Partial Obstruction Of Upper Airway Research Articles

Mandibular advancement with dental appliances in obstructive sleep apnoea

The purpose of this study was to compare the effects of a modified Herbst appliance (mHA) and a muscle relaxation appliance (MR) on nocturnal breathing and body movement activity in patients with obstructive sleep apnoea syndrome (OSAS). To increase the airway space posterior to the tongue base without severely affecting the craniomandibular joint, the mHA was adjusted to anchor the mandible at 50% of maximum protrusion. MR producing an occlusal coverage but no protrusion served as a control appliance. All-night static charge-sensitive bed (SCSB) and finger oximeter recordings were done to six male patients in three conditions: first without dental device and then with mHA and with MR, in a random order, after a 2 month period of habituation. The oxyhaemoglobin desaturation events were 44.7 h-1 of recording observed during the control night, 29.6 h-1 with mHA (P = 0.087). The frequency of body movements decreased from 34.9 to 20.4 h-1 (P = 0.0079), respectively. MR had no significant effects either on the frequency of the desaturation events or the frequency of body movements, but the increased respiratory resistance breathing, indicating presence of partial upper airway obstruction, was reduced from 14.3 to 6.9% of the time in bed (P = 0.022). We conclude that 50% protrusion chosen for these experiments, produced with a mHA, brought about some alleviation of upper airway obstruction in our preselected patients, but did not lead to sufficient control of apnoea. The reduction of partial upper airway obstruction induced with a MR warrants further studies in a larger patient population.

Airway obstruction and gastroesophageal reflux: An experimental study on the pathogenesis of this association

Gastroesophageal reflux (GER) frequently complicates the clinical course of children suffering from conditions leading to upper airway obstruction (UAO) (choanal atresia, tracheomalacia, esophageal atresia, vascular rings, etc). In an attempt to explore whether partial airway obstruction causes changes in the normal thoracoabdominal pressure gradients, we measured end-inspiratory intrathoracic and intraabdominal pressures in anesthetized rats under spontaneous breathing conditions, after tracheostomy, and under upper airway obstruction induced by tracheal intubation with three progressively narrower cannulae (inner diameters 1.0 mm, 0.5 mm, and 0.2 mm). We also measured the lower esophageal sphincter pressure (LESP) and length (LESL) and calculated the thoracoabdominal end-inspiratory pressure gradient (TAEIPG). Neither LESP nor LESL changed significantly before or after maximal tracheal obstruction (14.3 ± 6.2 v 18 ± 7.6 cm H 2 O [ P > .05] and 0.34 ± 0.09 v 0.41 ± 0.1 cm H 2 O [ P > .05] respectively) but TAEIPG significantly increased from 5.58 ± 1.34 cm H 2O to 17.62 ± 4.27 cm H 2O ( P < .01) under the same conditions, mainly as a result of progressively increasing negative intrathoracic pressures during inspiration. These experiments prove that the powerful thoracoabdominal pressure gradients developed after partial UAO may contribute to the pathogenesis of GER by overcoming the antireflux barrier function. This study points out the convenience of routinely screening for GER all children with airway obstructive conditions, bearing in mind that the reestablishment of normal respiratory conditions should be the primary goal of treatment.

Genioglossus hemorrhage after blunt facial trauma

We present the case of a 28-year-old man admitted to a Level I trauma center after a motorcycle crash in which he sustained blunt trauma to the face and neck, including a mandibular ramus fracture. The patient had no airway compromise on admission, but he acutely developed significant partial upper airway obstruction necessitating emergency endotracheal intubation and subsequent tracheostomy approximately 36 hours after admission. This obstruction was caused by an expanding hematoma of the genioglossus muscle. Potential causes of this complication are presented, and signs and symptoms of upper airway obstruction and airway management strategies are discussed. The etiology of traumatic upper airway obstruction is reviewed.

Translaryngeal jet ventilation and end-tidal PCO 2 monitoring during varying degrees of upper airway obstruction

