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

Gastrointestinal symptoms and CPAP-related aerophagia A questionnaire study

PURPOSE

Aerophagia is a functional gastrointestinal disorder including swallowing air, repeated belching, and disturbing symptoms of air retention in the gastrointestinal tract. Aerophagia can also occur during continuous positive airway pressure (CPAP) therapy. Pressurized air can leak into the stomach causing belching, abdominal distention, discomfort, and flatulence, among other symptoms. There are few studies on CPAP-related aerophagia (C-aerophagia), and the reported prevalence ranges from 8.28 to 16% Our aim was to evaluate aerophagia-related symptoms before and with CPAP therapy.

METHODS

A total of 2004 patients began CPAP therapy at the Helsinki Sleep Apnea policlinic during 2015-2019. A randomly selected sample of 1059 patients were sent a questionnaire to assess symptoms possibly related to aerophagia. Symptom severity was evaluated with a Visual Analogue Scale (VAS).

RESULTS

We received 324 responses. The most disturbing symptom was flatulence, with VAS increasing from a median of 24 before CPAP to 34 during CPAP (p ≤ 0.001). Dry mouth increased from 16 to 31 (p ≤ 0.001), heartburn decreased from 12 to 10 (p ≤ 0.001), and belching decreased from 12 to 9 (p = 0.018). A total of 29 patients abandoned CPAP therapy. Symptoms of aerophagia were the main cause of abandoning CPAP for 3 patients.

CONCLUSIONS

Most patients who reported symptoms of aerophagia with CPAP therapy were already symptomatic before CPAP initiation. Only flatulence and dry mouth increased slightly with CPAP. Although changes in symptoms were very mild overall, in rare cases (1%) symptoms can be very disturbing and even lead to abandoning CPAP therapy. For clinical practice, it is important to assess whether symptoms of aerophagia are actually related to and worsened by CPAP therapy to avoid unnecessary interventions.

Long-Term Management of Sleep Apnea-Hypopnea Syndrome: Efficacy and Challenges of Continuous Positive Airway Pressure Therapy-A Narrative Review

Sleep apnea-hypopnea syndrome (SAHS) is a respiratory disorder characterized by cessation of breathing during sleep, resulting in daytime somnolence and various comorbidities. SAHS encompasses obstructive sleep apnea (OSA), caused by upper airway obstruction, and central sleep apnea (CSA), resulting from lack of brainstem signaling for respiration. Continuous positive airway pressure (CPAP) therapy is the gold standard treatment for SAHS, reducing apnea and hypopnea episodes by providing continuous airflow. CPAP enhances sleep quality and improves overall health by reducing the risk of comorbidities such as hypertension, type 2 diabetes mellitus, cardiovascular disease and stroke. CPAP nonadherence leads to health deterioration and occurs due to mask discomfort, unsupportive partners, upper respiratory dryness, and claustrophobia. Technological advancements such as auto-titrating positive airway pressure (APAP) systems, smart fit mask interface systems, and telemonitoring devices offer patients greater comfort and enhance adherence. Future research should focus on new technological developments, such as artificial intelligence, which may detect treatment failure and alert providers to intervene accordingly.

Prevalence of continuous positive airway pressure-related aerophagia in obstructive sleep apnea: an observational study of 753 cases undergoing CPAP/BiPAP treatment in a sleep clinic - part one of a two-part series

PURPOSE

Aerophagia occurring during continuous positive airway pressure (C-aerophagia in CPAP) in patients with obstructive sleep apnea (OSA) disturbs CPAP therapy. However, the diagnostic criteria and exact prevalence of C-aerophagia are not well documented; therefore, this study aimed to evaluate them.

METHODS

Newly developed criteria (flatulence, eructation, and abdominal bloating, with quantitative evaluation of these symptoms and a clear timing of onset) were used to diagnose C-aerophagia. The study included 753 adults with OSA who underwent follow-up visits for positive airway pressure treatment (including CPAP and bilevel positive airway pressure). The observation period ranged from 6 months to 3 years past the survey date (between May 1 and July 31, 2023). Medical records of patients were retrospectively analyzed. Discomfort associated with C-aerophagia was examined using a visual analog scale (VAS); a score ≥ 7 was associated with definite discomfort. Association of patient demographics and CPAP parameters with occurrence of C-aerophagia was analyzed using multivariate analysis.

