Airway Occlusion Research Articles

Upper airway occlusion by soil – an unusual cause of death in vehicle accidents

Upper airway obstruction by soil is a rare cause of death in motor vehicle accidents. Four cases were found in a search of the records of the Forensic Science Centre in Adelaide, South Australia over a twenty-year period from January 1982 to December 2001. Case 1: A 68-year-old male driver died from sand inhalation after he was trapped in his vehicle following an accident. His mouth and upper airway were packed with sand. Case 2: A 33-year-old male pedestrian died from smothering after he had been knocked over and had his head pressed face down into sandy soil by a vehicle wheel. Case 3: A 12-year-old male passenger died from soil inhalation after the vehicle in which he was travelling rolled over and filled with soil. His mouth and upper airway were packed with soil. In these cases the victims had been trapped with the face covered in fine, or loose, soil or sand. In Case 4 a 41-year-old male passenger was ejected from a vehicle. He died from blunt chest trauma exacerbated by occlusion of the mouth and nose by soil. Careful scene descriptions are required in the assessment of such cases, in addition to evaluation of the relative contribution of injuries and asphyxia to the fatal episode.

Improving paediatric and newborn life support training by the use of modified manikins allowing airway occlusion

Manikins currently used in newborn and paediatric resuscitation training are limited in their effectiveness by an inability to allow instructors control over airway patency. This means that attempts to introduce situations that require interventions, other than just appropriate head positioning to achieve successful lung inflation, into training or testing scenarios are compromised by the obvious visual cue of the manikin's chest movement which may occur even when the head is incorrectly positioned. This report describes a modification to manikins, which allows such control and discusses its use in improving the effectiveness of teaching and the learning experience.

Sigh improves gas exchange and lung volume in patients with acute respiratory distress syndrome undergoing pressure support ventilation.

The aim of our study was to assess the effect of periodic hyperinflations (sighs) during pressure support ventilation (PSV) on lung volume, gas exchange, and respiratory pattern in patients with early acute respiratory distress syndrome (ARDS). Thirteen patients undergoing PSV were enrolled. The study comprised 3 steps: baseline 1, sigh, and baseline 2, of 1 h each. During baseline 1 and baseline 2, patients underwent PSV. Sighs were administered once per minute by adding to baseline PSV a 3- to 5-s continuous positive airway pressure (CPAP) period, set at a level 20% higher than the peak airway pressure of the PSV breaths or at least 35 cm H2O. Mean airway pressure was kept constant by reducing the positive end-expiratory pressure (PEEP) during the sigh period as required. At the end of each study period, arterial blood gas tensions, air flow and pressures traces, end-expiratory lung volume (EELV), compliance of respiratory system (Crs), and ventilatory parameters were recorded. Pao2 improved (P < 0.001) from baseline 1 (91.4 +/- 27.4 mmHg) to sigh (133 +/- 42.5 mmHg), without changes of Paco2. EELV increased (P < 0.01) from baseline 1 (1,242 +/- 507 ml) to sigh (1,377 +/- 484 ml). Crs improved (P < 0.01) from baseline 1 (40.2 +/- 12.5 ml/cm H2O) to sigh (45.1 +/- 15.3 ml/cm H2O). Tidal volume of pressure-supported breaths and the airway occlusion pressure (P0.1) decreased (P < 0.01) during the sigh period. There were no significant differences between baselines 1 and 2 for all parameters. The addition of 1 sigh per minute during PSV in patients with early ARDS improved gas exchange and lung volume and decreased the respiratory drive.

Tracheal polyp

Benign tumors of the tracheobronchial tree are extremely rare. A case of a benign inflammatory endotracheal polyp and literature review are presented, including classification and treatment options. Although rare, these lesions must be efficiently diagnosed and expeditiously removed to prevent airway occlusion or irreversible pulmonary disease.

Blockade of CD28/B7-2 costimulation inhibits experimental obliterative bronchiolitis in rat tracheal allografts: suppression of helper T cell type1-dominated immune response.

