Reflux Aspiration Research Articles

Reevaluating 30 cmH2O endotracheal tube cuff pressure: risks of airway mucosal damage during prolonged mechanical ventilation.

The optimal endotracheal tube (ETT) cuff pressure remains contentious. In the traditional consideration that the level 30 cmH2O is considered safe, balancing the prevention of reflux aspiration against airway mucosal damage. Whether this pressure level can cause potential damage to the airway mucosa remains to be discussed. Airway mucosa damage and structural changes at 30 cmH2O were examined in patients under general anesthesia and in rabbit mechanical ventilation models. Prior to this, we also interviewed some anesthesiologists about the level of concern about ETT cuff pressure. A total of 634 valid questionnaires suggested that anesthesiologists generally do not pay enough attention to ETT cuff pressure and the average established cuff pressure significantly exceeded 30 cmH2O. Airway mucosa images of 100 general anesthesia patients with different ventilation duration indicated that maintaining the pressure at 30 cmH2O did not cause significant damage to airway mucosa in a short period of time, while it still caused damage to airway mucosa in patients with long-term ventilation, with damage severity increasing with longer ventilation periods. This correlated strongly with postoperative sore throat (R 2 = 0.3884, p < 0.001). In rabbits, 4 h of ventilation at this pressure resulted in significant loss of ciliated epithelium and inflammation. Calculations suggested an effective dose (ED50) to prevent mucosal injury at a cuff pressure of 25.64 cmH2O (95% CI: 19.268-29.367 cmH2O). The currently established cuff pressure of 30 cmH2O is associated with airway mucosal damage in both clinical and animal models. Lowering the safety threshold of cuff pressure may be necessary to mitigate mucosal injury.

High-flow nasal cannula oxygen therapy versus noninvasive ventilation for elderly chronic obstructive pulmonary disease patients after extubation: a noninferior randomized controlled trial protocol

IntroductionNoninvasive ventilation (NIV) is widely used for sequential extubation in patients with chronic obstructive pulmonary disease (COPD). However, NIV may cause many adverse events such as claustrophobia, facial skin compression, air leakage, bloating, and even reflux aspiration, resulting in poor patient compliance/tolerance and high failure rate, especially for older adults who are at high risk of communication difficulties and consciousness disorder. High-flow nasal cannula (HFNC) oxygen therapy is a new alternative support to NIV, but whether it can effectively reduce the rate of re-intubation after extubation in elderly patients with COPD remains controversial. The purpose of this study is to explore the safety and efficacy of HFNC versus NIV for elderly COPD patients after extubation.Methods and analysisThis study is an investigator-initiated, single-center, prospective, non-inferior, randomized controlled trial. Elderly patients (age > 65 years) who have received invasive ventilation and was diagnosed with COPD will be randomly assigned to HFNC group or NIV group immediately after extubation with a planned enrollment of 168 patients. The primary outcomes will be reintubation rates at 72 h and 7 days after extubation. Secondary outcomes will include treatment failure, post-extubation vital signs and arterial blood gases, the scores of compliance and comfort of patients, duration of respiratory support after extubation, respiratory support related adverse events, sleep quality scores, usage of sedative and analgesic drugs after extubation, and the incidence of delirium. Additionally, clinical outcomes such as ventilator-free days at 28 days post-randomization, tracheotomy rate, duration of intensive care unit (ICU) and hospital stay, ICU and hospital mortality will be evaluated.Ethics and disseminationThis study has been approved by the Ethics Committee of West China Hospital of Sichuan University (2023–2284). Informed consent is required. It is expected that a follow-up randomized controlled trial will be conducted. The results will be submitted for publication in a peer-reviewed journal and presented at one or more scientific conferences.Trial registrationThe study was retrospectively registered at ClinicalTrials.gov (ChiCTR2400087312).

Ultrasonic assessment of gastric solid contents in patients undergoing upper endoscope with sedation

BackgroundPerioperative reflux aspiration presents a grave concern during sedation or general anesthesia, particularly when solid gastric contents prompt acute upper respiratory obstruction, potentially resulting in fatal consequences for patients. Currently, there are limited means for promptly assessing solid gastric contents in clinical settings. Therefore, this study examined the efficacy of ultrasound assessment for solid gastric contents, offering a rapid and non-invasive approach for early detection and decision-making regarding interventions.MethodsThe study included 400 patients scheduled for upper endoscopy procedures, which encompassed both gastroscope and gastroscope combined colonoscopy examinations with sedation. Ultrasound scanning of the antrum was performed while patients were positioned semi-sitting or in the right lateral decubitus (RLD) posture. The evaluation of solid gastric contents relied on direct visual observation during endoscopy. Gastric volume measurement occurred subsequent to endoscopic suction of gastric contents. Receiver operating characteristic curves were utilized to assess the effectiveness of ultrasonography in discerning solid contents.ResultSeven patients undergoing gastroscope with sedation were found to have solid gastric contents. The sensitivity, specificity, positive predictive value, and negative predictive value of the ultrasound qualitative evaluation of solid contents were 85.7%, 99%, 60%, and 99.7%, respectively.ConclusionSolid stomach contents can be evaluated qualitatively with reasonable accuracy using ultrasonography. Additionally, in patients undergoing upper endoscopy and assessed to have solid gastric contents with ultrasound, administration of mild sedation is recommended.Trial registrationwww.chictr.org.cn (ChiCTR2100048994); registered 19/07/2021.

