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Individuals with acquired brain injuries (ABIs) may experience various complications related to poor coughing or impaired cough reflex (including risk of aspiration pneumonia or respiratory infections). For this reason, cough assessment is an important component in the clinical evaluation since patients with ABI are not able to cough voluntarily due to severe motor deficits. When voluntarily coughing is not possible, it is essential for clinical practices to find a quick and minimally invasive way to induce a cough reflex. In the present study, we evaluated the cough reflex in ABI patients using a new method based on a capsaicin spray stimulation test. In total, 150 healthy controls demographically matched with 50 ABI patients were included in this study. Clinical observations demonstrated robust cough response in both healthy controls and ABI patients, as well as the safety and tolerability of capsaicin spray stimulation. ABI patients with dysphagia were characterized by slower and delayed cough responses. Further studies are needed to validate this feasible, less-invasive, and simple-to-comprehend technique in inducing cough reflex. According to this preliminary evidence, we believe that this test might be translated into a simple and effective treatment to improve reflexive cough modulation in ABI patients.

The family of calcium-activated chloride channels, TMEM16, plays a significant role in contributing to the pathogenesis of airway inflammatory diseases. Targeting these ion channels and aiming to modulate them may provide an interesting new approach to the therapy of these potentially fatal diseases.

Individuals with acquired brain injuries (ABIs) may experience various complications related to poor coughing or impaired cough reflex (including risk of aspiration pneumonia or respiratory infections). For this reason, cough assessment is an important component in the clinical evaluation since patients with ABI are not able to cough voluntarily due to severe motor deficits. When voluntarily coughing is not possible, it is essential for clinical practices to find a quick and minimally invasive way to induce a cough reflex. In the present study, we evaluated the cough reflex in ABI patients using a new method based on a capsaicin spray stimulation test. In total, 150 healthy controls demographically matched with 50 ABI patients were included in this study. Clinical observations demonstrated robust cough response in both healthy controls and ABI patients, as well as the safety and tolerability of capsaicin spray stimulation. ABI patients with dysphagia were characterized by slower and delayed cough responses. Further studies are needed to validate this feasible, less-invasive, and simple-to-comprehend technique in inducing cough reflex. According to this preliminary evidence, we believe that this test might be translated into a simple and effective treatment to improve reflexive cough modulation in ABI patients. [ABSTRACT FROM AUTHOR]

Abstract Background The incidence of cough reflex during extubation is 76%. Cough reflex causes severe hemodynamic fluctuations and airway complications. This prospective trial investigated the potential effects of tracheal tube cuff deflation on cough reflex during extubation. Methods One hundred and twenty-six patients scheduled for operations within 3 h under general anaesthesia with orotracheal intubation were randomly assigned to one of three groups: control (C), experimental (E) or syringe (S) groups. Patients in group C underwent tracheal tube cuff deflation using a 10-ml syringe in 1 s, patients in group E underwent tracheal tube cuff deflation continuously and slowly in 5 s using a cuff pressure gauge until the pressure was zero and patients in group S underwent tracheal tube cuff deflation using a 10-ml syringe at a speed of 1 ml s−1. The incidence and severity of cough reflexs during extubation and the incidence of postoperative airway complications within 48 h were assessed. Results Compared with group C (60.0%), the incidence of cough reflex in group E was 9.8% (p

A prospective observational study was done with the aim to analyze the difficulties during decannulation of tracheostomized head injury patients and to devise a sound protocol for decannulation. It was done over 2 years in a tertiary care Army Hospital with 40 tracheostomized head injury cases in the age group of 10-70 years. Once the indication of tracheostomy was over, their Glasgow Coma Scale score, airway adequacy, phonation, swallowing, cough reflex, and lung pathology were assessed. Fit patients were decannulated if they tolerated tube capping for 3 days. Data was statistically analyzed. Road traffic accident was the cause of head injury in 90% cases. 45% patients had traumatic brain injury. All the cases required ventilatory support. 80% patients required neurosurgery. Tracheostomy was done between 5th to 10th day. Decannulation could be achieved in 75% patients. Factors like neurological status, duration of ventilatory need, number of days on T piece, cough reflex, suction requirement, phonation, consistency of tracheal secretion, lung condition, and three days? capping of tracheostomy tube were significantly associated with outcome of decannulation trial (p <0.05). Factors like mode of injury, neurosurgical intervention, absence of phonation, and downsizing of tube did not affect the outcome significantly (p >0.05). The factors like strong cough reflex, thin minimal tracheal secretion, aspiration free swallowing, better GCS score, early weaning from ventilator and younger age favour early successful decannulation. Gradual downsizing of tube or presence of phonation are not essential prerequisites for decannulation. [ABSTRACT FROM AUTHOR]

