Nasal flow-resistive responses to challenge with cold dry air

Effect of Average Relative Humidity on Epistaxis

Background Epistaxis is a very common symptom. The occurrence of epistaxis may be affected by dry environments, but there are some differences among previous reports and this view is controversial. Objective We investigated the relationship between the number of epistaxes and daily average relative humidity. Methods Data on patients with epistaxis between March 2011 and February 2021 were collected from two hospitals. The daily average relative humidity was examined, and the change in the number of patients with epistaxis due to humidity was investigated using a generalized linear mixed model. Results A total of 4184 cases of epistaxis were identified. The number of epistaxis cases per day was significantly associated with the daily average relative humidity (p < 0.001). One percent increment in average relative humidity decreases the number of epistaxis cases per day by 1.1%. Conclusion A negative correlation was found to exist between daily average relative humidity and occurrences of epistaxis.

Functional short- and long-term effects of nasal CPAP with and without humidification on the ciliary function of the nasal respiratory epithelium

PURPOSE

Continuous positive airway pressure (CPAP) is the gold standard in the treatment of obstructive sleep apnea (OSA), but its impact on ciliary function is unclear to date. Furthermore, CPAP is associated with numerous side effects related to the nose and upper airway. Humidified CPAP is used to relieve these symptoms, but again, little is known regarding its effect on ciliary function of the nasal respiratory epithelium.

METHODS

In this prospective, randomized, crossover trial, 31 patients with OSA (AHI >15/h) were randomized to two treatment arms: nasal continuous positive airway pressure (nCPAP) with humidification or nCPAP without humidification for one night in each modality to assess short-term effects of ciliary beat frequency (CBF) and mucus transport time (MTT) and consecutively for 8 weeks in each modality to assess long-term effects in a crossover fashion.

RESULTS

The baseline CBF was 4.8 ± 0.6 Hz, and baseline MTT was 540 ± 221 s. After one night of CPAP with and without humidification, ciliary function increased moderately yet with statistical significance (p <0.05). The short-term groups with and without humidification did not differ statistically significant. Regarding long-term effects of CPAP, a statistically significant increase in ciliary function above the baseline level and above the short-term level was shown without humidification (7.2 ± 0.4 Hz; 402 ± 176 s; p <0.01). The increase above baseline level was even more pronounced with humidification (9.3 ± 0.7 Hz; 313 ± 95 s; p <0.01). There was a statistically significant difference between both groups at long-term assessment with regard to CBF (p <0.01).

CONCLUSIONS

Independent of airway humidification, nCPAP has moderate effects on short-term ciliary function of the nasal respiratory epithelium. However, a significant increase in ciliary function-both in terms of an increased CBF and a decreased MTT-was detected after long-term use. The effect was more pronounced when humidification was used during nCPAP.

A simple, innovative way to reduce rhinitis symptoms after sedation during endoscopy

BACKGROUND

Supplmental oxygen is routinely given via nasal cannula (NC) to patients undergoing moderate sedation for endoscopy. Some patients complain of profuse rhinorrhea and⁄or sneezing after the procedure, which results in additional medical costs and patient dissatisfaction.

OBJECTIVES

To determine the causal relationship between the route of oxygen delivery and troublesome nasal symptoms, and to seek possible solutions.

METHODS

Patients (n=836) were randomly assigned to one of the three following groups: the NC group (n=294), the trimmed NC (TNC) group (n=268) and the nasal mask (NM) group (n=274). All received alfentanil 12.5 μg⁄kg and midazolam 0.06 mg⁄kg, and adjunct propofol for sedation. Supplemental oxygen at a flow rate of 4 L⁄min was used in the NC and TNC groups, and 6 L⁄min in the NM group. The incidence of nasal symptoms and hypoxia were assessed.

RESULTS

The incidence of rhinitis symptoms was significantly higher in the NC group (7.1%) than in the TNC (0.4%) and NM (0%) groups (P<0.001). The incidence of hypoxia was lower in the NC group (3.1%) (P=0.040). All hypoxia events were transient (ie, less than 30 s in duration). On spirometry, the mean value of the lowest saturation of peripheral oxygen was found to be significantly lower in the NM group (96.8%) than in the NC group (97.7%) (P=0.004).

