Rebuttal: Cough Is an Expiratory Sound

Untreated obstructive sleep apnea (OSA) increases healthcare utilization and is associated with reduced work performance and occupational injuries. The economic burden related to untreated OSA is substantial, accounting for billions of dollars per year. Furthermore, therapy of OSA is an extremely cost-efficient use of healthcare resources, comparing highly favorably with other commonly funded medical therapies. Governments, transportation agencies, industry, and insurance companies need to be better informed concerning the economic impact of untreated OSA and the benefits of therapy.     

Rebuttal of the Con View: Albuminuria Is an Appropriate Therapeutic Target in Patients with CKD

Our opponents in this debate state that there are insufficient data to consider albuminuria as a valid target for therapy in patients with CKD. They base their opinion predominantly on two arguments: first, a decrease in albuminuria is not always associated with renoprotection, and second, no prospective randomized controlled trial has been conducted that really targeted albuminuria.     

Rebuttal: cough is an expiratory sound

What is a cough was debated at much length in the European Respiratory Society's Task Force on Cough Methodology. A definition favored by physiologists is "an inspiration followed by a characteristic expiration." Clinicians involved in cough counting favor "an expiration with a characteristic sound." Both are entirely arbitrary. We undertook a survey of clinicians and scientists working in the field and asked them to count examples of different coughs. The clinical definition was adopted by the majority and we suggest that it should be the gold standard.     

Diurnal Variation of Peak Expiratory Flow in Children with Cough Variant Asthma

Cough variant asthma (CVA) is thought to be a variant form of asthma in which cough is the sole clinical manifestation of airways hyperresponsiveness, a characteristic feature of asthma. Another characteristic feature of asthma includes an increased diurnal variation of peak expiratory flow (PEF) compared to normal subjects. To examine whether diurnal variation of PEF might also increase in children with CVA, we have examined the degree of diurnal variation of PEF in these children (n = 7) by measuring peak flow serially for a week, and compared it with those in mild to moderate asthma (n = 17) and in control children without cough (n = 8). In control children without cough, the average value of the mean diurnal variation of PEF was 10.4 ± 0.8%. In both groups of children with asthma and with CVA, there was a significant increase in the value (20.5 ± 1.3% and 23.6 ± 3.6%, respectively) compared to that in control children (p < 0.01 in both groups), although there was no significant difference between these 2 groups. These results show that mild, but significant airway obstruction is occurring in children with CVA, although clinical wheezing is not recognized. Serial measurements of diurnal variation of PEF may be helpful for the diagnosis of CVA in children.     

Cough Hypersensitivity Syndrome Is an Important Clinical Concept: A Pro/Con Debate

The major etiologies of chronic cough are generally accepted to consist of upper airway cough syndrome (formerly postnasal drip syndrome), eosinophilic airway inflammation (asthma, nonasthmatic eosinophilic bronchitis), and gastroesophageal reflux disease (GERD). However, only a small percentage of patients with these very common conditions suffers from chronic cough. Furthermore, acute cough due to viral upper respiratory tract infection (URI) is almost always a transient, self-limited condition, yet in a small subgroup of patients, URI heralds the onset of chronic, refractory cough. The cough hypersensitivity syndrome has been proposed to explain the occurrence of chronic cough in a subgroup of patients exposed to the same putative triggers as the vast majority of the population in whom chronic cough does not result. Although conceptually the cough hypersensitivity syndrome may be intellectually satisfying, differences of opinion remain as to whether this newly recognized entity is of clinical significance, i.e., useful for the treatment of patients suffering from chronic cough. The Third American Cough Conference, held in New York in June 2011, provided an ideal forum for the debate of this issue between two internationally recognized authorities in the field of cough.     

Peak Expiratory Flow Monitoring in Pediatric Asthma: Is There a Role?

In summary, it is difficult to define the proper role for PEF monitoring in the management of pediatric asthma. One can certainly state that not every child with asthma requires a PEF meter and that PEF-based asthma management plans are not suitable for widespread use in asthmatic children. Furthermore, measurements of PEF or PEFV are not suitable for diagnosing asthma, particularly mild asthma in children. However, it is more difficult to be certain when PEF monitoring should be used in children with asthma. Given the concerns expressed above, the approach adopted by the Australian Paediatric Respiratory Group, that is, “home monitoring PEF will be considered [in children J more than 6-8 years old who have persistent symptoms” and that “PEF monitoring be undertaken on a short term (weeks to months) rather than on a long term (years) basis,” appears reasonable, although this position is not based on any scientific evidence.     

Cough in tetraplegic subjects: an active process

STUDY OBJECTIVE: To determine the role of the clavicular portion of the pectoralis major during cough in tetraplegic subjects. PATIENTS: Eight patients with longstanding traumatic transection of the lower cervical cord. METHODS: The electromyographic activity of the pectoralis major and abdominal external oblique muscles and the changes in the anteroposterior diameter of the lower rib cage, the upper rib cage, and the abdomen were measured during voluntary coughing efforts in the seated posture. RESULTS: When coughing, all subjects showed a large amount of electrical activity in the pectoralis major with no activity in the external oblique. Simultaneously, they had a clear-cut decrease in the anteroposterior diameter of the upper rib cage together with an increase in the anteroposterior diameter of the abdomen. In five subjects, the anteroposterior diameter of the lower rib cage also showed an initial increase. These changes were seen when cough was initiated at functional residual capacity or at a higher lung volume; they were also seen during a fit of coughing. CONCLUSIONS: In tetraplegic subjects the clavicular portion of the pectoralis major plays a major role during coughing. Its contraction causes a reduction in the size of the upper part of the rib cage and a rise in intrathoracic pressure; this pressure rise results secondarily in an outward (paradoxical) motion of the abdomen and the lower rib cage. Cough in tetraplegic subjects is thus an active, rather than a passive, process, and its effectiveness might be improved by a combination of specific muscle training and abdominal binding.     