363. REFLUX MICRO-ASPIRATION: WHAT HAVE WE LEARNED

Abstract Background The accurate diagnosis of gastro-oesophageal reflux pulmonary microaspiration has only become possible recently with the introduction of a novel technique of reflux micro-aspiration scintigraphy study combined with single photon emission computed tomography (SPECT) combined with x-ray tomography (CT) in a hybrid instrument. This has allowed the accurate diagnosis of pulmonary and airway contamination with refluxate. Previously only patients with large volume symptomatic reflux aspiration were diagnosed clinically (Mendelson syndrome) or by 2-dimentional barium meal or an older plantar (2 dimensional) technique of scintigraphic aspiration studies. The concept of reflux micro-aspiration has been implicated in multiple pulmonary diseases but without absolute proof from an adequate diagnostic test. Little was known about the natural history, physiology, and response to treatment amongst patients with silent reflux micro-aspiration. The aim of this presentation is to summarise a series of research projects studying the natural history of the disease, common presenting symptoms, pathophysiology and response to treatment. Methods A prospectively populated database of patients referred to a tertiary specialist reflux diagnostic service with atypical and/or treatment resistant reflux was evaluated. The database contained records of consecutive patients including demographic information, presenting symptoms, investigations including imaging, upper gastro-intestinal physiology studies and novel reflux micro-aspiration scintigraphy studies. Treatment details including medical and surgical treatment and post treatment clinical information and investigations. Multiple studies were conducted using the information from the database and findings are summarised in this presentation. Results The novel reflux micro-aspiration scintigraphy with SPECT/CT was compared with other studies (multichannel intraluminal impedance and 24-hour pH monitoring) and was found to be sensitive to reflux occurring outside the oesophagus. Patients with reflux micro-aspiration can present a wide variety of symptoms, commonly a combination of typical symptoms of gastro-oesophageal reflux disease (heartburn and regurgitation) and respiratory symptoms. Reflux micro-aspiration was associated with reduced lower oesophageal sphincter pressure, severe ineffective oesophageal motility (IOM), and pharyngeal contamination with refluxate on reflux scintigraphy. Delayed liquid gastric emptying was not associated with reflux micro-aspiration, however gastroparesis with solids is associated with micro-aspiration. Micro-aspiration was common in patients with giant hiatus hernias and mostly resolved with surgery. Anti-reflux surgery resulted in resolution of aspiration in the majority of patients, however severe IOM was associated with lesser rates of microaspiration resolution. Conclusion Reflux micro-aspiration appears to be a more common manifestation of GORD than previously thought. The work summarised in this presentation discusses the presentation, physiological associations, and treatment of patients with reflux micro-aspiration.

427. THE ROLE OF CROSS-SECTIONAL IMAGING IN PATIENTS WITH PULMONARY MICRO ASPIRATION

Abstract Background There is increasing evidence of a strong relationship between pulmonary microaspiration of refluxate and pulmonary diseases such as bronchiectasis and lung fibrosis. This group has demonstrated the presence of co-location of pulmonary aspiration on modified reflux scintigraphy with lobar parenchymal lung changes on high resolution computed tomographic imaging of the lung (HRCT-L) in patients with typical and atypical reflux symptoms. There is, however, a cohort of patients who demonstrate evidence of reflux aspiration without evidence of parenchymal changes on HRCT-L. This study aims to demonstrate a group of patients with confirmed reflux micro-aspiration without corresponding changes in lung parenchyma on HRCT. Methods Data were obtained from a prospectively populated database of patients with treatment resistant typical and atypical GORD and suspected reflux pulmonary microaspiration. Modified novel digital technique of reflux pulmonary microaspiration scintigraphy using a previously validated technique was performed to evaluate the possibility of significant GORD or extra-oesophageal symptoms, including typical symptoms such as heartburn and reflux and atypical symptoms such as throat symptoms, cough, globus, mucous, throat clearing, dysphonia and recurrent respiratory infections. Patients who underwent microaspiration studies and had normal HRCT-L for chest symptoms were included. The group was compared to patients with lung changes on HRCT-L corresponding with micro-aspiration studies. Results Inclusion criteria were met by 14 patients (86% female, 14% male). The mean age was 54 years (range: 36 – 81 years). All patients demonstrated reflux microaspiration on scintigraphy in the supine delayed phase and all had intermittent or continuous full column gastro-oesophageal reflux. Lung parenchymal changes on HRCT-L corresponding to site of reflux micro-aspiration on scitigraphy were demonstrated in 66 out of 80 patients listed in the database. Amongst patients with normal HRCT-L typical reflux symptoms were reported in 1 patient, atypical symptoms in 6 patients, both in 5 patients and 2 did not report symptoms. Most common presenting symptom was cough. There was no difference in symptomatology of patients with or without HRCT-L pulmonary parenchymal changes. Patients with pulmonary changes on HRCT were on average 13 years older than patients without CT changes (mean age 67, range 31-91). Conclusion HRCT-L is an important additional investigation in patient with reflux micro-aspiration detected on scintigraphy to identify patients with reflux related lung parenchymal changes. Younger age of patients with normal HRCT-L suggests that parenchymal changes may be developing as a result of prolonged exposure to reflux micro-aspiration over time.

