Mechanisms Of Cough Research Articles

Pulmonary reflexes after human heart-lung transplantation

Heart-lung transplantation involves denervation of the lungs below the tracheal anastomosis, with associated permanent loss of all pulmonary innervation except post-ganglionic efferent nerves. This is supported by loss of the cough reflex to inhaled USNDW, which also implies that the RARs which mediate this cough mechanism lie in the central airways. Bronchoconstriction following inhalation of USNDW developed only in those HLT recipients with acute lung rejection; this was not related to methacholine responsiveness and may therefore represent a pathologic vascular response. Hyperresponsiveness to methacholine has been reported following HLT, which we found unrelated to inflammation or acute rejection. A similar hyperresponsiveness to histamine was seen, which correlated with the response to methacholine. This also implies that histamine may act directly on smooth muscle receptors, and not solely via a cholinergic reflex. Hyperresponsiveness following HLT may be due to development of a generalized denervation hypersensitivity. Bronchodilation following capsaicin inhalation has been observed in HLT recipients, and may be due to unopposed release of VIP from retained post-ganglionic efferent nerves.

Angiotensin Converting Enzyme Inhibitors and Cough

Angiotensin converting enzyme (ACE) inhibitors produce a dry, nonproductive cough in some patients. Retrospective surveys have suggested an incidence of cough of between 0.7 and 14%. Those patients who develop cough show a marked increase in the sensitivity of the cough reflex to inhalation of the extract of red pepper, capsaicin. They have a normal response before treatment, and the sensitivity of the cough reflex returns to normal when therapy is discontinued. The mechanism of this important side effect is not known. Further studies are required to clarify the mechanism of cough, both as a side effect of therapy and as a common symptom of respiratory disease.

A possible mechanism for cough developing with captopril therapy

A possible mechanism for cough developing with captopril therapy

Mechanism of cough with angiotensin-converting enzyme inhibition

Mechanism of cough with angiotensin-converting enzyme inhibition

Chronic Cough and the Use of Captopril: Unmasking Asthma-Reply

As Dr Salena points out, asthma has not been completely excluded as a diagnosis in our case without use of the methacholine inhalation challenge test, even though eosinophilia, a positive family history of atopic disease, and an association between cough and β-blocker therapy were not observed. The backgrounds of the patients should be carefully evaluated when the patients are considered to exhibit an adverse effect to a certain drug. On this point, asthma has to be discussed in our case, because asthmatic patients might be sensitive to the stimuli that produce the cough reflex. 1 However, it is difficult to attribute the cough that developed after captopril treatment and subsided with its withdrawal entirely to asthma. An association of cough with captopril can be acknowledged in our case, whatever the cough mechanisms or patients' backgrounds are.

The Muscular Basis of Aquatic and Aerial Ventilation in the Air-Breathing Teleost Fish Channa

Abstract The mechanisms of aquatic and aerial ventilation in four bimodally breathing species of teleosts of the genus Channa were studied by high-speed light and X-ray ciné films, pressure transducer recordings and electromyography. Neither inter- nor intraspecific differences were found in the pattern of aquatic and aerial ventilation. Aquatic ventilation proceeds with a partially air-filled buccopharyngeal cavity. The electromyographic patterns, pressure waveforms in the buccal and opercular cavities, and kinematics of jaw and opercula resemble those found for aquatically breathing teleosts. The pattern of aerial ventilation differs significantly from that of aquatic ventilation. Aerial ventilation is initiated by a reversed flow of water brought about by a low pressure in the buccal cavity. In this way the air in the suprabranchial cavity is moved forward and expelled from the mouth. The buccal, suprabranchial and opercular pressures are maintained at below ambient pressures throughout the aerial respiratory cycle. The kinematic pattern of bone movements, pressure waveforms and electromyographic profiles during air ventilation are identical to those of the cough and do not differ interspecifically. The complex aerial ventilation mechanism in Channa may be homologous with the primitive cough mechanism. Fishes employing the cough mechanism for air ventilation remain totally dependent on water and are therefore poorly adapted to explore terrestrial habitats.

Policies on antibiotics of south east London general practitioners for managing acute otitis media in children.

