Responses to different levels of esophageal acidification during waking and sleep

Nocturnal Gastroesophageal Reflux Disease (GERD) and Sleep: An Important Relationship That Is Commonly Overlooked

Gastroesophageal reflux disease (GERD) is a prevalent, chronic medical condition that affects 13% of the adult population globally at least once a week. Sleep disturbances are frequently encountered in up to 25% of the GERD patients, likely due to nocturnal gastroesophageal reflux (GER). With advance in diagnostic techniques allowing for an improved understanding of involved physiological mechanisms of nocturnal reflux, there is growing evidence of a bidirectional relationship between GERD and sleep disturbances. Furthermore, nocturnal GER is associated with more complicated GERD. Obstructive sleep apnea (OSA) and GERD also have been linked, but to what degree remains controversial. Treatment of nocturnal GER has been shown to improve both subjective and objective sleep measures. The therapeutic approach includes lifestyle modifications and medication individualization and optimization with proton-pump inhibitors serving as the mainstay of treatment. Antireflux surgery and newer endoscopic procedures have been demonstrated to control nocturnal GER.

Discounting the duration of bolus exposure in impedance testing underestimates acid reflux

Background

Combined impedance-pH testing (MII) allows for detection of reflux episodes regardless of pH. However impedance-based diagnosis of reflux may not routinely account for duration of the reflux episode. We hypothesize that impedance testing may be less sensitive than pH-testing in detecting acid reflux off therapy as a result of discounting duration of exposure.

Methods

Baseline characteristics and reflux parameters of MII studies performed off-anti-secretory medications were analyzed. Studies on acid suppressive medication and those with recording times less than 20 h or low baseline impedance were excluded.

Results

A total of 73 consecutive MII studies were analyzed of which 31 MII studies had elevated acid exposure while 16 were abnormal by impedance criteria. MII testing off-therapy was more likely to be abnormal by pH criteria (percent time pH < 4) than impedance criteria (total reflux):[42 vs 22 % (p =0.02)]. Acid exposure (percent time pH < 4) identified more studies as abnormal than MII-detected acid reflux episodes [42 vs 34 % (p < 0.01)]. Mean acid clearance time (pH-detected) was significantly longer than median bolus clearance time (impedance-detected) in the total [98.7 s vs 12.6 s (p < 0.01)], upright [58.6 s vs 13.1 s (p < 0.01)], and recumbent positions [136.7 s vs 14.2 s (p < 0.01)] with the greatest difference seen in the recumbent position. The mean ratio of mean acid clearance time (pH-detected) and the median bolus clearance time (impedance-detected) was significantly higher in the recumbent position compared to the upright position [11. vs 5.3 (p = 0.01)].

Conclusion

Ambulatory impedance testing underestimates acid reflux compared to esophageal acid exposure by discounting the prolonged period of mucosal contact with each acid reflux episode, particularly in the recumbent position.

Association between sleep disturbances and abdominal symptoms

OBJECTIVE

Although gastroesophageal reflux disease (GERD) is known to cause sleep disturbances, the relationships between other abdominal symptoms and sleep disorders have not been clarified. In the present study, we examined the relationships between daytime sleepiness and various abdominal symptoms in a non-clinical population.

METHODS

We enrolled 2,936 subjects who visited Matsue Red Cross Hospital for an annual health check examination during a 10-month consecutive period after excluding those with organic gastrointestinal diseases. The Izumo scale abdominal symptom and Epworth Sleepiness Scale (ESS) questionnaires were employed to evaluate the presence of abdominal symptoms and daytime sleepiness.

RESULTS

Among the 2,936 subjects, 233 (7.9%), 254 (8.6%) and 528 (18%) had GERD-like, functional dyspepsia (FD)-like and irritable bowel syndrome (IBS)-like symptoms, respectively. The ESS scores in the subjects with GERD-, FD- and IBS-like symptoms were significantly higher than those observed in the asymptomatic subjects. The subjects with multiple abdominal symptoms tended to have higher ESS scores than those with single symptoms. A multiple logistic regression analysis revealed a younger age and the presence of FD- and IBS-like symptoms to be significant influencing factors for sleep disturbances.

CONCLUSION

The presence of FD and IBS symptoms in addition to GERD symptoms exhibits a strong relationship with sleep disturbances from the viewpoint of daytime sleepiness.

