Simultaneous tracheal and oesophageal pH measurements in asthmatic patients with gastro-oesophageal reflux

Gastroesophageal reflux disease and asthma: an intriguing dilemma

BACKGROUND

Gastroesophageal reflux disease (GORD) is characterized by typical reflux symptoms and multiple atypical extraesophageal symptoms. Gastric asthma is a prominent extraesophageal manifestation of GORD. There is persistent debate about the pathophysiologic mechanisms triggering asthma by GOR.

METHODS

We conducted a review of the literature.

RESULTS

The pathogenic mechanism could be either a vagally transmitted reflex or an intratracheal aspiration of refluxed material. In both hypotheses, the role of inflammatory mediators has been proposed.

CONCLUSIONS

Neurogenic inflammation is a good theoretic basis for a pathogenic interpretation of the disorder. In atopic patients, food allergy has been recently proposed as a possible cause of GOR and associated respiratory symptoms, and it should be considered in the diagnostic work-up of all patients with GORD.

Gastroesophageal reflux disease and asthma: the two are directly related

GERD and asthma have met the three criteria set out to prove a relationship between the two diseases. Patients with GERD have a higher prevalence of asthma, and there are several pathophysiologic mechanisms by which acid reflux can cause bronchospasm. Furthermore, aggressive antireflux therapy in patients with asthma and GERD results in improvements in asthma outcome in as many as 70% to 80% of patients treated in both medical and surgical series. Nevertheless, there are design flaws in many of the outcome studies performed to date. To further clarify this issue, future studies should be multicentered and placebo controlled using acid-suppressive therapy for at least 3 to 6 months with documentation of asthma outcome, cost analysis, and quality-of-life assessment. As with many things in medicine, all the data are not consistent. However, I strongly believe that the available data support the aggressive search for GERD and treatment in any patient with difficult-to-control asthma.

Supraesophageal complications of gastroesophageal reflux

Supraesophageal complications of GERD have become more commonly recognized or suspected by physicians. However, the direct association between these complications and GERD has often been difficult, if not impossible, to establish. Furthermore, the majority of patients with suspected supraesophageal complications of GERD do not have either the characteristic symptoms of heartburn and regurgitation or the definitive findings of esophageal inflammation, which would help reinforce the suspicion of a connection between the supraesophageal complications and GERD. Frequent acid reflux has been shown in patients with various bron-chopulmonary, laryngopharyngeal, or oral cavity disorders. GERD is one of the most common gastrointestinal complaints in the population. It is possible that the supraesophageal problems and acid reflux are mutually independent disorders that occur in the same person. The suspected mechanisms of GERD-related supraesophageal complications appear to be directed through two pathways: by a vagal reflex between the esophagus and tracheobronchial tree triggered by acid reflux or by microaspiration that causes contact damage to mucosal surfaces. The most useful diagnostic modality available to the clinician to aid in the diagnosis of supraesophageal GERD complications is the ambulatory pH recording technique. However, the sensitivity and specificity of this test for recording esophageal or pharyngeal acid reflux events has been critically challenged. Despite the many clinical studies that support the theory that GER has a role in suspected supraesophageal complications, only 1 long-term prospective controlled study of a large group of patients with asthma has shown the positive effects of the elimination of acid reflux. With the focus now on "outcomes medicine," there is a serious need for appropriately designed, controlled studies to answer the many questions surrounding a cause-and-effect association between acid reflux and supraesophageal disorders. Because of the lack of convincing proof between acid reflux and suspected supraesophageal complications, the physician must resort to an intent-to-treat strategy as both a primary therapy and a diagnostic trial. High-dose PPI therapy for prolonged periods is the recognized conservative therapy. Operative therapy (i.e., fundoplication operation) is the procedure of choice when overt regurgitation occurs or when medical therapy, although successful, is not practical for long periods. Controlled, well-designed clinical trials and more sophisticated techniques to measure and quantify acid reflux are crucial in the future to help determine which patients with suspected supraesophageal complications actually have acid reflux as a primary cause. The medical community needs to be alerted to the possibility of an association between GERD and supra-esophageal complications so that patients with a GERD-related complication will be recognized and effectively treated.

