A potential mechanism by which aspiration of duodenogastric fluid augments the risk for bronchiolitis obliterans syndrome after lung transplantation.

OBJECTIVE: Aspiration of duodenogastric refluxate may damage the respiratory epithelium of lung allografts in transplant recipients. We sought to define a mechanism by which aspiration of duodenogastric fluid augments the risk of bronchiolitis obliterans syndrome after lung transplant in a murine model. METHODS: We analyzed the immunological effects of acute aspiration of duodenogastric fluid (0.5 mL/kg) on transplant naive (strain DBA/2J) and transplanted mice (strain B6D2F1/J to strain DBA/2J). Serum antibodies to the lung self-antigens (SAgs) K-alpha1 tubulin and collagen-V were determined by enzyme-linked immunosorbent assay. Exosomes were isolated from serum, and immunoblot membranes were probed for antibodies to lung SAgs. Lung sections were assessed for fibrotic burden and obliterative bronchiolitis lesions by histologic and immunohistochemical analyses, including trichrome staining. RESULTS: Transplanted mice that received duodenogastric fluid developed higher levels of antibodies to the lung SAgs K-alpha1 tubulin and collagen-V and exosomes with lung SAgs on posttransplant days 14 and 28 than transplanted mice with sham aspiration or transplant naive mice (with and without aspiration). All lung allografts demonstrated severe grade A4 rejection on posttransplant day 14, with the highest mean fibrotic burden and mean number of obliterative bronchiolitis-like lesions per microscopic field on day 28 in recipients with aspiration. CONCLUSIONS: This study links aspiration of duodenogastric fluid after lung transplant to higher autoimmune responses to lung SAgs and the release of circulating exosomes with lung SAgs, which together promote sustained immune responses leading to extensive lung parenchymal damage and, ultimately, severe obliterative bronchiolitis-the histologic hallmark of bronchiolitis obliterans syndrome.

Metabolomic profiling of extraesophageal reflux disease in children.

Although respiratory symptoms in children are often attributed to gastroesophageal reflux disease, establishing a clear diagnosis of extraesophageal reflux disease (EERD) can be challenging, as there are no sensitive or specific EERD biomarkers. The aim of this study was to evaluate the metabolite profile in bronchoalveolar (BAL) fluid from children with suspected EERD and assess the impact of reflux treatment on these metabolites. In this prospective pilot study, we performed nontargeted global metabolomic profiling on BAL fluid from 43 children undergoing testing with bronchoscopy, upper endoscopy, and multichannel intraluminal impedance with pH (pH-MII) for evaluation of chronic respiratory symptoms. Twenty-three (54%) patients had an abnormal pH-MII study. Seventeen (40%) patients were on proton pump inhibitors (PPIs) for testing. Levels of histamine, malate, adenosine 5'-monophosphate, and ascorbate were significantly lower in subjects with abnormal pH-MII studies compared to those normal studies. Furthermore, in children off PPI therapy, those with abnormal pH-MII studies had robust increases in a number of glycerophospholipids within phospholipid metabolic pathways, including derivatives of glycerophosphorylcholine, glycerophosphoglycerol, and glycerophosphoinositol, compared to those with normal pH-MII studies. These findings offer insight into the impact of reflux and PPIs on the lungs and provide a foundation for future studies using targeted metabolomic analysis to identify potential biomarkers of EERD.

Gastric Ultrasound Assessing Gastric Emptying of Preoperative Carbohydrate Drinks: A Randomized Controlled Noninferiority Study.