Purpose: Enhanced responsiveness to external triggers is thought to reflect hypersensitivity of the cough reflex. It may involve an enhanced sensitivity of the afferent nerves in the airways and/or an abnormal processing of the afferent information by the central nervous system (CNS). The CNS processing of cough has been shown to involve the same regions as those in symptom amplification, a phenomenon that often manifests as multiple symptoms. The main purpose of the present study was to define whether the presence of several cough triggers is associated with multiple symptoms. Methods: 2131 subjects with current cough responding to two email surveys filled in a comprehensive questionnaire about social background, lifestyle, general health, doctors' diagnoses and visits, symptoms, and medication. Multiple symptoms was defined as three or more non-respiratory, non-mental symptoms. Results: A carefully controlled multiple regression analysis revealed that the number of cough triggers was the only cough characteristic associating with multiple non-respiratory, non-mental symptoms [aOR 1.15 (1.12–1.19) per one trigger, p < 0.001]. Among the 268 subjects with current cough both in the first survey and in the follow-up survey 12 months later, the repeatability of the trigger sum was good with an intraclass correlation coefficient of 0.80 (0.75–0.84). Conclusion: The association between the number of the cough triggers and multiple symptoms suggests that the CNS component of cough hypersensitivity may be a manifestation of non-specific alteration in the CNS interpretation of various body sensations. The number of cough triggers is a repeatable measure of cough sensitivity. [ABSTRACT FROM AUTHOR]

It has been shown that muscarinic acetylcholine receptors (mAChRs) located within the caudal nucleus tractus solitarii (cNTS) mediate a cholinergic inhibitory control mechanism of the cough reflex. Thus, identification of the involved mAChR subtypes could be of considerable interest for novel therapeutic strategies. In pentobarbital sodium-anesthetized, spontaneously breathing rabbits we investigated the contribution of different mAChR subtypes in the modulation of mechanically and chemically induced cough reflex. Bilateral microinjections of 1 mM muscarine into the cNTS increased respiratory frequency and decreased expiratory activity even to complete suppression. Interestingly, muscarine induced strong cough-suppressant effects up to the complete abolition of the reflex. Microinjections of specific mAChR subtype antagonists (M1-M5) into the cNTS were performed. Only microinjections of the M4 antagonist tropicamide (1 mM) prevented muscarine-induced changes in both respiratory activity and cough reflex. The results are discussed in light of the notion that cough involves the activation of the nociceptive system. They also suggest that M4 receptor agonists may have an important role in cough downregulation within the cNTS. [ABSTRACT FROM AUTHOR]

Background: The incidence of cough reflex during extubation is 76%. Cough reflex causes severe hemodynamic fluctuations and airway complications. This prospective trial investigated the potential effects of tracheal tube cuff deflation on cough reflex during extubation. Methods: One hundred and twenty-six patients scheduled for operations within 3 h under general anaesthesia with orotracheal intubation were randomly assigned to one of three groups: control (C), experimental (E) or syringe (S) groups. Patients in group C underwent tracheal tube cuff deflation using a 10-ml syringe in 1 s, patients in group E underwent tracheal tube cuff deflation continuously and slowly in 5 s using a cuff pressure gauge until the pressure was zero and patients in group S underwent tracheal tube cuff deflation using a 10-ml syringe at a speed of 1 ml s−1. The incidence and severity of cough reflexs during extubation and the incidence of postoperative airway complications within 48 h were assessed. Results: Compared with group C (60.0%), the incidence of cough reflex in group E was 9.8% (p < 0.001) and in group S was 12.5% (p < 0.001). The severity of cough reflex was graded as 2 (1–2) in group C, 1 (1–1) in group E and 1 (1–1) in group S (p < 0.001 for group comparisons). The incidence of hoarseness in group C was 0.0%, in group E was 19.5% and in group S was 5.0% (p < 0.05 for all groups, p = 0.009 between group C and E). Conclusions: Compared with deflating a trachal tube cuff with a 10-ml syringe in 1 s, the use of a 10-ml syringe at a speed of 1 ml s−1 or a cuff pressure guage within 5 s can both reduce the incidence of cough reflex, but deflating with a cuff pressure guage can increase the incidence of postoperative hoarseness. Trial registration: Chinese Clinical Trial Registry, identifier: ChiCTR2100054089, Date: 08/12/2021. [ABSTRACT FROM AUTHOR]

