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PubMed2006

Adult laryngeal hemangioma CO2 laser excision. A single institution 3-year experience (Vittorio Veneto 2001-2003).

CONCLUSIONS: Adult supraglottic hemangiomas can be treated successfully with CO2 laser excision with limited morbidity. Extended laryngeal cavernous hemangiomas involving hypopharynx should be approached with staged CO2 laser surgical procedures. OBJECTIVES: Hemangioma of the adult larynx is an uncommon, benign lesion characterized by thin, friable mucosa overlying the vascular stroma. The optimal surgical approach to these lesions is still controversial because only anecdotal case reports or very limited series are available. We report a 3-year, retrospective, single institution study of the results of CO2 laser treatment of supraglottic hemangiomas in adults. PATIENTS AND METHODS: Six consecutive cases of adult laryngeal hemangioma were treated by the first author with CO2 laser microsurgery alone. RESULTS: In five of six cases, no recurrences have been diagnosed (median follow-up period: 29 months). One case presented limited persistence of disease in the retro-cricoid and arytenoids at 20-month follow-up control.

Adult↗

PubMed2002

Cancer of the larynx--treatment results after primary radiotherapy with salvage surgery in a series of 1005 patients.

The aim of this study is to present and discuss the results of initial radiotherapy with salvage surgery and to compare them with those from centres where primary surgery is the prevailing principle. The series comprised 1005 consecutive patients treated during the period 1965-1998. Salvage surgery was performed if patients had residual tumour or developed recurrence. Disease-specific survival (DSS) and crude survival (CS) after 5 years, among 643 patients with glottic carcinomas treated with curative radiotherapy was 88.6% (SE = 1.3) and 65.3% (SE = 2.0), respectively. Among T1 glottic carcinomas the locoregional control was 88%, i.e. 88% of patients were cured after radiotherapy alone, and the DSS was 99% both evaluated after 5 years, i.e. the salvage surgery added approximately 11% to the survival of T1 glottic patients. Only 4% (12/312) of T1 glottic patients had laryngectomies. Locoregional control among T2 glottic cases was 67% and the DSS 88%, but, 18% (41/233) of patients lost their larynx. The corresponding results among T3 glottic cases were 30% and 59%, i.e. the organ preservation was close to 50%. Among patients with supraglottic carcinomas, the two estimates were 440 and 63%, respectively. Compared with our results, recent results published in the literature after initial laser surgery of T1 glottic carcinomas indicate that there are only minor differences in DSS and organ preservation, but it is generally agreed, but not proven, that voice quality after radiotherapy is better. T2 glottic carcinomas treated by initial supracricoid partial laryngectomy in a selected series have yielded very high DSS rates with better organ preservation than was observed in the present series. As to T3 glottic carcinomas, initial surgery does not produce better survival rates than those produced in the present series but our organ preservation is higher. The treatment of patients with supraglottic carcinoma has benefited from optimization of radiotherapy during recent decades. The role of initial laser surgery is as yet undecided.

Adolescent↗

PubMed2004

Vocal fold vibration and voice source aperiodicity in 'dist' tones: a study of a timbral ornament in rock singing.

The acoustic characteristics of so-called 'dist' tones, commonly used in singing rock music, are analyzed in a case study. In an initial experiment a professional rock singer produced examples of 'dist' tones. The tones were found to contain aperiodicity, SPL at 0.3 m varied between 90 and 96 dB, and subglottal pressure varied in the range of 20-43 cm H2O, a doubling yielding, on average, an SPL increase of 2.3 dB. In a second experiment, the associated vocal fold vibration patterns were recorded by digital high-speed imaging of the same singer. Inverse filtering of the simultaneously recorded audio signal showed that the aperiodicity was caused by a low frequency modulation of the flow glottogram pulse amplitude. This modulation was produced by an aperiodic or periodic vibration of the supraglottic mucosa. This vibration reduced the pulse amplitude by obstructing the airway for some of the pulses produced by the apparently periodically vibrating vocal folds. The supraglottic mucosa vibration can be assumed to be driven by the high airflow produced by the elevated subglottal pressure.