BACKGROUND: Tools for the evaluation of gastric emptying have evolved over time. The purpose of this study was to show that the risk of pulmonary aspiration is not increased with carbohydrate drink, by demonstrating that the gastric antral cross-sectional area (CSA) of the NO-NPO group is either equivalent to or less than that of the NPO (nil per os) group. METHODS: Sixty-four patients scheduled for elective laparoscopic benign gynecologic surgery were enrolled and randomly assigned to the NPO group (n = 32) or the NO-NPO group (n = 32). After having a regular meal until midnight before surgery, the NPO group fasted until surgery, while the NO-NPO group ingested 400 mL of a carbohydrate drink at midnight and freely up to 2 hours before anesthesia. The primary outcome was the gastric antral CSA by gastric ultrasound in right lateral decubitus position (RLDP). Noninferiority was defined as a mean difference of CSA <2.8 cm2. Secondary outcomes included CSA in supine position, gastric volume (GV), GV per weight (GV/kg), GV/kg >1.5 mL/kg, and Perlas grade. RESULTS: CSA in RLDP was not different between the NPO group (6.25 ± 3.79 cm2) and the NO-NPO group (6.21 ± 2.48 cm2; P = .959). The mean difference of CSA in RLDP (NO-NPO group - NPO group) was 0.04 (95% confidence interval [CI], -1.56 to 1.64), which was within the noninferiority margin of 2.8 cm2. CSA was not different between the 2 groups (4.17 ± 2.34 cm2 in NPO group versus 4.28 ± 1.23 cm2 in NO-NPO group; P = .828). GV in NPO group (70 ± 56 mL) was not different from NO-NPO group (66 ± 36 mL; mean difference, 3.66; 95% CI, -20 to 27; P = .756). GV/kg in the NPO group (1.25 ± 1.00 mL/kg) was not different from the NO-NPO group (1.17 ± 0.67 mL/kg; P = .694). The incidence of GV/kg > 1.5 mL/kg was not different between NPO (31.3%) and NO-NPO group (21.9%; P = .768). The median (interquartile range) of the Perlas grade was 1 (0-1) in NPO group and 0.5 (0-1) in NO-NPO group (P = .871). CONCLUSIONS: Preoperative carbohydrates ingested up to 2 hours before anesthesia do not delay gastric emptying compared to midnight fasting, as evaluated with gastric ultrasound.

Nulla Per Os (NPO) guidelines: time to revisit?

PURPOSE OF REVIEW: Preoperative fasting guidelines are generalized to elective procedures and usually do not distinguish between the ambulatory and inpatient setting. Prevalence of aspiration is low while prolonged preoperative fasting is common clinical reality. Recently, changes in preoperative fasting guidelines have been widely discussed. RECENT FINDINGS: Rates of prolonged clear fluid fasting (>4 h) prior to surgery are reported in up to 80% of patients with mean fasting duration of up to 16 h and beyond. Prolonged fasting may result in adverse effects such as intraoperative hemodynamic instability, postoperative delirium, patient discomfort, and extended hospital length of stay. Liberal approaches allowing clear fluids up to 1 h prior to anesthesia or until premedication/call to the operating room have shown no increase in adverse events among children. Various anesthesia societies now encourage clear fluid intake up to 1 h prior to pediatric elective anesthesia. Similar reports in the adult cohort are scarce. SUMMARY: Allowing sips of water until call to the operating room may help reducing prolonged preoperative fasting and improving patient comfort while keeping a flexibility in operating room schedule. The feasibility and safety of a liberal clear fluid fasting regimen among adults undergoing elective anesthesia needs to be evaluated in future studies.

The profibrotic effects of chronic microaspiration of bile acids on lungs of rats at different stages.