CONCLUSIONS

Trimming the NC or using NMs reduced the incidence of rhinitis symptoms; however, the incidence of hypoxia was higher. Further investigation regarding the efficiency of oxygen supplementation is warranted in the design of novel oxygen delivery devices.

Nasal Physiological Reactivity of Subjects with Nonallergic Rhinitis to Cold Air Provocation: A Pilot Comparison of Subgroups

Background

Noninfectious nonallergic rhinitis (NINAR) is characterized by self-reported hyperreactivity to nonspecific physical or chemical stimuli. The relationship between these two classes of triggers is not well established, however. We compared NINAR subjects with predominantly physical or chemical triggers versus normal controls with respect to subjective (symptomatic) and objective (obstructive) responses to cold, dry air challenge.

Methods

We studied 14 NINAR subjects and 10 normal controls. Exposures consisted of 15 minutes of cold dry air (0°C/5% RH) or warm moist air (25°C/50% RH) on two separate days a week apart. Subjects rated symptoms using visual analog scales and had their nasal airway resistance measured at baseline, immediately after, and at 15-minute intervals for 1 hour postexposure.

Results

The majority of NINAR subjects reported physical triggers as more troublesome than chemical. Immediately postprovocation, the mean net proportional change in nasal airway resistance from baseline was +0.18 in NINAR (physical), +0.05 in NINAR (chemical), and –0.01 in control subjects (NS). However, a pooled linear regression by number of physical triggers (0–5) revealed a 7.5% increase in cold air–induced nasal airway resistance per trigger reported (p < 0.05). Similarly, raising the criterion number of physical triggers from ≥1 to ≥2 also distinguished NINAR subjects from controls in a bivariate analysis.

Conclusion

Either considering self-reported physical triggers as a continuous scale (0–5) or requiring more physical triggers (≥ 2 rather than ≥1) to define NINAR successfully predicts objective nasal reactivity to cold air provocation.

Effects of nasal mask leak and heated humidification on nasal mucosa in the therapy with nasal continuous positive airway pressure (nCPAP)

The purpose of this study was to determine the objective short-term influence of nasal continuous positive airway pressure (nCPAP) therapy, nasal mask leak (NML) and heated humidifiers (HH) to nasal conditioning of spontaneously breathing subjects. This was a prospective, non-randomized, non-blinded day-time study. Eighteen healthy subjects were enrolled in the study. All subjects received nCPAP therapy for 60 min in three different conditions successively: (1) nCPAP without humidification, (2) nCPAP with a defined leakage of nasal mask (slashed circle 28.3 mm2) and (3) nCPAP with HH. Nasal humidity and temperature were measured in the anterior turbinate area using a miniaturized thermocouple and a relative humidity sensor. The measurements were accomplished at the beginning of therapy, after 60, 120 and 180 min. Absolute humidity (aH) in the anterior turbinate area decreased significantly (p = 0.0075) from 17.41 +/- 3.81 mg/l (baseline) to 15.27 +/- 2.21 mg/l (nCPAP alone). With attachment of a NML, aH decreased from 15.27 mg/l not significantly (p = 0.058) to 13.77 +/- 2.28 mg/l (nCPAP and NML) compared to nCPAP alone. After addition of heated humidification to nCPAP, aH increased again from 13.77 mg/l significantly (p = 0.042) to 15.29 +/- 3.51 mg/l (nCPAP and HH) compared to aH (nCPAP+NML). No difference was found between aH (nCPAP and HH) and aH (nCPAP alone). Airway temperature did not change significantly after application of nCPAP alone, nCPAP and NML, and nCPAP and HH. These data indicate that nCPAP therapy with NML tends to have more remarkable reduction of the nasal humidity than nCPAP therapy without NML. nCPAP with heated humidifier is able to compensate the dehydration effects induced by nCPAP therapy with NML by increasing the aH at the anterior turbinate area to the levels observed during breathing with nCPAP alone.

