The effect of lignocaine on nasal resistance and nasal sensation of airflow

The effect of lignocaine on nasal sensation of airflow and nasal resistance was assessed in twenty-five subjects. A randomised crossover trial was conducted with lignocaine as the active drug and saline as the placebo. Both substances were delivered to the nasal mucosa as a nasal spray. Lignocaine caused a sensation of increased nasal patency in twenty-two of the twenty-five subjects studied. Saline had no such effect. The difference between this subjective effect of the two substances was highly significant (p less than 0.001). Neither spray had any significant effect on nasal resistance to airflow assessed objectively by rhinomanometry.     

The effects of nasal anaesthesia upon nasal sensation of airflow

The effect of nasal anaesthesia upon the sensation of nasal airflow and activity of menthol was investigated in 25 subjects using a visual analogue scale. Nasal anaesthesia was shown to decrease the sensation of nasal airflow, and also decrease the action of menthol in enhancing the sensation of nasal airflow. These differences were shown to be highly significant p less than 0.001. Physiological mechanisms responsible for conveying the subjective appreciation of a nasal airflow stimulus are discussed, and also the site and nature of the sensory nerve endings involved.     

The effect of nasal mucosal vasoconstriction on nasal airflow sensation

The correlation between the objective measurement of nasal resistance and nasal airflow sensation is usually regarded as poor. To investigate the relationship between these two parameters 20 healthy volunteers had nasal resistance to airflow measured by rhinomanometry compared with nasal sensation by visual analogue scoring before and after nasal mucosal vasoconstriction using topical 0.1% xylometazoline. The median change in nasal resistance was 0.2 kPal^-1s (95% CI 0.08–0.28 kPal^-1s) and in nasal sensation 24 mm (95% CI 17 mm-35 mm). A significant relationship between nasal sensation and nasal resistance to airflow was found (Kendall's Rank correlation (P < 0.05). This function can be described by the linear regression equation: dS = 13.2 + 70.dNR where dS = change in nasal sensation and dNR = change in nasal resistance. There may be a much closer relationship between subjective and objective measures of nasal patency than has previously been thought.     

The effect of histamine challenge on nasal airflow sensation

Objective nasal airflow resistance, as measured by the rhinomanometer, and the subjective sensation of nasal patency are usually regarded as showing poor correlation. However, previous population studies comparing nasal resistance and subjective nasal airflow sensation have failed to takee into account the great individual variation in resting nasal resistance. To investigate the potential relationship between the two parameters, 20 healthy volunteers underwent histamine nasal challenge tests. Nasal resistance prior to the intra-nasal administration of histamine (‘resting’ nasal resistance, NR_R) was compared with nasal resistance when the subject reported a subjective sensation of nasal blockage (‘obstructed’ nasal resistance, NR₀) and the two were found to be significantly correlated using the Spearman rank correlation method (r_s= 0.648, P = 0.002). Linear regression analysis using the method of least squares demonstrated an association between the two variables (P = 0.029), conforming to the formula NR₀= 1.26NR + 0.478, (resistance units kPa.s.1^?1). Subjective and objective measurements of nasal patency may be much more closely related than has previously been reported.     

薄荷冰片和麝香对鼻气道阻力及鼻感觉的影响

祖国医学常将薄荷、冰片作为改善鼻通气药以治疗鼻阻塞，但其作用机理尚不清楚。本实验在５２名受试者中研究了吸入薄荷冰、冰片、麝香对鼻气流阻力及鼻感觉的影响。结果发现这３种具有挥发性的药物都能够不同程度的引起鼻气道通畅的感觉，但对鼻气道阻力却无明显影响。因此作者认为此类药物可称为假性鼻通气药。     

薄荷冰片和麝香对鼻气道阻力及鼻感觉的影响

祖医学常将薄荷，冰片作为改善鼻通气药以治疗鼻阻塞，但其作用机理尚不清楚。本实验在５２名受试者中研究了吸入薄荷冰、冰片、麝香对鼻气流阻力及鼻感觉的影响。结果发现这３种具有挥发性的药物都能够不同程度的引起鼻气道通畅的感觉，但对鼻气道阻力却无明显影响，因此作者认为此类药物可称为假性鼻通气药。     

The effects of camphor, eucalyptus and menthol vapour on nasal resistance to airflow and nasal sensation

The effects of five minutes exposure to camphor, eucalyptus or menthol vapour on nasal resistance to airflow and nasal sensation of airflow were compared with the effects of exercise on the nose. Inhalation of camphor, eucalyptus or menthol had no effect on nasal resistance to airflow but the majority of subjects reported a cold sensation in the nose with the sensation of improved airflow. Exercise caused a decrease in nasal resistance but did not induce any nasal sensation of cold or improved airflow. The results indicate that camphor, eucalyptus and menthol stimulate cold receptors in the nose. The clinical significance of nasal sensation of airflow is discussed.     

