Acoustic rhinometry: do we need a standardized operating procedure?

The usefulness of a standardized operating procedure for acoustic rhinometry was assessed in a study on 51 healthy volunteers. Nasal measurements were made with acoustic rhinometry before and after application of a topical nasal decongestant. Our standard operating procedure used three consecutive readings of anterior nasal volume to obtain a valid estimate of mean nasal dimensions. The mean measurement was only accepted as valid if the three readings had a coefficient of variation (CV) of less than 20%. Twenty-two out of 192 (11.5%) nasal cavities required more than three consecutive readings to achieve this. Our data show that the error encountered by relying on a single reading of an acoustic trace can be greater than the changes caused by the topical nasal decongestant and that multiple readings using a standard operating procedure are essential to obtain valid data.     

Acoustic rhinometry: an explanation of some common artefacts associated with nasal decongestion

The nasal cavities of 51 healthy volunteers were examined using acoustic rhinometry before and after nasal decongestant. Several specific dimensions were studied, which included the minimum cross-sectional area, and three volumes corresponding to the anterior, middle and posterior regions of the nasal airway. An average acoustic rhinometry trace was constructed for the whole group of subjects, before and after decongestion, from data extracted from the raw data files written to the computer hard disk for each subject. A 27.5% (P < 0.0001) increase in the minimum cross-sectional area was observed, with no shift in its position. The greatest increase in nasal dimensions was seen in the anterior and middle parts of the nose, however, significant changes were also seen in the posterior nasal cavity and post nasal space. There are a number of possible sources of artefact. First, confusion of the first and second minima may produce apparent movement of the minimum cross-sectional area following nasal decongestion. Second, a postulated change in the acoustic path length may lead to apparent changes in volume in certain regions of the nose. Third, a variable and uncontrollable degree of sound energy loss will occur into the opposite nasal cavity beyond the posterior border of the septum. An apparent increase in the dimensions of this region will be seen as the opposite cavity decongests. We feel that all users of the acoustic rhinometer need to be aware of these potential sources of artefact, and attention needs to be focused on an agreed definition of the components of the acoustic rhinometry trace.     

Acoustic rhinometry in pre-school children

Acoustic rhinometry was performed in 35 normal nose-breathing children between 3 and 6 years. The average cross-sectional areas at the nasal valve, at the anterior end of the turbinates, and in the nasopharynx were 0.34±0.06 cm², 0.35±0.08 cm² and 1.37±0.48 cm² respectively. The average minimal cross-sectional area was 0.29±0.06 cm². The minimal cross-sectional area was located at the nasal valve in 14 and at the anterior end of nasal tubinates in 21 of the 35 children. As would be expected, the cross-sectional areas at different sites of the nasal cavity increased with increasing age of the children. But, whereas the minimal cross-sectional area increased by 0.024 cm² per year, the nasopharyngeal cross-sectional area increased by 0.20 cm² per year. No significant differences were found between boys and girls. Measurements of the posterior nasal and nasopharyngeal cross-sectional areas were unreliable, whenever the minimal cross-sectional area was less than 0.2 cm². Furthermore, assessment of the nasopharynx may be difficult because of involuntary movements of the soft palate.     