Air Pressure↗

PubMed1992

Effects of i.v. midazolam on upper airway resistance.

We have measured changes in supraglottic airway resistance (Rsg) produced by midazolam. Ten subjects were studied on two occasions, receiving in a random order either midazolam 0.1 mg kg-1 or placebo. Supraglottic pressures were measured using a balloon-tipped catheter and air flow with a pneumotachograph. Rsg were calculated at a flow rate of 0.3 litre s-1 during inspiration. No changes in Rsg and no apnoeic events were noted following placebo injection. Mean Rsg increased from 0.23 (SEM 0.07) kPa litre-1 s to 1.29 (0.38) kPa litre-1 s 5 min after injection of midazolam (P less than 0.01), and remained increased significantly for 20 min. Twenty-two apnoeic events were recorded in six subjects, including 11 obstructive events. We conclude that midazolam in sedative doses increases Rsg markedly and induces central apnoea during the first few minutes after i.v. administration and this is followed by obstructive apnoea.

Adult↗

PubMed2005

Effects of helium on high frequency jet ventilation in model of airway stenosis.

BACKGROUND: The addition of helium to the inspired gas may facilitate ventilation in the presence of clinically evident upper airway obstruction. However, there are no data on the effects of using a helium-oxygen mixture during high frequency jet ventilation (HFJV) in upper airway obstruction. METHODS: HFJV at a frequency of 150 min(-1) (driving pressure 2 bar, inspiratory time 30%) was applied to a trachea-lung model to simulate ventilation through varying degrees of fixed laryngotracheal stenosis (2.5-8.5 mm). HFJV was delivered from above, through and below the level of stenosis to simulate supraglottic, transglottic and infraglottic administration. Measurements of distal tracheal pressures were repeated for each route at steady state for each stenosis diameter using both 100% oxygen and helium-oxygen (50% oxygen, 50% helium). The output of the ventilator was measured during operation on oxygen and helium-oxygen. RESULTS: Peak, mean and end-expiratory pressures were greater during simulated supraglottic HFJV than during transglottic and infraglottic HFJV, and pressures increased markedly as the diameter of the stenosis decreased for all routes of ventilation (P<0.001). Generated pressures during HFJV using helium-oxygen and 100% oxygen were very similar overall, although reductions in pressures were observed during ventilation with helium-oxygen via the transglottic and transtracheal routes at stenosis diameters <4 mm (P<0.05). However, HFJV with the helium-oxygen mixture increased the delivered gas volumes by approximately 18%. CONCLUSIONS: Using 50% helium-oxygen during HFJV in the presence of airway stenosis allows an 18% increase in minute volume at generated airway pressures which are the same as or lower than those when using 100% oxygen.

Air Pressure↗

PubMed1991

Pattern of snoring in obstructive sleep apnea patients and in heavy snorers.

We measured respiratory mechanical characteristics during sleep in five heavy, nonapneic snorers (HS) and in five obstructive sleep apnea (OSA) patients. In two HS and in two OSA patients we obtained lateral pharyngeal cineradiographic images during sleep while snoring. Flow limitation preceded all snores in both HS and OSA. Pattern of snoring, hysteresis and temporal relationship between supraglottic pressure (Psg) and flow rate were different in HS and OSA. Maximal flow during snoring was less (p less than 0.05) in OSA (0.18 +/- 0.07 liter/second) than in HS (0.36 +/- 0.06 liter/second). Linear supraglottic resistance during inspiratory snoring was higher, though not significantly, in OSA patients (7.11 +/- 3.01 cm H2O/liter/second) than in HS (4.80 +/- 2.83 cm H2O/liter/second). We conclude that: 1) Snoring is characterized by high frequency oscillations of the soft palate, pharyngeal walls, epiglottis and tongue. 2) Flow limitation appears to be a sine qua non for snoring during sleep. 3) The pattern of snoring is different in OSA and HS. 4) Pharyngeal size during snoring is probably larger in HS than in OSA patients.