The effect of adenoidectomy on nasal resistance to airflow

The aim of the research was to determine whether the operation of adenoidectomy affected the nasal resistance to airflow. The total nasal respiratory resistance (TNR) was measured in forty-four children admitted for adenoidectomy and myringotomies, with or without tonsillectomy. The measurement was repeated three months post-operatively. There was significant correlation between the pre-operative TNR and the weight of adenoid removed at operation. A history of snoring pre-operatively, which was absent after operation, was related to a high pre-operative TNR and large adenoids. Those children in whom at least one gram of adenoid tissue was removed, were found to have a mean reduction in nasal resistance of 19%.     

Experimental studies on nasal sensation of airflow

Objective and subjective measurements of nasal airflow were made before and after inhalation of vanilla and a commercial mixture of aromatics used to treat nasal stuffiness. These substances had no effect on nasal resistance to airflow but caused significant changes in the subjective sensation of nasal airflow. The use of a visual numerical scale for the assessment of nasal sensation of airflow is discussed in terms of its significance as regards quantifying changes in nasal sensation of airflow before and after nasal surgery.     

鼻部气道的气流感觉

为了观察正常人鼻部气流感觉与鼻通气度的关系，采用视觉类比标度法和前鼻测压法进行研究，发现鼻部对气流的主观感觉与实际鼻通气度即鼻气道阻力之间无明显相关性；并证实感觉鼻通气度的部位主要在鼻前庭。传统中药治疗鼻阻塞的挥发类药物（樟脑和薄荷）只能改善鼻通气的感觉，并不能改善鼻气道阻力。提示鼻部对气流的主观感觉不能完全反映实际的鼻通气程度。临床上诊断和治疗以鼻阻塞症状为主诉的患者时，应将患者鼻部对气流的主观感觉和测定鼻气道阻力结合起来，以对实际的鼻通气度和治疗效果作出客观评价。     

Experimental studies on nasal sensation of airflow

Objective and subjective measurements of nasal airflow were made before and after inhalation of vanilla and a commercial mixture of aromatics used to treat nasal stuffiness. These substances had no effect on nasal resistance to airflow but caused significant changes in the subjective sensation of nasal airflow. The use of a visual numerical scale for the assessment of nasal sensation of airflow is discussed in terms of its significance as regards quantifying changes in nasal sensation of airflow before and after nasal surgery.     

Further studies on nasal sensation of airflow

The effect of applying a eutectic mixture of local anaesthetics cream (EMLA) to the nasal vestibule, upon both nasal sensation of airflow and action of menthol was studied in 25 normal subjects. Anaesthesia of the vestibule was shown to decrease nasal sensation of airflow, p less than 0.001. The action of menthol in enhancing the sensation of nasal airflow was unchanged, p greater than 0.05. This shows that sensory nerve endings located within the nasal vestibule and mucosa, are likely to be important in conveying nasal sensation. This study expands basic scientific knowledge in this important clinical area. The site and nature of sensory nerve endings responsible and possible neurophysiological mechanisms involved are discussed.     

The effects of menthol isomers on nasal sensation of airflow

The effects of inhalation of L-menthol, D-isomenthol and D-neomenthol, upon nasal resistance and sensation to airflow were investigated in 40 subjects. L-menthol caused a highly significant enhancement of nasal sensation of airflow but despite their great similarity in structure and a similar peppermint smell the isomers D-isomenthol and D-neomenthol had no effect on nasal sensation of airflow. These findings show that L-menthol has a specific pharmacological action on nasal sensory nerve endings which is not related to its peppermint smell.     