This study aimed to explore the profibrotic effects of chronic microaspiration of two major bile acids, including chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA), on lungs of rats at different stages, as well as the underlying mechanisms in vivo. A rat model was induced by weekly intratracheal instillation of DCA and CDCA. Our results showed that chronic microaspiration of bile acids resulted in alveolar structure disorder, and inflammatory cells infiltration in the pulmonary interstitium at the early stage. Subsequently, numerous fibroblasts were proliferated, and collagen deposition was profoundly increased over the interstitium of the airways and vessels. Compared with control group, the expression of α-smooth muscle actin, type I collagen, hydroxyproline, transforming growth factor-ß1 (TGF-ß1), and matrix metalloproteinase-9 in the lung tissues were remarkably elevated at the 2nd week, reached the highest level at the 6th week, and maintained high at the 8th week in both DCA- and CDCA-treated groups (P < 0.05). Furthermore, chronic microaspiration of bile acids led to higher levels of glutathione and malondialdehyde, while lower level of superoxide dismutase in lung tissues compared with controls (P < 0.05), thereby resulting in the oxidant/antioxidant enzyme imbalance in the formation of fibrosis. In addition, we also found a consistent growth in the expression of farnesoid X receptor (FXR) in both DCA- and CDCA-treated groups. Our findings suggested that chronic microaspiration of bile acids could initiate the process of pulmonary fibrosis from the early phase and promote its progression in a time-dependent manner, which likely involved the TGF-ß1, oxidative stress, and FXR-related pathways.

Reliability of gastric suctioning compared with ultrasound assessment of residual gastric volume: a prospective multicentre cohort study.

We aimed to compare the reliability of aspiration via a nasogastric tube with ultrasound for assessment of residual gastric volume. Sixty-one adult patients who were mechanically ventilated and received continuous enteral feeding through a nasogastric tube for > 48 h were included. A first qualitative and quantitative ultrasound examination of the gastric antrum was followed by gastric suctioning, performed by an operator blinded to the result of the ultrasound examination. A second ultrasound examination was performed thereafter, followed by re-injection of the aspirated gastric contents (≤ 250 ml) into the stomach. A third ultrasound assessment was then immediately performed. If the suctioned volume was ≥ 250 ml, 250 mg erythromycin was infused over 30 min. A fourth ultrasound was performed 90 min after the third. Sixty (98%) patients had a qualitatively assessed full stomach at first ultrasound examination vs. 52 (85%) after gastric suctioning (p = 0.016). The calculated gastric volume significantly decreased after gastric suctioning, without a significant decrease in the number of patients with volume ≥ 250 ml. Four of the nine patients with calculated gastric volume ≥ 250 ml had vomiting within the last 24 h (p = 0.013). The antral cross-sectional area significantly decreased between the third and the fourth ultrasound examination (p = 0.015). Erythromycin infusion did not make a significant difference to gastric volume (n = 10). Our results demonstrate that gastric suctioning is not a reliable tool for monitoring residual gastric volume. Gastric ultrasound is a feasible and promising tool for gastric volume monitoring in clinical practice.

Gastroesophageal reflux disease and chronic cough: A possible mechanism elucidated by ambulatory pH-impedance-pressure monitoring.

BACKGROUND: The pathophysiological mechanism(s) of gastroesophageal reflux disease (GERD)-related chronic cough (CC) is unclear. We aimed to determine the mechanism of reflux-induced cough by synchronous monitoring of reflux episodes, esophageal motility, and cough. METHODS: Patients with GERD were prospectively enrolled and classified into GERD with CC (GERD-CC) and without CC (GERD) groups. Twenty-four-hour ambulatory pH-impedance-pressure monitoring was performed; the reflux patterns, esophageal motility during prolonged exposure to acid and characteristics of reflux episodes that induced coughing paroxysms were analyzed. KEY RESULTS: Thirty-one patients with GERD-CC and 47 with GERD were enrolled; all of whose monitoring results fulfilled the criteria for diagnosis of GERD. Patients with GERD-CC had higher reflux symptom scores, longer exposure to acid, higher DeMeester scores, and more frequent reflux episodes, proximal extent reflux detected by impedance, and higher percentage of strongly acidic reflux than patients in the GERD group (all P < .05). Of 63 reflux-cough episodes identified in the GERD-CC group, 74.6% of distal reflux and 67.0% of proximal reflux episodes were acidic. More patients had low pan-esophageal pressure in primary peristalsis (48.5% vs 11.8%, P = .000) and synchronous contraction in secondary peristalsis during prolonged exposure to acid in the GERD-CC than in the GERD group (63.9% vs 9.1%, P = .000). CONCLUSIONS & INFERENCES: Proximal acidic reflux and distal reflux-reflex are jointly associated with reflux-induced cough in patients with GERD. Low pan-esophageal pressure in primary peristalsis and synchronous contraction in secondary peristalsis may play important roles in GERD-associated chronic cough.