Simultaneous in vivo measurements of intranasal air and mucosal temperature

Nasal cavity volume and blood temperature along the nasal airways, reflecting the mucosal temperature, are considered to be the most important predictors of nasal air conditioning. The purpose of this study was to simultaneously in vivo measure intranasal air as well as mucosal temperature for the first time. Fifteen healthy subjects were enrolled into the study. Two combined miniaturized thermocouples were used for simultaneous recording of intranasal air and mucosal temperature within the anterior turbinate area close to the head of the middle turbinate without interruption of nasal breathing. The highest air and mucosal temperature values were detected at the end of expiration, the lowest values at the end of inspiration. The difference was statistically significant (P < 0.05). The mean mucosal temperature ranged from 30.2 +/- 0.9 to 32.2 +/- 0.8 degrees C. The mean air temperature ranged from 28.5 +/- 1.2 to 34.1 +/- 0.7 degrees C. The mean differences between air and mucosal temperature were 1.7 +/- 0.5 degrees C after inspiration and 1.9 +/- 0.7 degrees C after expiration. Simultaneous measurements of intranasal air and mucosal temperature are practicable. The detected temperature gradient between air and mucosa confirm a relevant heat exchange during inspiration and expiration. This gradient between air and mucosa is obligatory for heat and water exchange to ensure adequate nasal air conditioning.

Short-term effects of nCPAP on nasal mucociliary clearance and mucus transportability in healthy subjects

Nasal mucociliary clearance is a primary defense mechanism of the upper airways and may be acutely affected by nasal continuous positive airway pressure (nCPAP). nCPAP treatment is effective and safe. However, it can cause nasal side effects and contribute to a low compliance to the treatment. The aim of this study was to investigate the short-term effects of nCPAP on nasal mucociliary clearance and on mucus transportability of healthy subjects. Eleven healthy subjects were submitted to 20 min of nCPAP (10 cm H2O). Five subjects were also evaluated before and after 20 min of rest on the consecutive study day. Nasal mucociliary clearance was measured by the saccharin nasal transit time test and nasal mucus was collected for the in vitro study of mucus transportability by the frog palate model, both before and after the nCPAP challenge. Saccharin nasal transit time decreased significantly after nCPAP (9.29+/-6.06 min and 4.83+/-5.57 min; P=0.002 before and after nCPAP respectively). No significant changes were observed on the control day (11.66+/-7.57 min and 12.40+/-5.62 min; P=0.70). Mucus transportability was not significantly affected by nCPAP. Our results suggest that nCPAP can acutely increase nasal mucociliary clearance but does not affect in vitro mucus transportability in healthy subjects.

Energetics of nose and mouth breathing, body size, body composition, and nose volume in young adult males and females

This research tests the relative ability of body size factors and sex to explain variation in nose volume and to explain metabolic measures during rest and moderate exercise in 50 young adults. It uses standard anthropometric measures plus two new measures of nose morphology (nose/face angle and nose volume) and evaluates body composition with a device for air displacement plethysmography. Standard physiological measures were obtained in nose-only and mouth-only breathing conditions with subjects at rest and using moderate exercise. A factor representing linear and bulk measures of body size and a factor representing lean body mass explain subjects' variation in nose volume, resting volume of oxygen consumed (VO2), and resting ventilation volume (VV) better than subject's sex does. By contrast, during exercise, sex explains VO2 and VV better than do body size factors, probably because hormone-mediated muscularity in males produced greater work output. Nose breathing was found to be more energetically efficient in most but not all subjects, but additional research is needed to explore this finding further. Qualitative comparisons between modes of breathing and the application of this research protocol to studies of climate-related patterns of nasal variation are discussed.