Systematic review: relationships between sleep and gastro-oesophageal reflux

BACKGROUND

Gastro-oesophageal reflux disease (GERD) adversely impacts on sleep, but the mechanism remains unclear.

AIM

To review the literature concerning gastro-oesophageal reflux during the sleep period, with particular reference to the sleep/awake state at reflux onset.

METHODS

Studies identified by systematic literature searches were assessed.

RESULTS

Overall patterns of reflux during the sleep period show consistently that oesophageal acid clearance is slower, and reflux frequency and oesophageal acid exposure are higher in patients with GERD than in healthy individuals. Of the 17 mechanistic studies identified by the searches, 15 reported that a minority of reflux episodes occurred during stable sleep, but the prevailing sleep state at the onset of reflux in these studies remains unclear owing to insufficient temporal resolution of recording or analysis methods. Two studies, in healthy individuals and patients with GERD, analysed sleep and pH with adequate resolution for temporal alignment of sleep state and the onset of reflux: all 232 sleep period reflux episodes evaluated occurred during arousals from sleep lasting less than 15 s or during longer duration awakenings. Six mechanistic studies found that transient lower oesophageal sphincter relaxations were the most common mechanism of sleep period reflux.

CONCLUSIONS

Contrary to the prevailing view, subjective impairment of sleep in GERD is unlikely to be due to the occurrence of reflux during stable sleep, but could result from slow clearance of acid reflux that occurs during arousals or awakenings from sleep. Definitive studies are needed on the sleep/awake state at reflux onset across the full GERD spectrum.

Nocturnal gastroesophageal reflux revisited by impedance-pH monitoring

Background/Aims

Impedance-pH monitoring allows detailed characterization of gastroesophageal reflux and esophageal activity associated with reflux. We assessed the characteristics of nocturnal reflux and esophageal activity preceding and following reflux.

Methods

Impedance-pH tracings from 11 healthy subjects and 76 patients with gastroesophageal reflux disease off acid-suppressive therapy were analyzed. Characteristics of nocturnal supine reflux, time distribution and esophageal activity seen on impedance at 2 minute intervals preceding and following reflux were described.

Results

Patients had more nocturnal reflux events than healthy subjects (8 [4-12] vs 2 [1-5], P = 0.002), with lower proportion of weakly acidic reflux (57% [35-78] vs 80% [60-100], P = 0.044). Nocturnal reflux was mainly liquid (80%) and reached the proximal esophagus more often in patients (6% vs 0%, P = 0.047). Acid reflux predominated in the first 2 hours (66%) and weakly acidic reflux in the last 3 hours (70%) of the night. Most nocturnal reflux was preceded by aboral flows and cleared by short lasting volume clearance. In patients, prolonged chemical clearance was associated with less esophageal activity.

Conclusions

Nocturnal weakly acidic reflux is as common as acid reflux in patients with gastroesophageal reflux disease, and predominates later in the night. Impedance-pH can predict prolonged chemical clearance after nocturnal acid reflux.

Advancements in the analysis of esophageal pH monitoring in GERD

Ambulatory 24 h esophageal pH monitoring enables quantification of esophageal acid exposure and assessment of the temporal relationship between symptoms and acid reflux events. Analysis of pH monitoring is currently divided into upright and recumbent periods based on the patient's body position. However, in this Review, we demonstrate that physiologic studies have shown that sleep, and not recumbency, has a greater impact on gastroesophageal reflux during night-time. The physiologic studies are further supported by clinical trials demonstrating that gastroesophageal reflux characteristics during the recumbent-awake period are similar to those in the upright rather than the recumbent-asleep period. The introduction of the integrated pH monitoring and actigraphy data analysis program offers better separation of the recumbent-awake and recumbent-asleep periods. The physiologic studies and clinical trials, as well as the availability of a better tool to measure pH during sleep, support a paradigm shift in the analysis of pH monitoring data from body position (upright or recumbent) to state of consciousness (awake or asleep).

Conscious awakenings are commonly associated with Acid reflux events in patients with gastroesophageal reflux disease

BACKGROUND & AIMS

More than half of patients with gastroesophageal reflux disease (GERD) report heartburn that awakens them from sleep. We aimed to determine the frequency of conscious awakenings associated with acid reflux events during sleep and their relationship with symptoms in patients with GERD compared with normal subjects.