Effects of different doses of alfentanil on cardiovascular response to rapid sequence intubation in elderly patients: a parallel-controlled randomized trial

BackgroundRapid sequence intubation (RSI) have been shown to be effective in preventing reflux aspiration in patients with a full stomach during anaesthesia induction and endotracheal intubation. However, there is currently no standardized operation protocol or anaesthesia induction drug standard for RSI. Furthermore, there is a lack of evidence regarding the use of RSI in patients older than 65. In this study, we aimed to investigate the cardiovascular effects of different doses of alfentanil combined with propofol and etomidate during RSI in elderly patients aged 65–80 years.MethodsA total of 96 patients aged 65–80 years who underwent general anaesthesia with tracheal intubation were selected for this study. The patients were randomly assigned to one of four groups using a random number table. Group A patients received an induction dose of 10 µg/kg alfentanil, group B patients received 15 µg/kg alfentanil, group C patients received 20 µg/kg alfentanil, and group D patients received 25 µg/kg alfentanil. Heart rate (HR), mean arterial pressure (MAP), cardiac index (CI), and ejection fraction (EF) were measured at three time points: 5 min before anaesthesia induction (T0), 1 min after endotracheal intubation (T1), and 5 min after endotracheal intubation (T2). Concurrently, 4 ml of arterial blood was collected from patients at three time points, and the concentrations of norepinephrine (NE) and cortisol (Cor) in plasma were detected. Occurrences of hypertension, hypotension, bradycardia and tachycardia during anesthesia induction to 5 min after tracheal intubation were noted.ResultsCompared with T0, the HR, MAP, NE and Cor concentrations in group A and group B were increased at the T1 and T2 time points, CI and EF values were decreased (P < 0.05). HR and MAP in groups C and D were increased at the T1 time point, while they were decreased at the T2 time point in group D (P < 0.05). The changes in CI and EF values, concentrations of NE and Cor, were not significant at T1 and T2 time points in group C (P > 0.05). Additionally, they were not significant in group D at the T1 time point (P > 0.05), but decreased at the T2 time point (P < 0.05). Compared with group A, the HR, MAP, NE and Cor concentrations in groups C and D were decreased at T1 and T2 time points (P < 0.05). The CI and EF values of groups C and D were increased at T1 time point but decreased at T2 time point in group D (P < 0.05). The incidence of hypertension and tachycardia in group A was significantly higher than that in group C and group D (P < 0.05), and the incidence of hypotension and bradycardia in group D was significantly higher than that in group A and group B (P < 0.05).ConclusionAlfentanil 20 µg/kg for RSI in elderly patients, can effectively inhibit the violent cardiovascular reaction caused by intubation, and avoid the inhibition of cardiovascular system caused by large dose, hemodynamics more stable.Trial registrationChiCTR2200062034 (www.chictr.org.cn).

Effect of High-Flow Nasal Cannula Flow on Intrapharyngeal Pressure During Fiberoptic Bronchoscopy Under Deep Sedation.