Continuous Cough Monitoring Using Ambient Sound Recording During Convalescence from a COPD Exacerbation

Purpose

Cough is common in chronic obstructive pulmonary disease (COPD) and is associated with frequent exacerbations and increased mortality. Cough increases during acute exacerbations (AE-COPD), representing a possible metric of clinical deterioration. Conventional cough monitors accurately report cough counts over short time periods. We describe a novel monitoring system which we used to record cough continuously for up to 45 days during AE-COPD convalescence.

Methods

This is a longitudinal, observational study of cough monitoring in AE-COPD patients discharged from a single teaching hospital. Ambient sound was recorded from two sites in the domestic environment and analysed using novel cough classifier software. For comparison, the validated hybrid HACC/LCM cough monitoring system was used on days 1, 5, 20 and 45. Patients were asked to record symptoms daily using diaries.

Results

Cough monitoring data were available for 16 subjects with a total of 568 monitored days. Daily cough count fell significantly from mean?±?SEM 272.7?±?54.5 on day 1 to 110.9?±?26.3 on day 9 (p?<?0.01) before plateauing. The absolute cough count detected by the continuous monitoring system was significantly lower than detected by the hybrid HACC/LCM system but normalised counts strongly correlated (r?=?0.88, p?<?0.01) demonstrating an ability to detect trends. Objective cough count and subjective cough scores modestly correlated (r?=?0.46).

Conclusions

Cough frequency declines significantly following AE-COPD and the reducing trend can be detected using continuous ambient sound recording and novel cough classifier software. Objective measurement of cough frequency has the potential to enhance our ability to monitor the clinical state in patients with COPD.

     

Evaluation of Factors Affecting Peak Expiratory Flow in Healthy Adults: Is It Necessary to Stand Up?

Background. Guidelines for the Diagnoses and Management of Asthma recommend that the peak flow meter should be used in a standing position. Objective. To determine whether the peak expiratory flow (PEF) varies with the position of the subject and to evaluate the impact of application of nose clip on PEF measurement. Methods. Using a Mini Wright Peak Flow Meter, the PEF was measured in 33 healthy adults in sitting and standing positions, with and without application of a nose clip. Each subject blew into the peak flow meter three times and best of the 3 blows was recorded. Results. The PEF was not significantly higher in standing than in sitting position. Application of nose clip had no significant impact on the PEF. Conclusion. The position of the subject and application of nose clip has no significant impact on PEF measurement.     

Cough in Asthma Is due to Eosinophilic Airway Inflammation: A Pro/Con Debate

Multiple prospective studies have demonstrated that asthma is among the most common etiologies of chronic cough, along with upper-airway cough syndrome (formerly known as postnasal drip syndrome) and gastroesophageal reflux disease. More recently, the entity of nonasthmatic eosinophilic bronchitis has been appreciated as a significant cause of chronic cough worldwide. Chronic cough associated with both of these conditions typically responds well to therapy with systemic or inhaled corticosteroids, thus leading to a general assumption that the suppression of eosinophilic airway inflammation explains the improvement in cough. However, some recent studies challenge a causal relationship between eosinophilic airway inflammation and cough in asthmatics. The 4th American Cough Conference, held in New York in June 2013, provided an ideal forum for discussion and debate of this issue between two internationally recognized experts in the field of asthma and chronic cough.     

Is the Leicester Cough Questionnaire useful for nontuberculous mycobacterial lung disease?

BackgroundAlthough the incidence of nontuberculous mycobacterial lung disease (NTM-LD) is increasing worldwide, there is no established standard of care leading to eradication. Therefore, research on health-related quality of life (HRQOL) is important for patients with NTM-LD. HRQOL is commonly evaluated using the St. George's Respiratory Questionnaire (SGRQ), developed for chronic obstructive pulmonary disease (COPD). However, NTM-LD differs from COPD in that few patients complain of dyspnea or wheezing, and cough and sputum are their main symptoms. The Leicester Cough Questionnaire (LCQ) is an HRQOL questionnaire dedicated to cough, but few studies have used it for NTM-LD. This study evaluated HRQOL in patients with NTM-LD using the SGRQ and LCQ and clarified the usefulness of the LCQ.MethodsInformation on age, height, weight, lung function, percent ideal body weight, laboratory data, radiological scores, exercise capacity, SGRQ, and LCQ were collected from the medical records of 81 patients. Correlations between SGRQ and LCQ domains were assessed using Spearman's rank correlation coefficients. Multivariate analysis was performed with SGRQ and LCQ total scores.ResultsStatistically significant correlations were observed between all domains, and the correlation between the total scores was ?0.67 (p < 0.01). Multivariate analysis with total scores as the dependent variable showed that the explanatory variables were lung function (p < 0.05) and radiological score (p < 0.05) in the SGRQ, and radiological score (p < 0.05) and C-reactive protein level (p < 0.05) in the LCQ.ConclusionThe LCQ, which evaluates an inflammatory response involved in the diagnosis of NTM-LD, may be useful to assess HRQOL in patients with NTM-LD.