RESULTS

The prevalence of C-aerophagia was 7.2%. Although more than half of these patients reported discomfort associated with aerophagia, only 44.4% reported to their physician. The multivariate analysis showed that increased CPAP pressure level (odds ratio [OR] = 1.24) and comorbid gastroesophageal reflux disease (GERD; OR = 2.52) promote C-aerophagia, while increased age (OR = 0.76) and body mass index (BMI; OR = 0.88) inhibit it.

CONCLUSION

The prevalence of C-aerophagia was 7.2%. Most patients with C-aerophagia experience discomfort, but may not report these symptoms. High CPAP pressure and GERD promoted C-aerophagia, while aging and increased BMI prevented it.

The effect of mechanical ventilation compared to high-flow nasal cannula on gastric residual volume and reflux events using novel automated technology

BACKGROUND & AIM

High flow nasal cannula (HFNC) oxygen therapy is frequently used following extubation. A case report, utilizing an innovative medical technology (The smART + Platform, ART MEDICAL Ltd., Netanya, Israel) that enables the detection of gastric refluxes and gastric residual volumes (GRV), has suggested that HFNC may be associated with increased reflux events and GRV. This study measured reflux events and GRV using smART+ in mechanically ventilated patients before and after extubation while they were receiving HFNC therapy. We aim to show if there is a significant difference in reflux events and GRV between HFNC users and mechanically ventilated patients.

METHODS

This is a post hoc analysis examines data of a randomized controlled trial (RCT) involving critically ill adult patients who received enteral nutrition through the smART + Platform. The study was approved by the local ethics committee. We compared the frequency and amplitude of reflux events and GRV in mechanically ventilated patients. These parameters were assessed both 3 h before extubation and subsequently after extubation when the patients were connected to HFNC. Patients served as their own controls. To evaluate the differences between the pre- and post-extubation measurements, we applied a parametric paired t-test.

RESULTS

Ten patients (mean age of 58 years; mean APACHE II score 22; mean 3.9 days of mechanical ventilation) were included. Three hours prior extubation the mean GRV was 4.1 ml/h compared to 14.03 ml/h on HFNC (p = 0.004). The mean frequency of major reflux events was 2.33/h in ventilated patients versus 4.4/h in the HFNC patients (p = 0.73). The mean frequency of major reflux events was 9.17/h in ventilated patients versus 9.83/h in HFNC patients (p = 0.14).

CONCLUSIONS

Leveraging the smART + Platform, we demonstrated that the use of HFNC significantly increases GRV compared with patients on mechanical ventilation and may increase the frequency of major reflux events, thereby increasing the risk of aspiration. Further studies are required to support our conclusions.

Esophageal Dysmotility in Multiple System Atrophy: A Retrospective Cross-Sectional Study

Background/Objective: Multiple system atrophy (MSA) is often associated with dysphagia and esophageal dysmotility (ED). However, ED in patients with MSA is poorly understood. To assess the relationship between ED, dysphagia, and other clinical findings in such patients and investigate the details of ED in MSA using high-resolution manometry (HRM). Methods: Patients from The University of Tokyo Hospital with MSA who underwent swallowing examinations, esophagography, and HRM between 2017 and 2022 were enrolled. A retrospective chart review of patients' backgrounds, swallowing function, and esophageal motility was performed. ED was evaluated using the Chicago Classification version 4.0. Results: Seventy-four patients with MSA were identified. The median age was 64 years, 48 patients (65%) were male, and the cerebellar variant type was predominant (69%). Abnormal upper esophageal sphincter (UES) resting pressure was observed in 34 patients (46%) and intraesophageal stasis in 65 (88%). High-severity MSA was a risk factor for developing dysphagia, vocal fold movement impairment, and abnormal UES function (p < 0.05). However, no overt clinical risk factors for ED were identified. Various types of ED were detected using HRM, and ineffective esophageal motility was the most frequent disorder. Conclusions: ED is a common occurrence in patients with MSA. Although a high-severity MSA may be a risk factor for developing dysphagia and vocal fold motion impairment, ED can occur regardless of clinical severity. Since ED is rarely detected based on subjective symptoms, careful evaluation of esophageal motility by esophagography or HRM is warranted in patients with MSA.

