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PubMed1993

Differences in the mode of cough augmentation by four angiotensin-converting enzyme inhibitors in guinea-pigs.

The effects of four angiotensin-converting enzyme (ACE) inhibitors, captopril, enalapril, quinapril and alacepril, on the cough responses caused by citric acid and capsaicin inhalation were studied in normal and bronchitic guinea-pigs. After an oral dose of 10 mg kg-1, none of the ACE inhibitors had an effect on the citric acid-induced coughing response in normal guinea-pigs. Enalapril 10 mg kg-1 significantly increased the number of coughs caused by capsaicin inhalation. In bronchitic guinea-pigs, 10 mg kg-1 captopril and enalapril significantly increased the number of capsaicin-induced coughs. When administered daily for 8 days, captopril was the only ACE inhibitor which significantly increased the number of coughs due to citric acid inhalation. The present results indicate that the ACE inhibitors had different modes of cough augmentation.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1994

Activity of bulbar respiratory neurons during fictive coughing and swallowing in the decerebrate cat.

1. The behaviour of medullary respiratory neurons was studied during fictive coughing and swallowing evoked by electrical stimulation of the superior laryngeal nerve (SLN) in decerebrate, paralysed and artificially ventilated cats. Fictive coughing, swallowing and respiration were monitored by recording activities of the phrenic, hypoglossal and abdominal nerves. 2. Extracellular recordings were made from respiratory neurons in the ventral respiratory group (VRG) and in the Bötzinger complex (BOT). The neuronal types analysed included decrementing inspiratory neurons (I-DEC), augmenting expiratory neurons (E-AUG) and decrementing expiratory neurons (E-DEC) from the BOT area, and augmenting inspiratory neurons (I-AUG) and augmenting expiratory neurons (E-AUG) from the VRG area. 3. During fictive coughing, all the inspiratory and expiratory neurons were active during the inspiratory and expiratory phases of coughing, respectively. The firing of both I-DEC and I-AUG neurons was increased and prolonged in association with the augmented inspiratory activity of the phrenic nerve. The activity of E-AUG neurons of the VRG did not parallel the abdominal nerve activity, suggesting the existence of additional neurons which participate in the generation of abdominal nerve activity during fictive coughing. 4. During fictive swallowing, half of I-DEC neurons fired transiently at the onset of hypoglossal bursts associated with swallowing; the firing was suppressed during the rest of the hypoglossal bursts. Other I-DEC neurons were silent during hypoglossal bursts. Some I-AUG neurons fired during the initial half of hypoglossal bursts, and others were silent. The brief phrenic activity accompanying the swallowing might have originated from this activity in I-AUG neurons. The discharges of all E-AUG neurons (BOT and VRG) and the majority of E-DEC BOT neurons were suppressed during swallowing. 5. We conclude that these five types of respiratory neurons of the BOT and VRG are involved in the generation of the spatiotemporally organized activity of coughing and swallowing, and that at least a part of the neuronal network for respiration is shared by networks for these non-respiratory activities.

Action Potentials↗
PubMed1999

Persistent nocturnal cough: randomised controlled trial of high dose inhaled corticosteroid.

OBJECTIVE: To investigate the effect of a short course of inhaled corticosteroid in the treatment of isolated and persistent nocturnal cough in children. DESIGN: Randomised double blind placebo controlled study. SETTING: Subjects' homes in east London, England. SUBJECTS: Consecutively referred children, 1-10 years old, with persistent nocturnal cough. INTERVENTIONS: Placebo or fluticasone propionate 1 mg twice daily for three nights and 500 microg twice daily for 11 nights. Videotaping of children at night: two nights' baseline, nights 3 and 4 after three days of inhaled corticosteroid, and nights 15 and 16. MAIN OUTCOME MEASURE: A fall in 75% of coughs from baseline. RESULTS: 50 subjects were recruited. The median number of coughs in the baseline period for the inhaled corticosteroid group and placebo group were 92 and 71, respectively (p = 0.43) and, on nights 15 and 16, 8 and 36, respectively (p < 0. 01). Compared to baseline, both groups of subjects improved significantly by nights 15 and 16 (p < 0.01; p < 0.01). Comparing the inhaled corticosteroid and placebo groups, coughs fell to a median of 22% and 57% of baseline totals on nights 3 and 4, respectively (p = 0.38), and 8% and 35% on nights 15 and 16, respectively (p = 0.02). 17 of 24 subjects on inhaled corticosteroid who completed the study and 8 of 23 on placebo improved by 75% after two weeks (p = 0.03). CONCLUSIONS: Children with persistent nocturnal cough improve in two weeks after referral on placebo. There is a modest benefit from a two week course of high dose inhaled corticosteroid.