Background: Ear surgeries performed under general anaesthesia mandate smooth emergence after surgery to facilitate a good surgical outcome. We conducted this study with primary objective of comparing dexmedetomidine and magnesium sulfate (MgSO4) in attenuating extubation response after mastoid surgeries. The secondary outcome was to study the adverse effects if any. Methods: Sixty patients of ASA grade I and II, aged 18 -50 yrs were randomized into 2 groups of 30 each receiving either dexmedetomidine 0.5μg/kg or MgSO4 30 mg/kg respectively 10 minutes prior to completion of surgery. Efficacy of both drugs in attenuating cough reflex, PONV, shivering and fluctuations in haemodynamic response were recorded. Postoperative sedation was noted. Any laryngospasm, bronchospasm, hypotension, bradycardia, desaturation was also noted. Statistical analysis: The observations were recorded and analysed using statistics calculator SPSS 19.00 version. Student’s t test and χ2 (chi square) test were used to analyze quantitative and qualitative data respectively. P-value

Cough is one of the most common symptoms and is present in diseases of the respiratory, cardiovascular, digestive, endocrine and other systems. Cough is a reflex act, therefore it is caused by stimulation of cough receptors due to pathological influences. The diagnosis takes into account the nature of the cough, its duration, the results of laboratory and instrumental examination methods. The most attention is required to diagnose chronic cough and exclude life-threatening causes. Symptoms of anxiety are hemoptysis, prolonged resistant cough, prolonged intoxication syndrome, weight loss, etc. In diagnostically unclear cases, the examination schedule must include computed tomography of the chest, magnetic resonance imaging and bronchoscopy. A dry, painful intense cough can lead to the development of complications: a decrease in the quality of life, hemorrhages, pneumothorax, etc., therefore, requires symptomatic treatment. A common cause of unproductive cough is viral diseases, whooping cough, diseases leading to overactive cough receptors. The variety of coughs determines a differentiated approach to its therapy. The main efforts should be directed to the treatment of the underlying disease. In the case of a productive cough, mucoactive drugs are used. To stop unproductive cough, antitussive drugs of central and peripheral action are used. The recommendations of the European Respiratory Society present the results of clinical trials assessing the efficacy and safety of antitussive drugs with morphine-like action. The study identified side effects that limit their use. One of the most effective and safe drugs is a non-opioid drug with a central action Sinekod. The effectiveness and safety of the drug is confirmed by clinical studies.

Cough is the most frequent symptom for which patients consult with their health care provider throughout the world. This symptom could be happened not only in sick individuals but also healthy individuals. At some stage, it is distressing, inhibits normal social activities, and reduces quality of life. Besides these detrimental effects, cough is the most effective defense mechanism to eliminate foreign materials, including various pathogens, from the respiratory tract. It begins with a series of breathing maneuvers which triggers sudden expulsion of air which is divided into three phases, i.e. inspiration, compression, and expiration phase. Cough occurs due to activation of mechanical or chemical sensory receptors in the larynx and lower respiratory tract which stimulates reflex arc complex. This stimulus is then transmitted to the afferent pathway to the cough center in the medulla through the vagus nerve to trigger expiration muscles to produce cough. It is important to know the cause of cough because cough is an indicator for patients and doctors for early diagnosis and therapy of disease. Therefore, cough is classified into acute, subacute, and chronic according to its duration. Available medications for symptomatic management of cough are inadequate due to lack of proven efficacy and/or their undesirable or intolerable side effects. This article aims to provide information on cough management to improve therapeutic effectiveness and patient quality of life.

Abstract Background The most common respiratory complications in cerebrovascular strokes were respiratory infection, pulmonary edema, acute lung injury (ALI) acute respiratory distress syndrome (ARDS) and pulmonary embolism (PE). The inhalation cough challenge facilitates the quantification of cough. Objectives To detect the level of cough reflex that is enough to protect against respiratory infection in stroke patients, and to identify predictors of post-stroke respiratory infection. Patients and methods One hundred and one of cerebrovascular stroke patients were assessed in the first week of symptoms by National Institutes of Health Stroke Scale (NIHSS) Arabic version, Mann Assessment of Swallowing Ability (MASA), cough challenge test, cough flow meter, and A2DS2 score. Then, follow up after 1 week. Results Post-stroke respiratory infection was higher in older patients and those who were not working. Respiratory infection was significantly associated with high A2DS2 and NIHSS score (p value < 0.001). A highly significant increase in the levels of the inflammatory markers was detected in patients with a respiratory infection. Eighty percent of stroke patients with no cough developed a respiratory infection. The Mann total scores and the peak cough flow were lower in patients who had a respiratory infection. Conclusion Preserved cough reflex is essential in preventing aspirations and consequent respiratory infections.