Duración del ayuno preoperatorio en pacientes con cirugía programada / Duration of preoperative fasting in patients with scheduled surgery

Antecedentes y objetivo: el ayuno preoperatorio disminuye el riesgo de aspiración del contenido gástrico y sus complicaciones. Sin embargo, si es excesivo, favorece la regurgitación y el riesgo de broncoaspiración tras la inducción anestésica, así como alteraciones metabólicas e hidroelectrolíticas. Analizamos su duración, en pacientes con cirugías programadas en un hospital público de agudos. Material y métodos: se encuestó a todos los pacientes mayores de 18 años con cirugías programadas. Se recolectaron datos sobre la prescripción médica de ayuno, la hora de inducción anestésica y personales. El ayuno prescripto se comparó con las recomendaciones de las guías de la AAARBA (Asociación de Anestesia, Analgesia y Reanimación de Buenos Aires). Resultados: se reclutaron 139 pacientes, con una mediana de edad de 48 años (30; 64), 53% femeninos. La mediana del ayuno prescripto fue de 12,5 horas tanto para sólidos como para líquidos. El ayuno para sólidos que realizaron los pacientes tuvo una mediana de 14 horas, la cual resultó significativamente mayor que la prescripción (p < 0,001). En cambio, el ayuno para líquidos tuvo una mediana de 12 horas, no hallándose una diferencia significativa (p = 0,452) con lo prescripto. En comparación con la guía de la AAARBA, el ayuno prescripto excedió la recomendación para sólidos (4,5 h) y para líquidos (10,5 h). El ayuno realizado por el paciente excedió lo prescripto para sólidos (1,5 h), mientras que para líquidos fue inferior (0,5 h). Conclusión: el ayuno preoperatorio prescripto no se adecuó a las recomendaciones actuales. Las horas de ayuno realizadas por el paciente resultaron excesivas. (AU)

Background and objective: preoperative fasting reduces the risk of aspiration of gastric contents and its complications. However, if fasting is excessive, it favours regurgitation and the risk of pulmonary aspiration in patients undergoing general anaesthetic, such as metabolic and electrolyte disorders. We analysed its duration in patients with elective surgeries in public acute care hospital. Material and methodologies: patients over 18 years old with elective surgeries were surveyed. Data about medical fasting indication, time of induction of anaesthesia and personal information was collected. The prescribed fast was compared with the recommendations of the AAARBA (Association of Anaesthesia, Analgesia and Reanimation of Buenos Aires) guidelines. Results: 139 patients were gathered with a median of 48 years old (30; 64), 53% of them were female. Fasting indication median was of 12.5 h for solids and liquids. The fasting made by the patient for solids had a median of 14 h which resulted to be significantly higher to the indication (p < 0.001). By contrast, the fasting for liquids had a median of 12 h which it did not show a significant difference (p = 0.452) with the indication. In comparison with the AAARBA guideline, the fasting indication exceeded the recommendation for solids (4.5 h) and for liquids (10.5 h). The fasting made by the patient exceeded to what was indicated for solids (1.5 h) while for liquids, it was inferior (0.5 h). Conclusion: the indicated preoperative fasting was not adequate to the current recommendations. The hours of fasting made by patient were excessive. (AU)

Swallowing speed is no adequate predictor of aspiration in Parkinson's disease.