Administration, Topical↗
PubMed1984

Children's coughs related to parental smoking.

A survey of the smoking habits, attitudes, and background of over 15 000 8-19 year olds in northern England in December 1982 showed a positive correlation between parental smoking and the reporting of frequent coughs by children who had never smoked. This was especially pronounced in the youngest children. Thirty five per cent of boys under 11 who had never smoked and whose parents did not smoke reported frequent coughs; with one parent smoking this increased to 42%, and when both parents smoked the proportion was 48%. Girls under 11 showed the same pattern, with 32%, 40%, and 52% respectively reporting frequent coughs. Fewer older children in general reported frequent coughs. Mothers' smoking had more influence on children's coughs than had fathers' smoking. Social area type had no significant effect. No significant effect of passive smoking was observed when the children themselves were smokers. These results are clear evidence of a definite link between smoking in the home and coughs in young children, which not only may present immediate problems but may also be a cause of illness in the future.

Adolescent↗
PubMed1995

Natural course of 500 consecutive cases of whooping cough: a general practice population study.

OBJECTIVE: To describe the natural course of whooping cough. DESIGN: Observational study of a general practice population. SETTING: Discrete semirural East Midlands practice of 11,500 patients. SUBJECTS: 500 consecutive cases of whooping cough diagnosed clinically during 1977-92. MAIN OUTCOME MEASURES: Incidence of vomiting, whooping, apnoea, admission to hospital, and complications; duration and frequency of paroxysms. Pattern of spread. RESULTS: The incidence in the practice population was 4347/100,000 population compared with a notification rate for England and Wales of 717/100,000. Most cases were relatively mild. 284 patients vomited after paroxysms, 242 whooped, and 57 had apnoea. Duration and frequency of paroxysms varied widely. Female and unimmunised patients suffered more severe disease. Bordetella was isolated from fewer immunised patients (24/96 v 63/122 unimmunised). Infection was usually spread through contacts with someone with clinical whooping cough. Five patients developed pneumonia, three of whom had been immunised. Three patients required hospital admission. CONCLUSIONS: Most cases of whooping cough are relatively mild. Such cases are difficult to diagnose without a high index of suspicion because doctors are unlikely to hear the characteristic cough, which may be the only symptom. Parents can be reassured that a serious outcome is unlikely. Adults also get whooping cough, especially from their children, and get the same symptoms as children. The difficulty of early diagnosis and probability of missed cases reinforces the need to keep the incidence low through immunisation in order to protect infants, who are the most vulnerable.

Adolescent↗
PubMed2005

Comparison of lidocaine and bronchodilator inhalation treatments for cough suppression in patients with chronic obstructive pulmonary disease.

BACKGROUND: This study aimed to assess and compare the effectiveness of lidocaine and bronchodilator inhalation treatments for rapid cough suppression in patients with chronic obstructive pulmonary disease (COPD). METHODS: Prospective comparison study carried out in a tertiary emergency department. Consecutive COPD patients presenting with intractable cough were randomly assigned to receive lidocaine or terbutaline inhalation treatments for cough suppression. Patients with dyspnoea, unstable vital signs, and pneumonia or neoplasm on chest x ray were excluded. A subjective, 10 point questionnaire based cough severity score was used for assessing the outcome. RESULTS: The final study sample included 127 patients (mean (SD) age, 69.2 (12.1) years; 33.1% women) of whom 62 received nebulised lidocaine and 65 nebulised bronchodilator. The cough severity score was significantly reduced one hour after inhalation treatment with both lidocaine and bronchodilator, with no significant difference in efficacy. Common but mild side effects in the lidocaine group included oropharyngeal numbness and bitter taste, and, in the bronchodilator group, tremor and palpitation. Dyspnoea, dizziness, and nausea and vomiting were equally uncommon in both groups. None of these problems caused any of the patients to discontinue their treatments and no allergic reactions were reported. CONCLUSIONS: Both lidocaine and bronchodilator inhalation treatments are equally effective for short term cough suppression in patients with COPD.

