Modified Reflux Scintigraphy Detects Pulmonary Microaspiration in Severe Gastro-Esophageal and Laryngopharyngeal Reflux Disease.

INTRODUCTION: Previously described methodologies for detecting laryngopharyngeal reflux (LPR) have limitations. Symptoms alone are non-diagnostic, and pH-impedance studies have poor sensitivity. Pulmonary micro-aspiration is under-recognised in LPR and gastro-esophageal reflux disease (GERD). The present study aimed to describe the results of a modified technique for scintigraphic reflux studies in two groups with severe reflux: those with typical reflux symptoms and those with laryngopharyngeal manifestations of reflux. METHODS: A prospective database of severely symptomatic, treatment-resistant reflux patients was grouped based upon predominant symptom profile of typical GERD or LPR. All patients underwent reflux scintigraphy. Results were obtained for early scintigraphic reflux contamination of the pharynx and proximal esophagus, and delayed contamination of the pharynx and lungs after 2 h. RESULTS: 187 patients were studied (82 GERD, 105 LPR). The LPR patients were predominantly female (70.5% vs. 56.1%; p = 0.042) and older than the GERD group (median age 60 years vs. 55.5 years; p = 0.002). Early scintigraphic reflux was seen at the pharynx in 89.2% (GERD 87.7%, LPR 90.4%; p = 0.133), and at the proximal esophagus in 89.7% (GERD 88.9%, LPR 90.4%; p = 0.147). Delayed contamination of the pharynx was seen in 95.2% (GERD 93.9%, LPR 96.2%; p = 0.468). Delayed pulmonary aspiration was seen in 46% (GERD 36.6%, LPR 53.3%; p = 0.023). CONCLUSION: Reflux scintigraphy demonstrated a high rate of reflux-related pulmonary aspiration. Contamination of the proximal esophagus and pharynx was observed frequently in both groups of severe disease. The likelihood of pulmonary aspiration and potential pulmonary disease needs to be entertained in severe GERD and LPR.

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.

Long-Term Radiologic Evaluation of Microaspirations among Patients after Esophagectomy.

OBJECTIVES: Aspirations are common after esophagectomy. Data are lacking regarding its long-term radiological manifestations. The purpose of this study is to determine the incidence and radiological patterns of aspirations among long-term survivors and evaluate their clinical significance. METHODS: The records of all patients who underwent esophagectomy between October 2003 and December 2011 and survived more than 3 years were reviewed. Preoperative, first routine postoperative, and latest chest computed tomography (CT)scans were reviewed. Imaging studies were reviewed for radiological signs suspicious of aspirations, conduit location, anastomotic site, and maximal intrathoracic diameter. Data regarding patients' complaints during clinic visits were also collected. RESULTS: A total of 578 patients underwent esophagectomy during the study period. One-hundred twenty patients met the inclusion criteria. Median follow-up was 83.5 months. Cervical and intrathoracic anastomoses were performed in 103 and 17 patients, respectively. A higher rate of CT findings was found in postoperative imaging (n = 51 [42.5%] vs. n = 13 [10.8%] respectively, p < 0.05). Most of these were found in the lower lobes (61%). A higher rate of lesions was found among patients in whom the conduit was bulging to the right hemithorax compared with totally mediastinal or completely in the right hemithorax (54.5 vs. 35.2% and 34.6%, respectively, p < 0.05). No correlation was found with conduit diameter or anastomotic site. These lesions were more prevalent among patients who complained of reflux or cough during meals (NS). CONCLUSIONS: A significantly higher rate of new CT findings was found in postoperative imaging of this post-esophagectomy cohort, suggesting a high incidence of aspirations. The locations of the conduit, rather than anastomosis site, seem to play a role in the development of these findings. Further research is needed to evaluate the clinical significance of these findings.

Proximal reflux: biochemical mediators, markers, therapeutic targets, and clinical correlations.

Airway reflux is implicated in the pathophysiology of a wide range of adult and pediatric upper and lower airway diseases. However, the diagnosis of proximal reflux-associated disease remains challenging due to evolving clinical criteria and institutional and regional variances in diagnostic practices. Evidence suggests that nonacidic contents of reflux may serve as both pathologic mediators of and biomarkers for reflux in the upper airway. Furthermore, they offer potential pharmaceutical and surgical intervention targets and are the focus of novel clinical diagnostic tools currently under investigation.