Gastroesophageal reflux disease in asthma: effects of medical and surgical antireflux therapy on asthma control

OBJECTIVE

To critique the English-language reports describing the effects of medical and surgical antireflux therapy on respiratory symptoms and function in patients with asthma.

METHODS

The Medline computerized database (1959-1999) was searched, and all publications relating to both asthma and gastroesophageal reflux disease were retrieved.

RESULTS

Seven of nine trials of histamine-receptor antagonists showed a treatment-related improvement in asthma symptoms, with half of the patients benefiting. Only one study identified a beneficial effect on objective measures of pulmonary function. Three of six trials of proton pump inhibitors documented improvement in asthma symptoms with treatment; benefit was seen in 25% of patients. Half of the studies reported improvement in pulmonary function, but the effect occurred in fewer than 15% of patients. In the one study that used optimal antisecretory therapy, asthma symptoms were improved in 67% of patients and pulmonary function was improved in 20%. Combined data from 5 pediatric and 14 adult studies of anti-reflux surgery indicated that almost 90% of children and 70% of adults had improvement in respiratory symptoms, with approximately one third experiencing improvements in objective measures of pulmonary function.

CONCLUSIONS

Fundoplication has been consistently shown to ameliorate reflux-induced asthma; results are superior to the published results of antisecretory therapy. Optimal medical therapy may offer similar results, but large studies providing support for this assertion are lacking.

Gastroesophageal reflux and asthma: are they related?

The relationship between asthma and gastroesophageal reflux (GER) is controversial. This paper reviews the evidence for an association between them, the effect of asthma on GER, and the effects of GER and antireflux therapy on asthma. The association between the two conditions seems firm but studies of the effects of GER on asthma and asthma on GER are contradictory. Critical review suggests that GER affects asthma symptoms but not pulmonary function. Antireflux therapy improves asthma symptoms and reduces medication requirements but does not improve pulmonary function. The paradox of GER causing asthma symptoms but not changing pulmonary function may be explained by its increasing minute ventilation rather than triggering bronchospasm.

Gastroesophageal reflux in asthmatics: A double-blind, placebo-controlled crossover study with omeprazole

STUDY OBJECTIVES

To investigate the prevalence of gastroesophageal reflux (GER) among patients with asthma and to determine the effect of omeprazole on the outcome of asthma in patients with GER.

DESIGN

A double-blind, placebo-controlled crossover study.

SETTING

Asthmatic patients who attended the pulmonary outpatient clinic of Turku University Central Hospital, Finland.

PATIENTS

One hundred seven asthmatic patients.

INTERVENTIONS

The patients who were found to have GER in ambulatory esophageal pH monitoring were randomized to receive either omeprazole, 40 mg qd, or placebo for 8 weeks. After a 2-week washout period, the patients were crossed over to the other treatment. Spirometry was performed at baseline and immediately after both treatment periods. Peak expiratory values, use of sympathomimetics, and pulmonary and gastric symptoms were recorded daily in a diary.

RESULTS

Pathologic GER was found in 53% of the asthmatic patients. One third of these patients had no typical reflux symptoms. Daytime pulmonary symptoms did not improve significantly (p = 0.14), but a reduction in nighttime asthma symptoms (p = 0.04) was found during omeprazole treatment. In the patients with intrinsic asthma, there was a decline in [corrected] FEV(1) values (p = 0.049). Based on symptom scores, 35% of the patients were regarded as responders to 8-week omeprazole treatment. The reflux (time [percent] of pH < 4) was found to be more severe (p = 0. 002) in the responders.

CONCLUSIONS

There is a high prevalence of GER in the asthmatic population. This reflux is often clinically "silent." After an 8-week omeprazole treatment, there was a reduction in nocturnal asthma symptoms, whereas daytime asthma outcome did not improve. There seems to be a subgroup of asthma patients who benefit from excessive antireflux therapy.