Executing and facilitating the successful combined multichannel intraluminal impedance and pH monitoring study

Successful multichannel intraluminal impedance and pH monitoring (MII-pHM) studies rely on constant attendants (CAs) or family members (and sometimes the patients themselves) to assist in the execution and facilitation of the MII-pHM study. While "pushing buttons" [corresponding to specific symptoms, body position (upright versus recumbent), and meal start and stop times] on the MII-pHM system recording box is indeed a big part of MII-pHM study execution and facilitation, there are other concerns and duties that are equally as important. This paper outlines some of the important duties of the study facilitator (or patient) during a MII-pHM study. When provided with the proper training, study facilitators invigilating the MII-pHM study will be better able to contribute to the data collection process and ultimately to produce data that when analyzed will lead to better interpretations, clinical recommendations, and good clinical outcomes. When executed properly, MII-pHM studies have the potential to assess diurnal exposure of the esophageal mucosa to gastric/duodenal contents, provide insight regarding the proximal extent of gastroesophageal reflux (GER), provide a measurement of the mean esophageal pH, and assess mucosal integrity and temporal relationship between GER and the symptoms of interest. While several groups have offered recommendations for proper execution of the MII-pHM study, to our knowledge, there have not been publications wherein recommendations were compiled to form a single source document.

Effect of High-Flow Nasal Oxygenation on Gastric Insufflation in Patients Undergoing Laryngeal Microsurgery under Tubeless General Anesthesia with Neuromuscular Blockade

BACKGROUND

High-flow nasal oxygenation is an oxygen delivery method by which high concentrations of heated humidified oxygen are supplied via the nasal cavity. This study aimed to investigate the effect of high-flow nasal oxygenation on gastric volume change in adult patients undergoing laryngeal microsurgery under tubeless general anesthesia with neuromuscular blockade.

METHODS

Patients aged 19-80 years with an American Society of Anesthesiologists physical status 1 or 2 who were scheduled to undergo laryngoscopic surgery under general anesthesia were recruited. Patients received high-flow nasal oxygenation therapy at 70 L/min during surgery under general anesthesia with neuromuscular blockade. The cross-sectional area of the gastric antrum was measured via ultrasound in the right lateral position before and after high-flow nasal oxygenation, and the gastric volume was calculated. The duration of apnea, i.e., the duration of administration of high-flow nasal oxygenation in the paralyzed state, was also recorded.

RESULTS

Of the 45 patients enrolled, 44 completed the study. There were no significant differences in the antral cross-sectional area in the right lateral position, gastric volume, and gastric volume per kg between before and after high-flow nasal oxygenation application. The median duration of apnea was 15 (interquartile range, 14-22) min.

CONCLUSION

High-flow nasal oxygenation at 70 L/min during apnea with the mouth open did not influence the gastric volume in patients undergoing laryngeal microsurgery under tubeless general anesthesia with neuromuscular blockade.

Diagnostic Yield of Chilaiditi's Sign in Advanced-Phase Late-Onset Pompe Disease

PURPOSE

Chilaiditi's sign (CS), hepatodiaphragmatic interposition of the intestine, was caused by morphological abnormalities such as diaphragmatic atrophy, intestinal dilation, and liver atrophy. The sign is potentially important due to associations with clinically recurrent abdominal pain or even colonic volvulus. Late-onset Pompe disease (LOPD) could have the high prevalence of CS because of widened hepatodiaphragmatic space, following diaphragmatic atrophy, and the abnormal dilation of intestine caused by glycogen accumulation in smooth muscle of intestine. Our aim was to investigate the prevalence of CS in LOPD, and to identify the risk factors of CS in LOPD patients.