Coughing is an essential airway protective reflex. In healthy young adults, cough somatosensation changes when attention is divided (dual tasking). Whether the same is true in populations at risk of aspiration remains unknown. We present findings from a controlled study testing the effects of divided attention (via a dual-task paradigm) on measures of reflex cough in Parkinson's disease. Volunteers with Parkinson's disease (n = 14, age = 43–79 years) and 14 age-matched controls underwent five blocks of capsaicin-induced cough challenges. Within each block, capsaicin ranging from 0 to 200 μM was presented in a randomized order. Two blocks consisted of cough testing only (single task), and two blocks consisted of cough testing with simultaneous tone counting (dual task). Finally, participants completed a suppressed cough task. Measures of cough motor response, self-reported urge to cough, cough frequency, and cough airflow were collected. Historical data from healthy young adults was included for comparison. Between-group analyses revealed no differences between single- and dual-cough-task responses. However, post hoc analysis revealed a significant relationship between dual-task errors and cough frequency that was strongest in people with Parkinson's disease [p = 0.004, r2 = 0.52]. Specifically, greater errors were associated with fewer reflexive coughs. Unlike healthy participants, participants with Parkinson's disease did not change the number of coughs between the single-, dual-, and suppressed-task conditions [p > 0.05]. When distracted, people with Parkinson's disease may prioritize coughing differently than healthy controls. Abnormal cortical resource allocation may be a mechanism involved in aspiration in this population. [ABSTRACT FROM AUTHOR]

Background/Aim: Tic habit cough (THC) is not easily recognized and requires a high index of suspicion. Since there is evidence for stress-related etiology, the study presents our experience during the eight-year period of the recent Greek financial crisis. Patients and Methods: This is a descriptive prospective cross-sectional clinical study using a consistent approach to diagnosis, possible triggers and treatment options. Results: Fifty-one children (26 girls, age 9.5±3.1y) from a total of 3,793 new referrals for chronic cough fulfilled the criteria of THC (1.34%). Incidence rates per 1,000 person-years were 1.34 (95%CI=0.34-5.40), 3.91 (95%CI=1 .86-8.19), 4.03 (95%CI=2.01-8.06) and 14.60 (95%CI=10 43-20 44) for every two years Poisson analysis showed an increased trend during the four time periods with an incidence rate ratio equal to 2.21 (95%CI=1.58-3.09, p<0.001). THC was mainly attributed to learning difficulties, as well as stress-related impact of peer or family bullying, family financial problems and child anxiety disorders. Conclusion: The incidence of THC is associated with the negative aspects of stressors during a period of financial crisis. The potential underlining psycho-physiological mechanisms are discussed as well as the fact that prompt diagnosis may result in successful interventions. [ABSTRACT FROM AUTHOR]

Background: Anorectal manometry is the most commonly performed test of anorectal function. The cough‐anorectal response is frequently assessed as part of a routine manometric investigation but has not previously been the subject of detailed analysis. This study systematically examined anorectal pressure responses to cough in health and evaluated the impact of parity and symptoms of fecal incontinence (FI) on measurements. Methods: High‐resolution anorectal manometry (HR‐ARM) traces from nulliparous (n = 25) and parous (n = 25) healthy volunteers (HV: aged 41, range 18‐64), and 57 parous patients with FI (age 47, range 28‐72) were retrospectively reviewed. Cough‐anorectal pressure responses were analyzed between groups by qualitative and quantitative approaches. Key results: In health, traditional anal pressure measurements ("rest" and "squeeze") were similar between nulliparous and parous women. In contrast, incremental anal‐rectal pressure difference during cough significantly differed: nulliparous 42 mm Hg (95% CI: 21‐64) vs. parous 6 mm Hg (−14‐25), P < 0.036). This measure also differed significantly between nulliparous HVs and patients with FI (−2 mm Hg (95% CI: −15‐12), P < 0.001), but not between parous HVs and FI. Qualitatively, a color‐contour trace resembling a "spear" in the upper anal canal was observed uniquely in FI. Of 25 patients with normal anal function by traditional measures, cough parameters were abnormal in 52%. Conclusions and inferences: Novel HR‐ARM measures during coughing revealed differences in anal function between nulliparous and parous HV, and patients with FI, which were not detected by traditional measures. Cough‐anorectal measurements may improve manometric yield, though clinical utility would require assessment by longitudinal studies. [ABSTRACT FROM AUTHOR]