BACKGROUND: There is still a lack of a clinical test to reliably identify patients with Parkinson's disease (PD) being at risk for aspiration. METHODS: In this prospective, controlled, cross-sectional study, we assessed if swallowing speed for water is a useful clinical test to predict aspiration proven by flexible endoscopic evaluation of swallowing (FEES). Due to this, we measured the swallowing speed for 90 mL water in 115 consecutive and unselected PD outpatients of all clinical stages and 32 healthy controls. KEY RESULTS: Average swallowing speed was lower in patients compared with controls (6.5 ± 3.9 mL/s vs 8.5 ± 3.2 mL/s; P < .01). The disease-independent widely used threshold of <10 mL/s showed insufficient sensitivity of 88% and specificity of 19% with high false-positive rates of 63% for patients and 69% for controls. Receiver operating characteristic (ROC) analysis was carried out to define a suitable cutoff value for detection of aspiration of water (area under the curve 0.72, P < .001) in PD patients. The optimized cutoff value was 5.5 mL/s with a sensitivity of 69% and a specificity of 64%. CONCLUSION AND INFERENCES: Measuring swallowing speed is prone to methodological errors and not suitable as a screening instrument to predict aspiration in PD patients.

LMA® Protector™ versus traditional LMA to perform endobronchial ultrasound-guided transbronchial needle aspiration: a retrospective analysis.

BACKGROUND: The aim of this study was to evaluate the use of laryngeal mask airway (LMA)® Protector™ by comparison with traditional LMA for performing endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). METHODS: This was a retrospective observational single-center study including 143 patients who underwent EBUS-TBNA for mediastinal staging of lung cancer. Patients were retrospectively divided into two groups based on whether a traditional LMA (traditional LMA group) or LMA Protector was used. Anesthesiologist outcomes, diagnostic yield of EBUS-TBNA, and complications related to the procedure were computed for each group and statistically compared. RESULTS: LMA traditional group and LMA Protector group counted 70 and 73 patients, respectively. LMA traditional group versus LMA Protector group showed no significant difference on time of LMA insertion (120±25 vs. 118±39 s; P=0.49), reposition rates (18% vs. 16%; P=0.78); systolic pressure (140±55 vs. 118±37 mmHg; P=0.59); diastolic pressure (82±15 vs. 90±26 mmHg; P=0.39); heart rate (82±9.9 vs. 83±20 bpm; P=0.49); SpO2 values (93±21% vs. 92±14%; P=0.63); diagnostic accuracy (91.3% vs. 92%; P=0.95), and patients' complications as nausea (4% vs. 3%; P=0.61); vomiting (3% vs. 1%, P=0.96); gastric aspiration (7% vs. 1%; P=0.08); and sore throat (7% vs. 3%; P=0.22). Conversely, LMA traditional group versus LMA Protector group presented a longer procedural time (47±23 vs. 38±17 s; P=0.02), higher number of passage to biopsy target lesion (4±0.5 vs. 3.1±0.6; P=0.01); higher rate of balloon ultrasound rupture (11% vs. 1%; P=0.01). CONCLUSIONS: EBUS-TBNA conducted with LMA Protector is a useful strategy that reduced the procedural time and in theory ensured the comfort of patients. Our results should be confirmed by larger, prospective, randomized studies.

Early Immune Response to Acute Gastric Fluid Aspiration in a Rat Model of Lung Transplantation.

OBJECTIVES: Chronic aspiration of gastric fluid contents can decrease long-term survival of pulmonary transplants due to development of obliterative bronchiolitis. However, little is known about the early immune response and the cascade of events involved in the development of obliterative bronchiolitis. MATERIALS AND METHODS: We utilized a rat orthotopic pulmonary transplant model and a single aspiration of either gastric fluid or normal saline to investigate the histologic, cellular, and cytokine changes associated with an acute gastric fluid aspiration event compared with normal saline at 2 and 10 days after aspiration. RESULTS: Our observations included a decrease in pulmonary compliance and increased airway inflammation and acute rejection of the transplanted lung, as well as increases in macrophages, granulocytes, and proinflammatory cytokines such as interleukin 1ß, transforming growth factor ß1 and ß2, and tumor necrosis factor α in bronchoalveolar lavage fluid from the transplanted lung of gastric fluid-aspirated rats compared with normal saline-aspirated rats. CONCLUSIONS: The acute inflammatory response observed in the present study is consistent with changes found in chronic models of aspiration-associated injury and suggests a potentially important role for mast cells in the development of obliterative bronchiolitis.

