Aerodynamic characteristics in upper airways among orthodontic patients and its association with adenoid nasopharyngeal ratios in lateral cephalograms.

BACKGROUND: Adenoid hypertrophy among orthodontic patients may be detected in lateral cephalograms. The study investigates the aerodynamic characteristics within the upper airway (UA) by means of computational fluid dynamics (CFD) simulation. Furthermore, airflow features are compared between subgroups according to the adenoidal nasopharyngeal (AN) ratios. METHODS: This retrospective study included thirty-five patients aged 9-15 years having both lateral cephalogram and cone beam computed tomography (CBCT) imaging that covered the UA region. The cases were divided into two subgroups according to the AN ratios measured on the lateral cephalograms: Group 1 with an AN ratio < 0.6 and Group 2 with an AN ratio ≥ 0.6. Based on the CBCT images, segmented UA models were created and the aerodynamic characteristics at inspiration and expiration were simulated by the CFD method for the two groups. The studied aerodynamic parameters were pressure drop (ΔP), maximum midsagittal velocity (Vms), maximum wall shear stress (Pws), and minimum wall static pressure (Pw). RESULTS: The maximum Vms exhibits nearly 30% increases in Group 2 at both inspiration (p = 0.013) and expiration (p = 0.045) compared to Group 1. For the other aerodynamic parameters such as ΔP, the maximum Pws, and minimum Pw, no significant difference is found between the two groups. CONCLUSIONS: The maximum Vms seems to be the most sensitive aerodynamic parameter for the groups of cases. An AN ratio of more than 0.6 measured on a lateral cephalogram may associate with a noticeably increased maximum Vms, which could assist clinicians in estimating the airflow features in the UA.

Reliability of alternative devices for postoperative patient temperature measurement: two prospective, observational studies.

Peri-operative hypothermia is associated with significant morbidity, yet limitations exist regarding non-invasive temperature assessment in the post-anaesthesia care unit (PACU). In this prospective study of 100 patients, we aimed to determine the reliability of two commonly used temperature measurement devices, forehead temporal artery temperature and tympanic measurement, in addition to an indwelling urinary catheter with temperature probe, in comparison with the final nasopharyngeal core temperature at the end of surgery. Agreement of forehead measurement with nasopharyngeal temperature showed a mean bias (±95% limits of agreement) of 0.15 °C (±1.4 °C), with a steep slope of the relationship on the Bland-Altman plot of -0.8, indicating a tendency to normalise patient temperature readings to 36.4 °C. Only 54% of hypothermic cases were correctly detected by the forehead measurement device. Agreement of tympanic measurement with nasopharyngeal core temperature measurement was marginally improved with a mean bias of 0.13 °C (95% limits of agreement ±1.15 °C). In contrast, agreement of bladder temperature with nasopharyngeal temperature showed a mean (SD) bias of 0.19 (0.28) °C (95% limits of agreement ±0.54 °C), with a relatively flat line of best fit. We demonstrated that two commonly used temperature measurement devices, forehead temporal artery temperature and tympanic measurement, compared with nasopharyngeal core temperature, were imprecise and unreliable following major surgery. However, the indwelling catheter with temperature sensor was precise and acceptable for continuous core temperature measurement in the PACU.

Orthonasal versus retronasal glomerular activity in rat olfactory bulb by fMRI.

Odorants can reach olfactory receptor neurons (ORNs) by two routes: orthonasally, when volatiles enter the nasal cavity during inhalation/sniffing, and retronasally, when food volatiles released in the mouth pass into the nasal cavity during exhalation/eating. Previous work in humans has shown that both delivery routes of the same odorant can evoke distinct perceptions and patterns of neural responses in the brain. Each delivery route is known to influence specific responses across the dorsal region of the glomerular sheet in the olfactory bulb (OB), but spatial distributions across the entire glomerular sheet throughout the whole OB remain largely unexplored. We used functional MRI (fMRI) to measure and compare activations across the entire glomerular sheet in rat OB resulting from both orthonasal and retronasal stimulations of the same odors. We observed reproducible fMRI activation maps of the whole OB during both orthonasal and retronasal stimuli. However, retronasal stimuli required double the orthonasal odor concentration for similar response amplitudes. Regardless, both the magnitude and spatial extent of activity were larger during orthonasal versus retronasal stimuli for the same odor. Orthonasal and retronasal response patterns show overlap as well as some route-specific dominance. Orthonasal maps were dominant in dorsal-medial regions, whereas retronasal maps were dominant in caudal and lateral regions. These different whole OB encodings likely underlie differences in odor perception between these biologically important routes for odorants among mammals. These results establish the relationships between orthonasal and retronasal odor representations in the rat OB.