Administration, Inhalation↗
PubMed1996

Airway and cough responsiveness and exhaled nitric oxide in non-smoking patients with stable chronic heart failure.

OBJECTIVE: To investigate the airway and cough responsiveness in non-smoking patients with stable chronic heart failure. Cough and wheeze, features associated with hyper-responsive airways, are not uncommon especially in decompensated chronic heart failure. Bronchial hyperresponsiveness has previously been demonstrated in chronic heart failure but this may have been confounded by smoking and acute decompensation. DESIGN: Case-control study. SETTING: Tertiary specialist hospital. PATIENTS AND INTERVENTIONS: Airway responsiveness to methacholine (a direct stimulant of smooth muscle in the airways), sodium metabisulphite (a putative stimulant of airway sensory nerves), and exercise was examined in 10 non-smoking patients with stable chronic heart failure (age 56.5 (3.2) (SEM) years; 7 men; radionuclide left ventricular ejection fraction 20.8 (2.9)%; radiographic cardiothoracic ratio 0.56 (0.02)). Exhaled nitric oxide, a product of the action of proinflammatory cytokines, was also measured to assess the contribution of local inflammation to airway responsiveness. The cough responses to low-concentration chloride solutions and to capsaicin were studied. Because all patients were receiving angiotensin-converting enzyme inhibitors, which may influence airway responsiveness and cough, 8 asymptomatic non-smoking controls taking angiotensin-converting enzyme inhibitors for essential hypertension were also studied (age 54.3 (2.8) years; 6 men; radiographic cardiothoracic ratio 0.46 (0.01)). RESULTS: The mean provocative concentration that induced a 20% decrease in forced expiratory volume in 1 second (FEV1) was 67.6 v 79.8 mg/ml (P = 0.71) for methacholine and 276.7 v 290.4 mg/ml (P = 0.79) for sodium metabisulphite in chronic heart failure patients and controls respectively. The change in FEV1 after maximal cardiopulmonary exercise testing was +1.44% in patients and +2.53% in controls (P = 0.47), indicating that there was no exercise-induced bronchospasm in either group (peak oxygen consumption was 16.9 (1.3) v 26.5 (2.3) ml/kg/min respectively, P < 0.01). Exhaled nitric oxide concentration was not increased in chronic heart failure (12.3 (1.7) v 16.2 (3.3) ppb, P = 0.32). The median cough counts after nebulised 0 mM and 37.5 mM chloride solutions were 2.5 v 1.0 (P = 0.6) and 5.5 v 5.5 (P = 0.5) respectively and the capsaicin concentration causing two or more coughs was 13.5 v 6.5 microM (P = 0.5). CONCLUSION: Airway hyper-responsiveness is not a predominant feature in non-smoking patients with stable chronic heart failure treated with, and tolerant to, angiotensin-converting enzyme inhibitors. It is unlikely to contribute to the exertional dyspnoea seen in these patients.

Adult↗
PubMed2003

Abnormal oesophageal motility in patients with chronic cough.

BACKGROUND: Although gastro-oesophageal reflux is a recognised cause of chronic cough, the role of oesophageal dysmotility is unknown. The aim of this study was to determine the prevalence of abnormal oesophageal motility in a selected group of patients with chronic cough. METHODS: Oesophageal manometry and 24 hour pH monitoring were performed in 43 patients with chronic cough, 34 of whom had symptoms suggestive of gastro-oesophageal reflux. Comparative manometric measurements were made in 21 healthy subjects. RESULTS: Nine patients with chronic cough had normal manometry and 24 hour pH. Of the remaining 34 patients, 11 (32%) had abnormal manometry alone, five (15%) had abnormal 24 hour pH monitoring alone, and in 18 (53%) both tests were abnormal. Only one patient in the control group had manometric abnormalities. CONCLUSIONS: These results point to a previously unrecognised high prevalence of abnormal oesophageal manometry in patients presenting with chronic cough. Oesophageal dysmotility may therefore be important in the pathogenesis of cough in these patients.

Adult↗
PubMed2006

Efficacy of speech pathology management for chronic cough: a randomised placebo controlled trial of treatment efficacy.