METHODS

The study included 39 patients with heartburn and/or regurgitation at least 3 times each week and 9 healthy individuals as controls. Subjects underwent pH testing concomitantly with actigraphy. Novel software simultaneously integrated raw actigraphy and pH data matched by time to determine patients' conscious awakenings during sleep and their temporal relationship with acid reflux events and GERD-related symptoms.

RESULTS

A total of 104 and 11 conscious awakenings were recorded in 89.7% of patients and 77.8% of normal controls, respectively. The mean number of conscious awakenings was significantly higher in the group with GERD compared with controls (3.0 ± 0.3 vs 1.8 ± 0.4, P < .05). Of the conscious awakenings, 51.9% (51/104) were associated with an acid reflux event in GERD patients and 0 in controls (P < .01). Only 16.3% of total conscious awakenings were symptomatic. In most of the conscious awakenings that were associated with an acid reflux event (85.6%), the awakening preceded the reflux event.

CONCLUSIONS

Acid reflux events occur primarily after an awakening episode. Conscious awakenings from sleep are common among patients with GERD and are frequently associated with acid reflux events. However, conscious awakenings associated with reflux events are seldom symptomatic.

Effect of gastroesophageal reflux disease on sleep

Recent studies have demonstrated a bidirectional relationship between gastroesophageal reflux disease (GERD) and sleep where night-time reflux leads to sleep deprivation and sleep deprivation per se can exacerbate GERD by enhancing perception of intra-esophageal stimuli. Presently, treatment has primarily focused on reducing night-time reflux and thus improving sleep quality. Future studies are needed to further explore the relationship between GERD and sleep and the potential of novel therapeutic options to interrupt the vicious cycle between GERD and sleep.

Reassessment of the principal characteristics of gastroesophageal reflux during the recumbent period using integrated actigraphy-acquired information

OBJECTIVES

Characterization of gastroesophageal reflux (GERD) events during the sleep period has been hampered by lack of any patient-friendly technique that allows accurate assessment of sleep duration and awakening time, without confining patients to a sleep laboratory. Our aim was to compare principal reflux characteristics during the upright, recumbent-awake, and recumbent-asleep periods as well as to determine the effect of sleep awakenings on the principal reflux characteristics of the recumbent-asleep period using novel technology that allows integration of recorded actigraphy data into collected pH information.

METHODS

Patients with heartburn at least three times a week for the previous 3 months were invited to participate in this study. All participants were evaluated by the demographics and the GERD Symptom Checklist questionnaires. Thereafter, patients underwent ambulatory 24-h esophageal pH monitoring concomitantly with actigraphy. A novel technique was used to superimpose simultaneously recorded raw actigraphy data over pH data, resulting in more accurate information about reflux events during upright, recumbent-awake, recumbent-asleep, and conscious awakening periods as well as the relationship between symptoms and acid reflux events in the aforementioned periods.

RESULTS

Thirty-nine subjects (M/F: 26/13, mean age 56.6+/-14 years) with an abnormal pH test were enrolled into the study. The recumbent period appeared heterogeneous and was clearly divided into recumbent-awake (123.0+/-20.2 min) and recumbent-asleep (485.6+/-23.6 min) periods. The percent total time pH<4, the mean number of acid reflux events, and the number of symptoms associated with reflux events were significantly greater in the recumbent-awake as compared with the recumbent-asleep period. The mean duration of an acid reflux event was not different among upright, recumbent-awake, and recumbent-asleep periods. However, short-duration reflux events during the sleep period were associated with conscious awakenings as compared with those during sleep (0.74+/-0.11 min vs. 1.64+/-0.3 min, P=0.01).

CONCLUSIONS

The recumbent period is divided into recumbent-awake and recumbent-asleep periods. The recumbent-awake period has significantly different principal reflux characteristics than the recumbent-asleep period. Duration of an acid reflux event during the recumbent-asleep period is not uniformly prolonged. Short-duration acid reflux events during the sleep period are likely due to conscious awakenings.

Review article: sleep-related gastro-oesophageal reflux as a distinct clinical entity

BACKGROUND

Many patients with chronic gastro-oesophageal reflux disease (GERD) have frequent nighttime heartburn as well as sleep-related gastro-oesophageal reflux (GOR). Sleep-related GOR has been shown to play an important role in the development of oesophagitis and other complications of GOR.