The flow reaching the vocal folds may be lower than that at the output of high-flow nasal cannula (HFNC) system. This could be due to upper-respiratory obstruction, oxygen leakage, or other factors. The objective of this study was to observe the effect of flow through a nasopharyngeal airway on intrapharyngeal pressure (IPP) in subjects undergoing fiberoptic bronchoscopy (FOB). Patients scheduled for FOB were invited to participate. Measurements were performed at flows of 0-60 L/min; the subjects wore WN-N95 folding medical protective masks (N95) and either underwent FOB or not. IPP at each flow was recorded following 15 s of ventilation, and the cross-sectional area (CSA) of the gastric sinus was measured before and after FOB. Hypoxemia, reflux aspiration, and other pertinent events were recorded. Sixty subjects undergoing FOB at the Affiliated Hospital of Jiaxing University participated in this trial from October 2022-September 2023. IPP increased significantly with an increase in flow and also increased after placing the N95 mask with the same flow (P < .001). When results from before to after FOB were compared, the difference in CSA was statistically significant 263.6 (220.7-300.5) mm2 vs 305.5 (275.4-329.5) mm2, P < .001, but the difference in the risk of reflux aspiration was not statistically significant (0% vs 6.7%, P = .13). Complication rates during treatment were 8.3% for hypoxemia, 0% for reflux aspiration, 1.7% for hypertension, 1.7% for hypotension, 6.7% for tachycardia, 5% for bradycardia, and 10% for postoperative nausea and vomiting. HFNC can provide effective oxygen therapy for people undergoing FOB, and increases in IPP with flow in the range of 0-60 L/min may not increase the risk of reflux aspiration.

A Case of Gastric Contents Reflux Aspiration during General Anesthesia Induction in A Patient with Femoral Vein Atrial Septal Defect Closure

Background: Aspiration of gastric contents during the induction of general anesthesia remains a significant cause of mortality and morbidity in anesthesia. We report an 18-year-old patient with a closed atrial septal defect who developed gastric content reflux aspiration and severe aspiration pneumonia despite abstaining from drinking and fasting for more than 12 hours. Case Presentation: An 18-year-old female patient with congenital heart disease (atrial septal defect) had no previous history of gastroesophageal reflux. After fully abstaining from drinking and fasting (more than 12h), conventional anesthesia was induced, and after the patient’s spontaneous breathing and consciousness disappeared, the patient was assisted with mandibular support with both hands and mask pressure. The induction process was smooth. When preparing for intubation, a large amount of yellow fluid was found in the patient’s mouth. Intubation was performed immediately after suction. Aspiration pneumonia still occurs after the operation even if the patient is treated promptly. Conclusions: As the incidence of perioperative pulmonary aspiration is relatively low, precautions to prevent aspiration tend to be overlooked. We should be alert to the complications of gastric contents regurgitation aspiration in patients with sufficient abstention and fasting during general anesthesia intubation.

OGBN P06 Co-location of pulmonary abnormalities on high resolution CT imaging and pulmonary microaspiration reflux scan: Suggests a causative relationship

Abstract Background The relationship between micro-aspiration of refluxate as a form of gastro-oesophageal reflux disease (GORD) and pulmonary diseases including bronchiectasis and lung fibrosis has been circumstantially suggested but not proven. Clarification of the role of GORD and microaspiration in pulmonary disease may enable targeted therapies. This study aims to determine whether there is a relationship between anatomical location of aspiration of radiological tracer on scintigraphic imaging and changes associated with pulmonary disease on high resolution computed tomographic imaging of the lung (HRCT-L). Methods Data were obtained from a prospectively populated database of patients with treatment resistant typical and atypical GORD and suspected reflux pulmonary microaspiration. Patients who underwent microaspiration studies and had concurrent HRCT-L for chest symptoms were included. Modified novel digital technique of reflux pulmonary microaspiration scintigraphy using a previously validated technique was performed to evaluate the possibility of significant GORD or extra-oesophageal symptoms, including typical symptoms such as heartburn and reflux and atypical symptoms such as throat symptoms, cough, globus, mucous, throat clearing, dysphonia and recurrent respiratory infections. HRCT-L was obtained in clinically indicated patients and compared with scintigraphic findings. Results Pulmonary reflux microaspiration scanning was performed in 121 patients (75% female, 25% male). The mean age was 67 years (range: 31 – 91 years). All patients demonstrated reflux microaspiration on scintigraphy in the supine delayed phase and all had intermittent or continuous full column gastro-oesophageal reflux. Lung parenchymal changes were apparent in 66 of 73 patients who underwent HRCT-L. Fibrotic changes were demonstrated in 51% of patients and bronchiectactic changes in 46%. Correlation at anatomical lobar levels with areas of aspiration of isotope on scintigraphic imaging was seen in 97% of fibrosis patients and 85% of bronchiectasis patients. Conclusions Modified reflux pulmonary microaspiration scintigraphy demonstrated the presence of pulmonary aspiration on delayed imaging. This is the first imaging technique with the ability to confirm the presence of lung aspiration of gastric content. Given the large proportion of cases showing lobar co-location of pulmonary abnormality on HRCT-L, this study indicates a strong relationship between aspiration of refluxate and parenchymal lung changes associated with pulmonary diseases such as IPF and bronchiectasis. There may be a significant role for modified technique scintigraphy to accurately diagnose the presence of reflux aspiration, allowing further research into pathogenesis and management of pulmonary disease.

