Modulation of upper and lower esophageal sphincter tone during sleep

Wake up to gastro-oesophageal reflux disease: The interplay between arousal and night-time reflux

This review examines the temporal association between nocturnal gastro-oesophageal reflux and sleep-arousal cycles. Most nocturnal gastro-oesophageal reflux events occur during the awake cycle, and arousals precede most nocturnal gastro-oesophageal reflux events, indicating that arousal from sleep predisposes to nocturnal gastro-oesophageal reflux. This sheds light on the complex relationship between nocturnal gastro-oesophageal reflux and sleep, and has implications for managing nocturnal gastro-oesophageal reflux symptoms. The appearance of symptoms and the pathophysiology of nocturnal gastro-oesophageal reflux are influenced by sleep hygiene, sleep disturbances and the misalignment of circadian rhythms. Nocturnal gastro-oesophageal reflux and its related sleep disorders are prevalent and negatively impact the quality of life. There is conflicting evidence on whether nocturnal gastro-oesophageal reflux and sleep disturbances are causally linked, and whether sleep disturbances drive nocturnal gastro-oesophageal reflux. Poor sleep quality increases oesophageal hypersensitivity and overall acid exposure. The nocturnal gastro-oesophageal reflux is linked to the more severe forms of gastro-oesophageal reflux disease, especially with atypical/extra-oesophageal manifestations and complications of mucosal damage such as oesophagitis and stricture, Barret's oesophagus, and oesophageal adenocarcinoma. This review highlights the role of sleep problems in presenting nocturnal gastro-oesophageal reflux, and the potential benefits of treating sleep disturbances in enhancing patient care and quality of life.

Respiratory activity of the cricopharyngeus muscle in the neonatal period

While phasic electrical activity of the cricopharyngeus muscle (EAcp)-the main component of the upper esophageal sphincter-occurs with inspiration and forceful expiration in adults, no such data is available for newborns. In addition, the effect of nasal respiratory support commonly used in newborns is unknown. We aimed to describe the phasic respiratory EAcp and to assess the potential effect of nasal CPAP (nCPAP, 6 cmH₂O) or high-flow nasal cannula (HFNC, 7 L/min) in newborn lambs during 6-h recordings. Phasic EAcp was present in 11/17 lambs, including in 32 % (25, 81) [(median (Q1, Q3)] of respiratory cycles in wakefulness, 40 % (27, 70) in NREM sleep, and 10 % (0, 23) in REM sleep. In addition, EAcp was observed only during post-inspiration and/or expiration. Nasal CPAP or HFNC assessed in 7 of the 17 lambs did not have any effect. We conclude that phasic respiratory EAcp occurs in post-inspiration and expiration in newborn lambs.

Influence of Acid Swallows on the Dynamics of the Upper Esophageal Sphincter

Mechanisms of the upper esophageal sphincter (UES) when exposed to acid are still incompletely understood. The presented work investigated the reaction of the UES to acid exposure during swallowing. Ten healthy individuals swallowed ten 2 ml neutral water boli of pH 7, followed by 10 swallows each of different levels of acidity (pH 1.8, pH 3 and pH 5). Effects were analyzed by high-resolution manometry (HRM) for the primary parameter Restitution Time, as well as Resting Pressures, maximal, minimal pressures and time intervals. Restitution Times measured mean values of 12.67 s (SD ± 7.03 s) for pH 1.8, pH 7 = 8.69 s (SD ± 2.72 s), pH 3 = 7.56 s (SD ± 2.23 s) and pH 5 = 7.29 s (SD ± 2.55 s), showing prolonged Restitution Times in the UES when exposed to strong bolus acidity. This difference was significant towards the neutral bolus, but also to less acidic boli (pH 5: p = 0.006, pH 3: p = 0.009, pH 7: p = 0.038). Considerable differences of mean values were found for Post-Swallow Maximum and Period of Sphincter Activity. Also, Pre-Swallow Maximum values were found to be highest with the strongest acid. Relaxation Times showed a slight trend of prolongation for the highest bolus acidity. Prolonged Restitution Times may represent a reflexive protective mechanism triggered by receptors in the pharyngeal mucosa or the UES preventing regurgitation of acid into the pharynx and larynx, besides representing ongoing attempts of acid clearance. Exposure to high levels of acidity by a swallowed bolus does influence UES functions during swallowing.

