Masashi Kanezaki

Perception of urge-to-cough and dyspnea in healthy smokers with decreased cough reflex sensitivity

BackgroundAlthough cigarette smoking has been implicated as an important risk factor for the development of respiratory symptoms, the perceptional aspects of two symptoms in smokers have not been fully elucidated. Therefore, we simultaneously evaluated the cough reflex sensitivity, the cognition of urge-to-cough and perception of dyspnea in both healthy smokers and non-smokers.MethodsFourteen male healthy never-smokers and 14 age-matched male healthy current-smokers were recruited via public postings. The cough reflex sensitivity and the urge-to-cough were evaluated by the inhalation of citric acid. The perception of dyspnea was evaluated by Borg scores during applications of external inspiratory resistive loads.ResultsThe cough reflex threshold to citric acid, as expressed by the lowest concentration of citric acid that elicited two or more coughs (C2) and the lowest concentration of citric acid that elicited five or more coughs (C5) in smokers was significantly higher than in non-smokers. The urge-to-cough log-log slope in smokers was significantly milder than that of non-smokers. There were no significant differences in the urge-to-cough threshold between non-smokers and smokers. There were no significant differences in perceptions of dyspnea between non-smokers and smokers.ConclusionsThe study showed that decreased cough reflex sensitivity in healthy smokers was accompanied by a decreased cognition of urge-to-cough whereas it was not accompanied by the alternation of perception of dyspnea. Physicians should pay attention to the perceptual alterations of cough in smokers.

Effect of cigarette smoking on cough reflex induced by TRPV1 and TRPA1 stimulations

BACKGROUND Recent studies have shown that neurogenic inflammation induced by cigarette smoke is inhibited by TRPA1 antagonist, but not by TRPV1 antagonist. Since cough reflex sensitivity is known to be modified by smoking status, we investigated the effects of cigarette smoking on TRPA1- and TRPV1-induced cough and urge-to-cough in healthy males. METHODS Twenty-six healthy never-smokers and 30 healthy current smokers were recruited via public postings. Cough reflex thresholds and urge-to-cough were evaluated by inhalation of capsaicin, a TRPV1 agonist, and cinnamaldehyde, a TRPA1 agonist. The cough reflex thresholds were defined as the lowest concentrations of capsaicin and cinnamaldehyde that elicited two or more coughs (C(2)) and five or more coughs (C(5)), respectively. The urge-to-cough was evaluated using the modified Borg scale. RESULTS In capsaicin-induced cough, the cough reflex thresholds, as expressed by C(2) and C(5), in current smokers were significantly higher than those in never-smokers (p<0.01 and p<0.001, respectively). The urge-to-cough log-log slopes in current smokers were significantly lower than those of never-smokers (p<0.001). There were no significant differences in the thresholds of the urge-to-cough between never-smokers and current smokers. In cinnamaldehyde-induced cough, there were no significant differences in cough reflex thresholds in C(2) and C(5) between never-smokers and current smokers, nor were there any significant differences in urge-to-cough log-log slope between never-smokers and current smokers. There were no significant differences in the thresholds of the urge-to-cough between never-smokers and current smokers. CONCLUSION The study suggests that smoking has a differential effect on cough responses between TRPV1 and TRPA1 stimulations.

Aging deteriorated perception of urge-to-cough without changing cough reflex threshold to citric acid in female never-smokers

BackgroundThe effect of aging on the cognitive aspect of cough has not been studied yet. The purpose of this study is to investigate the aging effect on the perception of urge-to-cough in healthy individuals.MethodsFourteen young, female, healthy never-smokers were recruited via public postings. Twelve elderly female healthy never-smokers were recruited from a nursing home residence. The cough reflex threshold and the urge-to-cough were evaluated by inhalation of citric acid. The cough reflex sensitivities were defined as the lowest concentration of citric acid that elicited two or more coughs (C2) and five or more coughs (C5). The urge-to-cough was evaluated using a modified the Borg scale.ResultsThere was no significant difference in the cough reflex threshold to citric acid between young and elderly subjects. The urge-to-cough scores at the concentration of C2 and C5 were significantly smaller in the elderly than young subjects. The urge-to-cough log-log slope in elderly subjects (0.73 ± 0.71 point · L/g) was significantly gentler than those of young subjects (1.35 ± 0.53 point · L/g, p < 0.01). There were no significant differences in the urge-to-cough threshold estimated between young and elderly subjects.ConclusionsThe cough reflex threshold did not differ between young and elderly subjects whereas cognition of urge-to-cough was significantly decreased in elderly subjects in female never-smokers. Objective monitoring of cough might be important in the elderly people.