Effect of trans-nasal humidified rapid insufflation ventilatory exchange on reflux and microaspiration in patients undergoing laparoscopic cholecystectomy during induction of general anesthesia: a randomized controlled trial.

Reflux aspiration is a rare but serious complication during induction of anesthesia. The primary aim of this study is to compare the incidence of reflux and microaspiration in patients undergoing laparoscopic cholecystectomy during induction of general anesthesia using either a facemask or trans-nasal humidified rapid insufflation ventilatory exchange. We conducted a single-center, randomized, controlled trial. Thirty patients were allocated to either a facemask or a trans-nasal humidified rapid insufflation ventilatory exchange (THRIVE) group. Pre-oxygenation for 5 min with a facemask or THRIVE, positive pressure ventilation for 2 min or THRIVE for 2 min after anesthesia induction was followed. Before endotracheal intubation, the secretion above and below the glottis was collected to measure pepsin content and analyze blood gas. The ELISA assay for supra- and subglottic human pepsin content was used to detect the presence of reflux and microaspiration. The primary outcome was the incidence of reflux and microaspiration. Secondary outcomes were apnea time, PaO2 before tracheal intubation, and the end-expiratory carbon dioxide partial pressure. Patients in the THRIVE group had a significantly longer apnea time (379.55 ± 94.12 s) compared to patients in the facemask group (172.96 ± 58.87 s; p < 0.001). There were no differences observed in PaO2 between the groups. A significant difference in gastric insufflation, reflux, and microaspiration was observed between the groups. Gastric insufflation was 6.9% in the THRIVE group vs. 28.57% kPa in the facemask group (p = 0.041); reflux was 10.34% in the THRIVE group vs. 32.14% kPa in the facemask group (p = 0.044); and microaspiration was 0% in the THRIVE group vs. 17.86% kPa in the facemask group (p = 0.023). The application of THRIVE during induction of general anesthesia reduced the incidence of reflux and microaspiration while ensuring oxygenation and prolonged apnea time in laparoscopic cholecystectomy patients. THRIVE may be an optimal way to administer oxygen during the induction of general anesthesia in laparoscopic cholecystectomy patients. Chinese Clinical Trial Registry, No: ChiCTR2100054086, https://www.chictr.org.cn/indexEN.html.

Relationship Between Esophageal Disease and Pulmonary Fibrosis

Esophageal disorders are prevalent among patients with chronic lung diseases, including idiopathic pulmonary fibrosis (IPF). Gastroesophageal reflux disease (GERD) has been associated with IPF prevalence, severity, and respiratory decline. The pathophysiologic relationship between GERD and IPF is likely bidirectional, with aspiration of refluxate leading to lung inflammation and fibrosis, while the restrictive pulmonary physiology may contribute to altered transdiaphragmatic pressure gradient and increased reflux. Esophageal symptoms are frequently absent and do not predict esophageal dysfunction or pathologic reflux in patients with IPF, and objective diagnostic tools including upper endoscopy, ambulatory reflux monitoring, and high-resolution manometry are often needed. Impedance-based testing that identifies both weakly/non-acidic and acid reflux may provide important additional diagnostic value beyond pH-based acid testing alone. Novel metrics and maneuvers, including advanced impedance measures on impedance-pH study and provocative testing on HRM, may hold promise to future diagnostic advancements. The main treatment options include medical therapy with acid suppressants and anti-reflux surgery, although their potential benefits in pulmonary outcomes of IPF require further validations. Future directions of research include identifying phenotypes of IPF patients who may benefit from esophageal testing and treatment, determining the optimal testing strategy and protocol, and prospectively assessing the value of different esophageal therapies to improve outcomes while minimizing risks. This review will discuss the pathophysiology, evaluation, and management of esophageal diseases, particularly GERD, in patients with IPF, as informed by the most recent publications in the field, in hopes of identifying targets for future study and research.

Extraesophageal reflux and reflux aspiration in dogs with respiratory diseases and in healthy dogs.

Salivary bile acids are used to diagnose extraesophageal reflux (EER) and to evaluate the risk of reflux aspiration that is associated with respiratory diseases in dogs. To study total bile acid (TBA) concentrations in saliva and in bronchoalveolar lavage fluid (BALF) to investigate EER and reflux aspiration in dogs with respiratory diseases and in healthy dogs. Thirty-one West Highland White Terriers (WHWTs) with idiopathic pulmonary fibrosis (IPF), 12 dogs with inflammatory airway disease (IAD), 6 dogs with recurrent pneumonia (RP), 26 brachycephalic dogs (BD), 27 healthy WHWTs (HW), 52 healthy dogs (HD). All privately-owned dogs. Saliva and BALF were collected from dogs in each group. Salivary TBA concentrations were higher in IPF (median 0.1692 μM, interquartile range [IQR] 0.1115-0.2925 μM, Cohen's d 3.4, 95% confidence interval [CI] 2.2-4.0, P < .001) and BD (0.0256 μM, IQR 0.0086-0.0417 μM, d 0.5, CI -0.1 to 1.1, P=.003) compared to HD (0μM, IQR not quantifiable [n.q.]-0.0131 μM). Bronchoalveolar lavage fluid TBA concentrations were higher in IPF (0.0117 μM, IQR 0.0048-0.0361 μM, d 0.5, CI 0-1.1, P < .001) compared to HD (0μM, IQR n.q.-0.0074 μM). Extraesophageal reflux and reflux aspiration occur in healthy dogs and those with respiratory diseases.