METHODS

Medical records of genetically confirmed patients of Pompe disease at the National Center Hospital, National Center of Neurology and Psychiatry were retrospectively reviewed. We evaluated CS using chest X-ray (CXR) and abdominal CT and assessed the prevalence of CS in LOPD patients. We also divided the patients into two groups, CS and non-CS group, and evaluated the factor associated with CS compared to clinical variables between groups.

RESULTS

Three of seven (43%) were detected in CS. CS group (P5-7) and non-CS group (P1-4) were obtained. In comparison of clinical variables, the severity of atrophy in right diaphragms was significantly higher in CS than non-CS groups (p = 0.029). Also, the frequency of abnormal position of right diaphragm and liver, and abnormally dilated bowel was seen in all of CS patients, but none of non-CS patient (p = 0.029, each).

CONCLUSION

In LOPD patients, the prevalence of CS was much higher of 43%, compared to healthy groups, or even in similarly respiratory muscle impaired neuromuscular diseases. The anatomically abnormal position of diaphragm and liver, atrophy and fat infiltration of diaphragms, and abnormally dilated bowel were significantly associated with CS in LOPD. We should pay more attention to CXR or abdominal CT as follow up in LOPD patients.

Treatment of Obstructive Sleep Apnea: Achieving Adherence to Positive Airway Pressure Treatment and Dealing with Complications

Obstructive sleep apnea is a common and treatable condition, but therapeutic adherence is limited by numerous factors. Despite advances in positive airway pressure (PAP) technology and a multitude of effective pharmacologic and behavioral therapeutic interventions to overcome the most common barriers to PAP, adherence has not increased significantly over the past 30 years. This review aims to identify the most important factors that impact adherence, common barriers to treatment, and evidence-based treatment strategies to maximize the effectiveness of PAP treatment. Complications of PAP treatment and mitigation techniques are also discussed.

Effect of continuous positive airway pressure on gastroesophageal reflux in patients with obstructive sleep apnea: a meta-analysis

PURPOSE

Gastroesophageal reflux disease (GERD) often occurs in patients with obstructive sleep apnea (OSA). Although continuous positive airway pressure (CPAP) is considered to be the preferred treatment for OSA, the effect of CPAP therapy on reflux events remains controversial. In this study, we utilized meta-analysis to investigate whether or not CPAP treatment reduces the incidence of reflux.

METHODS

Two independent reviewers obtained the data sources from the database of PubMed, Elsevier, Cochrane library, and CNKI using search terms, and then filtered the target articles based on the inclusion and exclusion criteria. RevMan (version 5.3) and STATA (version 12.0) were used for data synthesis. The effect of CPAP treatment on GERD was studied by calculating the weighted mean difference (WMD) and standard deviation (SD) before and after CPAP treatment.

RESULTS

Ten studies involving a total of 272 participants were included in this study. The results showed that the total of WMD before and after CPAP was - 17.68 (95% CI - 30.67 to - 4.69) for percentage time pH < 4, - 24.66 (95% CI - 36.15 to - 13.18) for the longest reflux duration, - 27.53 (95% CI - 49.53 to - 5.52) for number of reflux events, - 49.76 (95% CI - 60.18 to - 39.35) for DeMeester score, - 1.85 (95% CI - 3.00 to - 0.71) for reflux diseases questionnaire (RDQ) score, and - 8.95 (95% CI - 16.00 to - 1.89) for reflux symptom index (RSI). The subgroup analysis demonstrated that the improvement of reflux symptoms was more obvious with the extension of treatment time.

CONCLUSIONS

This meta-analysis showed that CPAP treatment significantly reduces the incidence of reflux events in patients with OSA.

The effect of postoperative CPAP use on anastomotic and staple line leakage after bariatric surgery

PURPOSE

Almost two-thirds of the population undergoing bariatric surgery (BS) suffers from obstructive sleep apnea (OSA). Continuous positive airway pressure (CPAP) is the standard treatment for moderate to severe OSA and is recommended in patients undergoing BS perioperatively. A severe and dreaded complication after BS is anastomotic leakage. There is theoretical concern that perioperative CPAP use may result in increased distension of the gastrointestinal tract and increase the risk of developing an anastomotic leakage. The aim of this study was to evaluate the effect of postoperative CPAP use on the risk of developing anastomotic leakages after BS.