Esophagopharyngeal acid regurgitation: dual pH monitoring criteria for its detection and insights into mechanisms

BACKGROUND & AIMS

A valid technique for the detection of esophagopharyngeal acid regurgitation would be valuable to evaluate suspected reflux-related otolaryngologic and respiratory disorders. The aim of this study was to derive pH criteria that optimally define esophagopharyngeal acid regurgitation and to examine patterns of regurgitation.

METHODS

In 19 healthy controls and 15 patients with suspected regurgitation, dual or quadruple pH sensors were used to monitor pharyngeal and esophageal pH. For each combination of the 2 variables, DeltapH and nadir pH, proportions of pH decreases that occurred during or independent of esophageal acidification were calculated to determine the likelihood that an individual pharyngeal pH decrease was a candidate regurgitation event or a definite artifact.

RESULTS

Overall, 92% of pharyngeal pH decreases of 1-2 pH units and 66% of pH decreases of this magnitude reaching a nadir pH of <4 were artifactual. Optimal criteria defining a pharyngeal acid regurgitation event were a pH decrease that occurred during esophageal acidification, had a DeltapH of >2 units, and reached a nadir of <4 units in less than 30 seconds. Regurgitation occurred more frequently in subjects in an upright (32 of 35) than in a supine (3 of 35 events; P </= 0.0001) position and was more frequently abrupt (synchronous with esophageal acidification) than delayed (P </= 0.05).

CONCLUSIONS

Accepted criteria for gastroesophageal reflux are not applicable to the detection of esophagopharyngeal acid regurgitation, and most regurgitation occurs abruptly and in upright position.

Nocturnal asthma: role of nocturnal gastroesophageal reflux

Gastroesophageal reflux (GER) is common in those with asthma, with 77% of asthmatics complaining of heartburn, with 41% experiencing reflux-associated respiratory symptoms. Likewise, 24% of those with asthma that is difficult to control have "clinically silent" GER. There are no studies examining nocturnal reflux symptoms in asthmatics. Esophageal dysmotility is also common, and abnormal esophageal acid contact times on 24h esophageal pH tests were found in 82% of asthmatics examined consecutively. Most asthmatics with GER also have abnormal esophageal acid contact times while in the supine position, reflecting sleep time. Endoscopic evidence of esophagitis was found in 43% of asthmatics. Two mechanisms of bronchoconstriction induced by esophageal acid have been proposed: a vagally mediated reflex, by which esophageal acid in the distal esophagus causes reflex bronchoconstriction, and microaspiration. Although there is conflicting evidence, distal esophageal acid causes a decrease in peak expiratory flow rates, an increase in respiratory resistance, and an increase in minute ventilation. If microaspiration is present, there is further augmentation of this airway response. Although only a few studies have been performed in those with nocturnal asthma with GER, one study in a pediatric population showed that esophageal acid infusions caused more airway responses at 04:00 than at 24:00. Also, asthmatic children with nocturnal asthma symptoms have a higher reflux score, with a positive correlation between reflux score and nighttime-associated wheezing. Despite these findings in children, a study performed in sleeping adults with nocturnal asthma noted no alterations in airflow resistance with esophageal acid, concluding that GER contributed little to the nocturnal worsening of asthma. There are also gastroesophageal circadian issues that may influence GER in asthmatics. Gastric acid secretion peaks at approximately 21:00, and gastric emptying is delayed when a meal is given at 20:00 versus 08:00. Esophageal acid clearance is delayed significantly during sleep, and acid clearance occurs during arousals. Upper esophageal sphincter (UES) pressure also decreases with sleep onset, which may predispose to microaspiration. Further research is needed to clarify what role nocturnal reflux has on nocturnal asthma and airway inflammation and whether circadian rhythm factors alter airway responses to esophageal acid.