A Preliminary Dynamic Investigation on Velopharyngeal Movements During Blowing: A New Approach for Evaluation.

PURPOSE: To explore an alternative approach to evaluate velopharyngeal function on those speakers with compensatory misarticulation. METHOD: Nasopharyngeal endoscopy was used to observe the velopharyngeal movement on 26 adult Mandarin speakers during articulation and different nonverbal state, including SCPS, DCPS, and ABS. RESULTS: There were significant differences for the rate of velopharyngeal incompetence (RVPI) among the 4 different states. The RVPI was least for the Articulation State, followed by the Air Blowing and DCPS. The RVPI was largest for the SCPS. CONCLUSION: The result indicated that the ABS may be used as an alternative approach to evaluate the velopharyngeal function instead of the articulation samples while patients cannot make clear articulation due to compensatory misarticulation habits. It merits further study on nonverbal activities, which could lay a foundation for exploring more effective approach for evaluation of the velopharyngeal function.

Study of the Anatomical Structure of the Nasopharyngeal Cavity and Distribution of the Air Flow Field.

To build a biomechanical numerical model of the nasopharynx, construct an accurate computerized numerical description of its specific anatomical structures, analyze the distribution of air flow field, starting with the anatomical structure of the pharyngeal recess, correlate its anatomical characteristics with the occurrence and development of nasopharyngeal carcinoma from the perspective of biomechanics. In this study, the nasal and nasopharyngeal cavities of healthy male adult, with the pharyngeal recess in an open state, were scanned by CT to obtain DICOM imaging data. Then, they were imported into Mimics 20.0 to build a model which was recorded in binary STL format. Each file was imported into Geomagic studio 12.0 to construct a 3D model saved in an IGES format. Then, it was imported into ANSYS Workbench for numerical simulation of air flow field. The authors found that:Above all, the causes and pathogenesis of nasopharyngeal carcinoma can be identified from the perspective of biomechanics through the construction of a 3D model and analysis of the characteristics of air flow field. With more in-depth research, it is expected that a more solid scientific foundation will be created for related quantitative analysis.

Nasopharyngeal Tube Effects on Breathing during Sedation for Dental Procedures: A Randomized Controlled Trial.

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: Dental procedures under sedation can cause hypoxic events and even death. However, the mechanism of such hypoxic events is not well understood. WHAT THIS ARTICLE TELLS US THAT IS NEW: Apnea and hypopnea occur frequently during dental procedures under sedation. The majority of the events are not detectable with pulse oximetry. Insertion of a nasal tube with small diameter does not reduce the incidence of apnea/hypopnea. BACKGROUND: Intravenous sedation is effective in patients undergoing dental procedures, but fatal hypoxemic events have been documented. It was hypothesized that abnormal breathing events occur frequently and are underdetected by pulse oximetry during sedation for dental procedures (primary hypothesis) and that insertion of a small-diameter nasopharyngeal tube reduces the frequency of the abnormal breathing events (secondary hypothesis). METHODS: In this nonblinded randomized control study, frequency of abnormal breathing episodes per hour (abnormal breathing index) of the patients under sedation for dental procedures was determined and used as a primary outcome to test the hypotheses. Abnormal breathing indexes were measured by a portable sleep monitor. Of the 46 participants, 43 were randomly allocated to the control group (n = 23, no nasopharyngeal tube) and the nasopharyngeal tube group (n = 20). RESULTS: In the control group, nondesaturated abnormal breathing index was higher than the desaturated abnormal breathing index (35.2 [20.6, 48.0] vs. 7.2 [4.1, 18.5] h, difference: 25.1 [95% CI, 13.8 to 36.4], P < 0.001). The obstructive abnormal breathing index was greater than central abnormal breathing index (P < 0.001), and half of abnormal breathing indexes were followed by irregular breathing. Despite the obstructive nature of abnormal breathing, the nasopharyngeal tube did not significantly reduce the abnormal breathing index (48.0 [33.8, 64.4] h vs. 50.5 [36.4, 63.9] h, difference: -2.0 [95% CI, -15.2 to 11.2], P = 0.846), not supporting the secondary hypothesis. CONCLUSIONS: Patients under sedation for dental procedure frequently encounter obstructive apnea/hypopnea events. The majority of the obstructive apnea/hypopnea events were not detectable by pulse oximetry. The effectiveness of a small-diameter nasopharyngeal tube to mitigate the events is limited.