Nil per os guidelines: what is changing, what is not, and what should?

Preoperative nil per os (NPO) guidelines have been in existence since the recognition of the risk of perioperative aspiration. These guidelines aim at reducing the risk for gastric content aspiration to the lowest possible, to avoid associated morbidity, unplanned hospital and/or an intensive care admission. Thus, such guidelines are not only considered for patients having major surgeries, but more so in those having ambulatory surgery including those performed at non-operating room anesthesia locations. NPO guidelines have always been controversial due to the paucity of data in support of one recommendation versus another and have seen multiple changes and updates by the issuing national anesthesiology societies as new evidence emerges. At the present time, they have become increasingly permissive, such that the ingestion of clear fluids is now encouraged up to two hours before elective surgery. This has added more fuel to the already heated controversies regarding NPO guidelines and contributed to the experienced variability among different local NPO policies adopted by different clinicians. In this article, we attempt to discuss many of these controversies, including the relationship between NPO duration and the risk of aspiration, NPO and the choice of airway device, NPO and operating room efficiency and NPO for procedural sedation.

¿El reflujo gastroesofágico y la aspiración de contenido gástrico están implicados en la etiopatogenia y la progresión de la fibrosis pulmonar idiopática? / Does gastroesophageal reflux and gastric content aspiration have some role in the pathogenesis and progression of Idiopathic Pulmonary Fibrosis?

Resumen El reflujo gastroesofágico (RGE) y la aspiración oculta de contenido digestivo están probablemente implicados en la etiopatogenia y progresión de la fibrosis pulmonar idiopática (FPI). Los mecanismos patogénicos involucrados son la disminución de la distensibilidad pulmonar y el consiguiente aumento de la presión negativa intratorácica durante la inspiración, así como la disminución de los mecanismos de control de la motilidad esofágica o del tono del esfínter esofágico inferior. La prevalencia de RGE y anomalías de la motilidad esofágica están aumentadas en los pacientes con FPI comparado con la población general. Entre los pacientes con FPI, el 67-76% demostraron exposición anormal al contenido ácido en el esófago. Sin embargo, no hubo relación entre la gravedad del RGE y la gravedad de la FPI. Los estudios que han examinado el tratamiento antirreflujo en esta población han sido escasos. Incluso, algunos datos sugieren que el tratamiento antiácido puede ser perjudicial en algunos pacientes con esta condición. Después de analizar toda la evidencia relevante encontrada hasta la fecha, concluimos que no se puede establecer una relación causal entre el RGE, la aspiración del contenido gástrico y la patogénesis de la FPI. Además, existe escasa evidencia clínica que haya examinado el tratamiento antirreflujo en pacientes con fibrosis pulmonar idiopática.

ABSTRACT Gastroesophageal reflux (GERD) and hidden aspiration of gastric contents are probably involved in the pathogenesis and progression of idiopathic pulmonary fibrosis (IPF). The pathological mechanisms involved are decreased pulmonary distensibility and consequent increase of intrathoracic negative pressure during inspiration, as well as decreased control mechanisms of esophageal motility or lower esophageal sphincter. The prevalence of GERD and oesophageal dysmotility was higher in patients with IPF as compared with general population. Among patients with IPF, 67-76% demonstrated abnormal oesophageal acid exposure. However, no relationship was demonstrated between severity of GERD and severity of IPF. Data are scant on outcomes of antireflux treatment in patients with IPF. Actually, some data suggests that antacid treatment may be deleterious in some IPF patients. After analyzing all the relevant evidence found to date, a causal relationship between GERD, gastric content aspiration and IPF pathogenesis cannot be established. There is scant evidence examining antireflux treatment in idiopathic pulmonary fibrosis patients.

Gastro-Oesophageal Reflux and Aspiration: Does Laparoscopic Fundoplication Significantly Decrease Pulmonary Aspiration?