BACKGROUND: Chronic cough that persists despite medical treatment may respond to speech pathology intervention, but the efficacy of such treatment has not been investigated in prospective randomised trials. The aim of this study was to determine the efficacy of a speech pathology intervention programme for chronic cough. METHODS: A single blind, randomised, placebo controlled trial was conducted in 87 patients with chronic cough that persisted despite medical treatment. Patients were randomly allocated to receive either a specifically designed speech pathology intervention or a placebo intervention. Participants in both groups attended four intervention sessions with a qualified speech pathologist. RESULTS: Participants in the treatment group had a significant reduction in cough (8.9 to 4.6, p<0.001), breathing (7.9 to 4.7, p<0.001), voice (7.3 to 4.6, p<0.001) upper airway (8.9 to 5.9, p<0.001) symptom scores and limitation (2.3 to 1.6, p<0.001) ratings following intervention. There was also a significant reduction in breathing (6.8 to 5.6, p = 0.047), cough (7.6 to 6.3, p = 0.014), and limitation (2.3 to 2.0, p = 0.038) scores in the placebo group, but the degree of improvement was significantly less than in the treatment group (p<0.01). Clinical judgement of outcome indicated successful ratings in 88% of participants in the treatment group compared with 14% in the placebo group (p<0.001). CONCLUSION: Speech pathology is an effective management intervention for chronic cough which may be a viable alternative for patients who do not respond to medical treatment.

Adult↗
PubMed1991

Citric acid cough threshold and airway responsiveness in asthmatic patients and smokers with chronic airflow obstruction.

The relation between citric acid cough threshold and airway hyperresponsiveness was investigated in 11 non-smoking patients with allergic asthma (mean FEV1 94% predicted) and 25 non-atopic smokers with chronic airflow obstruction (mean FEV1 65% predicted). Cough threshold was determined on two occasions by administering doubling concentrations of citric acid. Seven of the 11 asthmatic subjects and 14 of 25 smokers with chronic airflow obstruction had a positive cough threshold on both test days. Cough threshold measurements were reproducible in both groups (standard deviation of duplicate measurements 1.2 doubling concentrations in asthma, 1.1 doubling concentrations in chronic airflow obstruction). Citric acid provocation did not cause bronchial obstruction in most patients, though four patients had a fall in FEV1 of more than 20% for a short time on one occasion only. No significant difference in cough threshold was found between the two patient groups despite differences in baseline FEV1 values. There was no significant correlation between cough threshold and the provocative concentration of histamine causing a 20% fall in FEV1 (PC20) histamine in either group. Thus sensory nerves can be activated with a tussive agent in patients with asthma and chronic airflow obstruction without causing bronchial smooth muscle contraction.

Adult↗
PubMed1999

Increased neutrophils and cytokines, TNF-alpha and IL-8, in induced sputum of non-asthmatic patients with chronic dry cough.

BACKGROUND: The pathogenesis of non-asthmatic chronic dry cough remains unclear. METHODS: A study was undertaken to determine whether airway inflammation could be a contributing factor by analysing inflammatory cells and cytokines in induced sputum from 19 patients with chronic dry cough of varying aetiology, excluding asthma and bronchiectasis, and from 10 normal controls. The associated causes for the chronic cough were postnasal drip (n = 5), gastro-oesophageal reflux (n = 4), and idiopathic (n = 10). All patients had an enhanced cough reflex to capsaicin. RESULTS: Sputum neutrophilia (median (interquartile range)) was found in the patients with chronic cough (59.4 (27.1)%) compared with the normal controls (28.4 (22.0)%; p < 0.01, 95% CI 11.3 to 42.2). Sputum levels of interleukin-8 (IL-8) and tumour necrosis factor-alpha (TNF-alpha) were also significantly increased compared with normal controls (0.57 (1.08) and 0.25 (0.72) ng/ml; p < 0.05 (95% CI 0.05 to 1.75) for IL-8; 48.3 (34.4) and 12.6 (33.6) pg/ml, p < 0.01 (95% CI 8.8 to 69.8) for TNF-alpha). CONCLUSION: Neutrophils and cytokines associated with neutrophil chemotaxis and activation may contribute to the pathogenesis of non-asthmatic chronic dry cough.

Chemotaxis, Leukocyte↗
PubMed1987

Pulmonary arteriography: comparison of cough stimulation effects of diatrizoate and ioxaglate.