Vocal tract modelling in fallow deer: are male groans nasalized?

Males of several species of deer have a descended and mobile larynx, resulting in an unusually long vocal tract, which can be further extended by lowering the larynx during call production. Formant frequencies are lowered as the vocal tract is extended, as predicted when approximating the vocal tract as a uniform quarter wavelength resonator. However, formant frequencies in polygynous deer follow uneven distribution patterns, indicating that the vocal tract configuration may in fact be rather complex. We CT-scanned the head and neck region of two adult male fallow deer specimens with artificially extended vocal tracts and measured the cross-sectional areas of the supra-laryngeal vocal tract along the oral and nasal tracts. The CT data were then used to predict the resonances produced by three possible configurations, including the oral vocal tract only, the nasal vocal tract only, or combining the two. We found that the area functions from the combined oral and nasal vocal tracts produced resonances more closely matching the formant pattern and scaling observed in fallow deer groans than those predicted by the area functions of the oral vocal tract only or of the nasal vocal tract only. This indicates that the nasal and oral vocal tracts are both simultaneously involved in the production of a non-human mammal vocalization, and suggests that the potential for nasalization in putative oral loud calls should be carefully considered.

Acoustic Rhinometry for Evaluation of Velopharyngeal Function in Preschool Children Post Palatoplasty.

PURPOSE: To assess the feasibility of acoustic rhinometry for the evaluation of velopharyngeal function in preschool children by detecting changes in nasal cavity volume (NV) and minimal cross-sectional area (MCSA) after palatoplasty. MATERIALS AND METHODS: Sixty-one preschool children with incomplete cleft palate who underwent Sommerlad palatoplasty were examined by acoustic rhinometry. MCSA, distance of the MCSA from the nostril (DMCA), NV, and nasopharyngeal volume (NPV) were measured. Patients were grouped according to velopharyngeal state and lateral cephalographic findings. RESULTS: MCSA, NV, and NPV showed a meaningful difference between the experimental and control groups. DMCA in the experimental group (7.09 ± 1.33 mm) was not markedly different between the 2 sides. NV, NPV, and MCSA in the velopharyngeal insufficiency (VPI) subgroup were obviously larger than those in the velopharyngeal competence (VPC) and marginal VPI subgroups. NV in the VPC group showed no relevant difference from that in the control group. No relevant difference in MCSA, DMCA, and NPV was observed among the 3 subgroups at radiographic evaluation. NV in the noncontact group was markedly larger than in the control group. The curve showed marked constriction in the anterior part but an elevation in the posterior part, especially at a distance of 7.09 cm. CONCLUSION: Acoustic rhinometry is a rapid, noninvasive, and reproducible method that can be used in lieu of lateral cephalography for quantitative evaluation of the NV and MCSA. It can be used to assess postoperative velopharyngeal function in children and has good adaptability.

Nasopharynx is well-suited for core temperature measurement during hypothermia therapy.

BACKGROUND: Rectal temperature is commonly used as the core temperature during therapeutic hypothermia therapy in neonates with hypoxic-ischemic encephalopathy (HIE). The purpose of this study was to examine whether nasopharyngeal temperature could serve as a substitute for rectal temperature. METHODS: We prospectively investigated 40 neonates with HIE who underwent therapeutic hypothermia by selective head cooling, which involved cooling the body to 34°C for 72 h. During this period, nasopharyngeal temperature was measured and compared with rectal temperature every hour. RESULTS: For 40 neonates included in this study, the mean rectal and nasopharyngeal temperatures were 34.3 ± 0.4°C (n = 2920) and 34.3 ± 0.4°C (n = 2920), respectively. Nasopharyngeal temperature strongly correlated with rectal temperature (R2 = 0.623, P < 0.0001) and magnitude of the mean difference between nasopharyngeal and rectal temperature varied little during the 72 h of therapeutic hypothermia. CONCLUSIONS: Nasopharyngeal temperature in neonates with perinatal HIE undergoing therapeutic hypothermia may be a suitable substitute for rectal temperature.

Type IV Pilus Expression Is Upregulated in Nontypeable Haemophilus influenzae Biofilms Formed at the Temperature of the Human Nasopharynx.

