Bolus Types Research Articles

The pathophysiology of dysphagia post-lung transplant: A systematic review.

One major consequence of lung transplantation is the development of oropharyngeal dysphagia. This systematic review aims to appraise and synthesize the available evidence of the use of instrumental assessments to outline the characteristics of post-lung transplant dysphagia. Following the identification of appropriate search terms for the question, a literature search was conducted in PubMed, Scopus, and the Health and Medical Collection of Proquest Research Library and included records between inception and September 14, 2023. Search strategies included the use of text words and subject headings (e.g., MeSH and Index terms) related to (1) dysphagia or swallowing (swallow*, deglutition disorder*), (2) lung transplant (lung transplant*, post-operative, post-lung), and (3) complications (adverse effects, *complications, treatment outcome). The literature search strategy yielded a total of 883 studies from the electronic database search, with no additional records identified through other sources. After the removal of duplicates (n = 96), a total of 787 studies were screened through title and abstracts which eliminated 775 studies. Six studies were ultimately included in the systematic review. The selected articles included patients who underwent lung transplantation and all but one study utilized a retrospective design. A lack of transparency regarding instrumental evaluation protocols (videofluoroscopic [VFSS] and Flexible Endoscopic Evaluation of Swallowing [FEES]) including the number and bolus types used during the instrumental evaluations appeared as a theme in the studies included. The Penetration-Aspiration Scale (PAS) was systematically utilized to measure dysphagia safety outcome. Handling of the PAS scale was not consistent across studies, however penetration or aspiration ranged from 52.4% up to 100%. Additionally, silent aspiration rates ranged from 14.2% to 61.9%. This review sought to describe the post-operative swallowing function and its physiological parameters following lung transplantation. We examined the results reported and the methods utilized in obtaining these results in the existing literature. Limited reporting practices for physiological parameters were found, however the airway invasion was reported in all studies with variation in degrees of swallowing safety related deficits, with PAS being the most widely used scale to describe airway invasion depth and response. Future studies exploring dysphagia outcomes post-lung transplant should comment on the altered physiological mechanisms of the swallow to further expand on the physiological deficits observed following transplantation in this group and allow for treatment planning. Level 1.

Impact of Reducing Fluoroscopy Pulse Rate on Adult Modified Barium Swallow Studies

Modified Barium Swallow Studies (MBSS) are a critical part of the evaluation, treatment planning, and outcome assessment for persons with swallowing disorders. Since MBSSs use ionizing radiation with associated cancer risks, many clinicians have reduced radiation exposure by reducing the fluoroscopic pulse rate. However, by reducing pulse rate, we also decrease the temporal resolution of MBSSs which has been shown in pilot studies to significantly reduce diagnostic accuracy. Two hundred MBSSs from patients routinely undergoing MBSS as standard of care conducted at 30 pulses per second (pps) using the Modified Barium Swallow Study Impairment Profile (MBSImP™) standardized administration protocol were selected. A stratified sampling method ensured that a full range of swallowing impairments (etiology, type, and severity) was represented. Recordings were down sampled from 30 pps to 15, 7.5, and 4 pps. MBSSs were rated using the MBSImP components and Penetration–Aspiration Scale (PAS) score for each swallow. Percent agreement was calculated across raters for MBSImP and PAS scores by bolus type and volume. The Least-Squares Method was used for hypothesis testing. Statistically significant and clinically meaningful changes in scores of swallowing physiology and penetration/aspiration occurred when reducing pulse rate below 30pps. These changes were evident across bolus types and volumes. Given the impact on diagnostic accuracy and the low radiation risks to adults undergoing MBSSs, reducing pulse rate to 15pps or below is not aligned with the As Low As Reasonably Achievable (ALARA) principle and should not be used as a viable method to reduce radiation exposure from MBSSs.

Effects of Bolus Types and Swallowing Maneuvers on Laryngeal Elevation: Analysis of Healthy Young Adult Men and Healthy Older Men.

Peak velocity, distance, and time of laryngeal elevation during swallowing were measured with a laryngeal motion measurement system in eight healthy young adult men in their 20 and 30s (33.0 ± 4.3years) and ten healthy older men in their 60 and 70s (74.0 ± 3.9years). The participants performed swallowing five times each for a total of eight conditions: two bolus types (saliva and water) and four swallowing methods (normal swallow, effortful swallow, super-supraglottic swallow, and Mendelsohn maneuver). When the bolus type was saliva, peak velocity and distance increased more for swallowing maneuvers (effortful swallow, super-supraglottic swallow, and Mendelsohn maneuver) than for normal swallow. On the other hand, when the bolus type was water, there was no difference in peak velocity or distance between normal swallow and swallowing maneuvers. In healthy older men, distance was greater with Mendelsohn maneuver than with normal swallow, and peak velocity was increased with swallowing maneuvers than with normal swallow. Healthy young adult men had increased peak velocity and distance with water rather than saliva. The increase in peak velocity and distance obtained by swallowing maneuvers was influenced by age and bolus, suggesting that the subjects and conditions used are important in terms of promoting safer oral intake.