Adult↗

PubMed2001

Delayed regional metastases, distant metastases, and second primary malignancies in squamous cell carcinomas of the larynx and hypopharynx.

OBJECTIVE: To determine the impact of delayed regional metastases, distant metastases, and second primary tumors on the therapeutic outcomes in squamous cell carcinomas of the larynx and hypopharynx. STUDY DESIGN: Chart review and statistical analysis. METHODS: A retrospective tumor registry analysis was made of patients with squamous cell carcinomas of the larynx and hypopharynx who were treated with curative intent in the Department of Otolaryngology-Head and Neck Surgery and the Radiation Oncology Center of the Washington University School of Medicine (St. Louis, MO) between January 1971 and December 1991 and developed delayed regional metastases (2 y after treatment), distant metastases, and second primary malignancies. RESULTS: In 2550 patients, the mean age (59.8 y), sex (8.5 male patients and 1 female patient), and tumor differentiation did not affect the incidence of delayed distant, regional, or second primary malignancies. The overall incidence of delayed regional metastases was 12.4% (317/2550 patients); distant metastases, 8.5% (217/2550); and second primary tumors, 8.9% (228/2550), with a 5-year disease-specific survival of 41%, 6.4%, and 35%, respectively. Second primary malignancies were not statistically related to the origin of the primary tumor, tumor staging, or delayed regional and distant metastases (P =.98). Delayed regional metastases and distant metastases were related to advanced primary disease (T4 stage), lymph node metastases (node positive [N+]), tumor location (hypopharynx), and locoregional tumor recurrence (P < or =.028). Advanced regional metastases at initial diagnosis (N2 and N3 disease) increased the incidence of delayed and distant metastases threefold (P =.017). These two metastatic parameters were significantly greater in hypopharyngeal tumors than in laryngeal tumors (P =.037). The incidences of delayed regional metastases by anatomical location of the primary tumor were as follows: glottic, 4.4%; supraglottic, 16%; subglottic, 11.5%; aryepiglottic fold, 21.9%; pyriform sinus, 31.1%; and posterior hypopharyngeal wall, 18.5%. The incidences of distant metastases were as follows: glottic, 4%; supraglottic, 3.7%; subglottic, 14%; aryepiglottic fold, 16%; pyriform fossa, 17.2%; and posterior hypopharyngeal wall, 17.6%. Seventeen hypopharyngeal tumors (2%) presented with M1 disease. Delayed regional metastases to the ipsilateral treated neck had a significantly worse survival prognosis than delayed metastases to the contralateral nontreated neck (P =.001). CONCLUSIONS: Conclusions are as follows: 1) The incidence of second primary tumors is independent from the primary tumor staging and distant and delayed regional metastases. The highest incidence occurred in patient groups with the highest disease-free survival rates (P =.0378). 2) Highest incidence of delayed and distant metastases occurred in hypopharyngeal tumors and was three times greater than in laryngeal cancers (P =.028). 3) Salvage therapeutic rates were poor for delayed metastases to the ipsilateral treated nodes and distant metastases as compared with contralateral neck metastases and second primary tumors (P =.001). 4) Delayed and distant lymph node metastases were significantly higher in advanced primary disease (T4 stage), locoregional recurrences, and regional disease (N2 and N3) (P =.028) in both the larynx and hypopharynx. 5) The higher incidence of delayed and distant metastatic disease was related to more advanced initial tumor presentation in hypopharyngeal cancer as compared with laryngeal cancer (P =.039). 6) Incidence of distant metastases was greatest between 1.5 and 6 years after initial treatment with a mean incidence being less than or equal to 3.2 years.

Adult↗

PubMed2003

Expression of extracellular matrix metalloprotease inducer in laryngeal squamous cell carcinoma.