Gastroesophageal reflux and asthma: a review of pathogenesis, diagnosis, and therapy

Gastroesophageal reflux disease (GERD) occurs in up to one-third of the adult US population. Most affected individuals are either unaware of their condition or do not seek medical help, relying on nonprescription acid suppressants and antacids for relief. GERD, a common disorder of infancy, old age, and pregnancy, is particularly prevalent in patients with asthma. A causal relationship between the two diseases has been postulated by many investigators. The physiologic changes of asthma exacerbations and the actions of some of the medications used to treat asthma both aggravate GERD. The adverse effect of GERD on asthma and the pathophysiology of this relationship are still under debate. Some studies showed no objective improvement by spirometry of asthmatics treated for GERD, but recognized improvement in asthma symptoms and decreased use of asthma medication. Other studies, supporting GERD induction of asthma, have been performed to test two hypotheses: that asthma is exacerbated by endotracheal aspiration of gastric contents or by a reflex response to stimulation of esophageal receptors. Clinical experience has shown that early diagnosis and treatment of GERD often leads to better control of asthma.

Larynx vs. esophagus as reflexogenic sites for acid-induced bronchoconstriction in dogs

Bronchoconstriction in asthmatic patients is frequently associated with gastroesophageal reflux. However, it is still unclear whether bronchoconstriction originates from the esophagus or from aspiration of the refluxate into the larynx and larger airway. We compared the effect of repeated esophageal and laryngeal instillations of HCl-pepsin (pH 1.0) on tracheal smooth muscle activity in eight anesthetized and artificially ventilated dogs. Saline was used as control. We used pressure in the cuff of an endotracheal tube (Pcuff) as a direct index of smooth muscle activity at the level of the larger airways controlled by vagal efferents. The Pcuff values of the first 60 s after instillations were averaged, and the difference from the baseline values was evaluated. Changes in Pcuff were significantly greater with laryngeal than with esophageal instillations (P = 0.0166). HCl-pepsin instillation into the larynx evoked greater responses than did saline (P = 0.00543), whereas no differences were detected with esophageal instillations. Repeated laryngeal exposure enhanced the responsiveness significantly (P < 0. 001). Our data indicate that the larynx is more important than the esophagus as a reflexogenic site for the elicitation of reflex bronchoconstriction in response to acidic solutions.

A critical review of the studies of the effects of simulated or real gastroesophageal reflux on pulmonary function in asthmatic adults

OBJECTIVE

To identify and critically review the published peer-reviewed, English-language studies of the effects of both spontaneous and simulated gastroesophageal reflux (GER) on pulmonary function in asthmatic adults.

DESIGN

Using the 1966 to 1997 MEDLINE database, the terms asthma and lung disease were combined with GER to identify studies of the effects of GER and acid perfusion (AP) of the esophagus on pulmonary function. The bibliographies were also reviewed. Studies of asthmatics with and without symptomatic GER were analyzed both together and separately.

RESULTS

A total of 254 citations, including 180 published in English, were identified. Among these were 18 studies of GER and AP in asthmatic adults. These reports, which contain data on 312 asthmatics, found that the FEV1 and the midexpiratory rate did not change during AP and GER in the studies containing 97% and 94% of the asthmatics, respectively. Flow volume loop indexes, including the flow at 50% of the vital capacity (V50), flow at 25% of the vital capacity, and the peak expiratory flow rate, did not change during AP or GER in the studies with 77%, 60%, and 65% of the asthmatics, respectively. Small changes in the resistance were reported in the studies containing 42% of the asthmatics. Among asthmatics without symptomatic GER, no changes in spirometry, resistance, and flow volume indexes were found, except for a 10% decline in V50 in one study with seven subjects.

CONCLUSIONS

In asthmatics with GER, the effects of AP on pulmonary function are minimal, and only a minority are affected. The literature does not support the conclusion that asymptomatic reflux contributes to worsening lung function.

Gastroesophageal reflux disorders and asthma

Gastroesophageal reflux (GERD) may trigger asthma. Approximately 77% of asthmatic people experience reflux symptoms, although GERD may be clinically silent in some. Esophagitis is found in 43% of asthmatic people, and 82% have abnormal esophageal acid contact times on esophageal pH testing. Clearly, GERD is prevalent in asthmatic people. Pathophysiologic mechanisms of acid-induced bronchoconstriction include a vagally mediated reflex and microaspiration. Whether these airway responses are clinically significant is the subject of some debate. Interestingly, peak expiratory flow rates and specific airway resistance alterations persist despite esophageal acid clearance. Preliminary evidence shows that substance P, an inflammatory mediator that causes airway edema, is released with esophageal acid. Although therapeutic studies are limited by their small population sizes and study design, up to 70% of asthmatic people have asthma improvement with antireflux therapy. Possible predictors of asthma response include patients with symptomatic esophageal regurgitation; abnormal proximal esophageal acid exposure; and, in surgical studies, those with normal esophageal motility and asthma response with medical therapy. Future research will further define the association between asthma and gastroesophageal reflux.