METHODS

Retrospectively, all patients from a single bariatric center who underwent BS from November 2007 to August 2019 were included. Presence and severity of OSA were determined using poly(somno)graphy. To evaluate the effect of postoperative CPAP use on anastomotic leakage, a multivariable logistic regression analysis was performed.

RESULTS

A total of 4052 patients were included, with OSA being diagnosed in 62%. Overall, 970 patients (24%) used CPAP after BS. Anastomotic leakage occurred in 64 (1.6%) patients after BS. Leakage rate was 1.3% in non-CPAP group versus 2.5% in CPAP group (p = 0.01). CPAP use was associated with anastomotic leakage; however, after adjustment, CPAP use was not an independent predictor (OR = 1.40, 95% CI 0.60-3.28, p = 0.44).

CONCLUSION

There is no independent relation between postoperative CPAP use and anastomotic leakage after BS. Only revision surgery was an independent predictor of anastomotic leakage.

Esophageal Dysmotility is Common in Patients With Multiple System Atrophy

OBJECTIVES

Esophageal dysmotility (ED) in patients with multiple system atrophy (MSA) are poorly understood. This study aimed to investigate the prevalence of ED in patients with MSA and to assess the relationship of esophageal abnormalities with other clinical findings and characteristics in these patients.

METHODS

A retrospective chart review was conducted to identify patients with MSA and to compare them to the elderly controls without MSA (65+ years) who underwent a videofluorographic esophagram from 2014 to 2019. Disease type, disease severity, vocal fold mobility impairment, abnormal deglutitive proximal esophageal contraction (ADPEC), and intra-esophageal stasis (IES) were reviewed and compared between groups.

RESULTS

Thirty-seven patients with MSA were identified. The median age was 63 and 26 (70%) were male. These patients were matched to 22 elderly adults with presbylarynx but not MSA (median age 77, 68% male). In MSA patients, cerebellar variant type was predominant (59%), and ADPEC was recognized in 18 patients (49%). Disease severity level (P = 0.028) and existence of IES (P = 0.046) were associated with higher risks of developing ADPEC. The prevalence of IES was significantly higher in patients with MSA (95%) compared to controls without MSA (46%) (P < 0.001). Disease severity level and the existence of IES were significantly associated with the presence of ADPEC (p < 0.05).

CONCLUSION

ADPEC and IES were significantly more common in MSA than in elderly subjects without MSA. MSA severity is associated with the development of ADPEC. The data suggest that esophageal motility is predominantly affected in MSA.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:832-838, 2021.

Novel Use of Impedance Technology Shows That Esophageal Air Events Can Be Temporally Associated With Gastroesophageal Reflux Disease-like Symptoms

A few studies have shown that esophageal air events (EAEs), such as air-swallows, may be associated with symptoms that have historically been associated with gastroesophageal reflux disease (GERD). To objectively test a hypothesis that all EAE types (air-swallows, supragastric belches and gastric belches) can be associated with GERD-like symptoms, we removed the impedance "tags" from the GER episodes (placed during autoscan) and instead tagged either air-swallows, supragastric belches or gastric belches in each of 3 copies of the 24-hour impedance tracing for 2 infant patients who presented with symptoms suggestive of GER as an etiology. Impedance system software (MMS) analyses revealed that, in both infants, all EAE types were significantly associated (SAP >95%) with 1 or more of the GERD-like symptom types (cough, pain/crying, back-arching, and gagging). These data underscore the importance of considering other diagnoses when developing management strategies for treating GERD-like symptoms in infants.

Obstructive Sleep Apnea in Pregnant Women: A Review of Pregnancy Outcomes and an Approach to Management

Among obese pregnant women, 15%-20% have obstructive sleep apnea (OSA) and this prevalence increases along with body mass index and in the presence of other comorbidities. Prepregnancy obesity and pregnancy-related weight gain are certainly risk factors for sleep-disordered breathing in pregnancy, but certain physiologic changes of pregnancy may also increase a woman's risk of developing or worsening OSA. While it has been shown that untreated OSA in postmenopausal women is associated with a range of cardiovascular, pulmonary, and metabolic comorbidities, a body of literature is emerging that suggests OSA may also have serious implications for the health of mothers and fetuses during and after pregnancy. In this review, we discuss the following: pregnancy as a vulnerable period for the development or worsening of OSA; the associations between OSA and maternal and fetal outcomes; the current screening modalities for OSA in pregnancy; and current recommendations regarding peripartum management of OSA.