Predictive factors for gastrostomy at time of diagnosis and impact on survival in patients with amyotrophic lateral sclerosis.

BACKGROUND: Gastrostomy is recommended in patients with Amyotrophic Lateral Sclerosis (ALS) in the presence of weight loss over 10% as compared to usual weight, repeated aspirations or meal time duration longer than 45 min. Currently, the impact of gastrostomy on survival of ALS patients is not clear. AIMS: i) to describe diagnosis factors associated with the indication for gastrostomy ii) to evaluate survival of ALS patients with gastrostomy indication according to their acceptance of feeding tube placement. METHODS: Patients with ALS were included and followed in the ALS referral centre of Limoges's teaching hospital between 2006 and 2017. Neurological, nutritional and respiratory status was assessed prospectively from diagnosis to death. Statistical analysis was performed using Mann-Whitney test, Chi2 tests, Cox model and multivariate logistic regression. RESULTS: Two hundred and eighty-five patients were included. Among the 182 for whom gastrostomy was indicated, 63.7% accepted the placement. The median time was 7.3 months [IQR: 3.2-15.0] and 2.7 months [IQR: 0.9-5.8] respectively from diagnosis to indication and from indication to placement. Weight loss >5% significantly increased the risk of death by 17% (p < 0.0001). At time of diagnosis, bulbar onset, a loss of one point in the body mass index or on the bulbar functional scale were all positively associated with indication for gastrostomy (aOR = 10.0 [95%CI: 1.96-25.0]; p = 0.002, aOR = 1.17 [95%CI: 1.02-1.36]; p = 0.025 and aOR = 1.19 [95%CI: 1.06-1.32]; p = 0.002, respectively). However, gastrostomy placement did not have any impact on survival (aHR = 1.25 [95%CI: 0.88-1.79]; p = 0.22). CONCLUSION: Both neurological and nutritional criteria were associated with an indication for gastrostomy at diagnosis. Gastrostomy placement had no impact on survival. The study of earlier gastrostomy placement might be of interest in further prospective studies.

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.

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.

The association between temporal measures of swallowing with penetration and aspiration in patients with dysphagia: A meta-analysis.

INTRODUCTION: Temporal features of swallowing physiology vary with age in healthy normals and have the potential to impact swallow safety and efficiency in patients with dysphagia. We conducted a meta-analysis to assess the relation between temporal features of swallowing with penetration, aspiration and residue in adult patients with dysphagia regardless of etiology. METHODS: Operational definitions of relevant terms were defined a priori. A search of 5 databases was conducted to November 2016 without restriction to language. Two independent raters reviewed abstracts and full articles, with discrepancies resolved by consensus. All accepted articles advanced to data extraction and critical appraisal according to Cochrane standards. Analysis of pooled data compared measures between groups. RESULTS: Of the 11 articles accepted, the temporal measures used in three or more studies were grouped into morphofunctional categories: bolus transit time; pharyngeal response time; laryngeal closure time; and upper esophageal opening time. Across all selected articles, definitions varied for abnormal swallow and only 4 articles reported rater blinding and reliability for measures related to timing. Pooled data identified two main findings: a. longer pharyngeal response time was associated with penetration and/or aspiration (MD = 0.40 95% CI 0.59 - 0.22), and longer upper esophageal opening duration was associated with only aspiration (PAS ≥ 6) (MD = 0.09 95% CI 0.16 - 0,02). No studies were found that related temporal measures and residue. CONCLUSION: Our pooled findings identified an association of two temporal measures with penetration and/or aspiration but none with residue. The current evidence remains limited due to the heterogeneity across studies in how swallow measures were operationalized. Future work with a standardized and reproducible approach is direly needed.

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.

Laryngeal Closure during Swallowing in Stroke Survivors with Cortical or Subcortical Lesion.