Desiccation and hypertonicity of the airway surface fluid and thermally induced asthma

To determine whether drying and hypertonicity of the airway surface fluid (ASF) are involved in thermally induced asthma, nine subjects performed isocapnic hyperventilation (HV) (minute ventilation 62.2 +/- 8.3 l/min) of frigid air (-8.9 +/- 3.3 degrees C) while periciliary fluid was collected endoscopically from the trachea. Osmolality was measured by freezing-point depression. The baseline 1-s forced expiratory volume was 73 +/- 4% of predicted and fell 26.4% 10 min postchallenge (P > 0.0001). The volume of ASF collected was 11.0 +/- 2.2 microl at rest and remained constant during and after HV as the airways narrowed (HV 10.6 +/- 1.9, recovery 6.5 +/- 1.7 microl; P = 0.18). The osmolality also remained stable throughout (rest 336 +/- 16, HV 339 +/- 16, and recovery 352 +/- 19 mosmol/kgH(2)O, P = 0.76). These data demonstrate that airway desiccation and hypertonicity of the ASF do not develop during hyperpnea in asthma; therefore, other mechanisms must cause exercise- and hyperventilation-induced airflow limitation.

Supine position decreases the ability of the nose to warm and humidify air

We tested the hypothesis that decreasing nasal air volume (i.e., increasing nasal turbinate blood volume) improves nasal air conditioning. We performed a randomized, two-way crossover study on the conditioning capacity of the nose in six healthy subjects in the supine and upright position. Cold, dry air (CDA) was delivered to the nose via a nasal mask, and the temperature and humidity of air were measured before it entered and after it exited the nasal cavity. The total water gradient (TWG) across the nose was calculated and represents the nasal conditioning capacity. Nasal volume decreased significantly from baseline without changing the mucosal temperature when subjects were placed in the supine position (P < 0.01). TWG in supine position was significantly lower than that in upright position (P < 0.001). In the supine position, nasal mucosal temperature after CDA exposure was significantly lower than that in upright position (P < 0.01). Our data show that placing subjects in the supine position decreased the ability of the nose to condition CDA compared with the upright position, in contrast to our hypothesis.

Nitric oxide in the nasal airway: a new dimension in otorhinolaryngology

The discovery that the gas nitric oxide (NO) is an important signaling molecule in the cardiovascular system earned its Nobel prize in 1998. NO has since been found to play important roles in a variety of physiologic and pathophysiologic processes in the body including vasoregulation, hemostasis, neurotransmission, immune defense, and respiration. The surprisingly high concentrations of NO in the nasal airway and paranasal sinuses has important implications for the field of otorhinolaryngology. NO provides a first-line defense against micro-organisms through its antiviral and antimicrobial activity and by its upregulation of ciliary motility. Nasal treatments such as polypectomy, sinus surgery, removal of hypertrophic adenoids and tonsils, and treatment of allergic rhinitis may alter NO output and, therefore, the microbial colonization of the upper airways. Nasal surgery aimed at relieving nasal obstruction may do the same but would also be expected to improve pulmonary function in patients with asthma and upper airway obstruction. NO output rises in a number of conditions associated with chronic airway inflammation, but not all of them. Concentrations are increased in asthma, allergic rhinitis, and viral respiratory infections, but reduced in sinusitis, cystic fibrosis, primary ciliary dysfunction, chronic cough, and after exposure to tobacco and alcohol. Therefore, NO, similar to several other inflammatory mediators, probably subserves different functions as local conditions dictate. At present, it seems that the measurement of NO in the upper airway may prove valuable as a simple, noninvasive diagnostic marker of airway pathologies. The objective of this review is to highlight some aspects of the origin, physiology, and functions of upper airway NO, and to discuss the particular methodological problems that result from the complex anatomy.