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.

Nasal high-frequency oscillatory ventilation inhibits gastroesophageal reflux in the neonatal period

Nasal high-frequency oscillatory ventilation (nHFOV) in neonates is increasingly considered due to enhanced alveolar ventilation, absence of patient-ventilator asynchrony and lessened ventilator-induced lung injury. Although any type of non-invasive respiratory support can lead to gastric distension via esophageal air passage and thus promote gastroesophageal refluxes (GERs), we have shown that nasal continuous positive airway pressure (CPAP; 6 cmH₂O) and intermittent positive pressure ventilation (15/4 cmH₂O) conversely inhibit GERs in lambs. The current objective was to test the hypothesis that nHFOV also inhibits GERs compared to spontaneous ventilation without respiratory support. Eight lambs underwent five hours of polysomnographic and esophageal multichannel intraluminal impedance pHmetry recordings to assess GERs and air passage into the esophagus, with and without nHFOV (mean airway pressure = 8 cmH₂O, oscillation frequency = 8 Hz, amplitude ≈ 20 cmH₂O and I:E = 1:2). Results revealed that GERs were decreased with nHFOV (p = .03), despite an increase in gas-containing swallows (p = .01). In conclusion, similarly to nasal CPAP and intermittent positive pressure ventilation, nHFOV inhibits GERs in newborn lambs.

A pediatric case developing critical abdominal distension caused by a combination of humidified high-flow nasal cannula oxygen therapy and nasal airway

Background

We describe a pediatric patient who suffered from critical abdominal distention caused by a combination of humidified, high-flow nasal cannula (HHFNC) oxygen therapy and nasal airway.

Case presentation

A 21-month-old boy with a history of chronic lung disease was admitted to the intensive care unit (ICU). Immediately after admission, his airway was established using a tracheal tube and mechanical ventilation was started. Five days after the commencement of mechanical ventilation, finally, his trachea was extubated. Immediately after extubation, HHFNC therapy at 20 L/min with an FiO₂ of 0.35 was applied. However, severe stridor was observed, then a nasal airway was placed in the left nostril. However, he became restless. Critical abdominal distention was observed. A subsequent chest X-ray revealed that the nasal airway was placed too deeply, and the gastrointestinal air was severely accumulated. Immediately, the nasal airway was removed, and HHFNC flow was reduced to 10 L/min. Frequent suctioning and continuous gastric drainage were required, which achieved gradual improvement of respiratory condition.

Conclusions

We need to recognize that HHFNC therapy is one of the positive pressure ventilation system. Therefore, HHFNC therapy might cause the similar adverse events to noninvasive pressure ventilation.

Treatment of Obstructive Sleep Apnea: Achieving Adherence to Positive Airway Pressure Treatment and Dealing with Complications

Obstructive sleep apnea is a common and treatable condition, but therapeutic adherence is limited by numerous factors. Despite advances in positive airway pressure (PAP) technology and a multitude of effective pharmacologic and behavioral therapeutic interventions to overcome the most common barriers to PAP, adherence has not increased significantly over the past 30 years. This review aims to identify the most important factors that impact adherence, common barriers to treatment, and evidence-based treatment strategies to maximize the effectiveness of PAP treatment. Complications of PAP treatment and mitigation techniques are also discussed.

Mechanisms and prevention of sudden death in multiple system atrophy

BACKGROUND

Sudden death in multiple system atrophy (MSA) usually occurs during sleep and was therefore attributed to suffocation resulting from vocal cord abductor paralysis, a characteristic laryngeal finding of MSA. This led to the use of tracheostomy and noninvasive positive pressure ventilation (NPPV) for the prevention of sudden death. However, neither method has been able to prevent sudden death, and both have occasionally precipitated treatment-related complications, including central sleep apneas and exacerbation of floppy epiglottis. Therefore, it is important to determine the mechanisms and prevention of sudden death in MSA.