OBJECTIVES/HYPOTHESIS: Head and neck cancer tumor cell invasion is responsible for both local destruction and distant metastasis. Invasion is largely mediated by matrix metalloproteases that are thought to be induced by tumor cell derived extracellular matrix metalloprotease inducer (EMMPRIN) in surrounding fibroblasts. We hypothesize that EMMPRIN is overexpressed in laryngeal cancer. STUDY DESIGN: Retrospective analysis of patients with supraglottic laryngeal cancer. METHODS: Total protein immunoblotting and immunohistochemical analysis of normal and malignant tissue were performed to determine EMMPRIN expression. EMMPRIN immunoreactivity in 33 patients was correlated with clinicopathological features and survival. RESULTS: Whole-tissue lysates of tumors (n = 8) and metastatic lymph nodes (n = 2), but not normal skin (n = 8) or mucosa (n = 6), expressed significant amounts of EMMPRIN by immunoblotting. EMMPRIN membrane immunoreactivity (transmembrane EMMPRIN score) was associated with nodal positivity (P =.07), and it was a borderline significant predictor of survival (Hazards Ratio = 2.4; 95% CI, 0.88-6.55). As a categorical variable, higher transmembrane EMMPRIN score was associated with higher mortality. CONCLUSIONS: The present study helps to establish EMMPRIN as a widely expressed protein in dysplastic mucosa and supraglottic laryngeal cancer, but not in normal epithelial counterparts.

Antigens, CD↗

PubMed2004

Preoperative planning of airway management in critical care patients.

OBJECTIVE: The aim of this article is to review aspects of airway evaluation that may affect the care of the critical care patient whose airway is to be managed. This information must then be incorporated into the decision-making process of the "airway manager." DESIGN: Literature review. RESULTS: Historically used indexes of airway evaluation suffer from low sensitivity and only modest specificity in identifying the difficult-to-intubate patient. Using each index in isolation of others contributes to their poor predictive power. An understanding of anatomical relationships that these indexes measure should help the clinician in evaluating the airway. The clinician's impression of the airway, as well as the likelihood of trouble with supraglottic ventilation, the patient's inability to take food orally, and the patient's general condition can be used to formulate a management plan. This plan should be consistent with the American Society of Anesthesiologist's difficult airway algorithm. CONCLUSIONS: Rote decision making on airway management, based on commonly used indexes, is not adequate. The vital role of airway in anesthetic management of the critical care patient demands thoughtful consideration. Patient conditions including the need for airway control, the likelihood of difficult laryngoscopy or supraglottic ventilation, the patient's inability to take food orally, and the medical state of the patient must be incorporated.

Algorithms↗

PubMed2004

Smoking, alcohol drinking and cancer risk for various sites of the larynx and hypopharynx. A case-control study in France.

The aim of this work was to study the effects of alcohol and tobacco consumption on laryngeal and hypopharyngeal cancer and to compare these across subsites (glottis, supraglottis, epilarynx, hypopharynx). Data from a hospital-based case-control study including 504 male cases (105 glottic cancers, 80 supraglottic cancers, 97 epilaryngeal cancers and 201 hypopharyngeal cancers) and 242 male controls with non-respiratory cancers were used for this analysis. Information about sociodemographic characteristics, detailed alcohol and tobacco consumption was collected through face-to-face interviews. Statistical analysis used logistic regression, and subsites were compared with polytomous logistic regressions. The risk of laryngeal and hypopharyngeal cancer increased with tobacco (duration and amount) and alcohol consumption; the effect of both agents was multiplicative. From the lowest to the highest consumption level, odds ratios ranged from 1.4 to 5.9 among regular drinkers and from 3 to 44 among current smokers. Risks among ex-smokers were approximately one-third of those for current smokers. Slightly elevated odds ratios were associated with consumption of black tobacco (OR=1.2) and hand-rolled cigarettes (OR=1.2). The risk of cancer was not clearly associated with the type of alcoholic beverage. Subsites did not differ significantly according to tobacco smoking, but differed according to alcohol consumption, with a significantly higher increased risk for hypopharyngeal than for glottic and supraglottic cancers.

Adult↗

PubMed2006

Laryngeal cancer in the United States: changes in demographics, patterns of care, and survival.