Questionnaires on antibiotic treatment of acute otitis media in children were sent to the general practitioners who make regular referrals to clinics in the King's College Hospital group. The most popular first choice of drug was amoxycillin (44%), but 37% of general practitioners said that they often used oral phenoxymethylpenicillin. This drug has relatively low activity against Haemophilus influenzae and many strains of Staphylococcus aureus. It is poorly absorbed from the stomach, does not penetrate the middle ear well, and its use may be one factor in the development of chronic middle ear effusions after acute otitis media. Sixty two per cent of the doctors who replied never treated acute otitis media with intramuscular antibiotics, but 57% used oral loading doses. Ninety seven per cent never treated their patients without antibiotics.

Cough. Pathophysiology and pulmonary function testing--paediatric aspects (author's transl)

Cough is among the most effective clearance mechanisms of the lung. After glossopharyngeal and vagal stimulation glottic closure, leading to increased intrathoracic pressure, is followed by rapid expulsion of air. Normal cough mechanisms appear only after the 35th gestational week. Flow-volume curves may be used for diagnostic purposes.

Influence of Tracheal Muscular Tone on the Initiation of Cough Reflex

We devised a canine blood-perfusion preparation which made feasible administration of drugs directly at the local tracheal site. The hypothesis of Salem and Aviado on cough mechanism that a local airway constriction induced by stimuli may be a trigger in stimulating cough receptors was investigated using this preparation. Close intraarterial injections of acetylcholine (ACh) and histamine did not elicit a cough although intense tracheal constrictions were evident. The cough reflex elicited by electrical stimulation of the mucosa of isolated upper trachea in situ was accompanied by a slight systemic hypotension, tracheal vasodilatation and tracheal muscular constriction. The latter two changes occurred after a time lag following coughs. Close intraarterial infusions of isoproterenol and papaverine caused a prominent tracheal dilatation, but did not suppress the coughs. Pretreatment with atropine sufficiently inhibited cholinergic tracheoconstriction but had no effect on the electrically induced coughs. Furthermore, an augmentation of the tracheal muscular tone produced by an infusion of ACh did not enhance the cough reflex. In light of our observations, the aforementioned hypothesis should be reconsidered.

Surgical laryngeal closure to eliminate chronic aspiration.

WHEN the function of the laryngeal sphincter is lost, anything swallowed, including saliva, is directed through the incompetent larynx and into the trachea. The cough mechanism is impaired, and vocal function is nil or absent. Frequent bouts of aspiration pneumonia add to the patient's misery. Such patients require continuous hospitalization and nursing care, for a cuffed tracheotomy tube is necessary to control aspiration of saliva, and a nasogastric or gastrostomy feeding tube is needed to maintain nutrition. A patient suffering from chronic aspiration will gladly sacrifice any remaining vocal function in exchange for restoration of breathing and eating without impediment. . . .

Plethysmographic Observations on Intrathoracic Compression during Cough

An apparatus for the measurement of cough was devised. It consisted of a volume displacement body plethysmograph, Krogh spirometer, hot wire flow meter, and transducer for the esophageal pressure. A slower response of the volume displacement body plethysmograph than the pressure plethysmograph was compensated by “pressure correction” as suggested by previous authors. A semi-conductor transducer was used to measure pressure changes in the box. A mixing circuit of the output signal from the plethysmograph with that from the pressure transducer of the box was easily built since both signals were direct current.Simultaneous measurements of VBOX and VATPS showed new aerodynamic aspects in expirations. VBOX represented volume changes of a subject in the box while VATPS actually expired air from the mouth. A disagreement of VBOX and VATPS meant at least in part the intrathoracic compression of the air and pulmonary structures.As previously reported, a cough movent was divided into three phases. These were the inspiratory, minimum flow, and expiratory phase. The minimum flow phase corresponded to the period when the glottis was tightly closed. The intrathoracic compression was most manifest during this phase. Favourable effects of this compression on the cough mechanism were suggested from analyses of the data.