IntroductionCough is a major symptom frequently experienced during exercise, mainly in asthmatic patients. Inhaled glucocorticoids represent the keystone treatment in the management of asthma, but little is known about interactions between cough and exercise, especially in controlled patients. During exercise, cough reflex (CR) appears downregulated in healthy animal models whereas a lack of desensitization of CR has been shown in ovalbumin-sensitized animal models, mimicking asthmatic disease.Aims and ObjectivesThe goal of our study was to clarify the potential modulation of the CR induced by inhaled corticosteroids (CS) in ovalbumin (OVA) sensitized rabbits during artificial limb exercise.Materials and MethodsSeventeen OVA sensitized rabbits were studied. Among them, 9 were treated with CS delivered intravenously (OVA-Corticoids). The ventilatory response to direct tracheal stimulation, performed at rest and during exercise, was determined to assess the incidence and the sensitivity of the CR. Broncho-alveolar lavage (BAL) and cell counts were performed to determine the level of airway inflammation. Exercise was mimicked by electrically induced hindlimb muscular contractions (EMC).ResultsCompared to rest values, EMC increased minute ventilation by 28% without any decrease in respiratory resistance (Rsr). Among 322 tracheal stimulations, 172 (53%) were performed at rest and 150 (47%) during exercise. The sensitivity of CR decreased during artificial limb exercise compared to baseline in OVA-Corticoids rabbits (p = 0.0313) while it remained unchanged in OVA rabbits (p = NS).ConclusionCorticosteroids appear to restore the desensitization of the CR in OVA sensitized rabbits during artificial limb exercise, suggesting the potential role of airway inflammation in the pathophysiology of cough during exercise in asthmatics.

Platycodon grandiflorum (PG) has been extensively utilized as an herb to relieve phlegm. In this study, the effects of PG root extracts on airway inflammation and cough reflex were investigated, especially using fermented PG extracts (FPE) to increase an active compound, platycodin D by fermentation. FPE significantly reduced the numbers of eosinophils and total cells in the bronchoalveolar lavage fluid (BALF) obtained from lipopolysaccharide/ovalbumin (LPS/OVA)-induced asthma mice versus those of vehicle control. Moreover, in the BALF and the serum, FPE significantly reduced the concentration of IL-17E, a proinflammatory cytokine that causes TH2 immunity, including eosinophil amplification. It was also demonstrated that FPE might relieve inflammations through histological analysis of the lung separated from each mouse. Furthermore, in cough reflex guinea pigs induced by citric acid treatment, FPE treatment significantly reduced the number of coughs versus that of vehicle control, and consequently decreased cough reflex sensitivity. In addition, the total cell number and eosinophils significantly decreased in the BALF obtained from each guinea pig versus that of vehicle control. In in vitro study, pretreatment with FPE in LPS-stimulated RAW264.7 cells significantly reduced the levels of proinflammatory cytokines such as TNF-α, IL-6, and IL-1β, and inducible nitric oxide synthases (iNOS). Therefore, we demonstrated that FPE relieved airway inflammation and cough reflex sensitivity in vivo, and exhibited anti-inflammatory effects through suppression of iNOS and several proinflammatory cytokines. These findings suggest that FPE might have a beneficial effect on respiratory health, and may be useful as a functional food to prevent respiratory diseases. [ABSTRACT FROM AUTHOR]

Introduction: Cough is a major symptom frequently experienced during exercise, mainly in asthmatic patients. Inhaled glucocorticoids represent the keystone treatment in the management of asthma, but little is known about interactions between cough and exercise, especially in controlled patients. During exercise, cough reflex (CR) appears downregulated in healthy animal models whereas a lack of desensitization of CR has been shown in ovalbumin-sensitized animal models, mimicking asthmatic disease. Aims and Objectives: The goal of our study was to clarify the potential modulation of the CR induced by inhaled corticosteroids (CS) in ovalbumin (OVA) sensitized rabbits during artificial limb exercise. Materials and Methods: Seventeen OVA sensitized rabbits were studied. Among them, 9 were treated with CS delivered intravenously (OVA-Corticoids). The ventilatory response to direct tracheal stimulation, performed at rest and during exercise, was determined to assess the incidence and the sensitivity of the CR. Broncho-alveolar lavage (BAL) and cell counts were performed to determine the level of airway inflammation. Exercise was mimicked by electrically induced hindlimb muscular contractions (EMC). Results: Compared to rest values, EMC increased minute ventilation by 28% without any decrease in respiratory resistance (Rsr). Among 322 tracheal stimulations, 172 (53%) were performed at rest and 150 (47%) during exercise. The sensitivity of CR decreased during artificial limb exercise compared to baseline in OVA-Corticoids rabbits (p = 0.0313) while it remained unchanged in OVA rabbits (p = NS). Conclusion: Corticosteroids appear to restore the desensitization of the CR in OVA sensitized rabbits during artificial limb exercise, suggesting the potential role of airway inflammation in the pathophysiology of cough during exercise in asthmatics. [ABSTRACT FROM AUTHOR]

