Joerg Lindemann

A Numerical Simulation of Intranasal Air Temperature During Inspiration

Objectives/Hypothesis: In vivo measurements of the intranasal air temperature are feasible. The present study was designed to reproduce temperature distributions within the human nasal cavity by means of numerical simulation.

Numerical simulation of airflow patterns and air temperature distribution during inspiration in a nose model with septal perforation.

Background The most typical symptoms of patients with nasal septal perforation (SP) are crusting and recurrent nosebleed. The objective of the study was to determine the influence of SP on intranasal temperature profile and airflow patterns during inspiration by means of numerical simulation. Methods Two realistic bilateral models of the human nose with and without SP were reconstructed based on computed tomography (CT). A numerical simulation was performed. The intranasal air temperature distribution and airflow patterns during inspiration were displayed, analyzed, and compared. Results SP causes a highly disturbed airflow in the area of perforation. A spacious vortex within the perforation including various localized vortices was detected. A disturbed intranasal temperature distribution between the right and left nasal cavities developed. Conclusions The numerical simulation demonstrates the interaction between airflow patterns and heating of respiratory air. The disturbed airflow causes reduced air conditioning. This fact may contribute to crusting and recurrent nosebleed.

Nasal air temperature and airflow during respiration in numerical simulation based on multislice computed tomography scan.

Background Adequate nasal air-conditioning is of greatest importance. Because detailed processes of nasal air-conditioning still are not completely understood, numerical simulations of intranasal temperature distribution and airflow patterns during inspiration and expiration were performed. Methods A three-dimensional model of the human nose based on computed tomography scans was reconstructed. A computational fluid dynamics application was used displaying temperature and airflow during respiration based on time-dependent boundary conditions. Results Absolute air temperature and velocity values vary depending on detection site and time of detection. Areas of low velocities and turbulence show distinct changes in air temperature. The turbinate areas prove to be the main regions for heat exchange. The numerical results showed excellent comparability to our in vivo measurements. Conclusion Numerical simulation of temperature and airflow based on computational fluid dynamics is feasible providing entirely novel information and an insight into air-conditioning of the human nose.

Age-related changes in intranasal air conditioning in the elderly.

Objectives/Hypothesis: Elderly patients frequently complain about the feeling of a dry nose and recurrent crusting probably due to age‐related degenerative effects of the nasal mucosa. Data on intranasal air conditioning in elderly patients are missing. The aim of the study was to compare intranasal heating and humidification of respiratory air in elderly subjects and a younger control group. Additionally, rhinomanometrical and rhinometrical data were examined.

Impact of menthol inhalation on nasal mucosal temperature and nasal patency.

Background Menthol is a natural herbal compound. Its isomer L-menthol presents the characteristic peppermint scent and is also responsible for the cooling sensation when applied to nasal mucosal surfaces because of stimulation of trigeminal cold receptors. The aim of this study was to assess the effect of menthol inhalation on end-inspiratory nasal mucosa temperature and nasal patency. Methods Eighteen healthy volunteers with a mean age of 30 years were enrolled in this study. Objective measurements included the septal mucosal temperature within the nasal valve area by using a miniaturized thermocouple as well as active anterior rhinomanometry before and after inhalation of l-menthol vapor. All subjects completed a visual analog scale (VAS; range, 1–10) evaluating nasal patency before and after menthol. Results The mean end-inspiratory mucosal temperature ranged from 27.7°C (±4.0) before menthol inhalation to 28.5°C (±3.5) after menthol inhalation. There were no statistically significant differences between the temperature values before and after menthol inhalation (p > 0.05). In addition, no statistically significant differences between the rhinomanometric values before and after menthol inhalation were observed. Sixteen of the 18 subjects reported an improvement of nasal breathing after menthol inhalation by means of the VAS. Conclusion Menthol inhalation does not have an effect on nasal mucosal temperature and nasal airflow. The subjective impression of an improved nasal airflow supports the fact that menthol leads to a direct stimulation of cold receptors modulating the cool sensation, entailing the subjective feeling of a clear and wide nose.

Nasal mucosal temperature in relation to nasal airflow as measured by rhinomanometry.