Twenty-five patients were observed in a prospective crossover study to determine whether the new low-osmolality contrast agents would be less prone than conventional agents to produce coughing during pulmonary arteriography. Selective left and right pulmonary arteriography (two views of each side) was performed with alternating administrations of diatrizoate sodium meglumine and ioxaglate sodium meglumine. Twenty-one patients had all four injections while four patients received injections on only one side. Sixteen of 25 patients coughed on at least one injection of diatrizoate, with three of these experiencing explosive coughing. One of 25 patients coughed with ioxaglate, and that was only minimally. This difference is statistically significant (P less than .001, on the basis of McNemar chi 2 test for paired data). When no coughing occurred, the quality of the diatrizoate and ioxaglate radiographs was indistinguishable. We conclude that ioxaglate is useful in pulmonary arteriography because of its lack of cough stimulation.

Adult↗
PubMed1992

Action of the diaphragm during cough in tetraplegic subjects.

Subjects with traumatic tetraplegia use the pectoralis major to compress the upper rib cage and increase intrathoracic pressure during cough. It is not known, however, whether they also contact the diaphragm during the expiratory phase of cough, as normal subjects do. We have investigated the action of the diaphragm during single voluntary coughing efforts in subjects with complete transection of the lower cervical (n = 5) or midthoracic (n = 2) cord. All subjects showed at least one peak of transdiaphragmatic pressure during the expiratory phase of the effort, and simultaneous bursts of electrical activity were recorded from the diaphragm. Coughing also resulted in an outward (paradoxical) motion of the abdomen during the compressive phase. We conclude that antagonistic contraction of the diaphragm is present during the expiratory phase of cough in spinal cord-injured subjects with paralysis of the abdominal muscles; this contraction, therefore, does not occur in response to activation of these muscles. The present results also indicate that the cough-induced paradoxical expansion of the abdomen is due to contraction of the pectoralis major and not of the diaphragm.

Adult↗
PubMed1998

Ventrolateral medullary respiratory network and a model of cough motor pattern generation.

The primary hypothesis of this study was that the cough motor pattern is produced, at least in part, by the medullary respiratory neuronal network in response to inputs from "cough" and pulmonary stretch receptor relay neurons in the nucleus tractus solitarii. Computer simulations of a distributed network model with proposed connections from the nucleus tractus solitarii to ventrolateral medullary respiratory neurons produced coughlike inspiratory and expiratory motor patterns. Predicted responses of various "types" of neurons (I-DRIVER, I-AUG, I-DEC, E-AUG, and E-DEC) derived from the simulations were tested in vivo. Parallel and sequential responses of functionally characterized respiratory-modulated neurons were monitored during fictive cough in decerebrate, paralyzed, ventilated cats. Coughlike patterns in phrenic and lumbar nerves were elicited by mechanical stimulation of the intrathoracic trachea. Altered discharge patterns were measured in most types of respiratory neurons during fictive cough. The results supported many of the specific predictions of our cough generation model and suggested several revisions. The two main conclusions were as follows: 1) The Bötzinger/rostral ventral respiratory group neurons implicated in the generation of the eupneic pattern of breathing also participate in the configuration of the cough motor pattern. 2) This altered activity of Bötzinger/rostral ventral respiratory group neurons is transmitted to phrenic, intercostal, and abdominal motoneurons via the same bulbospinal neurons that provide descending drive during eupnea.

Animals↗
PubMed2000

Responses of the anterolateral abdominal muscles during cough and expiratory threshold loading in the cat.

The present study was conducted to determine the pattern of activation of the anterolateral abdominal muscles during the cough reflex. Electromyograms (EMGs) of the rectus abdominis, external oblique, internal oblique, transversus abdominis, and parasternal muscles were recorded along with gastric pressure in anesthetized cats. Cough was produced by mechanical stimulation of the lumen of the intrathoracic trachea or larynx. The pattern of EMG activation of these muscles during cough was compared with that during graded expiratory threshold loading (ETL; 1-30 cmH(2)O). ETL elicited differential recruitment of abdominal muscle EMG activity (transversus abdominis > internal oblique > rectus abdominis congruent with external oblique). In contrast, both laryngeal and tracheobronchial cough resulted in simultaneous activation of all four anterolateral abdominal muscles with peak EMG amplitudes 3- to 10-fold greater than those observed during the largest ETL. Gastric pressures during laryngeal and tracheobronchial cough were at least eightfold greater than those produced by the largest ETL. These results suggest that, unlike their behavior during expiratory loading, the anterolateral abdominal muscles act as a unit during cough.