In order to clear airways and lungs defensive reflexes are provoked rather by the dynamic phase of mechanical stimulus. It is speculated that provocation of defensive response depends not only on stimulus duration but also on stimulus velocity. Fourteen adult rabbits were anaesthetized and tracheotomized. Mechanical stimulus was provoked by a mechanical probe introduced through the tracheotomy and rotated by a small electrical motor using a rotational velocity of 40 rpm/s and 20 rpm/s. Threshold, incidence and intensity of cough reflex (CR) were analyzed for each animal. Statistical comparisons between two velocities were performed using Friedman nonparametric test for repeated measurements. Results are median (25-75 %). The threshold of CR was significantly increased (p=0.005) from 350 ms (300-500 ms) to 550 ms (350-1150 ms) and the incidence of cough reflex was significantly reduced (p=0.002) from 50 % (19-50 %) to 0 % (0-25 %) when the rotational velocity of the mechanical probe was reduced by half. The findings of this study are of interest as they show that protective reflex cough, an important mechanism that allows clearing airways even during sleep or anesthesia, is tuned by mechanical stimulus velocity. [ABSTRACT FROM AUTHOR]

Background: The most common respiratory complications in cerebrovascular strokes were respiratory infection, pulmonary edema, acute lung injury (ALI) acute respiratory distress syndrome (ARDS) and pulmonary embolism (PE). The inhalation cough challenge facilitates the quantification of cough. Objectives: To detect the level of cough reflex that is enough to protect against respiratory infection in stroke patients, and to identify predictors of post-stroke respiratory infection. Patients and methods: One hundred and one of cerebrovascular stroke patients were assessed in the first week of symptoms by National Institutes of Health Stroke Scale (NIHSS) Arabic version, Mann Assessment of Swallowing Ability (MASA), cough challenge test, cough flow meter, and A2DS2 score. Then, follow up after 1 week. Results: Post-stroke respiratory infection was higher in older patients and those who were not working. Respiratory infection was significantly associated with high A2DS2 and NIHSS score (p value < 0.001). A highly significant increase in the levels of the inflammatory markers was detected in patients with a respiratory infection. Eighty percent of stroke patients with no cough developed a respiratory infection. The Mann total scores and the peak cough flow were lower in patients who had a respiratory infection. Conclusion: Preserved cough reflex is essential in preventing aspirations and consequent respiratory infections. [ABSTRACT FROM AUTHOR]

Objective To compare the effects of remifentanil and dexmedetomidine on the prevention of cough during emergence in patients undergoing neurosurgery. Methods Eighty male patients undergoing supratentorial craniotomy were randomly divided into remifentanil group ( group R) and dexmedetomidine group ( group D) . Anesthesia was induced with propofol 2 mg/kg, target controlled infusion (TCD of remifentanil with effect site concentration of 2 ng/mL and rocuronium 0.6 mg/ kg. A strengthening steel tracheal catheter was intubated after muscular flaccidity and connected to the ventilator for respiratory control. Anesthesia was maintained with remifentanil (2 ng/ mL), TCI of propofol (3 μg/ mL) and sevoflurane inhalation. In group R, TCI of remifentanil with effective site concentration of 2 ng/mL was maintained during emergence until extubation. In group D, remifentanil was discontinued after the dural was closed,dexmedetomidine was given with loading dose of 1 μg/kg in 10 min and maintained with 0.2 mg/(kg • h) until extubation. The cough grade, hemodynamic values,respiration rate, and other recovery profiles were evaluated during the periextubation period. Results Compared with group R, the cough score was higher and the concentration of S100B was lower in group D(P < 0.05) . The time of spontaneous breathing recovery and extubation was shorter in group D( P < O. 05). There was no significant difference of the Observer's Assessment of Alertness/Sedation Scale ( OAA/S) score between the two groups ( P > O. 05) . However,the incidence of 3 points in group D was higher,and the lower of that of 4 points (P < O. 05) . T he respiratory rate was lower in group R at the time of extubation and 3 min after extubation than group D( P < O. 05) . The heart rate and mean artery pressure at 3 min and 5 min after extubation and t he incidence of nausea and vomiting in group D was lower than those in group R(P< O. 0 5) . Conclusion Remifentanil could reduce emergence of cough after neurosurgery more effectively than dexmedetomidine. However, dexmedetomidine might have the effect to maintain the respiratory and hemodynamic stability, and the effect of cerebral protection. [ABSTRACT FROM AUTHOR]