BACKGROUND: One of the major, and most harmful, symptoms of dysphagia in stroke survivors is aspiration. Survivors of unilateral cortical strokes with dysphagia and resulting aspiration have been reported to have greater initiation delays in laryngeal closure than those who did not aspirate. Few studies have reported such data in survivors of subcortical stroke. METHODS: This study measured initiation of laryngeal closure (ILC) and laryngeal closure duration (LCD) in 2 groups of subjects: 15 stroke survivors with cortical lesions and 15 stroke survivors with subcortical lesions. Means and standard deviations of ILC and LCD were analyzed on 5-mL thin liquid and 5-mL puree boluses using a 100-ms timer during subsequent analysis of videofluoroscopic swallowing examinations. Statistical comparisons were used by repeated measures analysis of variance. Significance level was set at P < .05. RESULTS: ILC was significantly longer in stroke survivors with a subcortical lesion than in those with a cortical lesion for both bolus consistencies. However, there were no significant differences between the 2 groups in LCD. Stroke survivors with a subcortical lesion had a greater incidence of penetration or aspiration and silent aspiration than those with a cortical lesion and a longer delay in the ILC. CONCLUSIONS: Subcortical lesions may put these survivors at greater risk of aspiration due to delayed initial laryngeal closure and reduced oral and laryngeal sensation. The subcortical damage, which occurs at the basal ganglia, may interrupt the ILC.

Measurement of Oxygen Desaturation Is Not Useful for the Detection of Aspiration in Dysphagic Stroke Patients.

BACKGROUND: Dysphagia is one of the most dangerous symptoms of acute stroke. Various screening tools have been suggested for the early detection of this condition. In spite of conflicting results, measurement of oxygen saturation (SpO2) during clinical swallowing assessment is still recommended by different national guidelines as a screening tool with a decline in SpO2 ≥2% usually being regarded as a marker of aspiration. This paper assesses the sensitivity of SpO2 measurements for the evaluation of aspiration risk in acute stroke patients. METHODS: Fifty acute stroke patients with moderate to severe dysphagia were included in this study. In all patients, fiberoptic endoscopic evaluation of swallowing (FEES) was performed according to a standardised protocol. Blinded to the results of FEES, SpO2 was monitored simultaneously. The degree of desaturation during/after swallows with aspiration was compared to the degree of desaturation during/after swallows without aspiration in a swallow-to-swallow analysis of each patient. To minimise potential confounders, every patient served as their control. RESULTS: In each subject, a swallow with and a swallow without aspiration were analysed. Overall, aspiration seen in FEES was related to a minor decline in SpO2 (mean SpO2 without aspiration 95.54 ± 2.7% vs. mean SpO2 with aspiration 95.28 ± 2.7%). However, a significant desaturation ≥2% occurred only in 5 patients during/after aspiration. There was no correlation between aspiration/dysphagia severity or the amount of aspirated material and SpO2 levels. CONCLUSIONS: According to this study, measurement of oxygen desaturation is not a suitable screening tool for the detection of aspiration in stroke patients.

Weakly acidic pH reduces inflammatory cytokine expression in airway epithelial cells.

BACKGROUND: Aspiration lung disease (ALD) is a common cause of respiratory morbidity in children and adults with severe neurodisability (sND). Recent studies suggest that chronic microaspiration of gastric contents is associated with mild rather than low, airway acidification. We investigated inflammatory responses to infection by airway epithelial cells (AECs) exposed to weakly acidic media. METHODS: Using pH measurements from children with sND at high risk of ALD as a guide, we incubated AECs in weakly acidic (pH5.5-7.4) media alone; in combination with lipopolysaccharide (LPS); or prior to LPS stimulation at normal pH. Interleukin (IL) -6 and IL-8 expression were measured. RESULTS: IL-6/8 expression in AECs simultaneously exposed to weakly acidic media and LPS for 4 h was reduced with no effect on cell viability. Pre-incubation of AECs at weakly acidic pH also reduced subsequent LPS-induced cytokine expression. Suppression of inflammation was greatest at lower pHs (pH 5.5-6.0) for prolonged periods (16/24 h), but this also adversely affected cell viability. CONCLUSION: AEC inflammatory responses to bacterial stimuli is markedly reduced in a mildly acidic environment.

The Intersection of GERD, Aspiration, and Lung Transplantation.

Lung transplantation is a radical but life-saving treatment option for patients with end-stage lung diseases, such as idiopathic pulmonary fibrosis (IPF) and scleroderma. In light of the proposed association and controversy linking gastroesophageal reflux disease (GERD) to IPF and lung transplant outcome, the American Gastroenterological Association convened during the DDW in Washington in May 2015 a multidisciplinary group of experts in the field of GERD and lung transplantation to make considerations about the care of these patients based on available data and subsequent expert panel discussion at this symposium. The following topics were discussed: (1) pathophysiology of GERD-induced pulmonary symptoms, (2) GERD evaluation before and after lung transplantation, (3) outcome of lung transplantation for IPF and scleroderma, and (4) role of laparoscopic fundoplication before or after lung transplantation.