PURPOSE: Pulmonary aspiration of gastric refluxate is one of the indications for anti-reflux surgery. Effectiveness of surgery in preventing pulmonary aspiration post-operatively has not been previously tested. The aim of this project is to assess effectiveness of anti-reflux surgery on preventing pulmonary aspiration of gastric refluxate. METHODS: Retrospective analysis of prospectively populated database of patients with confirmed aspiration of gastric refluxate on scintigraphy. Patients that have undergone anti-reflux surgery between 01/01/2014 and 31/12/2015 and had scintigraphy post-operatively were included. Objective data such as resolution of aspiration, degree of proximal aero-digestive contamination, surgical complications and oesophageal dysmotility as well as patient quality of life data were analysed. RESULTS: Inclusion criteria were satisfied by 39 patients (11 male and 28 female). Pulmonary aspiration was prevented in 24 out of 39 patients (61.5%) post-operatively. Significant reduction of isotope contamination of upper oesophagus supine and upright (p = 0.002) and pharynx supine and upright (p = 0.027) was confirmed on scintigraphy post-operatively. Severe oesophageal dysmotility was strongly associated with continued aspiration post-operatively OR 15.3 (95% CI 2.459-95.194; p = 0.02). Majority (24/31, 77%) of patients were satisfied or very satisfied with surgery, whilst 7/31 (23%) were dissatisfied. Pre-operative GIQLI scores were low (mean 89.77, SD 20.5), modest improvements at 6 months (mean 98.4, SD 21.97) and deterioration at 12 months (mean 88.41, SD 28.07) were not significant (p = 0.07). CONCLUSION: Surgery is partially effective in reversing pulmonary aspiration of gastric refluxate on short-term follow-up. Severe oesophageal dysmotility is a predictor of inferior control of aspiration with surgery.

Pulmonary aspiration in adjustable gastric banding carriers undergoing a second surgical procedure. Considerations on personal experience and review of the literature.

BACKGROUND: The observation of a relatively high number of pulmonary aspirations (PA) among gastric band (GB) carriers undergoing a second surgery, prompted us to modify our strategy for GB patients candidate to further operation under general anesthesia. MATERIAL OF STUDY AND RESULTS: In January 2013, following the occurrence of PA at the induction of general anesthesia in 1 GB carrier undergoing a further operation, we reviewed our Data Base between January 2005 and 2013, to explore the rate of pulmonary aspiration in patients GB carriers undergoing a second surgery. Considering the rate (3/172 - 1.7%) too high in comparison with non-GB carriers, we decided to deflate the banding before any further surgery planned under general anesthesia. We then retrospectively reviewed the occurrence of PA after having changed the protocol. Since February 2013, through December 2016, 81 GB carriers underwent a second surgery and not a single episode of PA occurred (0/81). DISCUSSION: The occurrence of PA in patients with GB seems greater than in non-GB patients. Larger series should be examined to assess the incidence of PA among this specific population. Awareness of the increased risk is important to general anesthesiologists and surgeons, considering the increasing number of GB carriers who may be in need of surgery. Our result after adopting the deflation policy, even though not statistically significant, seems highly suggestive. CONCLUSION: We believe that, considering the potentially severe consequences of PA, the gastric band should be deflated before any planned procedure requiring general anesthesia. Further data are needed. KEY WORDS: Adjustable gastric banding, Aspiration Pneumonia, Bariatric surgery, Morbid obesity, Pulmonary Aspiration.

Ultrasonographic gastric volume before unplanned surgery.

We aimed to measure gastric antral cross-sectional area with ultrasound and estimate the gastric volume of 300 patients before unplanned surgery, fasted for at least six hours. Measurements were successfully recorded in 263 semi-recumbent patients. The median (IQR [range]) area was 333 (241-472 [28-1803]) mm2 and the mean (SD) estimated volume was 45.8 (34.0) ml. The area exceeded 410 mm2 in 92/263 (35%) measurements. Body mass index and morphine administration were associated with larger gastric areas on multivariable linear regression analysis, with beta coefficient (95%CI) 0.02 (0.01-0.04), p = 0.01, 0.23 (0.01-0.46), p = 0.04, respectively. Fasting time was not associated with gastric area and therefore could not substitute for ultrasound measurements in this cohort.

