Gastro-oesophageal reflux and night-time asthma

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.

Scintigraphic detection of gastro-pulmonary aspiration in patients with respiratory disorders

The scintigraphic detection of small nocturnal aspirations of radio-labelled gastric contents is difficult in the presence of high remaining activity in the abdomen, causing a non-uniform background activity. This problem was examined in phantom experiments and a technique for interpolative background correction was further developed. The accuracy of this technique was found to be influenced by the distance between the lung and the abdominal source of activity, and the minimum detectable 'aspirated' activity was determined as 0.1 MBq at a distance of 15 cm and 1 MBq at 5 cm. The interpolative technique for background correction was evaluated on healthy volunteers and laryngectomized patients, examined 10 h after intragastric instillation of 200 MBq of 99Tcm-pertechnetate. After background subtraction, their calculated pulmonary mean net count value was comparable to that registered before the radioactive tracer was administered. No localized accumulation of activity was found in any of these controls. The technique was then applied clinically to 55 patients with chronic respiratory disorders and symptoms of gastroesophageal reflux. Aspiration was detected in 11 patients (20%). Five aspirators had asthma, two a chronic cough of unknown origin, two recurrent pulmonary infections, and one chronic bronchitis and chronic laryngitis respectively. Aspiration was detected among patients with and without demonstrated pathological gastroesophageal reflux.

Most asthmatics have gastroesophageal reflux with or without bronchodilator therapy

The relationship between gastroesophageal reflux and asthma has not been clearly defined. We measured the lower esophageal sphincter pressures and studied gastroesophageal reflux patterns over 24 hours using an ambulatory Gastroreflux Recorder (Del Mar Avionics, Irvine, CA) in 44 controls and 104 consecutive adult asthmatics. The presence or absence of reflux symptoms was not used as a selection criterion for asthmatics. All asthmatics had discrete episodes of diffuse wheezing and documented reversible airway obstruction of at least 20%. Patients underwent reflux testing while receiving, if any, their usual asthmatic medications: 71.2% required chronic bronchodilators and 28.8% required no bronchodilators. Compared with controls, asthmatics had significantly decreased lower esophageal sphincter pressures, greater esophageal acid exposure times, more frequent reflux episodes, and longer clearance times in both the upright and supine positions (P less than 0.0001 for all parameters tested). There were no differences in any of the measured reflux parameters between asthmatics who required bronchodilators and those who did not. Thus, the decreased lower esophageal sphincter pressures and increased levels of acid reflux in asthmatics were not entirely caused by the effects of bronchodilator therapy. Receiver-operating characteristic analysis generated reflux values that discriminated asthmatics from controls. More than 80% of adult asthmatics have abnormal gastroesophageal reflux. We conclude that most adult asthmatics, regardless of the use of bronchodilator therapy, have abnormal gastroesophageal reflux manifested by increased reflux frequency, delayed acid clearance during the day and night, and diminished lower esophageal sphincter pressures.

Nocturnal oxygen saturation and body movement in asthmatics treated with controlled-release preparations of theophylline or terbutaline

Nine adult asthmatics with a history of nocturnal symptoms and with morning dips in peak expiratory flow (PEF) were treated for 10-14 days with 24-h controlled-release preparation of theophylline (Th), or a controlled-release preparation of terbutaline (Te), in a double-blind cross-over experiment. During treatment with 450-900 mg Th in the evening morning, plasma drug levels ranged from 53-95 (mean 73) mumol/l. The Te dose was 7.5 mg twice daily. Morning PEF values during Th (mean 338 l.min-1) and Te (316 l.min-1) were not significantly different. There were no significant differences between the treatments in average nocturnal oximetric O2 saturation (91.9% during Th and 91.0% during Te), or the amount of nocturnal body movement, recorded with a static charge sensitive bed (total number of movements 146 during Th and 120 during Te). No difference between the treatments was seen with respect to assessment by the subjects of sleep quality, which was considered fair or good. The findings suggest that in moderately severe asthma, nocturnal oxygenation and sleep quality were similar during the two treatments.

Effects of ranitidine treatment on patients with asthma and a history of gastro-oesophageal reflux: a double blind crossover study

Forty eight patients with moderate to severe asthma were enrolled in a double blind crossover study designed to evaluate the effects of ranitidine treatment, 150 mg twice daily for four weeks, on gastro-oesophageal reflux, asthma control, and bronchial reactivity. All 48 had a history of reflux symptoms and 27 had in addition reflux associated respiratory symptoms. Thirty two patients had objective evidence of acid reflux on 24 hour pH monitoring (pH of less than 4 for more than 1% of the 24 hours) and 27 patients had a positive result in the acid perfusion test. Reflux symptoms were significantly improved after ranitidine treatment. Ranitidine treatment was associated with modest improvements in nocturnal asthma and daily use of inhaled bronchodilator drugs but there was no significant change in bronchial reactivity, lung function, peak flow, or the number of eosinophils in the blood. Comparisons between the effect of ranitidine treatment on asthma control were performed between patients with and without a history of reflux associated respiratory symptoms, with and without a positive result in the acid perfusion test, and with and without objective evidence of gastro-oesophageal reflux. A history of reflux associated respiratory symptoms was the only factor that predicted an improvement in asthma control after ranitidine treatment. These results indicate that antireflux treatment will produce only small improvements in asthma control in asthmatic patients with a history of gastro-oesophageal reflux.

Ambulatory pH monitoring of gastro-oesophageal reflux in "morning dipper" asthmatics

A causal relation between gastro-oesophageal reflux and nocturnal asthma has been postulated. Forty four adult asthmatics underwent ambulatory monitoring of their oesophageal pH over 24 hours to find out if there was such a relation. Of these 21 showed significant "morning dipping" in which the peak expiratory flow falls during the night. Asthmatics with morning dipping had a history of nocturnal wheeze and a higher incidence of reflux symptoms, but measurement of oesophageal pH showed no significant difference in the amount or pattern of reflux when compared with "non-dippers." Overall, 15 asthmatics had gastro-oesophageal reflux, and these participated in a randomised, double blind crossover trial of ranitidine versus placebo. No significant difference was found in the peak expiratory flow rates or subjective evaluation of well being of the patients.