Integrated response of the upper and lower respiratory tract of asthmatic subjects to frigid air

To evaluate the influence of cold air hyperpnea on integrated upper and lower airway behavior, 22 asthmatic volunteers hyperventilated through their mouths (OHV) and noses (NHV) while pulmonary and nasal function were determined individually and in combination. In the isolated studies, OHV at a minute ventilation of 65 +/- 3 l/min lowered the 1-s forced expiratory volume (FEV(1)) 24 +/- 2% (P < 0. 001) and NHV (40 l/min) induced a 31 +/- 9% (P < 0.001) increase in nasal resistance (NR). In the combined studies, oral hyperpnea reduced the FEV(1) (DeltaFEV(1) 26 +/- 2%, P < 0.001) and evoked a significant rise in NR (DeltaNR 26 +/- 9%, P = 0.01). In contrast, NHV only affected the upper airway. NR rose 33 +/- 9% (P = 0.01), but airway caliber did not change (DeltaFEV(1) 2%, P = 0.27). The results of this investigation demonstrate that increasing the transfer of heat and water in the lower respiratory tract alters bronchial and nasal function in a linked fashion. Forcing the nose to augment its heat-exchanging activity, however, reduces nasal caliber but has no effect on the intrathoracic airways.

Effects of humidification on nasal symptoms and compliance in sleep apnea patients using continuous positive airway pressure

STUDY OBJECTIVES

To evaluate the effects of humidification on nasal symptoms and compliance in sleep apnea patients using continuous positive airway pressure (CPAP).

DESIGN

A randomized, crossover design was employed.

SETTING

The study was conducted at two suburban community-based hospital sleep laboratories.

PATIENTS

Data were collected on 38 obstructive sleep apnea patients (mean age, 44.1 years) in whom CPAP was a novel treatment.

INTERVENTIONS

The interventions were heated humidity, cold passover humidity, and a washout period without humidity.

MEASUREMENTS AND RESULTS

Patients were titrated with heated humidity or cold passover humidity in the laboratory and subsequently initiated on humidity. Objective compliance, self-report of factors affecting CPAP use, satisfaction with CPAP, feeling upon awakening, and daytime sleepiness were assessed at the completion of each 3-week treatment period and a 2-week washout period. Outcome measures were assessed with one-way analysis of variance followed by Scheffe post hoc comparisons. Significant main effects were observed for compliance (F2,37 = 5.2; p = 0.008), satisfaction with CPAP (F2,37 = 4.5; p = 0.01), and feeling refreshed on awakening (F2,37 = 4.4; p = 0.02). A significant decrease in daytime sleepiness was observed between baseline and each of the conditions (F3,37 = 55.5; p<0.0001), but Epworth sleepiness scale scores did not differ between conditions (all p values >0.56). CPAP use with heated humidity (5.52+/-2.1 h/night) was greater than CPAP use without humidity (4.93+/-2.2 h/night; p = 0.008). Compliance differences were not observed between CPAP use with cold passover humidity and CPAP use without humidity. Patients were more satisfied with CPAP when it was used with heated or cold passover humidity (p< or =0.05). However, only heated humidity resulted in feeling more refreshed on awakening (p<0.05). No significant differences were observed among the three groups on the global adverse side effect score (F2,37 = 2.5; p = 0.09). Specific side effects such as dry mouth or throat and dry nose were reported less frequently when CPAP was used with heated humidity compared to CPAP use without humidity (p<0.001).

CONCLUSIONS

Compliance with CPAP is enhanced when heated humidification is employed. This is likely due to a reduction in side effects associated with upper airway symptoms and a more refreshed feeling upon awakening. Compliance gains may be realized sooner if patients are started with heated humidity at CPAP initiation.

Nasal patency and the effectiveness of nasal continuous positive air pressure in obstructive sleep apnea