成年人鼻声反射与鼻阻力测量的正常参数

目的:研究正常成人鼻声反射(AR)及鼻阻力(RM)测量的正常值,以及它们之间的关系.方法:健康成人82例,采用AR检查,获得单侧鼻腔第一狭窄面积(UA1),第二狭窄面积(UA2),最小截面积(UMCA),0～5 cm、2～5 cm鼻腔容积(UV5、UV2～5).RM为通过前鼻主动测压法测量鼻压差为150 Pa 时的RM值,如鼻压差达不到150 Pa,则采用Broms(半径为200 Pa)的RM值表示,分别测量单侧吸气阻力(URins150、URins200)、单侧呼气阻力(URexp150、URexp200)及鼻气道总阻力(TRins150、TRins200、TRexp150、TRexp200),并对RM和AR测量结果进行相关性分析.结果:健康成年男女UA1分别为(0.63±0.14)、(0.60±0.14)cm2;UA2分别为(0.72±0.48)、(0.6±0.4)cm2;UMCA分别为(0.50±0.16)、(0.47±0.18)cm2;UV5分别为(5.68±1.73)、(5.16±1.85)cm3 ;UV2～5分别为(4.13±1.56)、(3.83±1.66)cm3.男女各参数值比较均差异无统计学意义(T值分别为0.093、0.134、0.392、0.408,均P>0.05).有25例鼻压差未达到150 Pa,采用Broms测量,URins150、URins200、URexp150、URexp200、TRins150、TRinst200、TRexp150、TRexp200结果分别为(0.86±0.96)、(0.45±0.61)、(0.83±0.71)、(0.52±0.88)、(0.38±0.34)、(0.18±0.24)、(0.38±0.27)、(0.19±0.24)Pa/(cm3·s).URins150、URexp150、TRins150、TRexp150与UMCA、UV5、UV2～5有显著相关性(均P<0.05).结论:RM与AR测量结果有一定相关性,可为临床提供鼻腔状态的客观参数.     

Acoustic rhinometry compared with anterior rhinomanometry in the assessment of the response to nasal allergen challenge

Acoustic rhinometry was used to assess nasal airway patency objectively and was compared with the more established method of anterior rhinomanometry. Ten patients with allergic rhinitis underwent 15 nasal challenges with allergen to which they showed positive skin-prick tests. Responses were assessed by measuring the minimum nasal cross-sectional area (Amin.) using acoustic rhinometry and by measuring nasal airway resistance (NAR) using anterior rhinomanometry. The measurements of Amin. and NAR showed a significant negative correlation. Acoustic rhinometry appears to be superior to anterior rhinomanometry in quantifying the response to nasal allergen challenge and may be particularly useful in patients with initial nasal blockage.     

Evaluation of children nasal geometry,employing accoustic rhinometry

The area above the nasal cavity plays a role in respiratory physiology.     

The accuracy of acoustic rhinometry using a pulse train signal

The signal used in the original acoustic rhinometers was an impulse of short duration and wide energy spectrum. A rhinometer utilizing a new signal of a similarly broad energy but different time course has been developed. We investigated the accuracy of area reconstructions computed using this signal by comparing them with the original areas of simple models. This study demonstrates that, at present, acoustic rhinometry using a pulse train signal is subject to significant systematic errors. Some of these are intrinsic to the rhinometer. Others are caused by the geometry of the models. Area reconstructions beyond narrow constrictions are particularly inaccurate. The findings are significant because the nasal valve can act as such a constriction. The errors can cause the parameters used in the clinical application of acoustic rhinometry to deviate substantially from the true values.     

A comparison of the sensitivity of manometric rhinometry,acoustic rhinometry,rhinomanometry and nasal peak flow to detect the decongestant effect of xylometazoline

A study has been undertaken to compare the sensitivity of manometric rhinometry, rhinomanometry, nasal peak flow and acoustic rhinometry to detect the decongestant effect of xylometazoline. Twenty healthy volunteers were investigated before and after decongestion. The sensitivity of all four methods varied from 80 to 95%. These differences were not significant. Manometric rhinometry, a new method of investigating nasal physiology, is as sensitive as more established methods.     

应用鼻声反射技术对阻塞性睡眠呼吸暂停低通气综合征患者鼻周期的测量观察

目的:探讨阻塞性睡眠呼吸暂停低通气综合征(OSAHS)疾病是否对成人鼻周期有影响。方法:应用鼻声反射系统测量20例正常成人、18例鼾声患者、22例OSAHS患者的鼻周期,测量时间为7 h,间隔时间为0.5 h。结果:正常人、鼾声患者、OSAHS患者鼻周期的出现率分别为19/20(95.0%)、15/18(83.0%)、15/22(68.2%),典型鼻周期的出现率分别为11/20(55.0%)、8/18(44.4%)、6/22(27.3%),鼻周期的幅度变化分别为46.1%、33.2%、21.8%,3组之间鼻周期的特点存在明显差异(P<0.05)。结论:成人OSAHS患者鼻周期特点和正常人比较存在差异,OSAHS疾病可能影响成人鼻腔的生理功能。     