T cell activation is a proximal event in the initiation of chronic rejection that may ultimately lead to obliterative bronchiolitis (OB) after lung transplantation. In addition to primary signals generated by the T cell receptor, T cell activation relies on costimulatory signals, of which the most important are mediated via interaction between CD28 and its ligands B7-1 and B7-2. In nontreated rat tracheal allografts, B7-2, but not B7-1, expression peaked 10 d after transplantation, unlike in syngeneic grafts, where no B7-2 upregulation was observed. Selective blockade of the CD28/B7-1 T cell costimulatory pathway by a mutant form of CTLA4Ig (cytotoxic T lymphocyte antigen 4 immunoglobulin), CTLA4IgY100F, did not affect epithelial injury or degree of luminal occlusion in rat tracheal allografts. Treatment with CTLA4Ig fusion protein, which blocks both CD28/B7-1 and CD28/B7-2 interaction, significantly delayed the development of epithelial injury and airway occlusion. Immunohistochemical analyses of allografts showed that selective inhibition of the CD28/B7-1 pathway did not affect cytokine expression. In contrast, treatment with CTLA4Ig was associated with a significant decrease in the intragraft production of tumor necrosis factor alpha, interleukin 2, and interferon gamma, as well as slightly increased intragraft expression of interleukin 10. In conclusion, CTLA4Ig-mediated costimulatory blockade delays epithelial injury and attenuates obliterative changes and is associated with marked suppression of helper T cell type 1 (Th1)-dominated cytokine response. These observations emphasize the role of the CD28/B7-2 costimulatory pathway in regulating proinflammatory and Th1 cytokine responses and thereby in the development of epithelial and graft injury gradually leading to obliteration of the airway lumen.

Obstructive Sleep Apnea Is Independently Associated with Insulin Resistance

Epidemiological studies have implicated obstructive sleep apnea (OSA) as an independent comorbid factor in cardiovascular and cerebrovascular diseases. It is postulated that recurrent episodes of occlusion of upper airways during sleep result in pathophysiological changes that may predispose to vascular diseases. Insulin resistance is a known risk factor for atherosclerosis, and we postulate that OSA represents a stress that promotes insulin resistance, hence atherogenesis. This study investigated the relationship between sleep-disordered breathing and insulin resistance, indicated by fasting serum insulin level and insulin resistance index based on the homeostasis model assessment method (HOMA-IR). A total of 270 consecutive subjects (197 male) who were referred for polysomnography and who did not have known diabetes mellitus were included, and 185 were documented to have OSA defined as an apnea-hypopnea index (AHI) > or =5. OSA subjects were more insulin resistant, as indicated by higher levels of fasting serum insulin (p = 0.001) and HOMA-IR (p < 0.001); they were also older and more obese. Stepwise multiple linear regression analysis showed that obesity was the major determinant of insulin resistance but sleep-disordered breathing parameters (AHI and minimum oxygen saturation) were also independent determinants of insulin resistance (fasting insulin: AHI, p = 0.02, minimum O(2), p = 0.041; HOMA-IR: AHI, p = 0.044, minimum O(2), p = 0.022); this association between OSA and insulin resistance was seen in both obese and nonobese subjects. Each additional apnea or hypopnea per sleep hour increased the fasting insulin level and HOMA-IR by about 0.5%. Further analysis of the relationship of insulin resistance and hypertension confirmed that insulin resistance was a significant factor for hypertension in this cohort. Our findings suggest that OSA is independently associated with insulin resistance, and its role in the atherogenic potential of sleep disordered breathing is worthy of further exploration.

Combined MR proton lung perfusion/angiography and helium ventilation: Potential for detecting pulmonary emboli and ventilation defects

Three-dimensional (3D) perfusion imaging allows the assessment of pulmonary blood flow in parenchyma and main pulmonary arteries simultaneously. MRI using laser-polarized (3)He gas clearly shows the ventilation distribution with high signal-to-noise ratio (SNR). In this report, the feasibility of combined lung MR angiography, perfusion, and ventilation imaging is demonstrated in a porcine model. Ultrafast gradient-echo sequences have been used for 3D perfusion and angiographic imaging, in conjunction with the use of contrast agent injections. 2D multiple-section (3)He imaging was performed subsequently by inhalation of 450 ml of hyperpolarized (3)He gas. The MR techniques were examined in a series of porcine models with externally delivered pulmonary emboli and/or airway occlusions. With emboli, perfusion deficits without ventilation defects were observed; airway occlusion resulted in matched deficits in perfusion and ventilation. High-resolution MR angiography can unambiguously reveal the location and size of the blood emboli. The combination of the three imaging methods may provide complementary information on abnormal lung anatomy and function.

Prediction of extubation failure in preterm infants

Objective: To identify whether the results of assessment of respiratory muscle strength or respiratory load were better predictors of extubation failure in preterm infants than readily available clinical data. Patients:...

Respiratory Symptoms and Nocturnal Gastroesophageal Reflux: A Population-Based Study of Young Adults in Three European Countries

To estimate the possible association between reported symptoms of gastroesophageal reflux (GER) after bedtime, sleep-disordered breathing, respiratory symptoms, and asthma. Cross-sectional international population survey. Participants consisted of 2,661 subjects (age range, 20 to 48 years) from three countries (Iceland, Belgium, and Sweden), of whom 2,202 were randomly selected from the general population and 459 were added because of reported asthma. The investigation included a structured interview, spirometry, methacholine challenge, peak flow diary, skin-prick tests, and a questionnaire on sleep disturbances. In the random population sample, 101 subjects (4.6%) reported GER, which was defined as the occurrence of heartburn or belching after going to bed at least once per week. Subjects with nocturnal GER more often were overweight and had symptoms of sleep-disordered breathing than participants not reporting GER. Participants with GER were more likely to report wheezing (adjusted odds ratio [OR], 2.5), breathlessness at rest (adjusted OR, 2.8), and nocturnal breathlessness (adjusted OR, 2.9), and they had increased peak flow variability compared to the subjects without GER. Physician-diagnosed current asthma was reported by 9% of subjects with GER compared to 4% of those not reporting GER (p < 0.05). Subjects with the combination of asthma and GER had a higher prevalence of nocturnal cough, morning phlegm, sleep-related symptoms, and higher peak flow variability than subjects with asthma alone. The occurrence of GER after bedtime is strongly associated with both asthma and respiratory symptoms, as well as symptoms of obstructive sleep apnea syndrome. The partial narrowing or occlusion of the upper airway during sleep, followed by an increase in intrathoracic pressure, might predispose the patient to nocturnal GER and, consequently, to respiratory symptoms.

Sigh: tool to determine the respiratory viscoelastic properties.

In mechanically ventilated patients a high fraction of the pressure can be dissipated to overcome the viscoelastic components of the respiratory system. Recently it was demonstrated that sigh improved oxygenation in mechanically ventilated ARDS patients. We evaluated if, in acute lung injury (ALI) patients, the sigh can be used to measure the respiratory viscoelastic properties. Ten consecutive normal subjects undergoing general anaesthesia for minor abdominal surgery and ten ALI patients admitted to the ICU, were studied. Three sighs were administered every minute during the measurement period. The viscoelastic constants (E2, R2 and tau2) were determined by (i) a series of end-inflation airway occlusions (multiple breath method, MBM) and (ii) fitting the time course of the slow decay in pressure during end inspiratory pause of the sigh (sigh method, SM). The results were compared by means of the limits of agreement as modified for small sample sizes. Viscoelastic parameters were similar to those obtained in other studies. In normal subjects the mean differences (+/- SEM) of tau2, R2, and E2 given by the SM and the MBM were 0 +/- 0.04 s, 0.37 +/- 0.20 cmH2O L(-1) s, and 0.21 +/- 0.26 cmH2O L(-1), respectively. The mean differences (+/- SEM) of tau2, R2, and E2 in ALI patients were 0.02 +/- 0.02 s, 0.45 +/- 0.31 cmH2O L(-1) s, 0.34 +/- 0.36 cmH2O L(-1), respectively. No lack of agreement could be detected between the two methods in all variables in normal subjects and ALI patients. The long inflation time characteristic of the sigh allowed the determination of the viscoelastic constants by means of a simpler and faster method. Moreover it does not require very small tidal volumes, which can increase reabsorption atelectasis in ALI patients and can improve alveolar recruitment and oxygenation in these patients.

Evaluation of the interrupter technique in healthy, unsedated infants.

The interrupter technique may be used to monitor respiratory resistance and does not require active patient cooperation, but has yet to be applied in unsedated, spontaneously breathing infants. The aim of this study was to determine if the interrupter technique is feasible in spontaneously breathing infants and to investigate the influence of facemask types and analysis techniques on the interrupter resistance (Rint). Rint was measured in 14 healthy, unsedated, sleeping infants (aged 38.4 (31-56) days (mean (range)). Paired measurements were made using large volume, compliant (Mcomp) and small volume, rigid (Mrigid) facemasks. Flow and pressure were measured at the airway opening prior to- and following a brief airway occlusion (500 ms). Rint was calculated using four previously reported analysis techniques. Rint could be measured in all infants. Mcomp, independent of the analysis method significantly underestimated Rint (p<0.001). The variability and magnitude of Rint were significantly influenced by the choice of analysis method. The conclusion is that the interrupter technique is feasible in spontaneously breathing, unsedated infants. Equipment design and analysis method significantly influences interrupter resistance. Studies standardizing equipment and identifying the most appropriate analysis technique in this age group are needed.

Sleep apnea in renal patients.

In Western societies, sleep apnea (SA) has emerged as a major medical problem with important social ([1][1]) and financial implications. The issue may be even more relevant in nephrology because some of the factors involved in the pathogenesis of renal disease are the same that cause, or are

Diagnostic issues in unusual asphyxial deaths

Upper airway occlusion may be due to a variety of causes and may result from accidents, suicides or homicides. Underlying natural diseases may also predispose to lethal choking episodes. A series of nine cases is reported to illustrate a range of circumstances that resulted in fatal upper airway compromise. These included suicide from upper airway obstruction due to an impacted blanket, and accidental deaths due to inhalation of soil, a rock, and a video cassette sticker. One death resulted from glottic obstruction due to a mucosal cavernous haemangioma, another from an enlarged tonsil, and two deaths were precipitated by underlying organic disease in the form of dementia and insulin-dependent diabetes mellitus. The manner of death was not clear cut in two cases where there was evidence of possible accidental death or suicide.

Inhaled furosemide inhibits behavioral response to airway occlusion in anesthetized cats.

A recent study showed that inhaled furosemide greatly improves experimentally induced dyspnea in humans. The objective of the current study is to test the hypothesis that inhaled furosemide suppresses the behavioral response to airway occlusion without changing the behavioral response to a somatic noxious stimulus in anesthetized animals. In 10 spontaneously breathing cats anesthetized with isoflurane, anesthetic ED(50) was determined by measuring an end-tidal anesthetic concentration while observing escape behavior. The monitored behavior consisted of purposeful movement of the head and forearm after endotracheal tube occlusion. The duration from the start of airway occlusion to the onset of the positive response (DOCCL) was measured at the highest concentration of isoflurane permitting the positive motor response to airway occlusion before pretreatment. ED(50) values (minimum alveolar concentration) for the suppression of a somatic motor response to a noxious stimulus induced by toe pinch (toe-pinch ED(50)) were also determined. Then, the effects of inhaled furosemide or vehicle on the ED(50) for the suppression of the behavioral response to airway occlusion, DOCCL, and toe-pinch ED(50) were evaluated in a randomized, cross-over design. The ED(50) for the suppression of the behavioral response to airway occlusion significantly decreased (P < 0.01) and DOCCL was significantly prolonged (P < 0.01) after furosemide inhalation, whereas vehicle inhalation did not change these measurements. The decrease in ED(50) for the suppression of the behavioral response to airway occlusion after furosemide inhalation lasted 3 h. Furosemide inhalation did not affect the toe-pinch ED(50). Inhaled furosemide suppressed the behavioral response to airway occlusion in anesthetized animals without affecting the response to somatic noxious stimulus. The authors' animal model of respiratory distress may be applicable to the study of dyspnea in regard to its mechanism and treatment.

Continuous positive airways pressure for obstructive sleep apnoea.

Obstructive sleep apnoea is the periodic reduction (hypopnoea) or cessation (apnoea) of breathing due to narrowing or occlusion of the upper airway during sleep. The main symptom is daytime sleepiness although there it has been linked to premature death, hypertension, ischaemic heart disease, stroke and road traffic accidents. The main treatment for sleep apnoea is with continuous positive airways pressure (CPAP) treatment, which consists of a flow generator and mask. These are used at night to prevent apnoea, hypoxia and sleep disturbance. The objective was to assess the effects of CPAP in the treatment of obstructive sleep apnoea in adults. We searched the Cochrane Airways Group RCT register (MEDLINE 1966 to 2000, Embase 1974 to 2000, Cinahl 1982 to 2000) and the reference lists of articles. We consulted experts in the field. Randomised trials comparing nocturnal CPAP with placebo or other treatments in adults with obstructive sleep apnoea and an apnoea/hypopnoea index greater than five per hour. Trial quality was assessed and two reviewers extracted data independently. Study authors were contacted for missing information. Twelve trials involving 475 people were included. Most studies had methodological shortcomings. Most trials were of crossover design. Compared with placebo, CPAP showed significant improvements in objective and subjective sleepiness and several quality of life and depression measures. Patients preferred CPAP to placebo (odds ratio 0.4, 95% confidence interval 0.2 to 0.8). There was no significant effect on daytime blood pressure. Compared with oral appliances, CPAP significantly improved the apnoea/hypopnoea index (weighted mean difference -7.3, 95% confidence interval -10.0 to -4.7) and minimum oxygen saturation during sleep. Patients strongly preferred the oral appliance to CPAP (odds ratio 9.5, 95% confidence interval 4.3 to 21.1). CPAP is more effective than placebo in improving sleepiness and quality of life measures for people with obstructive sleep apnoea. It is more effective than oral appliances in improving respiratory disturbances. Although patients prefer CPAP to placebo, they preference oral appliances to CPAP.

Speed of collapse of the non‐ventilated lung during one‐lung anaesthesia: the effects of the use of nitrous oxide in sheep

By enhancing gaseous uptake from the non‐ventilated lung during procedures performed thoracoscopically, the rapid diffusion properties of nitrous oxide would be expected to speed lung collapse and so facilitate surgery. To assess the effect of nitrous oxide on the speed of absorptive lung collapse, a study was conducted using 11 anaesthetised sheep. Speed of collapse was assessed in an indirect manner by recording the time required in a closed‐chest situation for the airway pressure distal to a single lung airway occlusion to decrease to − 1.0 kPa. The influence of nitrous oxide was assessed by comparing the time taken for this decrease in airway pressure when the animal was being mechanically ventilated with 50% nitrous oxide in oxygen with the time taken when using 100% oxygen. In all assessments, it was found that the decrease in airway pressure to − 1.0 kPa occurred in a shorter time when nitrous oxide was used. The findings lend support to the hypothesis that during thoracoscopic surgery, mechanical lung ventilation with an oxygen/nitrous oxide mixture will increase the rate of gaseous uptake from the non‐ventilated lung and so hasten its absorptive collapse.

Speed of collapse of the non-ventilated lung during one-lung anaesthesia: the effects of the use of nitrous oxide in sheep.

By enhancing gaseous uptake from the non-ventilated lung during procedures performed thoracoscopically, the rapid diffusion properties of nitrous oxide would be expected to speed lung collapse and so facilitate surgery. To assess the effect of nitrous oxide on the speed of absorptive lung collapse, a study was conducted using 11 anaesthetised sheep. Speed of collapse was assessed in an indirect manner by recording the time required in a closed-chest situation for the airway pressure distal to a single lung airway occlusion to decrease to - 1.0 kPa. The influence of nitrous oxide was assessed by comparing the time taken for this decrease in airway pressure when the animal was being mechanically ventilated with 50% nitrous oxide in oxygen with the time taken when using 100% oxygen. In all assessments, it was found that the decrease in airway pressure to - 1.0 kPa occurred in a shorter time when nitrous oxide was used. The findings lend support to the hypothesis that during thoracoscopic surgery, mechanical lung ventilation with an oxygen/nitrous oxide mixture will increase the rate of gaseous uptake from the non-ventilated lung and so hasten its absorptive collapse.

Effects of PEEP on inspiratory resistance in mechanically ventilated COPD patients.

This study aimed to investigate the effect of increased lung volume with positive end-expiratory pressure (PEEP) on respiratory resistance in patients with chronic obstructive pulmonary disease (COPD). Ten patients with COPD were mechanically ventilated for acute respiratory failure. PEEP was set at 0, 5, 10 and 15 cm H2O. Using the rapid airway occlusion technique, the total inspiratory resistance of the respiratory system was partitioned into interrupter (Rint,rs) and additional effective (deltaRrs) resistances. At each level of PEEP, at constant inflation flow, the inflation volume (deltaV) was varied from 0.2-1 L, and, at constant deltaV, the inflation flow was varied from 0.2-1.2 L x s(-1). The changes in end-expiratory lung volume (deltaEELV) induced by PEEP were also measured. The difference between the EELV and the relaxation volume of the respiratory system (deltaFRC) increased significantly with PEEP of 10 and 15 cm H2O as compared to a PEEP of 0, the increase being associated with a significant reduction of Rint,rs. By contrast, deltaRrs was independent of deltaFRC. At constant deltaV, Rint,rs fitted Rohrer's equation (Rint,rs = K1 + K2 x flow). While K2 significantly declined with AFRC, K1 did not change. At all levels of PEEP, deltaRrs was not influenced by deltaFRC. With increasing lung volume induced by positive end-expiratory pressure, the inspiratory airway resistance decreased, whereas the viscoelastic behaviour of the respiratory system, as reflected by additional effective resistance, did not change.