Nasal airway obstruction may exacerbate sleep apnea and is difficult to quantify on clinical examination. In this study, we examined the relationship among nasal patency, the frequency of sleep apnea events, and effective nasal continuous positive air pressures. Acoustic rhinometry was used as an objective measurement of nasal cross-sectional areas in 76 patients without nasal symptoms who underwent study with diagnostic polysomnography because of obstructive sleep apnea. Patients with persistent obstructive sleep apnea were titrated to nasal continuous positive air pressure in a split night study. All subjects had a mean apnea/hypopnea index of 28, and those with obstructive sleep apnea had a mean apnea/hypopnea index of 43. Mean cross-sectional areas 1 to 4 cm into the nose were 1.7, 1.1, 2.1, and 2.8 cm2, respectively (F = 39, p < 0.001). However, there was no correlation between the apnea/hypopnea index and the cross-sectional area at the four distances (r = 0.03, 0.06, 0.02, and 0.02, respectively, p = not significant). Correlations between nasal continuous positive air pressures and cross-sectional areas did not reveal a significant relationship at any of the four sites (r = 0.09, 0.07, -0.03, 0.00, respectively). Findings in patients with apnea were also compared with those in patients without apnea and significant differences were not found (F = 0.019, p = not significant). Although it would seem intuitive that increased nasal obstruction is associated with the severity of obstructive sleep apnea and difficulty with the use of nasal continuous positive air pressure, this study shows that nasal patency, as measured by acoustic rhinometry, does not correlate with the severity of obstructive sleep apnea, as determined by the apnea/hypopnea index or the effective nasal continuous positive air pressure.

Continuous nasal positive airway pressure with a mouth leak: effect on nasal mucosal blood flux and nasal geometry

BACKGROUND

Obstructive sleep apnoea is a common condition. Treatment with nasal continuous positive airway pressure (CPAP), while effective and safe, causes nasal congestion and stuffiness in some patients. The hypothesis that this study aimed to test was that nasal CPAP with a mouth leak and subsequent unidirectional airflow across the nasal mucosa causes an increase in nasal mucosal blood flux and a fall in both nasal volume and minimal cross sectional area. A secondary aim was to study if this could be prevented by humidifying the air inspired with nasal CPAP.

METHODS

Nasal CPAP was applied to eight normal subjects who kept their mouths open until they had expired 500 litres. The effect of this on nasal mucosal blood flux and nasal geometry was studied with and without humidification using a laser Doppler blood flowmeter and acoustic rhinometer. In addition, nasal mucosal blood flux was measured in four of the eight subjects before and after nasal CPAP with the mouth closed.

RESULTS

Nasal CPAP using room air with the mouth closed did not result in any change in nasal mucosal blood flux; with a mouth leak nasal CPAP using room air was associated with a 65% increase in nasal mucosal blood flux. There was no change in nasal geometry. Nasal CPAP using humidified air with a mouth leak did not cause any change in nasal mucosal blood flux or nasal geometry.

CONCLUSION

Nasal CPAP used with an open mouth leads to an increase in nasal mucosal blood flux. This can be prevented by humidifying the air inspired with nasal CPAP.

Sensory information from the upper airway: role in the control of breathing

The functional integrity of extrathoracic airways critically depends on the proper orchestration of the activities of a set of patency-maintaining muscles. Recruitment and control of these muscles is regulated by a laryngeal and trigeminal affects that originate from pressure sensing endings. These sensors are particularly numerous among laryngeal receptors and, indeed, they constitute the main element in the respiration-modulated activity of the superior laryngeal nerve. Considering that the most compliant region of the upper airway, and thus more vulnerable to inspiratory collapse, lies cranially to the larynx, the laryngeal pressure-sensing endings seem to be ideally located for detecting collapsing forces and initiating reflex mechanisms for the preservation of patency. This process operates by activating upper airway dilating muscles and by decreasing inspiratory drive: both actions limit t he effect of the collapsing forces. Cold reception is differently represented in various mammalian species within nasal and laryngeal segments. Cooling of the upper airway has an inhibitory influence on breathing, especially in newborns, and a depressive effect on upper airway dilating muscles. The latter response is presumably mediated through the inhibitory effect of cooling on laryngeal pressure endings. These responses could be harmful during occlusive episodes. Powerful defensive responses with distinct characteristics can be elicited through the simulation of laryngeal and nasal irritant type receptors. Sneezing is elicited through the stimulation of trigeminal afferents, cough through the stimulation of laryngeal vagal endings. Changes in osmolality and ionic composition of the mucosal surface liquid can lead to conspicuous alterations in receptor activity and related reflexes.