Gender differences in perceptions of urge to cough and dyspnea induced by citric acid in healthy never smokers.

BACKGROUND The mechanism of the gender difference in cough reflex threshold has not been clearly elucidated. In the present study, we evaluated gender differences in the cough reflex threshold along with the perceptions of respiratory sensations, urge to cough, and dyspnea. METHODS Nineteen male and 20 female healthy never smokers were recruited through public postings. The cough reflex threshold and the urge to cough were evaluated by inhalation of citric acid. The perception of dyspnea was evaluated by Borg scores during applications of external inspiratory resistive loads. RESULTS The cough reflex threshold and suprathreshold to citric acid in women, as expressed by the log transformation of the lowest concentration of citric acid that elicited two or more and five or more coughs, was significantly lower than that in men. The urge-to-cough log-log slope in women (1.47 ± 0.81 point × L/g) was significantly steeper than in men (0.96 ± 0.28 point × L/g; P < .03). There were no significant differences in the urge-to-cough threshold estimated between men and women. The slope of the dyspnea Borg score change during the external inspiratory resistive loads is steeper in women (0.17 ± 0.04 point/cm H₂O/L/s) than that in men (0.13 ± 0.05 point/cm H₂O/L/s; P < .01). The urge-to-cough slope significantly correlated with the perception of dyspnea slope (r = 0.537; P < .01). CONCLUSIONS The gender difference in cough reflex threshold accompanied the gender difference in amplification rate of respiratory sensations in the same direction. The higher central gain for common pathways for respiratory sensations may play a role in lower cough reflex threshold in women. Further studies are needed to elucidate this issue.

Tongue Protrusion Strength in Arousal State Is Predictive of the Airway Patency in Obstructive Sleep Apnea.

Contraction of the genioglossus affects either tongue protrusion strength or dilating forces of the upper airway. The upper airway in patients with obstructive sleep apnea (OSA) is thought to collapse during sleep, at least in part because of a sleep related reduction in genioglossus muscle activity. Thus, although tongue protrusion strength by genioglossus activity during sleep contributes to the maintenance of airway patency in patients with OSA, the relationship between tongue protrusion strength in the arousal state and obstructive sleep apnea has not been fully elucidated. Conventional method of tongue protrusion strength cannot be used to evaluate in edentulous subjects and/or subjects with the decreased biting force. In this study, employing a novel measurement method that does not require biting a transducer, we investigated relationships between the tongue protrusion strength and polysomnographic findings. We enrolled twenty normal subjects and 26 subjects with OSA. All subjects completed the measurement of tongue protrusion strength. Each subject with OSA was evaluated by full polysomnography. The degree of tongue protrusion strength was assessed by maximum voluntary contraction against the tongue depressor connected with a strain gauge dynamometer. The tongue protrusion strength was negatively correlated with obstructive apnea time, apnea index (AI) and the percent of sleep stage 2 (r = -0.61, p < 0.0001, r = -0.41 p = 0.03 and r = -0.39 p = 0.04, respectively). Tongue protrusion strength measured in the arousal state is predictive of the airway patency during sleep in OSA.

Effect of Dyspnea Induced by Breath-holding on Maximal Muscular Strength of Patients with COPD

[Purpose] The purpose of the present study was to clarify the effect of dyspnea induced by breath-holding on maximum muscular strength of patients with COPD. [Subjects] This study recruited 14 COPD subjects via public posting. [Methods] Dyspnea was assessed by the modified Borg scale. The subject asked to stop breathing at end-expiration and to hold their breath with a nose clip for as long as possible. Both total breath-holding time and threshold time of dyspnea were measured with a chronograph. Dyspnea reserve time (DRT) was defined by subtracting the threshold time of perception dyspnea from total breath-holding time in order to calculate the 50% DRT. The muscular strengths of maximal handgrip contraction were measured at baseline, 50% threshold time of dyspnea (subliminal point of dyspnea), and the 50% DRT (supraliminal point of dyspnea). [Results] The maximal handgrip at the supraliminal point of dyspnea was significantly lower than the baseline and subliminal point of dyspnea values. There was no statistically significant difference in maximal muscular strength between baseline and the subliminal point of dyspnea value. [Conclusion] The present results demonstrate that dyspnea induced by breath-holding aggravates weakness in the maximum muscular strength of patients with COPD.