Resuscitation and anesthesia in crushed chest injuries

Extensive thoracic trauma resulting in crushed chest deformity imposes several unique problems in altered respiratory physiology which must be immediately corrected in preparing the patient for more definitive therapy. Mechanical disruption of the thoracic cage reduces ventilatory capacity and abolishes the cough mechanism for removal of foreign material. Immediate care of such patients is best accomplished by initially aspirating the airway and instituting manual positive pressure ventilation, followed by tracheal intubation or tracheostomy. The early use of positive pressure not only accomplishes adequate alveolar ventilation, but also provides internal stabilization of the chest wall. Anesthetic management of patients with crushed chest deformity is best accomplished by local infiltration or regional nerve block. When required, general anesthesia utilizing positive pressure respiration may be employed. Although several inhalation agents are suitable for such patients, the possible prolonged respiratory depressant effects of barbiturates, narcotics and muscle relaxants make them less desirable. The advantages and disadvantages of definitive care employing internal stabilization are discussed together with technical considerations in the use of respirators. A method of solving the problems of dehydration of the respiratory tract and inspissation of secretions is presented.

Pulmonary Atelectasis Due to Voluntary Suppression of Cough

Massive pulmonary atelectasis is encountered in a variety of circunistances that predispose to, or produce bronchial obstruction. The obstructing agents may be tumors, intrinsic or extrinsic, foreign bodies, or abnormal secretions retained in the airways. Precipitating factors may be inhibition of the cough mechanism by drug or metabolic depression, reflex inhibition due to pain, or ineffective motion due to interrupted integrity of the chest wall, to name but a few. An additional factor, not as a rule noted, may be voluntary suppression of cough, such as was observed in the five cases to be presented here. Emotional motivation toward suppression of cough was present in at least four of the five; repeated bronchoscopic examination and explorations ruled out intrinsic disease of the airways, and four of the five patients had recurrences of the atelectatic phenomenon until they ceased to suppress their cough mechanism. The importance of cough, unique in its capacity to accelerate expiratory air flow is indicated by the studies of Ross #{128}t al. and the particular importance of cough in preventing atelectasis has been demonstrated by Dayman and Manning. Case 1 presented at the age of 23 with massive atelectasis of the right lower lobe. The x-ray film (Fig. la) is classical. Bronchoscopy disclosed thick, airless mucoid secretions completely ifiling the lower lobe bronchus on the right. This was aspirated and partial re-expansion was noted immediately (Fig. lb), followed shortly by complete re-expansion. However, the condition recurred several times during ensuing months until it was discovered that this person considered a cough as a social handicap and therefore had learned to suppress it completely; this in spite of an almost continuous allergic mucoid secretion. The problem of recurring atelectasis was solved when it was impressed on the patient that coughing was less of a social handicap than recurring atelectasis.

Ivalon Sponge Prosthesis with Pulmonary Resections Over Five Years Experience

Ever since the beginning and acceptance of pulmonary resection as a procedure, surgeons have tried to find better ways of dealing with the residual empty space. The importance of getting rid of this space as rapidly as possible is well recognized. With lobectomy or partial resection, immediate obliteration seems to definitely reduce the incidence of complications such as persistent air leaks, and bronchial fistulae. This has been accomplished in various ways such as: (1) by division of the pulmonary ligament which allows the lower lobes and segments to rise in the chest cavity; (2) by crushing or cutting the phrenic nerve, thus elevating the diaphragm (not too desirable after lobectomy because of interference with the cough mechanism; (3) induction of pneumoperitoneum, ternporarily elevating the diaphragm; (4) the development of some type of so-called apical pleural tent; and (5) thoracoplasty. All of the temporary procedures are helpful, particularly during the immediate postoperative period; however, sooner or later their efficacy wears off and the residual lung begins to over-distend. This raises a new problem regarding a decrease in function of the remaining over-distended segments. Concomitant, pre-resection, and early post-resection thoracoplasty, being permanent collapse procedures, solve this point, but have the disadvantage of the accompanying deformity, and in some instances multiple operations. The pre-resection extra-periosteal plombage operation also has been used with satisfaction, eliminating resection of ribs. Following total pneumonectomy, obliteration of the space becomes even more important. Over-distention of the one remaining lung definitely limits exercise tolerance, and, in an individual who already has emphysema or much fibrosis due to disease in the contralateral lung, will cause him to be a pulmonary cripple. A young individual can get by for many years with pneumonectomy alone, but eventually will find it necessary to slow down his activity. With some older individuals who do not have emphysema, resection alone, as for carcinoma, may be tolerated very well for a short life period. If emphysema or pulmonary fibrosis is present, the residual space had better be taken care of in some manner. Also, obliteration of the space should be by some permanent procedure. Here again, phrenic crush, pre and post-resection, and concomitant thoracoplasties have proved their value. Since the beginning of this century, surgeons have tried a multitude of various and foreign substances to fill body cavities and to maintain a collapse of the lung. Air, fat, muscle, oil, cellophane, rubber, paraffin, fiber glass, metal, and recently the plastic substances, all have been used. Some have been discarded and revived again. In the words of J. C. Trent, “The search for the ideal substance goes on.” Two scores of articles in American and foreign literature written about these substances in the last fifteen years were reviewed and no final conclusion could be reached