To explore the ventilatory adequacy of translaryngeal jet ventilation (TLJV) during partial upper airway obstruction and the usefulness of monitoring end-tidal CO2 (PETCO2) during this condition. Prospective, nonrandomized, sequential crossover design. Apneic dog model (five dogs; mean weight, 23 kg). Animals were intubated with a 9.0-mm endotracheal tube with the tip positioned above the cricothyroid membrane. Upper airway obstructions of 40%, 69%, and 80% were created. TLJV was performed through the cricothyroid membrane using a 13-gauge catheter with 100% oxygen, 45 psi, 15 breaths per minute, and 30% inspiratory time for 15 minutes at each upper airway obstruction. Data collected at baseline (no upper airway obstruction) and one-minute intervals included arterial blood pressures, continuous PaCO2 measurements, and PETCO2 at the TLJV catheter tip and above the level of obstruction. Arterial blood gases were obtained at 0 and 15 minutes. Data were analyzed using Pearson's correlation, analysis of variance, and Turkey's multiple comparisons (significance, P less than .05). Baseline values for all variables did not significantly differ at the onset of each testing phase. Mean pH increased significantly from baseline during 69% upper airway obstruction (7.36 to 7.54, P less than .05) and 80% upper airway obstruction (7.39 to 7.61, P less than .01). Mean PaCO2 decreased significantly from baseline during all upper airway obstructions: 40% upper airway obstruction (39.9 to 33.6 mm Hg, P less than .01), 69% upper airway obstruction (38.3 to 25.6 mm Hg, P less than .001), and 80% upper airway obstruction (36.2 to 18.2 mm Hg, P less than .001). PaCO2, PETCO2, and pH differed significantly between each level of upper airway obstruction (P less than .01). PETCO2 was significantly correlated with PaCO2 (r = .84, P less than .001) and did not significantly differ from PaCO2. No signs of barotrauma were observed in any animal at any degree of upper airway obstruction. TLJV during partial upper airway obstruction in our model provided safe and adequate-to-supranormal minute ventilation. In fact, marked hypocapnia and alkalemia occurred at levels of 69% and 80% upper airway obstruction, thus dispelling concepts that TLJV may cause hypercapnia during partial upper airway obstruction. PETCO2 correlates well with PaCO2 and may be valuable for monitoring ventilation when using TLJV in the nonobstructed or partially obstructed upper airway.

Airway involvement and anesthetic management in Goltz's syndrome

A 13-year-old girl with Goltz's (Goltz-Gorlin) syndrome (focal dermal hypoplasia) and cloacal exstrophy underwent day surgery cystoscopy. During the administration of inhalation, anesthesia by mask, persistent partial upper airway obstruction was noted. Direct laryngoscopy unexpectedly showed variously sized verrucous lesions in the hypopharynx and supraglottic larynx, and the vocal cords and trachea could not be visualized. The patient later returned for a complete endoscopic examination, followed by cup forcep and laser excision of these verrucous and pedunculated lesions, and remained intubated in the intensive care unit (ICU). for 48 hours ,following this procedure. Airway management and pathology specific to this rare disorder are discussed.

Nearly fatal partial obstruction of the upper airway

The dangers of taking antihistamines while reactive small-airway disease is present are theoretically valid. In this case, an episode of coughing in a 33-year-old woman mobilized a thickened plug of mucus from the peripheral to the central bronchial region, which created a nearly fatal, partial upper airway obstruction. The mucous plug was discovered during an emergency bronchoscopy and quickly removed by suction.

Adenotonsillar Hypertrophy as a Cause of Failure to Thrive

Two infant aged 11 and 15 months presented to the Gastroenterology Clinic at Alberta Children's Hospital because of failure to thrive. Clinical and laboratory investigations excluded any underlying abnormality of 1he gastrointestinal tract. Because of a history of obstructive upper respiratory symptoms, both were referred for ear, nose and throat evaluation, and both were found to have partial upper airway obstruction secondary to adenotonsillar hypertrophy. Subsequent adenotonsillectomy led to resolution of obstructive upper respiratory symptoms and dramatic increases in weight gain and growth. Adenotonsillar hypertrophy should be included among the potential causes of failure to thrive in infancy, especially if the child has a history of obstructive upper respiratory symptoms.

Obstructive Sleep Apnea Syndrome or Abnormal Upper Airway Resistance During Sleep?

Obstructive sleep apnea syndrome is well known by now, but, at both extremes of age, increased upper airway resistance may lead to clinical symptoms without complete apnea. Abnormal craniofacial features appear to be responsible for the very early appearance during childhood of increased upper airway resistance. In adults, snoring, often related to partial upper airway obstruction located in the pharynx, may be associated with changes in respiratory timing and intermittent arousal. Many treatments are currently available to deal with obstructive sleep apnea syndrome. It is important to recognize the location(s) of the upper airway obstruction before considering treatment and to evaluate the associated risk factors. Early recognition of factors involved in increased upper airway resistance may allow prevention, a more efficacious approach than treatment of an already developed syndrome.

Partial upper airway obstruction in sleep after uvulopalatopharyngoplasty.

Uvulopalatopharyngoplasty is the treatment of choice for selected patients with obstructive sleep apnea, although the response to surgery is variable. We measured, in addition to obstructive apnea, the frequency of sleep-related partial upper airway obstruction in 11 patients with the obstructive sleep apnea syndrome both before and after uvulopalatopharyngoplasty. Partial obstruction was detected indirectly by recording the secondary hemodynamic changes and respiratory stimulation with the static charge sensitive bed. The frequency of obstructive apnea episodes was reduced from 56.3% to 18.4% by the operation, while the episodes of increased respiratory resistance rose from 3.6% to 20.4%. The various breathing anomalies decreased significantly, although they were still present during 75.6% of the recording time. The results suggest that uvulopalatopharyngoplasty substantially reduces the frequency of obstructive apnea, some of which persists as partial obstruction. The persistent partial obstruction may be the key factor contributing to further pharyngeal narrowing and a recurrence of obstructive sleep apnea syndrome.