METHODS

We reviewed the literature on the mechanisms and prevention of sudden death in patients with MSA.

RESULTS

Sudden death in MSA is hypothesized to be a consequence of disordered central respiration, suffocation caused by sputum and food, upper airway obstruction from NPPV acting on a floppy epiglottis, cardiac autonomic disturbance, or a combination of these factors.

CONCLUSION

Various factors may be involved in the mechanism of sudden death in MSA. A multidisciplinary approach is needed to prevent sudden death, and this requires an organized system of several medical specialties. Neurologists require a cooperative network that includes experts in otorhinolaryngology, sleep medicine, dysphagia rehabilitation, and cardiology.

Inhibitory Effect of Nasal Intermittent Positive Pressure Ventilation on Gastroesophageal Reflux

Non-invasive intermittent positive pressure ventilation can lead to esophageal insufflations and in turn to gastric distension. The fact that the latter induces transient relaxation of the lower esophageal sphincter implies that it may increase gastroesophageal refluxes. We previously reported that nasal Pressure Support Ventilation (nPSV), contrary to nasal Neurally-Adjusted Ventilatory Assist (nNAVA), triggers active inspiratory laryngeal closure. This suggests that esophageal insufflations are more frequent in nPSV than in nNAVA. The objectives of the present study were to test the hypotheses that: i) gastroesophageal refluxes are increased during nPSV compared to both control condition and nNAVA; ii) esophageal insufflations occur more frequently during nPSV than nNAVA. Polysomnographic recordings and esophageal multichannel intraluminal impedance pHmetry were performed in nine chronically instrumented newborn lambs to study gastroesophageal refluxes, esophageal insufflations, states of alertness, laryngeal closure and respiration. Recordings were repeated without sedation in control condition, nPSV (15/4 cmH₂O) and nNAVA (~ 15/4 cmH₂O). The number of gastroesophageal refluxes recorded over six hours, expressed as median (interquartile range), decreased during both nPSV (1 (0, 3)) and nNAVA [1 (0, 3)] compared to control condition (5 (3, 10)), (p < 0.05). Meanwhile, the esophageal insufflation index did not differ between nPSV (40 (11, 61) h^-1) and nNAVA (10 (9, 56) h^-1) (p = 0.8). In conclusion, nPSV and nNAVA similarly inhibit gastroesophageal refluxes in healthy newborn lambs at pressures that do not lead to gastric distension. In addition, the occurrence of esophageal insufflations is not significantly different between nPSV and nNAVA. The strong inhibitory effect of nIPPV on gastroesophageal refluxes appears identical to that reported with nasal continuous positive airway pressure.

Morgagni hernia with respiratory failure aggravated by noninvasive positive pressure ventilation: a case report and overview of the literature

An elderly woman diagnosed with multiple myeloma (MM) in 2007 had improved with chemotherapy. She had severe kyphosis and a diaphragmatic hernia (DH), but no respiratory symptoms. In 2011, because of thoracic deformity and emaciation, we advised her to continue the previously prescribed domiciliary noninvasive positive pressure ventilation (NPPV) therapy for chronic type II respiratory failure. However, she refused to continue NPPV. She was later admitted for deterioration in respiratory status and carbon dioxide (CO2) narcosis. We believed her low adherence to domiciliary NPPV caused CO2 narcosis; hence, we advised her to continue domiciliary NPPV and she complied. In May 2012, the now 79-year-old patient was admitted for acute exacerbation of chronic respiratory failure and CO2 narcosis. Chest imaging suggested that DH had caused a deterioration of her status. She underwent laparoscopic diaphragmatic hernia repair. Operative findings revealed a retrosternal hernia sac, and she was diagnosed as having a Morgagni hernia (MH). Her respiratory status subsequently improved. We hypothesize that NPPV increased intra-abdominal pressure, thereby worsening the MH and exacerbating respiratory failure. We believe that clinicians should be cautious when prescribing NPPV for MH patients.