鼻声反射结合鼻内镜检查评价功能性鼻内镜手术对慢性鼻窦炎的疗效

目的：运用鼻声反射结合鼻内镜检查评价功能性鼻内镜手术对慢性鼻窦炎的疗效。方法：分别于术前及术后4周对60例接受FESS的慢性鼻窦炎患者,使用鼻声反射仪器检测手术治疗前后鼻腔最小横截面积（MCSA）、鼻腔容积（NV）及鼻气道阻力（NAR）的变化,结合鼻内镜的检查,评估手术治疗慢性鼻窦炎的效果。结果：功能性鼻内镜手术后,鼻内镜下见患者各组鼻窦开放良好,同时MCSA、NV增加,NAR降低,与术前相比具有显著的统计学意义。结论：鼻声反射结合鼻内镜检查作为手术前后鼻功能的检测手段,可对手术疗效进行客观的综合评价。     

鼻声反射测试法在鼻中隔偏曲患者中的应用

目的 :研究鼻中隔偏曲患者鼻声反射参数值。方法 :应用Eccovision型声反射鼻测量计对 6 0例鼻中隔偏曲患者进行测试 ,记录鼻腔最小横截面积 (NMCA) ,鼻腔容积 (NCV) ,NMCA至前鼻孔距离 (DCAN)和鼻阻力 (NR) ,并进行统计学分析。结果 :NMCA为 (0 .37± 0 .14 )cm2 ;NCV(12 .30± 2 .32 )cm3 ;DCAN (2 .10± 0 .15 )cm ;NR(0 .348± 0 .115 )kPa·L-1·min-1。经统计学分析提示 ,NMCA和NVC的大小与NR呈反比 ,与DCAN无明显相关性。结论 :鼻声反射可作为鼻腔通气功能评价的客观指标 ,且可以精确确定NMCA的位置 ,为临床手术提供参考。     

Validation of acoustic rhinometry by using the Cavalieri principle to estimate nasal cavity volume in cadavers

The ability of acoustic rhinometry to provide valid estimates of nasal cavity volume has been tested using cadaveric heads. Values obtained for the cavities in five intact heads were compared with unbiased estimates of the volumes of the same specimens. An unbiased estimate is one which does not depart in a systematic manner from the true value. Here, unbiased estimates were made by applying the Cavalieri principle to uniform random samples of 4–7 macroscopic slices per specimen. Using acoustic rhinometry, the mean volume (left and right sides combined) amounted to 31.3 ml with a co-efficient of variation of 77%. On the same specimens, the Cavalieri estimate of mean volume (both cavities plus the adjacent nasopharynx) was 31.1 ml (66%). There was a significant and positive correlation between the two data sets (correlation co-efficient 0.97). Repeated acoustic measurements on the same cavities gave a measuring error of about 4%. We conclude that acoustic rhinometry can provide valid and efficient estimates of the volume of the nasal cavity plus nasopharynx.     

The magnitude of random errors in acoustic rhinometry and re-interpretation of the acoustic profile

By measuring the effect of incomplete acoustic seal and increasing nosepiece insertion depth on the derived nasal acoustic profile, this study quantifies the random errors that may arise in the course of the clinical practice of acoustic rhinometry using the insert nosepiece. The relative movement of the nose and nosepiece also enables us to separate the contribution of each to the acoustic curve. Sixteen volunteers were tested using a commercial rhinometer. As a consequence of this study we are able to formulate the following conclusions: (1) The first minimum of the nasal acoustic profile is due to the end of the nosepiece, but may be further diminished by the position of the nosepiece tip on or within the nose. (2) The second minimum is due to the nasal valve, to which the head of the inferior turbinate contributes. (3) Acoustic rhinometry is extremely sensitive to acoustic leaks and results obtained without a fluid acoustic sealant cannot be considered valid. (4) The errors associated with the nosepiece insertion technique are very small unless the nosepiece is forced into the nasal vestibule.     