Detailed surgical technique of tracheal fenestration, with a report of twenty-six cases.

Tracheal fenestration 1-5 is a new operative procedure for the treatment of chronic respiratory diseases. It is a skin-lined cervical tracheocutaneous communication equipped with two door-like skin valves at its external end. The valves can be opened at will for the purpose of tracheobronchial aspiration and medication, or self-aspiration and self-medication. When the valves are not held apart, the tracheocutaneous communication is airtight and leakproof; phonation and the cough mechanism remain normal. The purpose of this paper is to present the detailed surgical technique of tracheal fenestration, based on experience with 26 cases. Operative Technique A 4 in. long transverse skin incision is made over the lower anterior surface of the neck, about the level of the cricoid cartilage. This incision is then extended in such a way that one skin flap is outlined above, and one below, the level of the initial transverse incision. The base of each opposing

Physical dynamics of the cough mechanism.

Physical dynamics of the cough mechanism.

Cough, its pathology and management

1. 1. Importance of cough as a symptom as viewed both from the health and economic standpoint is stressed. Pathology of the cough mechanism is simplified by describing the causes and effects of harmful and helpful coughs. Pathways of the cough reflexes are described. Tussal insufficiency and tussive syncope are discussed. 2. 2. Surgical intervention, physiotherapy and postoperative prevention of atelectasis are discussed with reference to cough. The role of cough in emphysema is described. Common colds, “air conditioning” and the lack of acclimatization of the respiratory mucous membrane as a cause of cough are discussed. 3. 3. Drug therapy including morphine and its derivatives is described. Bronchocatharsis and the use of such drugs as potassium iodide, ammonium chloride and others are described in detail. A few of the common combinations of cough remedies are listed. The use of antispasmodic drugs and gases, including the use of carbon dioxide, is enumerated. Positive-negative oxygen therapy in chronic pulmonary disease is reviewed and emphasized. Inhalations and aerosols are evaluated, and newer liquefying aerosol combinations are described. Oils and antihistaminic drugs are discussed. 4. 4. Radiation therapy and “teaching the patient” are discussed in detail.

PHYSICAL METHODS SIMULATING COUGH MECHANISMS

The development of physical methods of eliminating bronchial secretions seemed to be especially desirable for patients who no longer had an effective cough, such as those with poliomyelitis and myasthenia gravis. In these conditions the majority of the fatal pulmonary complications are caused by atelectasis and secondary pneumonitis, which are the result of inability to expel saliva and mucopurulent exudate by an effective cough. Plugging of the bronchi by retained sputum may also impair respiratory function in such clinical entities as bronchial asthma, pulmonary emphysema, lung abscess, blocked tuberculous cavities, and pulmonary collapse following operations. The purpose of this paper is to report the therapeutic use of physical techniques by which retained bronchial secretions have been effectively eliminated and to describe the physiological responses that are involved, at least in part, in the results achieved. The two methods developed to simulate some of the mechanisms of the human cough are

Physical methods simulating mechanisms of the human cough: elimination of radiopaque material from the bronchi of dogs.

Physical methods simulating mechanisms of the human cough: elimination of radiopaque material from the bronchi of dogs.

Physical methods simulating mechanisms of the human cough.

Physical methods simulating mechanisms of the human cough.