Development and validation of a prediction model for preoperative anxiety in children aged 2-12 years old.

Children with preoperative anxiety are at risk of perioperative adverse events, such as reflux aspiration, prolonged induction time, wake agitation, and delirium. Identifying children at high risk of severe preoperative anxiety may help anesthesiologists intervene and manage them in advance. The authors hypothesized that the risk of developing serious preoperative anxiety in children is predictable by variables related to basic information about the parent and child. We developed a clinical prediction model to identify patients vulnerable to severe preoperative anxiety among children aged 2-12 years. We enrolled patients aged 2-12 years who underwent elective surgery under general anesthesia and divided them into derivation (n=340, 70.8%) and validation (n=140, 29.2%) groups. Preoperative anxiety was assessed using the modified Yale Preoperative Anxiety Scale, and a high level of preoperative anxiety was defined as a score of >30. The following predictors were collected preoperatively: gender, age, weight, children's education level, only child, history of surgery, waiting time in the anesthesia waiting area, parental education level, parental anxiety, whether venous access had been established in the ward, and whether they had received anti-anxiety interventions. A prediction model was built using binary logistic regression analysis; bootstrap was applied for internal validation, and external validation was performed using the validation datasets. The prediction model had good discrimination, with an area under the receiver operator characteristic curve (AUC) of 0.961 (95% CI=0.943-0.979) and 0.896 (95% CI=0.842-0.950) in the derivation and validation cohorts, respectively. The predictive variables included in the final clinical model were pharmacological intervention (OR=0.008, 95% CI=0.002-0.025), nonpharmacological intervention (OR=0.342, 95% CI=0.104-1.127), parental education level (OR=0.211, 95% CI=0.108-0.411), parental anxiety (OR=6.15, 95% CI=2.396-15.786), only child (OR=2.417, 95% CI=1.065-5.488), history of surgery (OR=3.513, 95% CI=1.137-10.860), and age (OR=0.692, 95% CI=0.500-0.957). In this study, a clinical prediction model was developed and validated for the first time. The proposed clinical prediction model can help doctors identify children most likely to develop a high level of preoperative anxiety. ChiCTR2100054409 (https://www.chictr.org.cn/index.aspx).

217. LAPAROSCOPIC FUNDOPLICATION EFFECTIVE IN TREATING REFLUX MICRO-ASPIRATION

Abstract Pulmonary micro-aspiration has become increasingly recognised subtype of severe gastro-oesophageal reflux disease (GORD). Acid suppression can help with symptoms in proportion of patients, however, does not reduce pulmonary contamination with gastric content. Laparoscopic fundoplication was found to be effective in reducing rates of reflux micro-aspiration. The aim of this study was to examine outcomes of surgical treatment of GORD in patients with confirmed reflux micro-aspiration on novel reflux scintigraphy. Data was extracted from prospectively populated single centre database. Patients with confirmed reflux aspiration by validated novel protocol scintigraphy and treated with laparoscopic 360-degree Nissen fundoplication between 2006–2018 were included. Primary outcome was resolution of reflux micro-aspiration on post-operative scintigraphy. Secondary outcomes included manometry and scintigraphy findings associated with ongoing aspiration, surgical complications, and patient-reported quality of life outcomes. Inclusion criteria were met by 159 patients (66% female); average age 58 (SD 14, range 18–88). Most common presenting symptoms were regurgitation and cough. Laparoscopic fundoplication was associated with resolution of reflux micro-aspiration in 138 (86.8%) of patients. Strongest predictors of persistent aspiration following surgery were severe ineffective oesophageal motility (p = 0.001) and reduced oesophageal clearance (p = 0.003). Complications (Clavien-Dindo grade III and above) occurred in 4 patients (2.5%). There was no perioperative death in this cohort. Patient satisfaction rate with surgery was 94%. Laparoscopic fundoplication is effective in treating reflux micro-aspiration with best outcomes observed in patients with normal oesophageal motility and good oesophageal clearance.

A putative link between pertussis and new onset of gastroesophageal reflux an observational study.