鼻声反射在学龄前儿童鼻腔容积测定中的应用

目的:使用鼻声反射技术检测学龄前儿童鼻腔容积,提出检测方法、结果分析方法以及相关正常参考值。方法:①在最小横截面积相同但容积不同的模拟鼻腔,通过鼻声反射仪和通气阻力检测仪测量管腔容积和通气阻力,比较最小横截面积和管腔容积在反映通气阻力变化时的敏感性。②使用鼻声反射仪测量97例4岁儿童和137例5岁儿童的鼻腔容积。结果:①在模拟鼻腔最小横截面积不变的情况下,通气阻力随鼻腔容积增加而减小。②学龄前儿童平均双侧鼻腔容积为(2.03±0.4)ml。不同年龄和不同性别学龄前儿童鼻腔容积差异均无统计学意义(均P>0.05)。结论:分析鼻声反射检测结果时,鼻腔容积变化比最小横截面积更能反映鼻腔通气阻力变化。本次研究提出鼻声反射检测结果评估方法和学龄前儿童鼻腔容积正常参考值。     

Acoustic rhinometry and paranasal cavities: a systematic study in box models

OBJECTIVE/HYPOTHESIS: Acoustic rhinometry (AR) is a well-established diagnostic tool in rhinology. The aim of the study was to test the hypothesis that the paranasal sinuses are a main cause for inaccuracy of AR in the posterior part of the nose. STUDY DESIGN: Experimental study to evaluate the influence of simulated paranasal sinus volume and of the contralateral side of the nose on AR measurements in "box models." METHODS: Models were measured with paranasal sinus volume simulated between 0 and 25 mL and with the junction between the models and the paranasal sinuses varying in length and diameter. RESULTS: Moderate but distinct modification of the posterior area-distance curve was found within the models after changing size of the paranasal sinuses and its junction to the cavity. The apparent cross-sectional area (CSA) measured in the posterior cavum decreased with the volume of the paranasal sinuses. This effect was limited by the length and the diameter of the paranasal junction, as well as by the concha. No influence of the contralateral side on AR measurements was seen. CONCLUSIONS: Acoustic rhinometry reveals reproducible measurements up to 4 cm from the nostril that correspond with the actual model CSA. Simulated paranasal sinuses appear to partially contribute to the inaccuracy in the posterior part of the area-distance curve.     

鼻声反射在儿童阻塞性睡眠呼吸暂停低通气综合征诊断中的价值

目的：探讨鼻声反射在儿童阻塞性睡眠呼吸暂停低通气综合征（OSAHS）诊断中的价值。方法：对36例OSAHS患儿在术前及术后1个月分别进行鼻声反射检查,其中20例患儿术中用“排水法”对切除的腺样体实际体积进行测量,并与通过鼻声反射所得到的腺样体体积进行比较。结果：术后1个月患儿鼻咽部容积均明显高于术前。20例患儿术中用“排水法”所测得的腺样体实际体积要高于通过鼻声反射所得到的腺样体体积,但两者之间有明显的相关性。结论：在OSAHS患儿中,鼻声反射是评估腺样体大小的较好方法,可作为腺样体切除术前常规的检查方法之一。     

Acoustic rhinometry in nasal provocation test in perennial allergic rhinitis

Acoustic rhinometry is one method to evaluate nasal geometry by an acoustic reflection technique. The aim of this study was to investigate the changes in acoustic rhinometry after nasal provocation in patients with exclusively perennial allergic rhinitis. In 19 patients, acoustic rhinometry and active anterior rhinomanometry were performed before and after nasal provocation test. There was a statistically significant nasal flow reduction measured by active anterior rhinomanometry after nasal provocation (p < 0.05) and a median symptom score of four points, both indicating a positive response to nasal provocation. On the other hand, there was no statistically significant change in the values of acoustic rhinometry after nasal provocation (p > 0.05). In patients with exclusively perennial allergic rhinitis, acoustic rhinometry does not seem to significantly change after nasal provocation. In contrast, active anterior rhinomanometry values decreased significantly after nasal provocation. The presented results indicate that acoustic rhinometry does not seem to be a diagnostic method superior to active anterior rhinomanometry in this context.