BACKGROUND: Survival has decreased among patients with laryngeal cancer during the past 2 decades in the United States. During this same period, there has been an increase in the nonsurgical treatment of laryngeal cancer. OBJECTIVE: The objectives of this study were to identify trends in the demographics, management, and outcome of laryngeal cancer in the United States and to analyze factors contributing to the decreased survival. STUDY DESIGN: The authors conducted a retrospective, longitudinal study of laryngeal cancer cases. METHODS: Review of the National Cancer Data Base (NCDB) revealed 158,426 cases of laryngeal squamous cell carcinoma (excluding verrucous carcinoma) diagnosed between the years 1985 and 2001. Analysis of these case records addressed demographics, management, and survival for cases grouped according to stage, site, and specific TNM classifications. RESULTS: This review of data from the NCDB analysis confirms the previously identified trend toward decreasing survival among patients with laryngeal cancer from the mid-1980s to mid-1990s. Patterns of initial management across this same period indicated an increase in the use of chemoradiation with a decrease in the use of surgery despite an increase in the use of endoscopic resection. The most notable decline in the 5-year relative survival between the 1985 to 1990 period and the 1994 to 1996 period occurred among advanced-stage glottic cancer, early-stage supraglottic cancers, and supraglottic cancers classified as T3N0M0. Initial treatment of T3N0M0 laryngeal cancer (all sites) in the 1994 to 1996 period resulted in poor 5-year relative survival for those receiving either chemoradiation (59.2%) or irradiation alone (42.7%) when compared with that of patients after surgery with irradiation (65.2%) and surgery alone (63.3%). In contrast, identical 5-year relative survival (65.6%) rates were observed during this same period for the subset of T3N0M0 glottic cancers initially treated with either chemoradiation or surgery with irradiation. CONCLUSIONS: The decreased survival recorded for patients with laryngeal cancer in the mid-1990s may be related to changes in patterns of management. Future studies are warranted to further evaluate these associations.

Antineoplastic Agents↗

PubMed2001

An acoustic model of the respiratory tract.

With the emerging use of tracheal sound analysis to detect and monitor respiratory tract changes such as those found in asthma and obstructive sleep apnea, there is a need to link the attributes of these easily measured sounds first to the underlying anatomy, and then to specific pathophysiology. To begin this process, we have developed a model of the acoustic properties of the entire respiratory tract (supraglottal plus subglottal airways) over the frequency range of tracheal sound measurements, 100 to 3000 Hz. The respiratory tract is represented by a transmission line acoustical analogy with varying cross sectional area, yielding walls, and dichotomous branching in the subglottal component. The model predicts the location in frequency of the natural acoustic resonances of components or the entire tract. Individually, the supra and subglottal portions of the model predict well the distinct locations of the spectral peaks (formants) from speech sounds such as /a/ as measured at the mouth and the trachea, respectively, in healthy subjects. When combining the supraglottic and subglottic portions to form a complete tract model, the predicted peak locations compare favorably with those of tracheal sounds measured during normal breathing. This modeling effort provides the first insights into the complex relationships between the spectral peaks of tracheal sounds and the underlying anatomy of the respiratory tract.

Acoustics↗

PubMed1997

The relationship of cervical lymph node metastases to primary sites of carcinoma of the upper aerodigestive tract: a pathological study.