BackgroundPertussis is an infectious disease of the respiratory tract with a changing epidemiology. An increasing incidence has been found in the adult population with recurrent infections possibly related to changes in the current vaccine. Is there an association between pertussis infection, refractory cough and atypical gastro-oesophageal reflux (GORD)? Does this magnify and compound respiratory complications?MethodsObservational study which compares post-pertussis (n=103) with non-pertussis patients (n=105) with established GORD. Patients were assessed for laryngopharyngeal reflux and aspiration of refluxate by a novel scintigraphic study.ResultsBoth groups showed severe GORD in association with high rates of laryngopharyngeal reflux (LPR) and pulmonary aspiration and lung disease. High rates of hiatus hernia and clinical diagnosis of “atypical” asthma showed correlations with pulmonary aspiration.ConclusionsA high level of new onset LPR and lung aspiration has been shown in patients with chronic cough after recent pertussis infection by a novel scintigraphic technique with fused hybrid x-ray computed tomography (SPECT/CT).

High incidence of dyspnoea and pulmonary aspiration in giant hiatus hernia: a previously unrecognised cause of dyspnoea.

Dyspnoea is common in patients with giant paraoesophageal hernia (PEH). Pulmonary aspiration has not previously been recognised as a significant contributory factor. Aspiration pneumonia in association with both gastro-oesophageal reflux disease (GORD) and PEH has a high mortality rate. There is debate about routine anti-reflux measures with surgical repair. Reflux aspiration has been examined in a consecutive cohort using scintigraphic scanning and symptoms. Reflux aspiration scintigraphy (RASP) results and symptoms were evaluated in consecutive patients with PEH managed in our service between January 2012 and March 2017. PEH was diagnosed in 96 patients. Preoperative reflux pulmonary scanning was performed in 70 patients: 54 were female (77.1%) and the mean age was 68years (range 49-85). Dyspnoea was the most common symptom (77.1%), and a symptomatic history of aspiration was seen in 18 patients (25.7%). Clinical aspiration was confirmed by RASP in 13 of these cases. Silent RASP aspiration occurred in a further 27 patients without clinical symptoms. RASP was negative in five patients with clinical symptoms of aspiration. No aspiration by either criterion was present in 27 patients. Dysphagia was negatively related to aspiration on RASP (p<0.01), whereas dyspnoea was not (p=0.857). GORD, dyspnoea and silent pulmonary aspiration are frequent occurrences in the presence of giant PEH. Subjective aspiration was the most specific and positive predictor of pulmonary aspiration. Dyspnoea in PEH patients may be caused by pulmonary aspiration, cardiac compression and gas trapping. The high rate of pulmonary aspiration in PEH patients may support anti-reflux repair.

Acute oxygen desaturation characterizes pulmonary aspiration in patients with gastroesophageal reflux disease and laryngopharyngeal reflux.

The aim of this study was to characterise pulmonary aspiration of refluxate in patients with gastroesophageal reflux disease (GORD) and laryngopharyngeal reflux (LPR) by continuous pulse oximetry (SpO2) during the supine phase of a scintigraphic reflux study. Variables assessed for significance included age, hiatus hernia, frequency, amplitude of reflux and clearance of reflux from the oesophagus/pharynx. The patients included in this study had established GORD and LPR by clinical history. All patients underwent fused three‐ dimensional scintigraphic/ X‐ray computed tomography (CT) and simultaneous continuous pulse oximetry when supine for 30 minutes. A total of 265 patients (40.4% M, 59.6% F) were studied. Mean age of aspirators was 57.0 years and non‐aspirators was 53.5 years. Seven patients had baseline oxygen saturation <95%, with 6/7 showing aspiration by scintigraphy. The remainder had mean baseline saturation of 97.7%. Continuous SpO2 monitoring showed a significant fall in pulmonary aspirators after 20 min of supine acquisition with significant variability. Analysis revealed a cyclic event every 1.5 min in aspirators only. Panel regression analysis showed a significant effect of age, hiatus hernia, pulse rate and reflux frequency on the fall in SpO2. Pulmonary aspiration in patients with LPR and GORD is characterised by acute oxygen desaturation. Variables affecting oxygen desaturation were age, hiatus hernia, pulse rate and reflux frequency. A cyclic event was observed every 1.5 min in aspirators and may be due to reflex homeostatic mechanism attempting to correct perceived hypoxia.