AIM

To present a conceptual argument that nighttime heartburn and associated sleep-related GOR should be recognized as a distinct clinical entity deserving special attention with regard to the diagnosis and treatment of GERD.

METHODS

The data presented come from surveys of GERD patients as well as from physiological studies to include studies monitoring oesophageal pH and spontaneous reflux events during polysomnographically (PSG) monitored sleep.

RESULTS

Evidence is presented to show that nighttime heartburn is prevalent and its occurrence separates patients from those who have heartburn most exclusively in the daytime. The evidence presented also supports the notion that nighttime heartburn sufferers have a more complicated disease and they have a greater risk of developing oesophagitis and other respiratory complications. The data also show that responses to acid mucosal contact are quite different during sleep compared to responses measured during the waking state.

CONCLUSIONS

Nighttime heartburn and GOR represent a distinct clinical entity which deserves specific attention in the diagnosis and optimal treatment of GERD.

Effect of zolpidem on the sleep arousal response to nocturnal esophageal acid exposure

BACKGROUND & AIMS

Nocturnal acid reflux is associated with complicated gastroesophageal reflux (GER) disease. Nocturnal GER initiates a protective arousal reflex, which induces a swallow to clear esophageal acid. The purpose of this study was to determine the effect of zolpidem on the sleep arousal mechanism and acid clearance in patients with documented GER, compared with control subjects with normal acid exposure.

METHODS

Eight controls and 16 GER patients were enrolled in a randomized, double-blind, placebo-controlled study. Zolpidem or placebo was given on separate nights. Reflux events and reflux-associated arousals or awakenings were recorded using simultaneous esophageal pH recording and standard polysomnography.

RESULTS

Nocturnal acid exposure resulted in a sleep arousal 89% of the time in participants (with and without GER) given placebo but only 40% in those given zolpidem (P < .01). In controls given placebo, acid reflux events lasted 1.15 +/- 0.28 seconds; in controls given zolpidem, they lasted 15.67 +/- 12.42 seconds (P < .01). In GER patients given placebo, the acid reflux events lasted 37.8 +/- 17.2 seconds compared with 363.3 +/- 139.3 seconds with zolpidem (P < .01). With zolpidem reflux events lasted 630.6 +/- 236.5 seconds when no arousal occurred and 49.2 +/- 19.11 seconds when an arousal was recorded (P < .001).

CONCLUSIONS

Zolpidem reduced the arousal response to nocturnal acid exposure and increased the duration of each esophageal acid reflux event in healthy individuals and patients with GER. Because nocturnal acid exposure was prolonged, hypnotic use by patients with GER could lead to increased risk for complicated disease.

The relationship between gastroesophageal reflux disease and sleep

Recent studies demonstrate a bidirectional relationship between gastroesophageal reflux disease (GERD) and sleep in which nighttime reflux leads to sleep deprivation and sleep deprivation can exacerbate GERD by enhancing perception of intraesophageal stimuli. Current treatment primarily focuses on reducing nighttime reflux, thus improving sleep quality. Future studies are needed to further explore the relationship between GERD and sleep and the potential of novel therapeutic options to interrupt the vicious cycle between them.

Analysis of 24-hour esophageal pH monitoring: the effect of state of consciousness

This review addresses current advances in the diagnosis of sleep-related gastroesophageal reflux using ambulatory esophageal pH monitoring and laboratory monitoring, which includes polygraphic assessment of the state of consciousness. This 24-hour pH monitoring uses a new strategy of interpretation that characterizes acidic reflux events and specifically assesses the patient's position and state of consciousness. Thus, the recognition of reflux events during waking and sleep will add to the overall assessment of gastroesophageal reflux and its severity and clinical relevance. The pH testing, together with overnight polysomnography, offers an opportunity to link nighttime reflux with disease severity. The application of multichannel impedance with pH monitoring allows detection of acidic and nonacidic reflux events during sleep and also helps to elucidate the physiologic response of the esophagus to these events during sleep. The significance of these findings will increase our knowledge of esophageal physiology and the pathologic mechanisms underlying gastroesophageal reflux disease.