Precipitating Factors and Outcome of Diabetic Ketoacidosis among Children and Adolescents with Type-1 Diabetes Mellitus.

To determine the precipitating factors and outcomes of diabetic ketoacidosis (DKA) among patients with type 1 diabetes mellitus. An analytical study. Place and Duration of the Study: Department of Paediatrics, National Institute of Child Health, Karachi, Pakistan, from July to December 2022. Children of either gender aged up to 18 years and presenting with DKA with a known diagnosis of type-1 diabetes were enrolled. Demographic, clinical, and anthropometric characteristics of all children were noted. Laboratory investigations were sent to the institutional laboratory. Presenting features, precipitating factors, severity of DKA, and outcomes noted. Among 131 children, 101 (77.1%) were girls. The socio-economic status of 75 (57.3%) patients was the lower middle. Celiac disease was the commonest associated disease noted in 23 (17.6%) patients. A total of 123 (93.9%) children were using basal plus bolus types. Adherence to diabetes-related drug therapy was seen in 105 (80.2%) patients. At the time of presentation, vomiting, fever, abdominal pain, and respiratory distress were the most frequent presenting features reported in 77 (58.8%), 67 (51.1%), 42 (32.1%), and 34 (26.0%) patients, respectively. The most common precipitating factors for DKA were infection/illness (n=90, 68.7%) and missed insulin dose (n=16, 12.2%); no cause was identified in 25 (19.1%) patients. The mean duration of hospital stay was 5.25±2.4 days. Four patients could not survive. The most common precipitating factor for the current episode of DKA were infection or illness, or missed insulin dose. Vomiting, fever, abdominal pain, and respiratory distress were the most frequent presenting features. In-hospital mortality was found to be 3% in DKA patients. Diabetic ketoacidosis, Type-1 diabetes mellitus, Insulin, Vomiting, Abdominal pain.

Rumen microbiome response to sustained release mineral bolus supplement with low- and high-quality forages

IntroductionLimited forage quantity and quality are challenges faced in livestock production systems in semi-arid rangelands of the western United States, particularly when livestock face stressors such as cold weather or have increased nutritional requirements such as during pregnancy and lactation. To meet livestock nutrient requirements, producers frequently provide supplemental nutrition, however there is limited knowledge regarding the effects of these practices on the rumen microbiome in these environments.MethodsA study was conducted to evaluate changes in the rumen microbiome in response to high- and low- quality forage with sustained release mineral boluses. The study consisted of 16 ruminally-cannulated 2–3-year-old black angus cows fed high quality grass alfalfa hay or low-quality grass hay with a 90 or 180 day sustained release mineral bolus. Rumen samples were collected pre-feeding and 8 hours post feeding and bacterial 16S rRNA gene amplicons were sequenced from the rumen fluid.ResultsAlpha diversity as measured by Shannon’s diversity index decreased significantly over time (p<0.01) and averaged 5.6 pre-feeding and 5.4 post- feeding and was not significantly different between high- and low-quality forages or between mineral bolus types (p>0.05). Principal coordinates analysis (PCoA) of the Bray-Curtis dissimilarity matrix showed distinct grouping by feed quality and time but not by mineral bolus type. Bacteroidetes and Firmicutes were the dominant phyla in all treatments and significant increases (p<0.05) in the relative abundance of the family Lachnospiraceae and the genus Prevotella were observed in high quality forage diets. Rumen VFA and NH3-N concentrations were also strongly associated with the high-quality forage diet. Predictive functional profiling indicated that functions associated with methanogenesis were negatively correlated with feed quality.DiscussionThe results of this study suggest that mineral bolus type is unlikely to affect rumen bacterial community structure or function while forage quality can significantly alter community structure and predicted functions associated with methanogenesis and VFA production.

Directed Functional Coordination Analysis of Swallowing Muscles in Healthy and Dysphagic Subjects by Surface Electromyography.

Swallowing is a complex sequence of highly regulated and coordinated skeletal and smooth muscle activity. