Assessment of pharyngeal airway stability in normal and micrognathic infants

A current hypothesis for obstructive sleep apnea states that 1) negative airway pressure during inspiration can collapse the pharyngeal airway, and 2) neural control of pharyngeal airway-dilating muscles is important in preventing this collapse. To test this hypothesis we performed nasal mask occlusions to increase negative pharyngeal airway pressures during inspiration in eight normal and five micrognathic infants. Both groups developed midinspiratory pharyngeal obstruction, but obstruction was more frequent in micrognathic infants and varied in some infants with sleep state. The airway usually reopened with the subsequent expiration. The occasional failure to reopen was presumably due to pharyngeal wall adhesion. If airway obstruction occurred in sequential breaths during multiple-breath nasal mask occlusions in normal infants, there was a breath-by-breath change in the airway pressure associated with airway closure (airway closing pressure); the airway closing pressure became progressively more negative. Micrognathic infants showed less ability to improve the airway closing pressure, but this ability increased with age. These findings suggest that nasal mask occlusion can test the competence of the neuromuscular mechanisms that maintain pharyngeal airway patency in infants. Micrognathic infants had spontaneous midinspiratory pharyngeal airway obstructions during snoring. Their episodes of obstructive apnea began with midinspiratory pharyngeal obstruction similar to that seen during snoring and nasal mask occlusions. These findings imply a similar pathophysiology for snoring, spontaneous airway obstruction, and obstruction during snoring.     

Influence of passive changes of lung volume on upper airways

The total upper airway resistances are modified during active changes in lung volume. We studied nine normal subjects to assess the influence of passive thoracopulmonary inflation and deflation on nasal and pharyngeal resistances. With the subjects lying in an iron lung, lung volumes were changed by application of an extrathoracic pressure (Pet) from 0 to 20 (+Pet) or -20 cmH2O (-Pet) in 5-cmH2O steps. Upper airway pressures were measured with two low-bias flow catheters, one at the tip of the epiglottis and the other in the posterior nasopharynx. Breath-by-breath resistance measurements were made at an inspiratory flow rate of 300 ml/s at each Pet step. Total upper airway, nasal, and pharyngeal resistances increased with +Pet [i.e., nasal resistance = 139.6 +/- 14.4% (SE) of base-line and pharyngeal resistances = 189.7 +/- 21.1% at 10 cmH2O of +Pet]. During -Pet there were no significant changes in nasal resistance, whereas pharyngeal resistance decreased significantly (pharyngeal resistance = 73.4 +/- 7.4% at -10 cmH2O). We conclude that upper airway resistance, particularly the pharyngeal resistance, is influenced by passive changes in lung volumes, especially pulmonary deflation.     

Influence of respiratory drive on upper airway resistance in normal men

The variations in nasal and pharyngeal resistance induced by changes in the central inspiratory drive were studied in 10 normal men. To calculate resistances we measured upper airway pressures with two low-bias flow catheters; one was placed at the tip of the epiglottis and the other in the posterior nasopharynx, and we measured flow with a Fleisch no. 3 pneumotachograph connected to a tightly fitting mask. Both resistances were obtained continuously during CO2 rebreathing (Read's method) and during the 2 min after a 1-min voluntary maximal hyperventilation. The inspiratory drive was estimated by measurements of inspiratory pressure generated at 0.1 s after the onset of inspiration (P0.1) and by the mean inspiratory flow (VT/TI). In each subject both resistances decreased during CO2 rebreathing; these decreases were correlated with the increase in P0.1. During the posthyperventilation period, ventilation fell below base line in seven subjects; this was accompanied by an increase in both nasal and pharyngeal resistances. These resistances increased exponentially as VT/TI decreased. Parallel changes in nasal and pharyngeal resistances were seen during CO2 stimulus and during the period after the hyperventilation. We conclude that 1) the indexes quantifying the inspiratory drive reflect the activation of nasopharyngeal dilator muscles (as assessed by the changes in upper airway resistance) and 2) both nasal and pharyngeal resistances are similarly influenced by changes in the respiratory drive.     

Changes in upper airway resistance during progressive normocapnic hypoxia in normal men

The effects of normocapnic progressive hypoxia on nasal and pharyngeal resistances were evaluated in nine normal men. To calculate resistances, upper airway pressures were measured with two low-bias flow catheters; one was placed at the tip of the epiglottis and the other in the posterior nasopharynx, and we measured flow with a Fleish no. 3 pneumotachograph connected to a tightly fitting mask. Both resistances were obtained during a baseline period and during progressive normocapnic hypoxia achieved by a rebreathing method. We collected the breath-by-breath values of upper airway resistances, minute ventilation, O2 and CO2 fractions, arterial O2 saturation (SaO2), and changes in functional residual capacity (inductance vest). The central respiratory drive was evaluated by the mouth occlusion pressure 0.1 s after the onset of inspiration (P0.1), and breath-by-breath P0.1 values were estimated by intrapolation from the linear relationship between P0.1 and SaO2. In each subject both resistances decreased during the hypoxic test. The slope of the decrease in resistance with decreasing SaO2 (%baseline/%SaO2) was steeper for pharyngeal resistance than for nasal resistance [2.67 +/- 0.29 and 1.61 +/- 0.25 (SE), respectively; P less than 0.05]. The slope of the decrease in resistance with increasing P0.1 (%baseline/cmH2O) was -0.24 +/- 0.05 for nasal resistance and -0.39 +/- 0.07 for pharyngeal resistance (P less than 0.05). Functional residual capacity progressively increased during the test, but the decrease in resistance was greater than expected from an isolated increase in lung volume. We conclude that nasal and pharyngeal resistances decrease during progressive normocapnic hypoxia.(ABSTRACT TRUNCATED AT 250 WORDS)     

Isolation of varicella-zoster virus from pharyngeal and nasal swabs in varicella patients

Thirteen children aged 5 months to 4 years were observed during a varicella epidemic in an Infants' Hospital; except for two normal individuals, the children had various forms of congenital defects. Eleven of the children developed varicella. During the first 3 days of exanthem, a total of 17 VZ virus strains were isolated: 12 from vesicular fluid, 3 from 23 nasal and 2 from 22 pharyngeal swabs. No strain was isolated during the incubation period despite 57 and 56 swabs having been collected from the throat and nose, respectively; nor was VZ virus isolated from 6 pharyngeal and 7 nasal swabs taken on the first day of exanthem. Isolation attempts performed from vesicular fluid to control quality of the isolation conditions gave a positivity rate of 100%. Under these optimal isolation conditions VZ virus was found in the nose or throat alongside skin vesicles in four of the 11 ill children. Besides VZ virus, the pharyngeal and nasal swabs yielded, respectively, four and four cytomegalovirus strains. The cytomegalovirus infections were inapparent.     

A new nasal acoustic reflection technique to estimate pharyngeal cross-sectional area during sleep.

The conventional acoustic reflection technique in which acoustic waves are launched through the mouth cannot be applied during sleep, nor can it be applied to the nasopharynx, which is the major site of occlusion in patients with obstructive sleep apnea syndrome. We propose a new technique of nasal acoustic reflection to measure pharyngeal cross-sectional areas including the nasopharynx. The acoustic waves are introduced simultaneously to both nostrils during spontaneous nasal breathing. A new algorithm takes into account the nasal septum with asymmetric nasal cavities on both sides and assumes prior knowledge of the cross-sectional area of the nasal cavities and the position of the nasal septum. This method was tested on an airway model with a septum and on healthy human subjects. The conventional technique gave inaccurate measurements for pharyngeal cross-sectional areas for an airway model with asymmetric branching, whereas the new technique measured them almost perfectly. The oro- and hypopharyngeal cross-sectional area measurements acquired by the new method were not different from those obtained by the conventional method in normal subjects. This new method can be used as a monitor of upper airway dimensions in nocturnal polysomnography.     

Dependence of pharyngeal resistance on genioglossal EMG activity, nasal resistance, and airflow.

We investigated the quantitative relationships among pharyngeal resistance (Rph), genioglossal electromyographic (EMGge) activity, nasal resistance (Rna), and airflow in 11 normal men aged 19-50 while they were awake. We made measurements with subjects seated with the head erect, seated with the head flexed forward approximately 40 degrees, and supine. Each subject wore a face mask connected to a pneumotachograph to measure airflow. After topical anesthesia of the nose, two catheters for measuring nasal and pharyngeal airway pressures were passed through one nostril: the nasal pressure catheter was positioned at the nasal choanae, and the pharyngeal pressure catheter was positioned just above the epiglottis. We measured EMGge activity with an intraoral surface electrode. The subjects breathed exclusively through the nose while inhaling room air or rebreathing CO2. We measured Rph, Rna, airflow, and EMGge activity at approximately 90-ms intervals throughout each inspiration. Rph was invariant as head position was changed. At any given head position, EMGge activity rose as airflow increased, and Rph remained constant. In contrast, Rna increased as airflow increased. Because Rph was constant, EMGge activity was not correlated with Rph, but EMGge was positively correlated with Rna and airflow. On the basis of the stability of Rph in the face of marked changes in collapsing forces, we conclude that the dynamic interplay of posture, head and jaw position, and upper airway muscle activity quite effectively maintains pharyngeal patency, and interactions among these factors are subtle and complex.     