A randomised trial of the effect of different fluid consistencies used in the management of dysphagia on quality of life: a time trade-off study.

BACKGROUND: thickened fluids are commonly advised to minimise the risk of aspiration in people with dysphagia, although many do not comply with this treatment. In health economics, utilities are values that reflect an individual's preferences for different health states. We examined the healthcare utilities, elicited using a time trade-off approach (TTO), from healthcare professionals and non-dysphagic patients, associated with long-term use of thickened fluids. METHODS: the risk of aspiration with thin fluids was explained to consecutive hospital patients without dysphagia (n = 76) and to a convenience sample of healthcare professionals (n = 75) who were then randomly allocated to drink as much as possible of 200 ml of pre-prepared water of Grade 1 (very mildly thick) or Grade 2 (mildly thick) consistency. A standardised script with a ping-pong approach was then used to elicit TTO utilities for use of thickened fluids using a 10-year horizon. RESULTS: median (inter-quartile range) utilities were 0.7 (0.5-0.9) for those receiving Grade 1 and 0.5 (0.3-0.7) for those receiving Grade 2 consistency fluid (Mann-Whitney test, P = 0.001). Thus, for example, on average those allocated to Grade 2 fluid would be willing to sacrifice 5 years of a 10-year lifespan not to be restricted to fluid of that consistency. There were no significant differences between patient and professional values. CONCLUSION: patients and professionals judge that long-term use of thickened fluids would significantly impair quality of life. Utilities associated with more viscous fluids are particularly low.

Is the External Branch of the Superior Laryngeal Nerve Dispensable in Thyroid Surgery?

BACKGROUND: There is growing evidence that the external branch of the superior laryngeal nerve (eSLN) participates in thyroarytenoid (TA) contraction, but little data quantify its role in vocal cord adduction. Injury to the eSLN, such as in thyroid surgery, is difficult to diagnose and likely underappreciated. It is the authors' belief that eSLN injury contributes to aspiration by depriving its contribution to the laryngeal plexus. The goal of this study was to measure the glottic closing force (GCF) from eSLN stimulation in a porcine model. METHODS: The recurrent laryngeal nerve (RLN) and eSLN were identified bilaterally in four porcine necks. Bilateral RLNs and eSLNs were stimulated simultaneously to obtain a control GCF using a pressure transducer placed in the glottis. Subsequently, bilateral eSLNs were stimulated and the GCF measured to quantify its percent contribution to the control value. RESULTS: Stimulation of the RLNs and the eSLNs each led to TA muscle contraction and a measureable GCF in all four porcine necks. The control GCF was 1000.1 mmHg, while the eSLN mediated CGF was 800 mmHg. The percentage GCF attributable to the eSLN was thus 800/1000 = 80%. CONCLUSIONS: Reflex glottic closure is one of the most important mechanisms for the prevention of aspiration during deglutition. The biomechanical quantification of glottic closure can be shown as the GCF. This study has shown that the eSLN contributes in a significant way to the GCF in a porcine model, a finding that has not been quantified to the best of the authors' knowledge. Therefore, greater focus should be placed on preserving this nerve in thyroid surgery.

Does positioning affect tracheal aspiration of gastric content in ventilated infants?

OBJECTIVES: Gastroesophageal reflux and aspiration can occur in premature infants who are supported with mechanical ventilation. The relation between physical positioning and gastric aspiration in ventilated infants has not been studied. Pepsin measured in tracheal aspirate (TA) emerged as a specific marker for aspiration. The objective of our study was to assess pepsin in TA of ventilated infants at 2 different positions: supine and right lateral. METHODS: We conducted a randomized controlled trial on premature infants who were enterally fed and supported with mechanical ventilation. Patients were randomized into intervention and control groups. In the intervention group, infants were placed supine for 6 hours before a sample of TA was obtained. A second sample was collected 6 hours later while lying in the right lateral position. In the control group, the 2 samples of TA were obtained while infants remained in the supine position during the entire study time. Pepsin in TA was measured while blinded to the group assignment. RESULTS: A total of 34 patients were enrolled and randomized to intervention (n = 17) and control (n = 17) groups. Gestational age was 32.7 ± 2.7 weeks, and birth weight was 1617 ± 526 g; both groups had similar demographic and clinical characteristics. Pepsin concentration did not differ between groups at baseline. In the intervention group, pepsin concentration significantly declined from 13 ng/mL (interquartile range [IQR] 11.9-38.7) to 10 ng/mL (IQR 7-12; P < 0.001), whereas it did not change in the control group (P = 0.42). CONCLUSIONS: The right lateral positioning is associated with decreased TA pepsin. The implications of the present study on hospital practice and clinical outcomes need further investigations.