Gastroesophageal reflux disease as an etiology of sleep disturbance in subjects with insomnia and minimal reflux symptoms: a pilot study of prevalence and response to therapy

BACKGROUND

Gastroesophageal reflux disease (GERD) is a well-recognized cause of impaired sleep in patients with frequent GERD symptoms, as well as those with sleep apnea. GERD's role in sleep disturbance of minimally symptomatic patients with poor sleep quality is less clear.

AIM

We aimed to define the prevalence of GERD-related sleep disturbance in minimally-symptomatic subjects with demonstrated insomnia, and to assess the changes in sleep efficiency in these subjects after vigorous acid suppression.

METHODS

We recruited subjects aged 18-75 years reporting at least 6 months of insomnia, and sleep difficulty at least three nights per week. Subjects with a BMI > 30, a history of snoring or ongoing use of proton pump inhibitor or H2 receptor antagonist were excluded. Subjects underwent concurrent sleep study with dual channel 24-h pH study. Sleep efficiency, defined as the percentage of time after sleep initiation that the subject actually slept, and spontaneous arousal index, defined as the number of arousals per hour, were calculated. Those with a sleep study demonstrating poor sleep quality (sleep efficiency of < 83%, and > 10 arousals/h for those aged < 45, and > 15 for those who were 45 or older) and no obstructive sleep apnea were treated with rabeprazole 20 mg PO BID x 14 days. After 14 days, the subjects underwent repeat sleep study with pH monitoring. The GERD Symptom Assessment Scale (GSAS), the Epworth Sleepiness Scale (ESS) and the Functional Outcomes of Sleep Questionnaire (FOSQ) were administered to subjects at study inception and after 2 weeks of therapy.

RESULTS

Twenty-four subjects reporting insomnia were enrolled, and 20 met criteria for disordered sleep and no OSA. Seventeen completed both the first and second studies, and 16 were adequate for analysis. Baseline GSAS demonstrated trivial or no reflux symptoms in the cohort (no subject scored > 8 out of 45 on GSAS, corresponding to a median rating of reflux symptoms of "not at all"). Four of 16 subjects (25%) demonstrated abnormal pH studies at baseline. All four had normalization of acid exposures on PPI. After 2 weeks of treatment, three of these four subjects had normalization of sleep efficiency, compared to 4 of 12 of the subjects with normal Johnson-DeMeester scores. Repeated measures analysis showed significant improvement in spontaneous arousal index between the first and second study for the whole group (P < 0.0035). Pre- and post-therapy ESS and FOSQ scores were not significantly different.

CONCLUSIONS

Despite the lack of GERD symptoms, a significant minority of subjects with sleep disturbance have abnormal acid exposures. These preliminary data suggest that aggressive treatment of GERD in such patients may result in improvement in sleep efficiency.

Unrecognized GERD symptoms are associated with excessive daytime sleepiness in patients undergoing sleep studies

Sleep disturbances are commonly reported by patients who suffer from gastroesophageal reflux disease (GERD) but it is uncertain if GERD plays a role in patients with sleep disorders of undetermined origin. The prevalence of GERD in patients with sleep disorders of unknown etiology is uncertain; the aim of this study was to determine this prevalence. Three hundred eighty-five consecutive patients reporting to an outpatient clinic for evaluation of sleep disorders were assessed for their sleepiness in relation to reflux symptom intensity. Reflux symptoms that met the survey criteria for a diagnosis of GERD were present in 45 of the 385 subjects (12.8%). These subjects did not have a diagnosis of GERD and were not being treated. Multiple regression analysis showed that excessive sleepiness was associated with intensity of GERD symptoms. Patients with GERD had significantly higher Epworth sleep scores than patients without GERD (12.8 vs. 10.6; p=0.007), indicating more daytime sleepiness. We conclude that unrecognized and untreated GERD are present in many patients presenting with sleep disorders. Patients with GERD had significantly greater sleepiness. Further studies of the impact of GERD treatment in this population are necessary.

Preoperative gastric emptying and patterns of reflux as predictors of outcome after laparoscopic fundoplication

BACKGROUND

Some studies have suggested that patients with predominantly upright reflux have a poor outcome after laparoscopic antireflux surgery. It has been proposed that this might be related to gastric emptying. The aim of this study was to evaluate the relationship between preoperative upright reflux pattern, gastric emptying rate and outcome after laparoscopic fundoplication.