Respiratory complications of gastrointestinal diseases

Further advances in the ability to diagnose GER disease by use of ambulatory pH monitoring have unveiled a host of extraesophageal manifestations of GERD. These include pulmonary symptoms of asthma, recurrent pneumonia, cough or bronchitis, and infant apnea. Many of these symptoms may be the sole presentations of GER in these patients. It is important that the clinician is aware of these atypical presentations of GERD. The expanding use of ambulatory pH monitoring is helping to clarify the underlying pathophysiology of these disorders as well as to improve the ability to diagnose the atypical manifestations of GERD.

Is gastro-oesophageal reflux a factor in exercise-induced asthma?

Exercise-induced bronchoconstriction (EIB) occurs in the majority of patients with asthma. The relationship between asthma and gastro-oesophageal reflux (GER) is well defined, and the reports of exertional gastro-oesophageal acid reflux in healthy subjects, prompted us to study the relationship between EIB and GER. Following an overnight fast and medication withholding, 15 asthmatics and 15 normal subjects were placed on continuous monitoring of oesophageal pH and ECG. After baseline monitoring of oesophageal pH, at rest, for 30 min, spirometry was performed. Thereafter, the subjects underwent rigorous treadmill exercise for 8 min followed by spirometry, 10 min after running. Twelve out of 15 asthmatics and none in the control group demonstrated significant fall in FEV1 in response to exercise. However, only six out of 15 normal subjects and three in the asthmatic group had evidence of GER during or following exercise. We concluded that there is no significant correlation between EIB and GER in patients with asthma.

Allergen and irritant control: importance and implementation

The Expert Panel Report 2. Guidelines for the Diagnosis and Management of Asthma (1) begins its section on controlling factors that precipitate or worsen asthma with the statement: "For successful long-term asthma management, it is essential to identify and reduce exposures to relevant allergens and irritants and to control other factors that have been shown to increase asthma symptoms and/or precipitate asthma exacerbations." The presence of allergy to indoor allergens and certain seasonal fungal spores has been found to be a risk factor for asthma in epidemiologic studies around the world. Generally between 70% and 85% of asthmatic populations studied have been reported to have positive skin-prick tests. Exposure of allergic patients to inhalant allergens increases airway inflammation, airway hyper-responsiveness, asthma symptoms, need for medication, severe attacks, and even death due to asthma. Environmental tobacco smoke exposure has been shown to increase the prevalence of childhood asthma and to increase asthma symptoms and bronchial hyperresponsiveness while reducing pulmonary function in children chronically exposed. Exposure to other indoor irritants, largely products of unvented combustion, has also been found to increase asthma symptoms. Outdoor air pollution increases asthma symptoms; levels of specific pollutants correlate with emergency room visits and hospitalization for asthma. Rhinitis/sinusitis and gastroesophageal reflux are commonly associated with asthma, and treatment of these conditions has been shown to improve asthma. In patients sensitive to aspirin and nonsteroidal anti-inflammatory drugs or metabisulfites, exposure to these agents can precipitate severe attacks of asthma. Viral infections are common causes for exacerbations of asthma. Infections with Mycoplasma pneumoniae and Chlamydia pneumoniae contribute to acute exacerbations and perhaps to long-term morbidity, as well. This chapter will discuss preventive and therapeutic measures that have been found effective in reducing the impact of aggravating or precipitating factors in patients with asthma.

