mixed gas can only relieve dyspnea, upper airway obstruction is not relieved.Surgery for laryngeal or tracheal tumor or stenosis due to upper airway obstruction, can be laryngotracheal resection and reconstruction treatment, 87% of patients receive good treatment. Airway obstruction, tonsillar hypertrophy on tonsillectomy its symptoms improve. Caused by oropharyngeal stenosis, to pharyngeal surgery has a therapeutic effect.Laser treatment laser treatment allows the tumor, granulomatous lesions carbonation, narrow, and partial resection of tracheal tumors, so as to achieve the lifting of tracheal stenosis, to relieve symptoms, has a therapeutic effect. It can be used by fiberoptic bronchoscopy.The tracheal stent use in recent years nitinol tracheal stent prepared to have a better clinical effect in experimental animal and human resettlement, and long-term placement without deformation and rust color, do not have serious airway inflammatory response and stimulation received wide attention. For tracheal granuloma, cicatricial stenosis due to benign stricture, or tumor-induced malignant stricture. General first stent placed in ice water cooling and shaping fine tubular and loaded into the inserter, the guide wire into a narrow airway by fiberoptic bronchoscopy, so patients with head thrown back as far as possible, and will be placed along the guide wire placement airway stenosis, and then pull out the guide wire. Again fiberoptic bronchoscopy determine the stent placed stenosis. After implantation, the stent body temperature, restored to its original shape and airway snug fit, the stenosis and gradually softened expansion, to achieve the lifting of the narrow effect.Upper airway obstruction - complicationsPulmonary edema.Upper airway obstruction - prognosis and prevention
Prognosis: the majority of patients with previously healthy, fully recovered after early diagnosis and effective treatment.
Prevention: aggressive treatment of the primary disease of the airway infarction.
Upper airway obstruction - Epidemiology
The disease was first upper airway obstruction Gross wrote in 1854, usually occurs in the restaurants restaurants coronary heart disease "(CafeCoronary) term to describe cause sudden death due to food asphyxiation. After 100 years in 1963 Hauqen this also described. Haugen and others, to anyone, at any time, such as swallowing, sudden loss of consciousness, upper airway obstruction should be the first suspect. If death ensuing diagnosis of "coronary heart disease" or "natural causes" should be questioned. After 20 years of development in 1974 cardiopulmonary resuscitation step description widely used, the 1976 thoracic surgeon Heimlich his operation, the lifting of a complete airway obstruction has been described as the Heimlich practices.