Recently, there have been robust changes in our knowledge of the neurophysiology of cough and novel clinical etiologies. Specifically, cough hypersensitivity in adults and protracted bacterial bronchitis (PBB) in children have been increasingly investigated, and differences between chronic cough in children and adults have been widely reported. In young children, postinfectious cough, bronchiectasis, airway malacia, PBB, and asthma appear to be the main causes of cough; however, by adolescence, the causes of cough are more likely to become those common in adults, namely, gastroesophageal reflux, asthma, and upper airway syndrome. These differences are attributed to changes in various characteristics of the respiratory tract, immune system, and nervous system between children and adults. New knowledge about the neural aspects of cough has revealed a complex network of pathways that initiate cough. The effect of inflammation on cough neural processing occurs at multiple peripheral and central sites within the nervous system. Evidence exists that direct or indirect neuroimmune interaction induces a complex response, which can be altered by mediators released by the sensory or parasympathetic neurons and vice versa. During childhood, the respiratory tract and the nervous system undergo a series of anatomical and physiological maturation processes that produce the cough neural circuits. Alterations provoked by various pathological processes, noxious agents, infection, and inflammation during the developmental period can lead to persistent or irreversible modifications, which may explain why many adult patients, in addition to expressing high cough sensitivity, remain refractive to disease-specific therapies. [ABSTRACT FROM AUTHOR]

Cough is a common symptom in respiratory pathology which is associated with 30% of all visits to therapist and more than 50% to pediatrician, especially during the period of respiratory infection outbreak. Cough (Latin tussis) is a natural reflex to clear airways. The spectrum of diseases accompanied by cough is varied, thus it is required from a doctor to understand the etiological causes and pathogenic mechanisms of its development to make the adequate choice of therapy.

Highlights • Hyperoxia has been shown to be toxic in many animal models depending on oxygen exposure, age, nutrition or endocrine status. • The respiratory epithelium is a major target for oxidative injury that manifested in lung function changes including cough. • Experiments on hyperoxia indicate that a 50% oxygen exposure does not affect cough reflex in animal model. • High oxygen concentration evokes down regulation of cough reflex in animal model. • Antioxidants reverse hyperoxia-related cough suppression in animal model. Abstract Hyperoxia-induced lung injury is well known in animal and human studies. The respiratory epithelium including sensory nerve endings is a major target for oxidative injury that manifested in lung function changes including cough. On the basis of available information we supposed that hyperoxia alone or in combination with primary lung tissue injury should have a damaging effect on lungs, including the airway nerve endings with the changes in the sensitivity of the central and peripheral neuronal pathways regulating cough. We have previously demonstrated that long-term exposure to 100% oxygen inhibits the cough reflex in cat. This review article summarizes the effect of hyperoxia on the cough reflex in guinea pig model using different concentrations of oxygen and different time of exposure. We also present information on the potential role of antioxidants in reversal of the detrimental effects of hyperoxia on coughing and additional analysis of experiments from previously published studies were obtained and analysed for the cough reflex sensitivity. [ABSTRACT FROM AUTHOR]