鼻部气道的气流感觉

为了观察正常人鼻部气流感觉与鼻通气度的关系，采用视觉类比标度法和前鼻测压法进行研究，发现鼻部对气流的主观感觉民实际鼻通气度即鼻气道阻力之间无明显相关性；并证实感觉鼻通气度的部位主要在鼻前庭。传统中药治疗鼻阻塞的挥发类药物只能改善鼻通气的感觉，并不能改善鼻气道阻力。提示鼻部对气注的主观感觉不能完全反映实际的鼻通气程度，临床上诊断和治疗以鼻阻塞症状为主诉的患者时，应将患者鼻部对气流的主观感觉和测定鼻气     

The effect of aromatics on inspiratory and expiratory nasal resistance to airflow

Unilateral inspiratory and expiratory nasal resistance to airflow were measured in 35 subjects using active anterior rhinomanometry. No significant difference was found between inspiratory and expiratory resistance. Inhalation of a mixture of aromatics, camphor, menthol, oil of pine needles and methyl salicylate had no effect on inspiratory or expiratory nasal resistance. Factors influencing inspiratory and expiratory resistance and the actions of aromatics are discussed.     

Nasal airflow: resistance and sensation

For many years nasal resistance to airflow measured by rhinomanometry has been regarded as the objective measure of nasal patency. However, recently it has become apparent that this may not be the case. The present study was designed to affirm or refute this view by using large numbers of subjects and observations. Five hundred estimations of (objective) nasal resistance to airflow and (subjective) nasal sensation of airflow where carried out. No correlation could be demonstrated between these two parameters. It is concluded nasal resistance to airflow and nasal sensation of airflow are two separate modalities which are not directly related. The possible reasons for this finding are discussed with reference to previous work on nasal sensation.     

The role of mucosal receptors in the nasal sensation of airflow

50 subjects were admitted into a randomized double-blind placebo controlled cross-over trial with 4% lignocaine as the active drug and normal saline as the placebo. Each subject had 2 ml of solution sprayed into each nasal cavity and all subjects had both sprays but on different occasions. The order in which the sprays were administered was randomized. The subjective sensation of nasal airflow was measured using a visual anologue scale before and after the spray. These measurements were made under conditions of the same airflow rate, which was monitored throughout the experiment using a reprogrammed NR6 rhinomanometer. Objective nasal patency was measured as peak nasal inspiratory flow rate. It was found that the nasal sensation of airflow decreased slightly after both lignocaine (difference between medians 5.0; 95% confidence interval —2.91 to 6.11) and normal saline (difference between medians 6.0; 95% confidence interval — 1.02 to 7.21). Nonparametric analysis of variance showed this difference to be non-significant (P = 0.73). In addition there was no significant change in objective nasal patency. The results suggest that nerve endings in the nasal mucosa play no part in sensing nasal airflow during respiration.     

The role of mucosal receptors in the nasal sensation of airflow.

50 subjects were admitted into a randomized double-blind placebo controlled cross-over trial with 4% lignocaine as the active drug and normal saline as the placebo. Each subject had 2 ml of solution sprayed into each nasal cavity and all subjects had both sprays but on different occasions. The order in which the sprays were administered was randomized. The subjective sensation of nasal airflow was measured using a visual analogue scale before and after the spray. These measurements were made under conditions of the same airflow rate, which was monitored throughout the experiment using a reprogrammed NR6 rhinomanometer. Objective nasal patency was measured as peak nasal inspiratory flow rate. It was found that the nasal sensation of airflow decreased slightly after both lignocaine (difference between medians 5.0; 95% confidence interval -2.91 to 6.11) and normal saline (difference between medians 6.0; 95% confidence interval -1.02 to 7.21). Nonparametric analysis of variance showed this difference to be non-significant (P = 0.73). In addition there was no significant change in objective nasal patency. The results suggest that nerve endings in the nasal mucosa play no part in sensing nasal airflow during respiration.     

Nasal mucosal anaesthesia and airflow resistance

The effect of topical lidocaine solution on nasal airflow resistance was examined in five adult subjects with normal noses, seated and recumbent. The increasing use of upper airway anaesthesia in the investigation of upper airway function and the lack of published information concerning its effect on nasal airflow resistance led to this investigation. Nasal airflow resistance did not significantly change during 30 minutes observation following topical application of 4% lidocaine solution.