Cough related to swallowing in asthma patients

BACKGROUND: Occurrence of cough during swallowing is common among asthma patients, but has not been investigated in detail. OBJECTIVE: We conducted an observational study to determine the prevalence of swallowing-related cough (SRC) and its characteristics in asthma patients. METHODS: Asthma patients attending our outpatient department between May 2005 and April 2007 were interviewed to investigate if they had ever experienced SRC, as well as postnasal drip or heartburn and cough related to these conditions. RESULTS: Among 417 patients who completed the questionnaire, 121 patients (29.0%) had experienced SRC. Spicy and sour foods were the most frequent tussigenic foods, causing cough in 76.0% and 53.7% of the 121 patients, respectively. In patients without SRC, the prevalence rates of postnasal drip and postnasal drip-induced cough were 35.8% (106 of 296) and 7.8% (23 of 296), respectively. The corresponding prevalence rates in patients with SRC were 50.4% (61 of 121) and 37.2% (45 of 121), which were both significantly higher than in patients without cough (p = 0.006 and p < 0.001 respectively). In patients without SRC, the prevalence rates of heartburn and heartburn-induced cough were 22.2% (66 of 296) and 2.4% (7 of 296), respectively. The corresponding prevalence rates in patients with SRC were 45.5% (55 of 121) and 16.5% (20 of 121), with both being significantly higher than in patients without cough (p = 0.002 and p < 0.001, respectively). CONCLUSION: SRC was frequent in asthma patients, and was closely related to postnasal drip and heartburn. Irritable larynx is one of the possible underlying mechanisms of SRC. This study was registered with the University Hospital Medical Information Network clinical trials registry (registration number: UMIN000017426).

Influence of oral care on fractional exhaled nitric oxide

BACKGROUND: Fractional exhaled nitric oxide (FeNO) is an indicator of bronchial inflammation in asthma patients. However, nitric oxide is also produced in the oral cavity, with production depending on the local anaerobic flora and intraoral acidity. OBJECTIVE: To evaluate the influence of oral care on measurement of FeNO, to investigate the influence of sleep when the oral environment changes dramatically, and to assess the impact of oral care on FeNO in the real clinical setting. METHODS: FeNO was measured before and after oral care in 14 subjects on awakening and at bedtime on 2 consecutive days to investigate variation of nitric oxide derived from the oral cavity. It was also measured before and after oral care in 62 outpatients with asthma to assess the clinical relevance of oral cavity nitric oxide. RESULTS: On both days, FeNO was significantly decreased by oral care on awakening (day 1: decrease = 10.6 ± 12.4 ppb, p = 0.0020; day 2: decrease = 11.6 ± 23.7 ppb, p = 0.0009), and the decrease was larger than at bedtime. In addition, FeNO was significantly reduced by oral care in asthma outpatients (decrease = 1.73 ± 0.95 ppb, p = 0.0090), and older age was significantly correlated with the decrease (p = 0.0261). CONCLUSION: Oral care resulted in a decrease of FeNO, especially on awakening. While nitric oxide derived from the oral cavity generally has a limited impact in outpatients with asthma, its influence on measurement of FeNO may need to be considered, especially in elderly patients.

The effects of daily bathing on symptoms of patients with bronchial asthma

BACKGROUND: The influence of bathing in asthma patients is not yet fully known. OBJECTIVE: We conducted an observational study to investigate changes in symptoms and their degree by bathing in asthmatic patients. METHODS: A questionnaire focusing on ever experienced bathing-induced symptom changes and their degree, as well as contributing factors, was designed and administered to asthmatic patients in the outpatient department of our institute between January 2012 and November 2013. RESULTS: Two hundred fifteen cases were recruited. In 60 cases (27.9%), asthmatic symptoms appeared, including 20 cases of chest discomfort (33.3%), 19 cases of cough (31.7%), and 21 cases of wheezing (35.0%). The triggering factors included vapor inhalation (32 cases, 53.3%), hydrostatic pressure on the thorax due to body immersion in the bathtub (26 cases, 43.3%), and sudden change of air temperature (16 cases, 26.7%). Thirty-eight cases (17.7%) experienced improvement in active asthmatic symptoms by bathing. Vapor inhalation was the most common contributing factor (34 cases, 89.5%), followed by warming of the whole body (13 cases, 34.2%). There was no relationship between asthma severity and the appearance of bathing-induced symptoms or improvement of active asthmatic symptoms by bathing. CONCLUSION: The effects of bathing in asthmatic patients widely differed from patient to patient and their etiology includes several factors. For those who suffer from bathing-induced asthma symptoms, preventive methods, such as premedication with bronchodilators before bathing, should be established. This study is registered in the University Hospital Medical Information Network (UMIN) clinical trials registry in Japan with the registration number UMIN000015641.