UNLABELLED: Nontypeable Haemophilus influenzae (NTHI), a commensal of the human nasopharynx (hNP), is a common cause of biofilm-associated diseases of the respiratory tract. However, NTHI biofilm biology at the average hNP temperature, i.e., 34°C, has not been well studied. Here we grew NTHI biofilms at 34°C and 37°C, to evaluate relative biofilm growth, expression, and function of the type IV pilus (Tfp), a critical adhesin important for NTHI biofilm formation. The kinetics and regulation of Tfp expression in NTHI biofilms are unclear, especially at 34°C. Tfp expression, as estimated by pilA promoter activity, was distributed throughout the biofilms, with a unique pattern that was dependent on temperature, time in culture, and position within the maturing biofilm. Tfp expression was required for the formation of the characteristic tower structures of NTHI biofilms and was significantly upregulated in NTHI biofilms formed at 34°C versus 37°C. This increase correlated with significantly greater twitching motility at 34°C than at 37°C. Treatment with antisera targeting the major subunit of Tfp (PilA) significantly inhibited NTHI biofilm formation at both temperatures, confirming the importance of this critical adhesin in biofilm formation. Additionally, treatment of preestablished biofilms with antisera against PilA significantly decreased biofilm biomass and mean thickness at both temperatures. These results demonstrated a pivotal role for Tfp in NTHI biofilm formation and stability at the temperature of the hNP, and they underscore the utility of PilA as a vaccine candidate for treatment and/or prevention of NTHI biofilm-associated diseases. IMPORTANCE: NTHI is an important cause of chronic respiratory tract infections, including otitis media, chronic rhinosinusitis, and exacerbations of chronic obstructive pulmonary disease and cystic fibrosis. The chronic and recurrent nature of these diseases is attributed to the presence of bacterial biofilms, which are highly resistant to antimicrobials. We characterized NTHI biofilm growth and expression of PilA, the major subunit of the Tfp, at the temperature of the hNP, which is the commensal habitat of NTHI. Our results expand the current understanding of the role of Tfp during biofilm formation and maturation at the temperature of both the hNP and the middle ear, and they strengthen support for PilA as a vaccine candidate for the prevention and treatment of NTHI biofilm-associated diseases.

Awake Craniotomy: A New Airway Approach.

Awake craniotomies have been performed regularly at the University of Pennsylvania since 2004. Varying approaches to airway management are described for this procedure, including intubation with an endotracheal tube and use of a laryngeal mask airway, simple facemask, or nasal cannula. In this case series, we describe the successful use (i.e., no need for endotracheal intubation related to inadequate gas exchange) of bilateral nasopharyngeal airways in 90 patients undergoing awake craniotomies. The use of nasopharyngeal airways can ease the transition between the asleep and awake phases of the craniotomy without the need to stimulate the airway. Our purpose was to describe our experience and report adverse events related to this technique.

Intraoperative temperature monitoring with zero heat flux technology (3M SpotOn sensor) in comparison with sublingual and nasopharyngeal temperature: An observational study.

BACKGROUND: Perioperative hypothermia is common in patients undergoing general anaesthesia and is associated with important adverse events. The 'gold standard' for monitoring body core temperature - the pulmonary artery catheter - is invasive and unsuitable for most patients. For routine clinical practice, other sites and methods of temperature monitoring are commonly used. OBJECTIVE: The aim of this study was to evaluate a new temperature sensor (3M SpotOn) using the 'zero heat flux' method attached to the forehead, and compare it to sublingual and nasopharyngeal sensors in terms of correlation, accuracy and precision. DESIGN: An observational study. SETTING: University Medical Center Schleswig Holstein, Campus Kiel, Germany from October 2013 to January 2014. PATIENTS: One hundred and twenty patients scheduled for elective gynaecological or trauma surgery undergoing general anaesthesia were enrolled into this study. Data of 83 patients were finally analysed. Patients with unexpected blood loss, haemodynamic instability determined by the need for continuous norepinephrine infusion and/or need for postoperative ventilation were excluded from this study. INTERVENTION: Temperature monitoring was established after induction of anaesthesia with sublingual and nasopharyngeal probes, and the SpotOn sensor. MAIN OUTCOME MEASURES: Body temperature was measured 15, 45 and 75 min after induction of anaesthesia from sublingual and nasopharyngeal probes and the 3M SpotOn sensor at precisely the same moment. RESULTS: Analysis of 83 data sets revealed that 3M SpotOn temperatures were almost identical with nasopharyngeal temperatures (mean difference 0.07 °C; P = 0.1424) and slightly lower than sublingual temperatures by 0.35 °C (P < 0.0001). Coefficients of determination (r) for both methods were between 0.87 (SpotOn vs. nasopharyngeal measurement) and 0.77 (SpotOn vs. sublingual measurement). Bland-Altman analysis revealed a bias (SD) between 0.07 °C (0.21) (SpotOn vs. nasopharyngeal) and -0.35 °C (0.29) (SpotOn vs. sublingual measurement). CONCLUSION: With respect to correlation, accuracy and precision, the 3M SpotOn sensor provides a good measurement of body temperature in comparison to the nasopharyngeal probe and an acceptable measurement in comparison with sublingual thermometry. It is adequate for clinical use. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT02031159.