Distractive Auditory Stimuli Alleviate the Perception of Dyspnea Induced by Low-Intensity Exercise in Elderly Subjects With COPD

BACKGROUND: Although recent studies have shown that distractive auditory stimuli (DAS) in the form of music increase adherence to exercise in subjects with COPD, the effect of DAS on dyspnea induced by low-intensity, constant-load exercise in elderly patients with COPD has not been elucidated. Therefore, the purpose of this study was to investigate the effect of DAS on the perception of dyspnea induced by low-intensity, constant-load exercise in elderly subjects with COPD. METHODS: We enrolled 16 male out-patients with COPD. Subjects completed cycling exercises with and without DAS at 40% maximum oxygen consumption. They were asked to rate their perception of dyspnea using the modified Borg scale every 3 min during exercise and every 1 min during the recovery period. RESULTS: Dyspnea perception during low-intensity exercise showed a significant correlation between the exercise condition (DAS and control) and exercise duration (P = .04). Exercise-induced dyspnea perception under the DAS condition was significantly lower than that under the control condition from 18 min after the start of exercise to 3 min after the end of exercise (18, 20, 21, 22, and 23 min, P = .01, P < .001, P = .009, P = .006, and P = .006, respectively). However, oxygen consumption and ventilation in response to low-intensity exercise did not significantly differ in the DAS and control conditions (P = .39 and .14, respectively) CONCLUSIONS: Our results suggest that DAS is a non-pharmacologic therapy that can be used to reduce the dyspneic sensation in elderly patients with COPD.

Effect of the cooling sensation induced by olfactory stimulation by L-menthol on dyspnoea: a pilot study

It is common for us to encounter patients suffering from dyspnoea who can occasionally obtain subjective relief when they sit near an open window or in front of a fan. In fact, a recent randomised controlled study showed the effectiveness of a handheld fan blowing air across the nose and mouth in reducing the sensation of breathlessness in patients with advanced disease [1]. It has also been reported that, in patients with chronic obstructive pulmonary disease, breathing cold air reduces the sensation of dyspnoea and improves exercise performance [2]. However, the mechanism behind this effect remains unclear. Olfactory stimulation by L-menthol and dyspnoea http://ow.ly/tL77308wKSS

Recent Advances in Assessment of Dyspnea

As pulmonary rehabilitation can provide various benefits on managing the symptoms of dyspnea, alleviating dyspnea represents a major goal in pulmonary rehabilitation. Dyspnea appears not to be just a single sensation, as it includes the three sensory quality of dyspnea; work/effort, air-hunger and chest tightness. In addition to sensation of dyspnea, complex emotions including anxiety, attention and fear can involve through processing of the limbic system. Recent studies emphasized the multidimensional nature of dyspnea in the sensory-perceptual (intensity and quality), affective distress and impact domains. This review focused on the underlying mechanism of dyspnea and recent advances in assessment in pulmonary rehabilitation in chronic obstructive pulmonary disease (COPD).

Sleep apnea and lateral balance instability in older adults

arrhythmia that resulted from pyrethroid ingestion. Although it is still possible that the patient had paroxysmal atrial fibrillation before pyrethroid ingestion, it is unlikely because previous annual medical examinations showed no abnormality, and an ECG carried out before joint surgery 6months prior also did not show any abnormalities. Additionally, no atrial fibrillation was detected on followup ECG several days after gastric lavage. Thus, we speculate that this patient developed a cardiac arrhythmia after ingesting pyrethroid and the arrhythmia caused cardiogenic embolism, which led to cerebral infarction. We believe that older adults have a higher probability of consuming an insecticide by mistake. Furthermore, older adults have a higher likelihood of atrial fibrillation occurrence than young adults. Consequently, we believe that pyrethroid intake could have facilitated the atrial fibrillation occurrence of the present patient. It was difficult to clearly confirm the time the cerebral infarction occurred, because his initial decline in consciousness was severe and the related symptoms were mild. However, the possibility of cerebral infarction should be considered when treating patients who ingest pyrethroid. Disclosure statement