115: THE PULMONARY SEQUELAE OF GASTRO-OESOPHAGEAL REFLUX DISEASE

Abstract Background and aim Gastro-oesophageal reflux disease (GORD) and a spectrum of pulmonary diseases, including idiopathic pulmonary fibrosis (IPF) and bronchiectasis have a complex but poorly understood relationship. IPF is characterised by chronic progressive interstitial pneumonia due to the deposition of fibrous tissue in the pulmonary interstitium. It has a median survival time from diagnosis of 2 to 5 years. Bronchiectasis is defined as irreversible dilatation of the bronchial tree, leading to severe pulmonary infections and gradual deterioration in lung function. Chronic micro aspiration of acid and non-acid refluxate leading to airway irritation, repeated lung injury and respiratory tree remodelling has been implicated in the pathophysiology and progression of both diseases. Current studies have shown that patients with severe GORD will demonstrate pulmonary aspiration of refluxate on scintigraphic scanning. We aim to demonstrate the presence of pulmonary aspiration of refluxate on oesophageal scintigraphy and correlate this with changes of fibrosis, scarring, bronchiectatic and ground glass changes on high resolution computed tomography (HRCT) chest imaging. Methods Retrospective data was obtained from 114 patients who underwent oesophageal scintigraphy reflux studies at a single nuclear medicine imaging facility to evaluate for significant GORD or extra-oesophageal symptoms. Scintigraphy results were then compared with HRCT chest studies of the respective patients. Lobar locations of parenchymal changes on CT were correlated with location of isotope in lungs seen during aspiration on scintigraphy. Results 114 of patients demonstrated evidence of pulmonary aspiration on scintigraphy in the delayed study. All patients had intermittent or continuous full column gastro-oesophageal reflux with evidence of tracer in both lungs or the right lung. Of these patients, 35 underwent HRCT chest studies. 23 of the 35 patients had evidence of pulmonary disease on HRCT, demonstrated by fibrosis, scarring, bronchiectatic changes or ground glass opacities. 11 patients showed evidence of pulmonary fibrosis or scarring, and 10 of these demonstrated co-location of pulmonary aspiration on scintigraphy. 10 of 11 patients with bronchiectactic change were co-located with pulmonary aspiration. Conclusion These results demonstrate a likely relationship between GORD, IPF and bronchiectasis, indicating that the current clinical paradigm of GORD and respiratory disease being two separate entities must be re-evaluated.

Quantitative proteomic analysis of bronchoalveolar lavage fluid in West Highland white terriers with canine idiopathic pulmonary fibrosis

BackgroundCanine idiopathic pulmonary fibrosis (CIPF) is a chronic, progressive, interstitial fibrosing lung disease, manifesting as cough, exercise intolerance and ultimately, dyspnea and respiratory failure. It mainly affects West Highland white terriers (WHWTs), lacks curable treatment and has a poor prognosis. Aspiration of gastroesophageal refluxate may play a role in the development of CIPF. In the first part of this study, we completed label-free quantitative proteomic analysis of bronchoalveolar lavage fluid (BALF) from CIPF and healthy WHWTs. In the second part, we evaluated potential protein markers of reflux aspiration from canine gastric juice and vomitus and whether these were present in BALF from the two groups.ResultsAcross all BALF samples, 417 proteins were identified, and of these, 265 proteins were identified by two or more unique tryptic peptides. Using the 265 high confidence assignments, the quantitative proteome profiles were very similar in the two cohorts, but they could be readily resolved by principal component analysis on the basis of differential protein expression. Of the proteins that were differentially abundant in the two groups, several (including inflammatory and fibrotic markers) were elevated in CIPF, and a smaller, more diverse group of proteins were diminished in CIPF. No protein markers indicative of reflux aspiration were identified.ConclusionsLabel-free proteomics allowed discrimination between CIPF and healthy WHWTs, consistent with fibrotic process but did not provide clear evidence for gastrointestinal aspiration. The measurement of proteins may provide a proteomics signature of CIPF that could be used to evaluate treatment options.

Failed fundoplication with delayed gastric emptying: efficacy of subtotal gastrectomy.

The management of patients with gastroparesis and recurrent reflux after previous fundoplication is challenging. The aim of this study was to evaluate the safety and efficacy of subtotal gastrectomy with Roux-en-Y reconstruction as a remedial procedure in this select patient population. Retrospective analysis of a prospectively populated database identified all patients that underwent subtotal gastrectomy with Roux-en-Y reconstruction (SGRNY) due to reflux symptoms and delayed gastric emptying (DGE). Demographic, intra-operative and post-operative data including pre and post-operative modified reflux aspiration scintigraphy studies were evaluated. Standardized questionnaires were used to assess symptomatic outcomes. From 2018 SGRNY has been selectively performed in 13 patients. Preoperative workup confirmed DGE and severe symptomatic reflux in all patients. The median number of previous fundoplication and or hiatal hernia operations was two (range 1-3). The mean hospital length of stay was 10± 6 days. Post-operative morbidity was experienced in three patients (23%). Seven patients (64%) had significant improvement or complete resolution of reflux on post-operative scintigraphy. Symptom improvement was reported in 92% of patients. In a select patient cohort with post-fundoplication reflux and DGE symptoms, SGRNY is a moderately safe and effective salvage option.