Core temperature--the intraoperative difference between esophageal versus nasopharyngeal temperatures and the impact of prewarming, age, and weight: a randomized clinical trial.

Unplanned perioperative hypothermia is a well-known complication to anesthesia. This study compares esophageal and nasopharyngeal temperature measured in the same patient for a period of 210 minutes of anesthesia. Forty-three patients undergoing colorectal surgery were randomly assigned in 2 groups, with or without a prewarming period (group A = prewarming [n = 21] or group B = no prewarming [n = 22]). Demographics were similar in both groups. Mean temperatures at 210 minutes were statistically different between the groups at both sites of measurement. Esophageal temperature in group A was 36.5 ± 0.6 vs 35.8 ± 0.7 in group B (P = .001), and nasopharyngeal temperature was 36.7 ± 0.6 and 36.0 ± 0.6 in group A and group B, respectively (P = .002). A negative correlation was found between esophageal temperature and age (r2 = -.381, P < .012). Esophageal temperature was different with respect to BMI below or above 25. The temperatures were 35.81 ± 0.66 in the lower BMI group vs 36.46 ± 0.59 (P < .001). These results demonstrate a difference between the 2 measurement techniques and that prewarming, age and BMI have an impact on measured temperatures.

Optimal nasopharyngeal temperature probe placement.

BACKGROUND: Although the nasopharynx is a commonly used temperature-monitoring site during general anesthesia, it is unknown whether the position of nasopharyngeal temperature probes placed blindly by anesthesia practitioners is optimal. The purposes of this study were (1) to determine where the nasopharyngeal mucosa is in closest proximity to the internal carotid artery (ICA) and (2) to evaluate the tip position of nasopharyngeal temperature probes that were placed by anesthesiology residents and nurse anesthetists. METHODS: In the first phase of the study, we reviewed enhanced axial computed tomography images of 100 patients to determine where the nasopharyngeal mucosa was in closest proximity to the left or the right ICA. The distance from this point to the nares was then measured in the sagittal image. In the second phase of the study, nasendoscopy was used to evaluate the positioning of nasopharyngeal temperature probes placed by anesthesiology residents (244 patients) or nurse anesthetists (116 patients). Malpositioned probes were repositioned to an optimal location, and the temperature differences were recorded. RESULTS: In the computed tomography images, the mucosa in closest proximity to the ICA was in the upper, mid-, and lower nasopharynx in 60%, 38%, and 2% of patients, respectively. The average distances between the ICA and the nasopharyngeal mucosa in the upper portion were significantly shorter than those in the lower portion (female: 9.4 vs 16.8 mm, P < 0.001; male: 12.4 vs 18.8 mm, P < 0.001). The average distances (95% prediction interval) from the nares to the upper portion of the nasopharynx through the inferior meatus were 9.1 (8.1-10.2) cm in females and 9.7 (8.6-10.8) cm in males. Temperature probes were correctly positioned in the upper or mid-nasopharynx by residents and nurses in 43% (95% confidence interval [CI], 37%-49%) and 41% (95% CI, 36%-50%), respectively. When the probe was inadvertently placed in the nasal cavity, the median (95% CI) temperature difference from the upper nasopharynx was 0.2°C (0.15°C-0.25°C). CONCLUSIONS: The closest portion of the nasopharyngeal mucosa to the ICA is within the upper or mid-nasopharynx. The depth from the nares to the upper one-third of the nasopharynx is approximately 10 cm. Less than half of nasopharyngeal temperature probes placed blindly by practitioners were optimally positioned.