Abdominal Muscles↗
PubMed2002

Involvement of thromboxane A(2) in airway mucous cells in asthma-related cough.

The aim of this study was to elucidate the role of thromboxane A(2) (TxA(2)) on asthma-related cough in guinea pigs. Animals were immunosensitized and repeatedly challenged with ovalbumin as an antigen. Coughs were induced by the inhalation of 10(-5) M capsaicin solution for 10 min. Thromboxane synthetase (TxS) inhibitor OKY-046 and thromboxane-receptor antagonist AA-2414 significantly inhibited cough responses in repeatedly challenged animals. Inhalation of TxA(2) mimic STA-2- potentiated cough responses in normal and immunosensitized animals but not in repeatedly challenged ones. Moreover, STA-2-potentiated coughs were inhibited by administration of neurokinin-receptor antagonist FK-224. In repeatedly challenged animals, concentration of TxB(2) in airway lavage fluid, expression of TxS mRNA in tracheal epithelia, and the immunostaining intensity against TxS in mucous cells of the epithelium significantly increased compared with normal and sensitized animals. These results suggest that TxA(2) derived from mucous cells potentiated cough responses to capsaicin in allergic airway inflammation.

Animals↗
PubMed2006

Na+-K+-2Cl- cotransporters and Cl- channels regulate citric acid cough in guinea pigs.

Loop diuretics have been shown to inhibit cough and other airway defensive reflexes via poorly defined mechanisms. We test the hypothesis that the furosemide-sensitive Na+-K+-2Cl- cotransporter (NKCC1) is expressed by sensory nerve fibers innervating the airways where it plays an important role in regulating sensory neural activity. NKCC1 immunoreactivity was present on the cell membranes of most nodose and jugular ganglia neurons projecting to the trachea, and it was present on the peripheral terminals of putative mechanosensory nerve fibers in the airways. In urethane-anesthetized, spontaneously breathing guinea pigs, bolus application of citric acid (1 mM to 2 M) to an isolated and perfused segment of the tracheal mucosa evoked coughing and respiratory slowing. Removal of Cl- from the tracheal perfusate evoked spontaneous coughing and significantly potentiated cough and respiratory slowing reflexes evoked by citric acid. The NKCC1 inhibitor furosemide (10-100 microM) significantly reduced both the number of coughs evoked by citric acid and the degree of acid-evoked respiratory slowing (P < 0.05). Localized tracheal pretreatment with the Cl- channel inhibitors DIDS or niflumic acid (100 microM) also significantly reduced cough, whereas the GABAA receptor agonist muscimol potentiated acid-evoked responses. These data suggest that vagal sensory neurons may accumulate Cl- due to the expression of the furosemide-sensitive Cl- transporter, NKCC1. Efflux of intracellular Cl-, in part through calcium-activated Cl- channels, may play an important role in regulating airway afferent neuron activity.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMedDate not supplied

Sputum cell counts and exhaled nitric oxide in patients with gastroesophageal reflux, and cough or asthma.

BACKGROUND: Gastroesophageal reflux (GER) is commonly associated with chronic cough and asthma, but there is little or no information on the nature of any associated airway inflammation. OBJECTIVE: To observe whether the association with GER worsens airway inflammation in patients with chronic cough or asthma. PATIENTS AND METHODS: The airway inflammatory indexes in induced sputum and exhaled air were examined in a cross-sectional study of 11 patients with cough and GER, nine patients with mildly symptomatic asthma and GER, nine patients with mildly symptomatic asthma without GER and nine normal, healthy control subjects. GER was shown objectively by 24 h ambulatory pH recording. RESULTS: The sputum total cell count, the proportion of neutrophils and macrophages, and the fibrinogen level were normal in all four groups, with no significant differences among the groups. The sputum eosinophil and metachromatic cell percentages, and eosinophil cationic protein levels were normal in patients with cough and GER. They were significantly increased in patients with asthma compared with healthy subjects (P<0.01) and patients with cough (P<0.01), but were not different between groups with and without GER. Exhaled nitric oxide levels showed similar results (P<0.01). The correlations between the number of episodes of reflux and the proportion of sputum eosinophils, neutrophils or exhaled nitric oxide were modest but not significant. CONCLUSIONS: GER, when associated with cough or mildly symptomatic asthma, does not cause or aggravate existing airway inflammation as measured by induced sputum cell counts and fibrinogen level, or by exhaled nitric oxide.

Adult↗