Effects of HCl-pepsin laryngeal instillations on upper airway patency-maintaining mechanisms

Gastroesophageal reflux has been indicated as an etiopathological factor in disorders of the upper airway. Upper airway collapsing pressure stimulates pressure-responsive laryngeal receptors that reflexly increase the activity of upper airway abductor muscles. We studied, in anesthetized dogs, the effects of repeated laryngeal instillations of HCl-pepsin (HCl-P; pH = 2) on the response of laryngeal afferent endings and the posterior cricoarytenoid muscle (PCA) to negative pressure. The effect of negative pressure on receptor discharge or PCA activity was evaluated by comparing their response to upper airway (UAO) and tracheal occlusions (TO). It is only during UAO, but not during TO, that the larynx is subjected to negative transmural pressure. HCl-P instillation decreased the rate of discharge during UAO of the 10 laryngeal receptors studied from 56.4 +/- 10.9 (SE) to 38.2 +/- 9.2 impulses/s (P < 0.05). With UAO, the peak PCA moving time average, normalized by dividing it by the peak values of esophageal pressure, decreased after six HCl-P trials from 4.29 +/- 0.31 to 2.23 +/- 0.18 (n = 6; P < 0.05). The responses to TO of either receptors or PCA remained unaltered. We conclude that exposure of the laryngeal mucosa to HCl-P solutions, as it may occur with gastroesophageal reflux, impairs the patency-maintaining mechanisms provided by laryngeal sensory feedback. Inflammatory and necrotic alterations of the laryngeal mucosa are likely responsible for these effects.

Is there a place for laparoscopic antireflux surgery in The Netherlands?

BACKGROUND

Antireflux surgery has not gained wide acceptance in The Netherlands in the past two decades. The introduction of laparoscopic fundoplication seems to have had no impact on the number of antireflux operations performed per year.

METHODS

The SIG data were consulted in order to compile an inventory on the number of antireflux operations performed in The Netherlands between 1977 and 1995. The data were compared with those kindly supplied by the Laparoscopic Societies of the Scandinavian countries.

RESULTS

The number of antireflux operations per year in The Netherlands, 1.7/100,000 per year, is far less than reported in the four Scandinavian countries, 15/100,000 per year, and also far below the 10/100,000 per year needed for antireflux surgery on a yearly basis.

CONCLUSIONS

In The Netherlands, 1.7/100,000 inhabitants per year undergo antireflux surgery. This figure has remained virtually stable in the past two decades, i.e. it has not changed even since the introduction of H2-receptor antagonists, proton-pump inhibitors and laparoscopic antireflux surgery. The success of medical treatment and personal, anecdotal, experience of gastroenterologists with patients they have referred for surgery explain the low number of antireflux operations performed. Currently, a randomized trial is being conducted in The Netherlands comparing the effectivity, costs and quality of life after conventional Nissen fundoplication with the laparoscopic approach. All operations are performed or supervised by a limited number of experienced surgeons who have gone through the learning curve of both the open and conventional technique.

Gastric asthma: a pathophysiological entity?

BACKGROUND

Gastro-oesophageal reflux disease (GORD) is manifested by typical reflux symptoms and atypical extra-oesophageal symptoms. Important in this respect are respiratory conditions. Gastric asthma is a prominent example of these extra-oesophageal manifestations of GORD. There is, however, much debate about its prevalence, pathophysiology and clinical importance.

METHODS

Narrative review of the literature.

RESULTS

In asthmatics, the prevalence of GORD is generally reported to be higher than in normals, but with a wide range, probably due to patient selection. In a minority of asthmatics GORD aggravates or triggers asthma. The pathogenetic mechanisms can be a vagally transmitted reflex as well as micro-aspiration of refluxed material. The association with inflammatory mediator release has been insufficiently investigated. Selecting those who are likely to respond to anti-reflux measures is important: those with difficult to treat asthma, non-allergic asthma, adult-onset asthma with GORD. Oesophageal pH-metry to prove GORD and gastroscopy to diagnose Barrett's metaplasia are advisable.