Safety evaluation of nasopharyngeal cooling (RhinoChill®) in stroke patients: an observational study.

INTRODUCTION: New technologies for therapeutic cooling have become available. The objective of our study was to investigate the safety of nasopharyngeal cooling with the RhinoChill(®) device in stroke patients, focusing on systemic and neurovital parameters. METHODS: In this prospective observational study, consecutive patients with severe ischemic or hemorrhagic stroke who underwent intracranial pressure (ICP) and brain temperature monitoring have been enrolled. Ten patients who were treated with the RhinoChill(®) device were analyzed. Brain and bladder temperature and systemic and neurovital parameters were monitored continuously. Additional evaluations of safety included bleeding complications and otolaryngological examinations. RESULTS: Baseline brain temperature of 36.7 °C (SD 0.9) decreased by an average of 1.21 °C (SD 0.46) within 1 h, the effect of brain temperature decrease ranged from a maximum of 2 °C (patients 3 and 7) to a minimum of 0.6 °C (patient 4). Within the first several minutes after initiating RhinoChill(®) treatment, 3 of 10 patients experienced an increase in systolic arterial pressure by 30, 30, and 53 mmHg, respectively. Heart rate rose as well (mean 3 bpm, SD 2.9). ICP and oxygen saturation were unaffected by the treatment. We observed 1 bleeding complication in the control CT scan of patient 10. Rhinoscopical findings 3 days after nasopharyngeal cooling and at the follow-up (>6 months) and a 16-item smell test were normal. CONCLUSION: The RhinoChill(®) system cools the brain efficiently. However, steep increases in blood pressure raise serious concerns regarding the safety of its use in stroke patients.

Improving the endoscopic endonasal transclival approach: the importance of a precise layer by layer reconstruction.

BACKGROUND. The endoscopic endonasal transclival approach (EETCA) is a minimally-invasive technique allowing a direct route to the base of implant of clival lesions with reduced brain and neurovascular manipulation. On the other hand, it is associated with potentially severe complications related to the difficulties in reconstructing large skull base defects with a high risk of postoperative cerebrospinal fluid (CSF) leakage. The aim of this paper is to describe a precise layer by layer reconstruction in the EETCA including the suture of the mucosa as an additional reinforcing layer between cranial and nasal cavity in order to speed up the healing process and reduce the incidence of CSF leak. METHODS. This closure technique was applied to the last six cases of EETCA used for clival meningiomas (2), clival chordomas (2), clival metastasis (1), and craniopharyngioma with clival extension (1). RESULTS. After a mean follow-up of 6 months we had no one case of postoperative CSF leakage or infections. Seriated outpatient endoscopic endonasal controls showed a fast healing process of nasopharyngeal mucosa with less patient discomfort. CONCLUSIONS. Our preliminary experience confirms the importance of a precise reconstruction of all anatomical layers violated during the surgical approach, including the nasopharygeal mucosa.

[Sneezing as a mechanical defence - a numerical simulation and analysis of the nasal flow]. / Niesen als mechanische Abwehr - Numerische Simulation mit Analyse der durchströmten Nasenbereiche.

INTRODUCTION: The nose is responsible for humidification, heating and cleaning of the inhaled air. The sneeze reflex leads to a shock-like cleaning of the nose in strong particle exposure. The aim of this study was the simulation of intranasal air flow of sneezing in a realistic computer model. MATERIALS AND METHODS: Based on the CT scan of a 40 year old man a three-dimensional computer model of the nasal cavity and the ethmoid sinuses was created. Flow simulations were performed for different inspiratory and expiratory velocities (± 2 m/s to ± 45 m/s) in order to simulate sneezing. RESULTS were visualized and analyzed by video simulation. RESULTS: During inspiration the main airflow takes place along the middle turbinate. During expiration, the flow is located more cranially. This effect is caused by the shape of the nasopharynx and the posterior portions of the nasal turbinates. During very high speeds (sneezing) also adjacent ethmoid sinuses and the olfactory region are covered by the shock-like expiratory flow. A large vortex formation in the nasopharynx is responsible for a uniform distribution of the airflow also on lower nasal areas. CONCLUSION: Sneezing is a protective reflex that provides for cleaning of the nose. From a flow rate of 10 m/s, the cranial nasal areas as well as adjacent ethmoid sinuses are covered by the -airflow. Compared to the inspiratory airflow the exhalation is not just vice versa. Particles that deposed in the cranial nasal areas during quiet breathing are removed.