Highlights • Sphingosine-1-phosphate (S1P) is an inflammatory mediator increased in the tissue in a variety of inflammatory conditions. • Literature data indicate that the vagal afferent neurons express several S1P receptors including S1PR 1-5. • We evaluated the effect of inhaled S1P on the cough reflex as an indicator of airway inflammation. • Data have shown that neither inhaled S1P alone nor in combination with TRPA1 or TRPV1 agonists did not enhance coughing. • S1P was ineffective to induce/sensitize cough in naïve guinea pigs, but its role can be important in pathological conditions. Abstract Sphingosine-1-phosphate (S1P) is an inflammatory mediator increased in the tissue in the number of inflammatory conditions. Preliminary data indicate that the vagal afferent neurons express several S1P receptors including S1PR 2-3. We therefore evaluated the hypothesis that S1P induces cough and/or enhances the cough evoked by other tussive stimuli (TRPA1 and TRPV1 activators) in naïve guinea pigs. Inhalation of S1P in the concentrations of 0.1 mM and 1 mM did not evoke cough. Preinhalation and continuing inhalation of S1P (1 mM) during citric acid (0.2 M) challenge did not enhance citric acid-induced cough. Preinhalation of S1P and continuing inhalation during AITC (3 mM) challenge also did not enhance AITC-induced cough. We conclude that S1P was not efficient to evoke cough in awake naïve guinea pigs. S1P was also not effective to sensitize the cough evoked by stimulation of TRPV1 and TRPA1 receptors. Nonetheless it cannot be excluded that S1P influences cough in the context of inflamed airways when the cough-mediating nerves undergo sensory neuroplasticity. [ABSTRACT FROM AUTHOR]

Highlights • Continuous positive airway pressure (CPAP) is associated with marked alteration in the pattern of response to mechanical stimulation of trachea. • CPAP is associated with inhibition of the cough reflex and up regulation of the sequence expiration reflex – cough reflex. • The relevance of these findings to clinical settings of chronic cough and lung hyperinflation deserves further investigations. Abstract Lung hyperinflation may alter the pattern of ventilatory reflexes in chronic respiratory disorders. The aim of the study was to test the effect of continuous positive airway pressure (CPAP) on ventilatory responses to mechanical stimulation of the trachea. [ABSTRACT FROM AUTHOR]

Highlights • Acetylcholine downregulates the cough reflex in the caudal NTS of the rabbit. • Depressant effects on the cough reflex are mediated by muscarinic receptors. • Central muscarinic cholinergic mechanisms are involved both in cough and pain. • Cholinergic control on the cough reflex may suggest novel therapeutic strategies. Abstract A cholinergic system has been described in the nucleus tractus solitarii (NTS). However, no information is available on the role played by acetylcholine (ACh) in the modulation of the cough reflex within the caudal NTS that has an important function in cough regulation. We addressed this issue making use of bilateral microinjections (30–50 nl) of 10 mM ACh combined with 5 mM physostigmine as well as of 10 mM mecamylamine or 10 mM scopolamine into the caudal NTS of pentobarbital sodium-anesthetized, spontaneously breathing rabbits. Microinjections of ACh/physostigmine caused depressant effects on the cough reflex induced by mechanical and chemical stimulation of the tracheobronchial tree. They also elicited transient increases in respiratory frequency and decreases in abdominal activity. These effects were prevented by scopolamine, but not by mecamylamine. The results show for the first time that ACh exerts an inhibitory modulation of the cough reflex through muscarinic receptors within the caudal NTS. They also may provide hints for novel antitussive approaches. [ABSTRACT FROM AUTHOR]

Highlights • Xanthine derivatives inhibit PDEs non-selectively leading to bronchodilation, anti-inflammatory, and antitussive effects. • The inhibition of PDEs leads to bronchodilation, suppression of TRPV channels and anti-inflammatory action in cough suppression. • Selective PDE3, PDE4 and PDE5 inhibitors have demonstrated significant antitussive effects, confirming their benefits in COPD and asthma. Abstract A group of 11 enzyme families of metalophosphohydrolases called phosphodiesterases (PDEs) is responsible for a hydrolysis of intracellular cAMP and cGMP. Xanthine derivatives (methylxanthines) inhibit PDEs without selective action on their single isoforms and lead to many pharmacological effects, e.g. bronchodilation, anti-inflammatory and immunomodulating effects, and thus they can modulate the cough reflex. Contrary, selective PDE inhibitors have been developed to inhibit PDE isoforms with different pharmacological effects based on their tissue expression. In this paper, effects of non-selective PDE inhibitors (e.g. theophylline) are discussed, with a description of other putative mechanisms in their effects on cough. Antitussive effects of selective inhibitors of several PDE isoforms are reviewed, focusing on PDE1, PDE3, PDE4, PDE5 and PDE7. The inhibition of PDEs suggests participation of bronchodilation, suppression of TRPV channels and anti-inflammatory action in cough suppression. Selective PDE3, PDE4 and PDE5 inhibitors have demonstrated the most significant cough suppressive effects, confirming their benefits in chronic inflammatory airway diseases associated with bronchoconstriction and cough. [ABSTRACT FROM AUTHOR]