Unexpected difficult intubation

Two cases of asymptomatic epiglottic cysts which presented as partial upper airway obstruction following induction of anaesthesia are described. The incidence, pathology and anaesthetic management are discussed.

A practical method for oxygen administration during cosmetic facial surgery.

An effective and practical method of oxygen administration during cosmetic facial surgery under local anesthesia is described. A large volume of oxygen is delivered directly to the nasopharynx, and partial upper airway obstruction caused by the tongue falling into the pharynx is resolved, yet the apparatus does not interfere with execution of the operation.

Abnormalities of breathing control and airway maintenance in infants and children as a cause of cor pulmonale

Respiratory control abnormalities may result in cor pulmonale. This report summarizes the clinical history, diagnostic evaluation, treatment, and outcome of 16 infants and children presenting with cor pulmonale subsequently found to be due to sleep-dependent hypoventilation. Eleven patients had cardiomegaly and electrocardiographic evidence of right ventricular hypertrophy (RVH) while 5 had only severe RVH or biventricular hypertrophy (BVH). Four infants with central hypoventilation syndrome (CHS)--absence of sleep-related ventilatory drive--had severe sleep-dependent asphyxia and resultant acute respiratory failure; all were ultimately treated with phrenic nerve pacing. One patient with alveolar hypoventilation syndrome (AHS)--a partial deficit in ventilatory drive during sleep--presented with severe pulmonary hypertension and ultimately died despite symptomatic relief with respiratory stimulants. Eleven patients presented with obstructive sleep apnea (OSA) and sleep-dependent asphyxia secondary to intermittent complete or to prolonged partial upper airway obstruction. Localized airway obstruction due to an anomalous innominate artery in 1 child was corrected by arteriopexy. Four children underwent adenotonsillectomy (T&A) with disappearance of symptoms in 1, clinical improvement in 2 and no clinical improvement in another. This unimproved patient and the 6 remaining OSA children improved dramatically after tracheostomy to bypass the sleep-dependent airway obstruction; none presently has evidence of cor pulmonale. In summary, early recognition and appropriate treatment of respiratory control disorders will improve sleep ventilation, eliminate asphyxia during sleep, and prevent the development of cor pulmonale.

155 ABNORMALITIES OF BREATHING CONTROL AND AIRWAY MAINTENANCE IN INFANTS AND CHILDREN AS A CAUSE OF COR PULMONALE

Respiratory control abnormalities may result in cor pulmonale. This report summarizes the clinical history, diagnostic evaluation, treatment, and outcome of 16 infants and children presenting with cor pulmonale subsequently found to be due to sleep-dependent hypoventilation. Eleven patients had cardiomegaly and electrocardiographic evidence of right ventricular hypertrophy (RVH) while 5 had only severe RVH or biventricular hypertrophy (BVH). Four infants with central hypoventilation syndrome (CHS)—absence of sleep-related ventilatory drive—had severe sleep-dependent asphyxia and resultant acute respiratory failure; all were ultimately treated with phrenic nerve pacing. One patient with alveolar hypoventilation syndrome (AHS)—a partial deficit in ventilatory drive during sleep—presented with severe pulmonary hypertension and ultimately died despite symptomatic relief with respiratory stimulants. Eleven patients presented with obstructive sleep apnea (OSA) and sleep-dependent asphyxia secondary to intermittent complete or to prolonged partial upper airway obstruction. Localized airway obstruction due to an anomalous innominate artery in 1 child was corrected by arteriopexy. Four children underwent adenotonsillectomy (TA none presently has evidence of cor pulmonale. In summary, early recognition and appropriate treatment of respiratory control disorders will improve sleep ventilation, eliminate asphyxia during sleep, and prevent the development of cor pulmonale.

The Respiratory Mechanism of Aerosol Inhalation in the Treatment of Partial Airway Obstruction

There is a sensory system within the mucosa of the nose and supraglottic larynx that appears to be both mechanosensitive and chemosensitive. Our data suggest that the respiratory modification produced by microaerosol inhalation represents a mechanoreceptor rather than chemoreceptor response. Furthermore, the sensitivity of this reflex system appears aged-dependent, the data indicating a more active response early in life. From a clinical perspective, it is postulated that aerosol inhalation reflex alters the pattern of breathing, resulting in improved respiratory flow rates during partial upper airway obstruction. The mechanism of a favorable clinical response to mist inhalation has not been previously appreciated in this context.