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.

Potential for Volitional Control of Resting Pressure at the Upper Oesophageal Sphincter in Healthy Individuals

Resting pressure at the upper oesophageal sphincter (UOS) has been reported to be susceptible to factors such as emotional stress or respiration. This exploratory study investigated the potential for behavioural modulation of UOS resting pressure in healthy adults to increase our understanding of volitional control of UOS pressure, and the potential development of rehabilitation approaches. Six healthy adults were seen one hour daily for two weeks (10 days) and for one post-training session after a training break of two weeks. Manipulation of UOS resting pressure was practised during a protocol of alternating increased and decreased pressure. A high-resolution manometry contour plot was used as a biofeedback modality. Participants were asked to explore how to achieve warmer and cooler colours (pressure increase and decrease, respectively) at the UOS resting pressure band, without changing head position or manipulating activity of other muscles. Performance was analysed prior to training start and following daily training. Participants were able to increase resting pressure following one week of practice; however, there was no evidence for purposeful pressure decrease. The increased resting pressure achieved by participants indicates a capacity for purposeful pressure modulation given intensive biofeedback training. The lack of volitional reduction in pressure may be explained by sustained pressure generation due to the intrinsic muscular characteristics of the UOS and a flooring effect in healthy subjects, in whom physiology mandates a minimum degree of resting pressure to fulfil the barrier function. Distention caused by the presence of the intraluminal catheter cannot be ruled out.

Gastroesophageal Reflux Disease in the Neonatal Intensive Care Unit Neonate: Controversies, Current Understanding, and Future Directions

Gastroesophageal reflux (GER) is considered physiologic and is a normal process; whereas, when aerodigestive consequences are associated, it is often interpreted as GER disease (GERD). However, the distinction between them remains a challenge in infants in the NICU. Reflux-type of symptoms are heterogeneous, and often managed with changes in diet, feeding methods, and acid-suppressive therapy; all these empiric therapies lack objectivity; hence, practice variation is universal. We clarify the current controversies, explain the potential role of GERD in causing symptoms and complications, and highlight current advances. The evidence basis for the diagnostic strategies is discussed.

Clinical and polysomnographic predictors of laryngopharyngeal reflux in obstructive sleep apnea syndrome

Introduction

Obstructive sleep apnea syndrome and laryngopharyngeal reflux are diseases with a high prevalence in the overall population; however, it remains unclear whether they are diseases with the same risk factors present in the same populations or if there is any association between them.

Objectives

To evaluate and determine the prevalence of laryngopharyngeal reflux in patients with moderate and severe obstructive apnea syndrome and also to determine its predictive factors.

Methods

Historical cohort, cross-sectional study of patients aged 18–70 years, referred to a tertiary service Otorhinolaryngology outpatient clinic with a polysomnographic diagnosis of moderate or severe obstructive sleep apnea syndrome. The reflux symptom index questionnaire and the reflux finding score at indirect videolaryngoscopy were applied to the assessed population, considering the inclusion and exclusion criteria.

Results

Fifty-six patients were evaluated, of which 64.3% had a positive laryngopharyngeal reflux (positive reflux symptom index and/or positive endolaryngeal reflux finding score). Body mass index was a predictor of reflux presence in this group of patients with moderate to severe obstructive sleep apnea syndrome. In patients with positive score for endoscopic findings and reflux symptom index (12.3%), there was a trend toward significance for a higher mean apnea–hypopnea index and a higher percentage of sleep time with oxyhemoglobin saturation below 90% (p = 0.05).

Conclusion

The prevalence of laryngopharyngeal reflux was higher in this group of patients with moderate to severe obstructive sleep apnea syndrome, and the body mass index was a predictor of laryngopharyngeal reflux in these patients. There was a trend toward greater oxyhemoglobin desaturation in patients with a positive score for reflux symptoms index (RSI) and reflux finding score (RFS).