Significance of the changes in the respiratory system pressure-volume curve during acute lung injury in rats.

The hypothesis that the changes in the respiratory system pressure- volume (PV) curve during pulmonary edema mainly reflect distal airway obstruction was investigated in rats. Normal rats had a well-defined upper inflection point (UIP) at low airway pressure. Airway occlusion by liquid instillation decreased compliance (Crs) and the volume (Vuip) of the UIP, and increased end-inspiratory pressure. The same changes were observed during the progression of edema produced by high volume ventilation (HV). Changes in Vuip and in Crs produced by HV were correlated with edema severity in normal rats or rats with lungs preinjured with alpha-naphthylthiourea. Vuip and Crs changes were proportional, reflecting compression of the PV curve on the volume axis and suggesting reduction of the amount of ventilatable lung at low airway pressure. In keeping with this explanation, the lower Vuip and Crs were before HV, the more severe HV-induced edema was in alpha-naphthylthiourea-injected rats. When edema was profuse, PV curves displayed a marked lower inflection point (LIP), the UIP at low pressure disappeared but another was seen at high volume above the LIP, and the correlation between Vuip changes and edema severity was lost. These observations may have clinical relevance in the context of the "open lung" strategy. ventilator-induced lung injury; respiratory mechanics; acute respiratory distress syndrome

Discussion

Advancement of the lower border of the anterior mandible for the treatment of obstructive sleep apnea syndrome (OSAS) was first described in 1984. 1 Riley R Guilleminault C Powell N et al. Mandibular osteotomy and hyoid bone advancement for obstructive sleep apnea: A case report. Sleep. 1984; 7: 79 Crossref PubMed Scopus (120) Google Scholar The initial rationale for this surgical approach was based on the findings that patients with OSAS have decreased posterior airway space (PAS) and increased distance between the mandible and the hyoid. The initial version of the procedure was just a high sliding genioplasty to advance the genioglossus, geniohyoid, and the anterior belly of the digastric muscles. With increasing understanding that the genioglossus muscle plays an important role in nocturnal airway obstruction, 2 Remmers JE Degroot WJ Sauerland EK et al. Pathogensis of upper airway occlusion during sleep. J Appl Physiol. 1978; 44: 931 PubMed Google Scholar , 3 Mezzanotte WS Tangel DJ White DP Waking genioglossal electromyogram in sleep apnea patients versus normal controls (a neuromuscular compensatory mechanism). J Clin Invest. 1992; 89: 1571 Crossref PubMed Scopus (589) Google Scholar an extension superiorly to fully incorporate the genioglossus muscle was developed. Although Prinsell, 4 Prinsell JR Maxillomandibular advancement surgery in a site-specific treatment approach for obstructive sleep apnea in 50 consecutive patients. Chest. 1999; 116: 1519 Crossref PubMed Scopus (212) Google Scholar as well as Hendler et al recently described the “modified mortise genioplasty,” a similar osteotomy design has been previously published. 5 Powell NB Riley RW Obstructive sleep apnea. Orthognathic surgery perspectives, past, present and future. Oral Maxillofac Clin North Am. 1990; 2: 843 Google Scholar , 6 Powell NB Riley RW Guilleminault C The hypopharynx: Upper airway reconstruction in obstructive sleep apnea syndrome. in: Snoring and Obstructive Sleep Apnea (ed 2). Raven Press, New York, NY1994: 193-209 Google Scholar , 7 Riley RW Powell NB Guilleminault C Inferior sagittal osteotomy of the mandible with hyoid myotomy-suspension: A new procedure for obstructive sleep apnea. Otolaryngol Head Neck Surg. 1986; 94: 589 PubMed Google Scholar