The localization of IgA and IgE globulins in the palatinal tonsils,nasal mucous membrane and nasal polypi

Using the immunofluorescence method, the localization of IgA and IgE globulins was studied in tonsillar tissue, nasal and pharyngeal mucous membranes and nasal polypi of patients hospitalised at the Clinic of Otorhinolaryngology. No difference in either localization and number of cells containing blood and/or secretory IgA globulin could be found in individual patients. Great amounts of IgE globulin were found in nasal mucous membrane and nasal polypi in subepithelial plasma cells even in patients without demonstrable allergy.     

Control of respiratory activity of the genioglossus muscle in micrognathic infants

The genioglossus (GG) muscle activity of four infants with micrognathia and obstructive sleep apnea was recorded to assess the role of this tongue muscle in upper airway maintenance. Respiratory air flow, esophageal pressure, and intramuscular GG electromyograms (EMG) were recorded during wakefulness and sleep. Both tonic and phasic inspiratory GG-EMG activity was recorded in each of the infants. On occasion, no phasic GG activity could be recorded; these silent periods were unassociated with respiratory embarrassment. GG activity increased during sigh breaths. GG activity also increased when the infants spontaneously changed from oral to nasal breathing and, in two infants, with neck flexion associated with complete upper airway obstruction, suggesting that GG-EMG activity is influenced by sudden changes in upper airway resistance. During sleep, the GG-EMG activity significantly increased with 5% CO2 breathing (P less than or equal to 0.001). With nasal airway occlusion during sleep, the GG-EMG activity increased with the first occluded breath and progressively increased during the subsequent occluded breaths, indicating mechanoreceptor and suggesting chemoreceptor modulation. During nasal occlusion trials, there was a progressive increase in phasic inspiratory activity of the GG-EMG that was greater than that of the diaphragm activity (as reflected by esophageal pressure excursions). When pharyngeal airway closure occurred during a nasal occlusion trial, the negative pressure at which the pharyngeal airway closed (upper airway closing pressure) correlated with the GG-EMG activity at the time of closure, suggesting that the GG muscle contributes to maintaining pharyngeal airway patency in the micrognathic infant.     

Use of the pharyngeal flap in the treatment of congenital velopharyngeal incompetence

Seventy-four patients were referred to the senior author because of presumed velopharyngeal incompetence without cleft palate. As a result of an extensive preoperative evaluation that included assessment of articulation patterns, nasal emission, oronasal resonance, and general speech intelligibility, 57 of the 74 patients were selected for a pharyngeal flap procedure. In 54 of the 57 patients (95 percent), the operation corrected inappropriate nasal emission and hypernasality and improved intraoral air pressure to allow normal speech production.     

Nosopharyngeal microflora in ambulatory treated children and adults with upper respiratory tract infections

Upper respiratory tract consists resident and transient bacterial microflora, which in appropriate condition can cause infection. Bacteriological study was performed among 201 patients with upper respiratory tract infections treated in ambulatory. From nasal and pharyngeal swabs Staphylococcus aureus, Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, and Streptococci group A, B, C, G were isolated. Antibiotic susceptibility testing of isolated strains was performed using CLSI criteria. All isolated strains of streptococci were susceptible to penicillin; some of them demonstrated resistance to macrolides and lincosamides. Few isolated strains of H. influenzae demonstrated resistance to penicillin and cotrimoxazole. Azitromycin resistant strains were not detected. All isolated strains of M. catarrhalis were beta-lactamase positive and demonstrated resistance to penicillin. Strains of methicillin sensitive S. aureus (MSSA) were isolated most frequently from pharyngeal swabs (35.4%) and S. pneumoniae (33.3)--from nasal swabs.     