Sleep and Nocturnal Gastroesophageal Reflux: An Update

Nocturnal gastroesophageal reflux has been associated with poor sleep quality. Normal physiological adaptations of the aerodigestive system to sleep prolong and intensify nocturnal reflux events. This occurrence leads to sleep disruption, as well as to esophageal, laryngeal, and laryngopharyngeal reflux. Controversy exists on whether OSA and nocturnal reflux are causally linked or merely associated because of shared risk factors. Advances in diagnostic technology have provided new insights into gastroesophageal reflux and the mechanisms of nocturnal reflux during sleep. This update reviews new data on causal links between sleep and gastroesophageal reflux disease.

[Physiology of the upper esophageal sphincter]

The upper esophageal sphincter (UES) forms a barrier between the pharynx and the esophagus. When opened, the UES allows the food bolus to pass into the esophagus, as well as permitting emesis and eructation. The basal sphincter tone constitutes a barrier function which serves to prevent reflux and passive aerophagia in the case of deep breathing. Basal sphincter tone is dependent on several influencing factors; during swallowing, sphincter opening and closure follow a complex multiphase pattern. This article presents an overview of the current understanding of UES physiology.

Physiology of sleep and breathing before and after lung transplantation

During the past 20 years, lung transplantation (LTX) has evolved and it is now accepted as a mainstream modality for care of patients with severe life-threatening respiratory diseases that are refractory to maximal conventional therapies. Improvements in surgical techniques and in antirejection medications have resulted in prolonged survival in these patients. Several studies have explored quality of life after LTX and its improvement has been noted especially in the early period between 3 and 6 months. This article discusses the salient features of the physiology of breathing and sleep disturbances before and after LTX and its alterations during sleep.

Insult of gastroesophageal reflux on airway: clinical significance of pharyngeal nozzle

At the very time of global paying the highest attention to the worst insults of smoking as well as haze on the airway, everybody knows both are exogenous and noticeable. However, people mostly, including many medical personnel, do not know how badly the gastroesophageal reflux (GER) insults on our own airway. Symptoms of GER are commonly seen as heartburn and regurgitation, which can be mostly tolerated. However, when the up going gastric content reversely passes the esophagus and then the distal pharynx, where it appears a beak like stricture, serving as a nozzle, so as to produce numerous micro-particles and reach the oro-nasal cavity and also the airway causing allergic rhinitis and asthmatic attacks, even pulmonary parenchyma lesions. It will reduce life quality or even jeopardize life. The point that the endogenous insult appears in the respiratory system, but originates from the digestive tract is not well known and often undiagnosed and not correctly treated. The GER induced airway challenge is a treatable and preventive entity, as soon as a diagnosis is made, a good relief could be expected by means of life style adjustment, medicine, or fixation of the patulous cardia through radiofrequency or fundoplication. The author Dr. Zhonggao Wang had suffered it for long and symptoms disappeared for 8 years after anti-reflux surgery. Here is a presentation of Dr. Zhonggao Wang and his team's work and would call attention to the public so as to recognize this relatively unknown entity - a treatable condition occurring from human itself, but not from outside surroundings as smoking or haze does.

Symptoms of aerophagia are common in patients on continuous positive airway pressure therapy and are related to the presence of nighttime gastroesophageal reflux

STUDY OBJECTIVES

Continuous positive airway pressure (CPAP), the mainstay treatment for obstructive sleep apnea (OSA), involves administration of air under pressure to the upper airway. A well-known but poorly understood side effect of positive airway pressure therapies is aerophagia, air entering the esophagus and stomach rather than the lungs. Gastric distension, a consequence of aerophagia, can increase gastroesophageal reflux (GER) by increasing transient lower esophageal sphincter relaxations, the most common cause of reflux. This study aimed to determine: (i) the prevalence of aerophagia symptoms in a group of OSA patients on CPAP therapy, and (ii) whether aerophagia symptoms are related to an increase in prevalence of GER symptoms.

METHODS

Consecutive OSA patients undergoing polysomnography for the purpose of optimizing their CPAP therapy completed a validated questionnaire regarding GER symptoms and aerophagia symptoms. Complete datasets were collected for 259 individuals (203 males).