Lung mechanical changes following bronchoaspiration in a porcine model: differentiation of direct and indirect mechanisms.

Bronchoaspiration results in local deterioration of lung function through direct damage and/or indirect systemic effects related to neurohumoral pathways. We distinguished these effects by selectively intubating the two main bronchi in pigs while a PEEP of 4 or 10cm H2O was maintained. Gastric juice was instilled only into the right lung. Lung mechanical and ventilation defects were assessed by measuring unilateral pulmonary input impedance (ZL,s) and the third phase slope of the capnogram (SIII) for each lung side separately before the aspiration and for 120min thereafter. Marked transient elevations in ZL,s parameters and SIII were observed in the affected lung after aspiration. Elevating PEEP did not affect these responses in the ZL,s parameters, whereas it prevented the SIII increases. None of these indices changed in the intact left lung. These findings furnish evidence of the predominance of the local direct damage over the indirect systemic effects in the development of the deterioration of lung function, and demonstrate the benefit of an initially elevated PEEP following aspiration.

Hunger and thirst numeric rating scales are not valid estimates for gastric content volumes: a prospective investigation in healthy children.

AIM: A rating scale for thirst and hunger was evaluated as a noninvasive, simple and commonly available tool to estimate preanesthetic gastric volume, a surrogate parameter for the risk of perioperative pulmonary aspiration, in healthy volunteer school age children. METHOD: Numeric scales with scores from 0 to 10 combined with smileys to rate thirst and hunger were analyzed and compared with residual gastric volumes as measured by magnetic resonance imaging and fasting times in three settings: before and for 2 h after drinking clear fluid (group A, 7 ml/kg), before and for 4 vs 6 h after a light breakfast followed by clear fluid (7 ml/kg) after 2 vs 4 h (crossover, group B), and before and for 1 h after drinking clear fluid (crossover, group C, 7 vs 3 ml/kg). RESULTS: In 30 children aged 6.4-12.8 (median 9.8) years, participating on 1-5 (median two) study days, 496 sets of scores and gastric volumes were determined. Large inter- and intra-individual variations were seen at baseline and in response to fluid and food intake. Significant correlations were found between hunger and thirst ratings in all groups, with children generally being more hungry than thirsty. Correlations between scores and duration of fasting or gastric residual volumes were poor to moderate. Receiver operating characteristic (ROC) analysis revealed that thirst and hunger rating scales cannot predict gastric content. CONCLUSION: Hunger and thirst scores vary considerably inter- and intra-individually and cannot predict gastric volume, nor do they correlate with fasting times in school age children.

Nasal backflow and the difficulty of relaxation in the upper esophageal sphincter.

OBJECTIVES/HYPOTHESIS: Nasal backflow is the regurgitation of material into nasopharynx during swallowing and it can be easily observed by videofluoroscopy. We aimed to evaluate the association between nasal backflow and the prevalence of aspiration, as well as the relationship between nasal backflow and the opening of the upper esophageal sphincter. STUDY DESIGN: Retrospective case-control study. METHODS: There were 182 cases of videofluoroscopic swallowing studies that were retrospectively reviewed. The presence of nasal backflow and laryngeal aspirations were checked, and the anteroposterior maximum width of the upper esophageal sphincter opening was measured on lateral images of videofluoroscopic swallowing studies. The difference in maximum upper esophageal sphincter width between the group with nasal backflow and the group without nasal backflow was statistically verified. RESULTS: Twenty patients showed nasal backflow, which was closely related to laryngeal aspiration (odds ratio = 10.97; 95% CI = 2.46-48.85; P < 0.05). Their maximal upper esophageal sphincter width (mean ± standard deviation) was 6.82 ± 1.96 mm and significantly different from the group without nasal backflow (9.35 ± 1.56 mm) (P < 0.05). CONCLUSION: Nasal backflow was closely associated with the presence of aspiration; the opening of upper esophageal sphincters significantly decreased in the cases of nasal backflow.