芪菊袋泡茶在慢性鼻窦炎伴鼻息肉功能性鼻内镜术后的临床疗效

目的:评估芪菊袋泡茶对功能性鼻内镜术(FESS)术后的临床疗效。方法:采用随机数字表法将纳入观察的FESS术后患者分为两组,对照组为常规处理,治疗组在常规处理的基础上给予芪菊袋泡茶雾化吸入及饮用:术后6h开始予芪菊袋泡茶治疗,以芪菊袋泡茶一袋配30 mL饮用水,作雾化吸入,另予一袋配100 mL饮用水泡服,每天2次,雾化联合饮用共1周。雾化疗程结束后,则以每次2袋,每天2次泡服,再饮用2周,并随访12周。比较两组间鼻窦炎相关症状(包括鼻塞、头痛、面痛、嗅觉障碍、鼻涕)评分、鼻腔粘膜改变和术腔上皮化程度、术后咽喉部症状(包括咽痛、异物感、排痰、咳嗽)评分。结果:术后2、4、8、12周,治疗组鼻窦炎相关症状总评分与对照组比较差异有统计学意义(P0.05);治疗组在术后4、8、12周鼻腔粘膜评分、上皮化程度较对照组显著改善,差异有统计学意义(P0.05);治疗组在术后1d、3d咽喉部症状总评分、咽痛和异物感症状评分显著较对照组改善,差异有统计学意义(P0.05)。结论:芪菊袋泡茶在慢性鼻窦炎伴鼻息肉FESS术后能取得良好的临床疗效,明显改善术后症状,值得临床推广。     

Pharyngeal resistance in normal humans: influence of gender, age, and obesity

Investigation into the etiology of obstructive sleep apnea is beginning to focus increasing attention on upper airway anatomy and physiology (patency and resistance). Before conclusions concerning upper airway resistance in these patients can be made, the normal range of supraglottic and, more specifically, pharyngeal resistance needs to be better defined. We measured supraglottic and pharyngeal resistances during nasal breathing in a normal population of 35 men and women. Our technique measured epiglottic pressure with a balloon-tipped catheter, choanal pressure using anterior rhinometry, and flow with a sealed face mask and pneumotachograph. Resistance was measured at a flow rate of 300 ml/s during inspiration. Men had a mean pharyngeal resistance (choanae to epiglottis) of 4.6 +/- 0.8 (SE) cmH2O X l-1 X s, whereas women demonstrated a significantly (P less than 0.01) lower value, 2.3 +/- 0.3 cmH2O X l-1 X s. Supraglottic resistance was also higher in men (P = 0.01). Age (r = 0.73, P less than 0.01) correlated closely with pharyngeal resistance in men, but no such correlations could be found in women. These results may have implications in the epidemiology of obstructive sleep apnea.     

The expression pattern of opticin during chicken embryogenesis

We isolated the chicken homologue of opticin (cOptc), a member of the small leucine-rich repeat protein (SLRP) family. cOptc is expressed in the brain and the neural tube from stage 9 onward. At later stages, cOptc is expressed in the ciliary epithelium of the eye, optic stalk, Rathke's pouch, pharyngeal pouches, nasal pit and otic vesicle.     

Nasal lymphoid tissue in the rat

Summary The structure and organization of paired lymphoid tissue in the nasal mucosa, situated in the transitional zone on both sides of the septal opening to the pharyngeal duct, of conventionally-housed rats was examined by light microscopy and scanning and transmission electron microscopy. Each lymphoid structure consisted of follicles containing T- and B-cell areas, and was covered with specialized epithelium. This epithelium consisted of cuboidal ciliated cells with oval nuclei parallel to the basal lamina. Goblet cells were sparse. Occasionally, islands of microvilli-bearing cells (so called membraneous or M cells) covered the lymphoid structures. M Cells were also found as single cells among the ciliated cells. The morphological characteristics and the particular localization justify the conclusion that the nasal lymphoid tissue described belongs to the mucosa-associated lymphoid tissue. It is therefore suggested that this nasal structure be designated nasal lymphoid tissue.     

Analysis of somatic and salivary gland antigens of third stage larvae of Rhinoestrus spp. (Diptera, Oestridae)

Larvae of Rhinoestrus spp. (Diptera, Oestridae) infect nasal and sinus cavities of horses, causing a nasal myiasis characterized by severe respiratory distress. Presently, the diagnosis of horse nasal botfly relies on the observation of clinical signs, on the post mortem retrieval of larvae or on molecular assays performed using pharyngeal swabs. The present study was carried out to characterize larval somatic proteins and salivary glands of Rhinoestrus spp. in a preliminary assessment towards the immunodiagnosis of equine rhinoestrosis. Out of the 212 necropsied horses 13 were positive for the presence of Rhinoestrus spp. larvae. The analysis of the sera from the infected animals by Western blotting assay showed the presence of a specific host humoral immune response against Rhinoestrus spp. larvae and proved that the salivary glands are the major immunogens in horse nasal botflies.     