Using quality improvement methods to reduce clear fluid fasting times in children on a preoperative ward.

OBJECTIVES: We applied quality improvement (QI) methodology to identify the different aspects of why children fasted for prolonged periods in our institution. Our aim was for 75% of all children to be fasted for clear fluid for less than 4 hours. BACKGROUND: Prolonged fasting in children can increase thirst and irritability and have adverse effects on haemodynamic stability on induction. By reducing this, children may be less irritable, more comfortable and more physiologically stable, improving the preoperative experience for both children and carers. METHODS: We conducted a QI project from January 2014 until August 2016 at a large tertiary pediatric teaching hospital. Baseline data and the magnitude of the problem were obtained from pilot studies. This allowed us to build a key driver diagram, a process map and conduct a failure mode and effects analysis. Using a framework of Plan-Do-Study-Act cycles our key interventions primarily focused on reducing confusion over procedure start times, giving parents accurate information, empowering staff and reducing variation by allowing children to drink on arrival (up to one hour) before surgery. RESULTS: Prior to this project, using the 6,4,2 fasting rule for solids, breast milk, and clear fluids, respectively, 19% of children were fasted for fluid for less than 4 hours, mean fluid fasting time was 6.3 hours (SD 4.48). At the conclusion 72% of patients received a drink within 4 hours, mean fluid fasting reduced to 3.1 hours (SD 2.33). The secondary measures of aspiration (4.14:10 000) and cancellations have not increased since starting this project. CONCLUSIONS: By using established QI methodology we reduced the mean fluid fasting time for day admissions at our hospital to 3.1 hours and increased the proportion of children fasting for less than 4 hours from 19% to 72%.

[Preoperative fasting period of fluids in bariatric surgery]. / Präoperative Flüssigkeitskarenz in der bariatrischen Chirurgie.

BACKROUND: Aspiration of stomach content is a severe complication during general anaesthesia. The DGAI (German Society for Anesthesiology and Intensive Care Medicine) guidelines recommend a fasting period for liquids of 2 h, with a maximum of 400 ml. Preoperative fasting can affect the patients' recovery after surgery due to insulin resistance and higher protein catabolism as a response to surgical stress. OBJECTIVES: The aim of the study was to compare a liberal fasting regimen consisting of up to 1000 ml of liquids until 2 h before surgery with the DGAI recommendation. MATERIALS AND METHODS: The prospective observational clinical study was approved by the ethics committee of the University of Leipzig. In the liberal fasting group (Glib) patients undergoing bariatric surgery were asked to drink 1000 ml of tea up to 2 h before surgery. Patients assigned to the restrictive fasting group (Gres) who were undergoing nonbariatric abdominal surgery were asked to drink no more than 400 ml of water up to 2 h preoperatively. Right after anaesthesia induction and intubation a gastric tube was placed, gastric residual volume was measured and the pH level of gastric fluid was determined. Moreover, the occurrence of aspiration was monitored. RESULTS: In all, 98 patients with a body mass index (BMI) of Glib 51.1 kg/m2 and Gres 26.5 kg/m2 were identified. The preoperative fasting period of liquids was significantly different (Glib 170 min vs. Gres 700 min, p < 0.001). There was no difference regarding the residual gastric volume (Glib 11 ml, Gres 5 ml, p = 0.355). The pH of gastric fluid was nearly similar (Glib 4.0; Gres 3.0; p = 0.864). Aspiration did not occur in any patient. CONCLUSIONS: There is evidence suggesting that a liberal fluid fasting regimen (1000 ml of fluid) in the preoperative period is safe in patients undergoing bariatric surgery.