The influence of nasopharyngeal patency on the morphology of nasomaxillary complex.

OBJECTIVE: The aim of this study was to compare the nasomaxillary complex in subjects with nasopharyngeal obstruction symptoms and the group with normal nasopharyngeal patency. MATERIALS AND METHODS: The study analyzed lateral cephalograms and dental plaster casts of 229 orthodontic subjects from the orthodontic clinic, i.e. 129 (56%) females and 100 (44%) males, age range of 6-30 years (mean age = 13.79). The analysis of radiographs and cephalometric measurements were performed using Orto-TestPor-ZPaluch software. The study population examined according to the stage of cervical vertebral maturation was divided into three sub - groups [the CVM A group consisted of 57 (24.9%) subjects, the CVM B group consisted of 85 (37.1%) subjects and the CVM C group consisted of 87 (38%) subjects]. RESULTS: In the youngest age group with less than 50% airway patency, smaller values of SNA angle were observed together with diminished anterior palatal width compared with the non-obliterated group. The decrease in the area of the nasomaxillary complex and the decrease in posterior palatal width were observed in the oldest age group with less than 50% airway patency as compared to the subjects with normal patency. CONCLUSIONS: The nasomaxillary complex morphology in subjects with decreased nasopharyngeal patency pre - disposes to air flow impediment through nasal respiratory passage. Non-extraction treatment of the upper dental arch and possible maxillary expansion can be considered when orthodontic treatment is planned in subjects with decreased patency of < 50% and CVM A.

Volume-activated chloride currents in fetal human nasopharyngeal epithelial cells.

Volume-activated chloride channels have been studied by us extensively in human nasopharyngeal carcinoma cells. However, the chloride channels in the counterpart of the carcinoma cells have not been investigated. In this study, volume-activated chloride currents (I(cl,vol)) were characterized in normal fetal human nasopharyngeal epithelial cells using the whole-cell patch-clamp technique. Under isotonic conditions, nasopharyngeal epithelial cells displayed only a weak background current. Exposure to 47% hypotonic solution activated a volume-sensitive current. The reversal potential of the current was close to the calculated equilibrium potential for Cl(-). The peak values of the hypotonicity-activated current at +80 mV ranged from 0.82 to 2.71 nA in 23 cells. Further analysis indicated that the density of the hypotonicity-activated current in most cells (18/23) was smaller than 60 pA/pF. Only five cells presented a current larger than 60 pA/pF. The hypotonicity-activated current was independent of the exogenous ATP. Chloride channel inhibitors ATP, tamoxifen and 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB), inhibited the current dramatically. The anion permeability of the hypotonicity-activated chloride channels was I(-) > Br(-) > Cl(-) > gluconate. Unexpectedly, in isotonic conditions, ATP (10 mM) activated an inward-rectified current, which had not been observed in the nasopharyngeal carcinoma cells. These results suggest that, under hypotonic challenges, fetal human nasopharyngeal epithelial cells can produce I(cl,vol), which might be involved in cell volume regulation.

Detecting nasopharyngeal reflux: a novel pH probe technique.

OBJECTIVES: We sought to ascertain the normal pH values in the aerosolized environment of the nasopharynx in healthy subjects and utilize a novel pH probe that allows measuring acidity in a nonliquid environment. METHODS: Between November 2009 and February 2011, healthy volunteers without a history of reflux or eustachian tube dysfunction were enrolled in the prospective study. A total of 20 subjects had a Dx-pH Measurement System Probe (Respiratory Technology Corp) placed near the torus tubarius. The pH probe records the pH throughout the 24-hour study. A pH below 5.5 while the subject was upright or below 5.0 while the subject was supine was used as a criterion to determine a reflux event. Recording was stopped during meals. RESULTS: For normal individuals with no history of reflux or eustachian tube dysfunction, the pH values obtained from the nasopharynx ranged from 6.10 to 7.92. The average pH was 7.03 (SD, 0.67). Eight subjects (40%) had at least 1 reflux event during the 24-hour pH study. CONCLUSIONS: By utilizing a novel self-condensing pH probe, we were able to perform a 24-hour pH study in the nasopharynx of 20 healthy individuals. In our study, the average pH for individuals without symptomatic reflux or eustachian tube dysfunction was 7.03. Interestingly, 8 control subjects had at least 1 episode of pH below 5.5 while awake or below 5.0 while asleep, which was considered to be a reflux event in our study.