A model of a snorer's upper airway

In snorers, the physiologic decrease of postural muscle tone during sleep results in increased collapsibility of the upper airway. Measurement of nasal pressure changes with prongs is increasingly used to monitor flow kinetics through a collapsing upper airway. This report presents a mathematical model to predict nasal flow profile from three critical components that control upper airway patency during sleep. The model includes the respiratory pump drive, the stiffness of the pharyngeal soft tissues, and the dynamic support of the muscles surrounding the upper airway. Depending on these three components, the proposed model is able to reproduce the characteristic changes in flow profile that are clinically observed in snorers and non-snorers during sleep.     

Effects of respiratory drive on upper airways in sleep apnea patients and normal subjects

We compared the changes in nasal and pharyngeal resistance induced by modifications in the central respiratory drive in 8 patients with sleep apnea syndrome (SAS) with the results of 10 normal men. Upper airway pressures were measured with two low-bias flow catheters; one was placed at the tip of the epiglottis and the other above the uvula. Nasal and pharyngeal resistances were calculated at isoflow. During CO2 rebreathing and during the 2 min after maximal voluntary hyperventilation, we continuously recorded upper airway pressures, airflow, end-tidal CO2, and the mean inspiratory flow (VT/TI); inspiratory pressure generated at 0.1 s after the onset of inspiration (P0.1) was measured every 15-20 s. In both groups upper airway resistance decreased as P0.1 increased during CO2 rebreathing. When P0.1 increased by 500%, pharyngeal resistance decreased to 17.8 +/- 3.1% of base-line values in SAS patients and to 34.9 +/- 3.4% in normal subjects (mean +/- SE). During the posthyperventilation period the VT/TI fell below the base-line level in seven SAS patients and in seven normal subjects. The decrease in VT/TI was accompanied by an increase in upper airway resistance. When the VT/TI decreased by 30% of its base-line level, pharyngeal resistance increased to 319.1 +/- 50.9% in SAS and 138.5 +/- 4.7% in normal subjects (P less than 0.05). We conclude that 1) in SAS patients, as in normal subjects, the activation of upper airway dilators is reflected by indexes that quantify the central inspiratory drive and 2) the pharyngeal patency is more sensitive to the decrease of the central respiratory drive in SAS patients than in normal subjects.     

Neural crest cell survival is dependent on Rho kinase and is required for development of the mid face in mouse embryos

Neural crest cells (NCC) give rise to much of the tissue that forms the vertebrate head and face, including cartilage and bone, cranial ganglia and teeth. In this study we show that conditional expression of a dominant-negative (DN) form of Rho kinase (Rock) in mouse NCC results in severe hypoplasia of the frontonasal processes and first pharyngeal arch, ultimately resulting in reduction of the maxilla and nasal bones and severe craniofacial clefting affecting the nose, palate and lip. These defects resemble frontonasal dysplasia in humans. Disruption of the actin cytoskeleton, which leads to abnormalities in cell-matrix attachment, is seen in the RockDN;Wnt1-cre mutant embryos. This leads to elevated cell death, resulting in NCC deficiency and hypoplastic NCC-derived craniofacial structures. Rock is thus essential for survival of NCC that form the craniofacial region. We propose that reduced NCC numbers in the frontonasal processes and first pharyngeal arch, resulting from exacerbated cell death, may be the common mechanism underlying frontonasal dysplasia.     

Three dimensional assessment of the pharyngeal airway in individuals with non-syndromic cleft lip and palate

Introduction

Children with cleft lip and palate (CLP) are known to have airway problems. Previous studies have shown that individuals with CLP have a 30% reduction in nasal airway size compared to non-cleft controls. No reports have been found on cross-sectional area and volume of the pharyngeal airway in clefts. Introduction of Cone-Beam CT (CBCT) and imaging software has facilitated generation of 3D images for assessment of the cross-sectional area and volume of the airway.

Objective

To assess the pharyngeal airway in individuals with CLP using CBCT by measuring volume and smallest cross-sectional areas and compare with 19 age- and sex-matched non-cleft controls.

Methods

Retrospective study of CBCT data of pre-adolescent individuals (N = 19, Mean age = 10.6, 7 females, 12 males, UCLP = 6, BCLP = 3) from the Center for Craniofacial Anomalies. Volumetric analysis was performed using image segmentation features in CB Works 3.0. Volume and smallest cross-sectional were studied in both groups. Seven measurements were repeated to verify reliability using Pearson correlation coefficient. Volume and cross-sectional area differences were analyzed using paired t-tests.

Results

The method was found to be reliable. Individuals with CLP did not exhibit smaller total airway volume and cross sectional area than non-CLP controls.

Conclusion

3D imaging using CBCT and CB Works is reliable for assessing airway volume. Previous studies have shown that the nasal airway is restricted in individuals with CLP. In our study, we found that the pharyngeal airway is not compromised in these individuals.