Spectrum of supraesophageal complications of gastroesophageal reflux disease

There is a growing body of clinical and research evidence to support the role of gastroesophageal reflux in the etiology of certain disorders occurring in structures located above the body of the esophagus. These supraesophageal complications have only recently been identified but substantiation of the role of gastroesophageal reflux has been difficult and sometimes impossible with the technology currently available. This introductory article to the clinical issues involved in supraesophageal complications of GERD presents several index cases and asks far more questions than it gives answers about these patients. Clinical evidence supporting the role of GERD is discussed and the results of therapy reviewed. Education of the practicing physician to the role of supraesophageal complications of GERD is urged to help recognize the likelihood of such clinical conditions. There is a real need for additional clinical use and evaluation of multi site intraesophageal and pharyngeal pH probes in patients with suspected supraesophageal complications of GERD. More importantly, development of new techniques for measuring micro reflux events and sophisticated methods for determining the duration of acid exposure in tissues above the esophagus is essential. Finally, more prospective controlled outcome studies of patients with supraesophageal complications of GERD are needed utilizing specific treatment algorithms.

Medical therapy of gastroesophageal reflux and management of esophageal strictures

The goals of modern medical therapy for gastroesophageal reflux disease are threefold: first, eliminate symptoms; second, heal injured esophageal mucosa; third, manage and/or prevent complications. Selection of a particular medical regimen depends on the severity of the disease, effectiveness of the therapy, cost, and convenience of the medical regimen. An accurate diagnosis needs to be made in patients suspected with esophageal strictures. If there is a treatable underlying disease, specific therapy is essential. The goal of dilation therapy should be established and set about to accomplish in a timely, but unhurried fashion. Fluoroscopy and wire-guided dilators should be used liberally, especially for difficult strictures.

Adult asthma and gastro-oesophageal reflux: the effects of omeprazole therapy on asthma

BACKGROUND

Approximately 40-60% of patients with asthma have gastro-oesophageal reflux (GOR) and it has been postulated that this may worsen asthma severity.

AIMS

To investigate the effect of the potent gastric acid inhibitor omeprazole 40 mg orally daily on peak expiratory flow rate (PEFR), asthma symptoms and histamine bronchial responsiveness in adult patients with both asthma and GOR.

METHODS

This was a double blind, randomised, placebo controlled, crossover study. Upper gastrointestinal endoscopy, 24 hour oesophageal pH measurements, spirometry and histamine bronchoprovocation test (HIT) were performed prior to entry. Phase 1:2 week placebo run-in period, with baseline recording of PEFR, asthma and GOR symptoms, and use of inhaled beta 2-agonist. Phase 2: patients randomised to receive either placebo or omeprazole 40 mg/d for four weeks. Phase 3: placebo for two weeks. Phase 4: patients crossed over to opposite treatment from that of phase 2. Spirometry, and diary cards were assessed at beginning and end of phases 2 and 4. HIT was performed at the end of phase 2 and at the beginning and end of phase 4.

RESULTS

Twenty patients (eight female and 12 male) completed the study. The evening but not morning PEFR (% predicted) were significantly higher on omeprazole vs placebo (82 +/- 4% SEM vs 79 +/- 4% SEM; p < 0.05). No significant differences were found in FEV1, FVC, histamine bronchial responsiveness and diurnal variation of PEFR between placebo and omeprazole treatments. Similarly, there were no significant differences during placebo and omeprazole periods in day time wheeze, cough, breathlessness, beta 2-agonist use or night time wheeze and breathlessness. Day and night heartburn symptoms were significantly better on omeprazole vs placebo (p < 0.05).

CONCLUSIONS

Omeprazole 40 mg daily improved evening PEFR in asthma patients with GOR. However, asthma symptoms, inhaled beta 2-agonist use and histamine bronchial responsiveness did not change.

Diagnosis and management of chronic persistent dry cough

Cough is one of the commonest symptoms of lung disease and is a frequent problem encountered in general practice as well as in hospital practice. A wide range of disease processes may present with cough and definitive treatment depends on making an accurate diagnosis of the cause. A diagnostic work-up for patients with persistent dry cough is presented. The most common associated conditions are post-viral cough, asthma, rhinosinusitis (post-nasal drip or 'nasal catarrh') and gastro-oesophageal reflux. Treatment with angiotensin-converting enzyme inhibitors can also lead to a persistent dry cough. Specific treatment of the cause should control the cough, but this may not occur in all cases and in a sizeable proportion of patients, no associated cause can be found. An increased sensitivity of the cough reflex can be observed in patients with persistent dry cough. Symptomatic relief must be considered when the cough interferes with the patient's health and sleep but the most effective antitussive opiates cause sedation and may be addictive. Treatment of persistent dry cough remains a challenge in some patients and there is still scope for improvement in its diagnosis and effective therapy.