RESULTS

The group with aerophagia symptoms (n = 130) had a greater prevalence of frequent (≥ once a week) GER symptoms (29% vs. 10%, p < 0.05) and nighttime GER symptoms (9 vs. 2%, p < 0.05) than those without aerophagia (n = 129). The group with nighttime GER symptoms (n = 27) had a greater prevalence of aerophagia symptoms (63% vs. 23%, p < 0.05) than those without nighttime GER symptoms (n = 232).

CONCLUSIONS

In patients with OSA being treated with CPAP, the prevalence of GER and nighttime GER symptoms is greater in those with symptoms of aerophagia than those without. CPAP-induced aerophagia might precipitate GER, particularly nighttime GER, by exacerbating transient lower esophageal relaxations through gastric distension.

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).

Hyperdynamic upper esophageal sphincter pressure: a manometric observation in patients reporting globus sensation

OBJECTIVES

Although globus sensation is a common symptom, its pathogenesis is poorly defined. The aim of this study was to quantify the timing and magnitude of respiratory variation in upper esophageal sphincter (UES) pressure with high-resolution manometry (HRM) in patients with globus sensation, normal controls, and gastroesophageal reflux disease (GERD) patients without globus sensation.

METHODS

HRM recordings spanning from the hypopharynx to the stomach were analyzed in 131 consecutive globus patients with normal (64) and abnormal (67) distal esophageal motility. Resting UES pressure was analyzed up to 5 min before 10 5-ml water swallows. Change in UES pressure, its average magnitude between inspiration and expiration, and nadir UES relaxation pressure in globus patients were compared with those in 68 controls and 46 GERD patients without globus.

RESULTS

UES pressure typically increased during inspiration in both controls and patients. Respiration-related change in resting UES pressure was significantly amplified in globus patients (37.3 mm Hg) compared with controls (10.6 mm Hg) and GERD patients (13.0 mm Hg) (P<0.0001). A respiratory change in UES pressure>27 mm Hg was found in >60% of globus patients and <15% of controls and GERD patients without globus. This hyperdynamic UES was not associated with other abnormalities of esophageal motor function.

CONCLUSIONS

Hyperdynamic respiratory UES pressure changes were prevalent in patients reporting globus sensation irrespective of their deglutitive UES and distal esophageal motility. Although the etiology of this hyperdynamic UES is unclear, it does appear to be a frequent manometric observation in this patient group and may provide a new focus for further studies into pathogenesis and therapy.

Obesity and the lung: 3. Obesity, respiration and intensive care

Obesity is a major problem from a public health perspective and a difficult practical matter for intensivists. The obesity pandemic has required treating clinicians to develop an appreciation of the substantial pathophysiological effects of obesity on the various organ systems. The important physiological concepts are illustrated by focusing on obstructive sleep apnoea, obesity hypoventilation syndrome, abdominal compartment syndrome and ventilatory management of the obese patient with acute respiratory distress syndrome.

Obstructive sleep apnoea and nocturnal gastroesophageal reflux are common in lung transplant patients

BACKGROUND AND OBJECTIVE

Gastroesophageal reflux (GOR) has been implicated in the pathogenesis of bronchiolitis obliterans syndrome (BOS), possibly due to pulmonary aspiration of refluxed acid. Risk of aspiration of gastric contents is increased during sleep due to decreased oesophageal clearance mechanisms and may be further increased by the presence of OSA. This study investigated the relationship between nocturnal GOR, OSA and BOS in a group of lung transplant patients.

METHODS

Fourteen lung transplant patients underwent overnight polysomnography with simultaneous dual oesophageal pH monitoring.

RESULTS

Patients had an FEV(1) of 84 +/- 15% of their best post-transplant FEV(1). Six of the 14 patients were in various stages of BOS. The average proportion of time spent overnight with a pH of <4 was 1.7 +/- 3.1%. Increased GOR was evident in 8/14 patients during the postprandial period and/or overnight in the distal and/or proximal oesophagus. All patients had OSA (AHI >5 events per hour). There were no relationships between severity of OSA or GOR and severity of BOS.

CONCLUSION

Both nocturnal GOR and OSA were common in this group of patients but their occurrences were not related. Neither was there any relationship between the presence of nocturnal GOR or OSA and severity of BOS.