METHODS

Patients presenting for antireflux surgery underwent 24-h ambulatory pH testing and dual-isotope radionuclide gastric emptying studies. Reflux pattern was determined by the acid exposure in the distal oesophagus (percentage of time at pH < 4) during supine and upright posture. Outcome after fundoplication was assessed by a standardized postal questionnaire administered at 3 months, and 1, 2 and 5 years after surgery.

RESULTS

Of 372 patients identified from a prospectively maintained database, 109 had upright reflux, 57 supine reflux and 206 bipositional reflux. Overall patient satisfaction was not influenced by reflux pattern at any time after surgery. Delayed gastric emptying was documented in 31.0 per cent of patients, but there was no relationship with reflux pattern.

CONCLUSION

Patients with upright reflux did not have a less favourable outcome after fundoplication. Categorizing patients according to reflux pattern is of no value in predicting outcome or selecting patients for surgery.

Acidic and Non-Acidic Reflux During Sleep Under Conditions of Powerful Acid Suppression

BACKGROUND

During sleep, individuals are uniquely vulnerable to acid reflux. Acid reflux during sleep has been studied by a number of investigators, but non-acid reflux is largely unexplored.

METHODS

In this study, 15 individuals with significant subjective complaints of heartburn were treated with esomeprazole, 40 mg bid, and with placebo, in random order, for 1 week each. After 1 week of treatment, participants underwent combined impedence/pH monitoring and polysomnography. In both drug and placebo conditions, these procedures were done after participants consumed a meal designed to increase the likelihood of reflux events.

RESULTS

Total reflux events and acid reflux events were significantly decreased with proton-pump inhibitor (PPI) treatment as compared to placebo. Nonacid reflux events were more common with PPI treatment as compared to placebo, but this result was not statistically significant. The ratio of non-acidic to acidic events was significantly greater with PPI treatment, however. Similar results were found for reflux events that occurred only during sleep. Proximal migration of acidic vs non-acidic reflux events was found to be similar. There was no difference in sleep architecture between placebo and drug conditions.

CONCLUSION

PPI treatment reduced overall reflux events, but non-acidic reflux events were relatively more likely to occur with PPI treatment. The occurrence of these non-acidic reflux events on PPI might conceivably explain why some individuals continue to have symptoms after PPI treatment.

Review article: sleep and its relationship to gastro-oesophageal reflux

Gastro-oesophageal reflux disease (GERD) is among the most common gastrointestinal conditions in the USA. For most symptomatic patients, reflux events occur during both daytime and night-time hours. Whereas daytime reflux events tend to be frequent but brief, reflux events that occur during sleep are comparatively less frequent but significantly longer. Longer oesophageal acid-clearance and acid-mucosal contact times during sleep are at least partly due to several physiological changes associated with sleep, including dramatic declines in saliva production and frequency of swallowing, decreased conscious perception of heartburn and consequent arousal and clearance behaviours, and slower gastric emptying. Obstructive sleep apnea syndrome and obesity seem to predispose some patients to nocturnal GERD, and the presence of either of these conditions may help to identify patients with symptoms consistent with GERD. Recognition and treatment of night-time GERD are important because it can be associated with decreased quality of life (including sleep disruption) and increased risk of serious oesophageal and respiratory complications.

Sleep and gastroesophageal reflux: what are the risks?

To understand the phenomenon of sleep-related gastroesophageal reflux, it is necessary to understand how sleep alters basic physiologic mechanisms. Several mechanisms are depressed during sleep, which may lead to prolonged acid contact times. These mechanisms include the warning signal of heartburn, the frequency of swallowing, and the suppression of salivary secretion. Several investigations have shown that esophageal acid clearance is significantly prolonged during sleep, compared with the waking state; this is true even when sleeping subjects are compared with awake subjects in the supine position. Studies have also demonstrated an enhanced risk of pulmonary aspiration of gastric contents associated with depressed consciousness, likely related to the depression of upper airway protective mechanisms such as cough and swallowing. Available data also support the theory that certain endogenous response mechanisms involving the central nervous system that protect against the potentially damaging consequences of prolonged acid mucosal contact are invoked during sleep.