BACKGROUND: Therapeutic and elective dissection of the neck is accepted management in the treatment of squamous cell carcinoma (SCC) of the upper aerodigestive tract (UADT). Accurate histological assessment of the levels of involvement of cervical metastatic spread from different sites within the UADT has allowed the increasing use of less than radical procedures, with associated reduced morbidity. METHODS: A total of 168 necks in 126 patients were examined pathologically. All levels were identified at surgery, marked and oriented by pinning the specimen to a cork board, and examined histologically. A total of 114 necks had a comprehensive neck dissection (CND) in which all levels were dissected. The number and level of involvement and the occult rate (114 necks) for each primary site was assessed. Of the total of 168 necks, 80 had pathologically involved nodes, and the number with greater than one node involved (N2b) was compared for each primary site. The number with extracapsular spread for each nodal staging was also examined. RESULTS: The sites of primary SCC were the oral cavity, oropharynx, hypopharynx, supraglottic and glottic larynx. In those patients with a primary in the oral cavity, no patient had level 5 involvement, but in two patients (7%) level 4 was involved. In the oropharynx, level 1 and 5 were involved in two patients (11%) each. In the hypopharynx, level 1 was not involved in any patient, however, level 5 contained metastasis in 7 (23%). In the supraglottic larynx, level 1 was involved in one (4%) patient and level 5 was involved in three (11%). In the glottis only one patient had bilateral multiple nodes which included level 5. In no case was level 5 involved without positive nodes in other levels. The occult rate for each primary site was 45%, 22%, 77%, 54% and 29%, respectively. The multiple node rate in the 80 necks with positive nodes was, respectively, 31%, 54%, 66%, 45% and 40%. All patients with a node larger than 3 cm had extracapsular spread of tumour. CONCLUSIONS: The level of nodal involvement and therefore the type of neck dissection should be determined by the site of the primary within the UADT and the presence or absence of nodes at surgery. There is a high number (39-66%) of pathologically involved necks which have multiple nodes and also nodes with extracapsular spread of tumour, which may influence the decision for postoperative radiotherapy.

Adult↗

PubMed2005

Use of CobraPLA for airway management in a neonate with Desbuquois syndrome. Case report and anesthetic implications.

We present the anesthetic management of an infant with Desbuquois syndrome (a rare form of micromelic dwarfism) with a possible difficult airway. The anesthetic implications of this syndrome are presented. The airway was managed with a new supraglottic device - the CobraPLA. Although intubation through this device was not possible in this instance, CobraPLA provided a satisfactory supraglottic airway. It was easy to insert and provided satisfactory conditions for positive pressure ventilation. The CobraPLA provides another option for airway management.

Abnormalities, Multiple↗

PubMed2006

Dependence of phonation threshold pressure on vocal tract acoustics and vocal fold tissue mechanics.

Analytical and computer simulation studies have shown that the acoustic impedance of the vocal tract as well as the viscoelastic properties of vocal fold tissues are critical for determining the dynamics and the energy transfer mechanism of vocal fold oscillation. In the present study, a linear, small-amplitude oscillation theory was revised by taking into account the propagation of a mucosal wave and the inertive reactance (inertance) of the supraglottal vocal tract as the major energy transfer mechanisms for flow-induced self-oscillation of the vocal fold. Specifically, analytical results predicted that phonation threshold pressure (Pth) increases with the viscous shear properties of the vocal fold, but decreases with vocal tract inertance. This theory was empirically tested using a physical model of the larynx, where biological materials (fat, hyaluronic acid, and fibronectin) were implanted into the vocal fold cover to investigate the effect of vocal fold tissue viscoelasticity on Pth. A uniform-tube supraglottal vocal tract was also introduced to examine the effect of vocal tract inertance on Pth. Results showed that Pth decreased with the inertive impedance of the vocal tract and increased with the viscous shear modulus (G") or dynamic viscosity (eta') of the vocal fold cover, consistent with theoretical predictions. These findings supported the potential biomechanical benefits of hyaluronic acid as a surgical bioimplant for repairing voice disorders involving the superficial layer of the lamina propria, such as scarring, sulcus vocalis, atrophy, and Reinke's edema.

Biomechanical Phenomena↗

PubMed1987

The development of skill in producing word-final English stops.