Respiratory complications of gastroesophageal reflux disease

There is a relationship between gastroesophageal reflux disease and certain respiratory symptoms and findings. Among these are cough, laryngitis, and wheezing dyspnea. The pathophysiology of these conditions can vary from actual aspiration of gastric content to esophageal mucosal inflammation with the respiratory symptoms induced by a vagally mediated reflex mechanism.

Simultaneous tracheal and oesophageal pH monitoring during mechanical ventilation

OBJECTIVE

To simultaneously record tracheal and oesophageal pH in mechanically ventilated children to determine: (1) the feasibility and safety of the method; (2) the incidence of gastro-oesophageal reflux (GOR) and pulmonary contamination; and (3) their associated risk factors.

DESIGN

Prospective study.

SETTING

Paediatric intensive care unit in a university hospital.

PATIENTS

Twenty mechanically ventilated children (mean age 6.7 years) who met the following inclusion criteria: endotracheal tube with an internal diameter of 4 mm or more (cuffed or uncuffed), mechanical ventilation for an acute disease, no treatment with antiacids, prokinetics, or H2-receptor blockers, and no nasogastric or orogastric tube.

METHODS

The tracheal antimony pH probe was positioned 1 cm below the distal end of the endotracheal tube. The oesophageal antimony pH probe was positioned at the lower third of the oesophagus. pH was recorded on a double channel recorder and analysed with EsopHogram 5.01 software and by examination of the trace. The following definitions were used: GOR index, percentage of time pH < 4; pathological GOR, GOR index > 4.8%; tracheal reflux, fall in tracheal pH < 4, 4.5, or 5, or a decrease of one unit from baseline, in both cases preceded by an episode of GOR. The results were analysed statistically by Fisher's exact and the Kruskal-Wallis test.

RESULTS

The procedure was well tolerated and the median duration of analysable recording was 6 hours (range 5-22.6). Pathological GOR was observed in eight (40%) children. GOR was more frequent with an uncuffed endotracheal tube than with a cuffed one (p = 0.01). Tracheal reflux (pH < 4) was observed in four children (20%) without clinical evidence of pulmonary aspiration. Episodes of tracheal reflux were associated with a GOR index > 10% (p < 0.01) and were more frequent with a maximal inspiratory pressure of < 25 cm H2O (p = 0.03), but were not related to the indication for mechanical ventilation, whether the endotracheal tube was cuffed or not, age, or drug treatment.

CONCLUSIONS

Simultaneous tracheal and oesophageal pH monitoring was feasible in the setting of this study. Tracheal reflux can occur without pathological GOR, and GOR may occur without tracheal reflux. Further prospective studies in larger groups of patients are now justified.

Asthma

Bronchial asthma is now recognised to be a major cause of morbidity and even mortality in people of all ages. Two important ideas have changed our approach to asthma management. The first is understanding that asthma is a chronic inflammatory disorder which needs regular treatment with anti-inflammatory drugs such as inhaled corticosteroids to prevent further attacks. The second development is the availability of prescribable peak flow meters, which allows both confident diagnosis and early prediction of relapse. Asthma management guidelines provide a logical treatment framework for most patients, but a few difficult cases still consume large amounts of medical time. The commonest problem is one of compliance with treatment which may respond to patient education, although this is not universally so. Other problems include misdiagnosis, acid reflux and, rarely, true corticosteroid-resistant asthma. Several potentially important new treatments have been developed. These include longer acting anticholinergic drugs, drugs with bronchodilator and some anti-inflammatory properties which antagonise or inhibit the production of leukotrienes, sub-types of phosphodiesterase inhibitor with anti-inflammatory properties and immunosuppressive drugs such as cyclosporin. Ultimately these new treatments must be rigorously tested and integrated into a care plan that remains centred on patient education.