Gastrointestinal functioning during sleep: a new horizon in sleep medicine

A body of clinical and research literature is accumulating suggesting that there are significant alterations in gastrointestinal functioning during sleep, as well as sleep complaints and disorders in patients suffering from gastrointestinal disease. This review addresses the clinical applications of some basic alterations in gastrointestinal functioning during sleep, with a particular focus on gastroesophageal reflux disease and functional bowel disorders. Recent studies have shown that gastroesophageal reflux during sleep results in a marked prolongation of esophageal acid clearance time, and consequent mucosal damage. Data are reviewed which suggest that the more serious complications of gastroesophageal reflux, e.g. esophagitis and the extra-esophageal complications of reflux such as the exacerbation of bronchial asthma, laryngopharyngitis, and pulmonary aspiration are the result of sleep-related gastroesophageal reflux. Recent studies have also shown that patients with functional bowel disorder (e.g. irritable bowel syndrome and dyspepsia) have a high incidence of sleep complaints as well as abnormalities of autonomic functioning. Recent studies have shown that the measurement of autonomic functioning during sleep can differentiate the patients with functional bowel disorders from normal controls. The continued study of gastrointestinal functioning during sleep clearly establishes a new horizon of investigation in both sleep medicine and gastroenterology. 2001 Harcourt Publishers Ltd

Helicobacter pylori infection influences nocturnal gastric acid breakthrough

BACKGROUND

Nocturnal gastric acid breakthrough is defined as night-time periods when gastrin pH falls below 4.0 for greater than 1h during administration of a proton pump inhibitor. This phenomenon is a serious problem for patients who require strict control of their gastric acid secretions.

AIM

To investigate the prevalence of nocturnal gastric acid breakthrough in Japanese subjects during administration of rabeprazole, and to clarify the relationship between Helicobacter pylori infection and nocturnal gastric acid breakthrough.

METHODS

Thirty-one normal male volunteers were examined by ambulatory 24 h gastric pH monitoring four times: without medication, after a morning or an evening dose of 20 mg rabeprazole, and after administration of an H2-receptor antagonist at bedtime, in addition to the morning dose of rabeprazole. H. pylori infection was determined by the 13C-urea breath test and an assay for serum anti-H. pylori antibody.

RESULT

Nocturnal gastric acid breakthrough was observed in 12 patients (39%) after the morning dose of 20 mg rabeprazole. In all cases, nocturnal gastric acid breakthrough was inhibited completely by administration of the H2-receptor antagonist at bedtime. Only one patient with nocturnal gastric acid breakthrough had H. pylori infection.

CONCLUSION

The absence of H. pylori infection appears to be closely related to the occurrence of nocturnal gastric acid breakthrough during dosing with a proton pump inhibitor.

Proximal migration of esophageal acid perfusions during waking and sleep

OBJECTIVE

Proximal acid migration resulting from gastroesophageal reflux has been implicated in aerodigestive complaints and disorders. This study was designed to investigate the effects of acid volume, posture, and sleep on proximal esophageal acid migration (drop in pH to <4.0).

METHODS

The study was performed in 15 healthy adults. A distal esophageal acid perfusion technique to simulate gastroesophageal reflux was used. Esophageal acid perfusions of 1 ml and 3 ml were accomplished at a site 5 cm above the proximal border of the lower esophageal sphincter in the upright and supine positions during waking, and during polysomnographically monitored sleep. Esophageal pH was recorded by two sensors located in the mid- and proximal esophagus at 10 and 15 cm above the lower esophageal sphincter.

RESULTS

Acid volume clearly increased the incidence of migration to the mid and proximal sensors during both waking and sleep, and also significantly increased acid clearance time. Posture failed to significantly affect the incidence of acid migration and acid clearance. Sleep clearly enhanced migration to the proximal pH sensor of even those perfusions as small as 1 ml. For instance, 40% of 1 ml perfusions during sleep migrated to the proximal sensor compared with <1% during waking. Acid clearance times were significantly longer during sleep as measured by the mid- and proximal esophageal pH sensors.

CONCLUSIONS

In healthy individuals, volume enhances the likelihood of migration to both mid- and proximal esophagus, and significantly prolongs clearance time in the waking state. Posture appears to be a less significant parameter with regard to both the incidence of acid migration and acid clearance. Sleep is a significant risk factor for acid migration to the proximal esophagus for even minute volumes, and markedly prolongs acid clearance.