Background The aim of this study was to measure in vivo nasal mucosal temperature and assess its relationship to nasal patency. Methods Nasal mucosal temperature of 30 nasal cavities was measured by means of a miniaturized thermocouple within the anterior turbinate area during respiration. Temperature values were compared with corresponding rhinomanometrical data. Results The median mucosal temperature ranged from 30.2°C (range, 28.9–31.7°C) after inspiration to 32.2°C (range, 31.0–33.9°C) after expiration. The end-inspiratory (r = -0.85) and end-expiratory mucosal temperature values (r = -0.88) negatively correlated with the rhinomanometrical data. Conclusion This study supports the fact that there is a negative correlation between nasal mucosal temperature and nasal resistance. Changes in nasal patency seem to influence nasal mucosal temperature. Within this context, nasal thermoreceptors might play an important role concerning the perception of nasal patency.

Nasal air conditioning in relation to acoustic rhinometry values

Background Changes of nasal dimensions can influence the air-conditioning capacity of the nose because of alterations of airflow patterns. The goal of this study was to evaluate the correlation between intranasal temperature and humidity values and nasal dimensions, assessed by means of acoustic rhinometry. Methods Eighty healthy volunteers (40 men and 40 women; median age, 51 years; range, 20–84 years) were enrolled in the study. In total, 160 nasal cavities were examined. All volunteers underwent a standardized acoustic rhinometry. Additionally, intranasal air temperature and humidity measurements at defined intranasal detection sites within the anterior nasal segment were performed. Results There was no statistically significant difference between the right and left side of the nose regarding air temperature, absolute humidity, and acoustic rhinometric values. A negative correlation was established between the rhinometric nasal volumes/minimal cross-sectional areas and air temperature and absolute humidity values at the three intranasal detection sites. Conclusion According to our results, nasal volumes and cross- sectional areas relevantly influence nasal air conditioning. A healthy nasal cavity with smaller volumes and cross-sectional areas seems to present a more effective air-conditioning function than a too “wide” open nose because of changes in airflow patterns. This observation should be considered as a limitation for overly extensive nasal surgery especially of the turbinates.

Nasal Air Conditioning in Patients Before and After Septoplasty With Bilateral Turbinoplasty

Objective: Septoplasty is one of the most frequently performed surgical procedures by ear, nose, and throat surgeons. Yet the objective control of success concerning septal surgery still is very difficult and causes controversy. Data concerning one of the main functions of the nose, namely the heating and humidification of inspired air, before and after nasal surgery, are still missing. Therefore, the aim of this study was to compare intranasal air temperature and humidity values before and after septoplasty with bilateral turbinoplasty.

Numerical simulation of airflow patterns in nose models with differently localized septal perforations

The most typical complaints of patients with nasal septal perforation (SP) are nasal obstruction, crusting, and recurrent epistaxis depending on the size and site of the SP mainly due to disturbed airflow patterns. The objective of the study was to determine the influence of differently localized SPs on intranasal airflow patterns during inspiration by means of numerical simulation.

Early influence of bilateral turbinoplasty combined with septoplasty on intranasal air conditioning.

Background Too extensive resection of the inferior turbinates (ITs) during nasal surgery leads to a severely disturbed intranasal air conditioning. Data comparing nasal air conditioning before and after turbinoplasty in nasal surgery are still lacking. The aim of this study was to determine the early effect of bilateral turbinoplasty combined with septoplasty on intranasal heating and humidification. Methods Twelve patients were included into this prospective study. In one-half of the patients a bilateral turbinoplasty of the IT during nasal surgery was performed, in the other half no surgery on the IT was performed. Intranasal air temperature and humidity were measured before and after surgery. A combined miniaturized thermocouple and a humidity sensor were used for simultaneous in vivo intranasal measurements. Results There were no statistically significant differences in temperature and humidity values between the two study groups before surgery (p > 0.05). In both groups, the postoperative temperature and humidity values were statistically significantly higher compared with the preoperative ones (p < 0.05). Regarding the two patient groups, the postoperative increase in temperature and humidity was even more pronounced in patients undergoing additional bilateral turbinoplasty. Conclusion According to the results of this study, patients seemed to overall benefit from nasal surgery, with and without a preserving bilateral turbinoplasty, because intranasal air conditioning was improved after surgery. A carefully performed and conservative reduction of the IT in nasal surgery seems to even improve intranasal air conditioning.