This study examined production of word-final English /p/ and /b/ by subjects whose native language does not possess voiced stops in word-final position. Native Chinese adults resembled native English adults, native English children, and native Chinese children in producing /p/ with greater peak oral air pressure than /b/. However, unlike subjects in the other groups, the Chinese adults' /b/ was sometimes misidentified as /p/. This may have occurred, at least in part, because the Chinese adults produced a much smaller difference between /p/ and /b/ in labial closure duration and voicing than the other subjects. The English adults sustained voicing in /b/ significantly longer than subjects in the other three groups. To help determine the basis for this ability, the shape of oral air pressure waveforms was examined systematically. The percentage of "delayed" and "bimodal" waveforms, in which pressure stopped increasing, or decreased, prior to the release of labial constriction, was calculated for each group. Only the English adults showed more such waveforms for /b/ than /p/. Voicing continued 18 ms longer in /b/ tokens with delayed and bimodal waveforms than in tokens in which oral pressure increased continuously. The duration of closure voicing was correlated with the rate at which pressure increased in the English adults' /b/ waveforms. Previous aerodynamic modeling has shown that delayed and bimodal waveforms may result from an active enlargement of the supraglottal cavity. This, together with the pattern of between-group differences observed here, suggests that the English adults learned to enlarge the supraglottal cavity to sustain voicing in /b/. It appears that neither the children nor the Chinese adults had as yet acquired this skill.

Adult↗

PubMed1991

Effects of CO2 rebreathing on pulmonary mechanics in premature infants.

The effects of hypercapnia produced by CO2 rebreathing on total pulmonary, supraglottic, and lower airway (larynx and lungs) resistance were determined in eight premature infants [gestational age at birth 32 +/- 3 (SE) wk, weight at study 1,950 +/- 150 g]. Nasal airflow was measured with a mask pneumotachograph, and pressures in the esophagus and oropharynx were measured with a fluid-filled or 5-Fr Millar pressure catheter. Trials of hyperoxic (40% inspired O2 fraction) CO2 rebreathing were performed during quiet sleep. Total pulmonary resistance decreased progressively as end-tidal PCO2 (PETCO2) increased from 63 +/- 23 to 23 +/- 15 cmH2O.l-1.s in inspiration and from 115 +/- 82 to 42 +/- 27 cmH2O.l-1.s in expiration between room air (PETCO2 37 Torr) and PETCO2 of 55 Torr (P less than 0.05). Lower airway resistance (larynx and lungs) also decreased from 52 +/- 22 to 18 +/- 14 cmH2O.l-1.s in inspiration and from 88 +/- 45 to 30 +/- 22 cmH2O.l-1.s in expiration between PETCO2 of 37 and 55 Torr, respectively (P less than 0.05). Resistance of the supraglottic airway also decreased during inspiration from 7.2 +/- 2.5 to 3.6 +/- 2.5 cmH2O.l-1.s and in expiration from 7.6 +/- 3.3 to 5.3 +/- 4.7 cmH2O.l-1.s at PETCO2 of 37 and 55 Torr (P less than 0.05). The decrease in resistance that occurs within the airway in response to inhaled CO2 may permit greater airflow at any level of respiratory drive, thereby improving the infant's response to CO2.

Airway Resistance↗

PubMed1991

Pattern of simulated snoring is different through mouth and nose.

Cineradiography of the pharynx during simulated snoring was done in 6 healthy volunteers, and supraglottic pressure and flow rate were recorded in 12 others. We observed, immediately before snoring, a decrease in the sagittal diameter of the oropharynx followed, during snoring, by high-frequency oscillations of soft palate and pharyngeal walls. The pattern of soft palate oscillations was different while snoring through the nose or mouth. During inspiratory snoring through the nose, the soft palate remained in close contact with the back of the tongue and only the uvula presented high-frequency oscillations. Snoring through the mouth resulted in ample high-frequency oscillations of the whole soft palate. Frequency of airflow and supraglottic pressure oscillations was less (P less than 0.05) during mouth (28.2 +/- 7.5 Hz) than during nasal snoring (77.8 +/- 36.7 Hz). This difference may be related to the smaller oscillating mass (i.e., uvula) during nasal snoring. At variance with our previous data, which showed that snoring during sleep, in both heavy (nonapneic) snorers and obstructive sleep apnea patients, was systematically preceded by flow limitation, this was not true during simulated snoring.

Adult↗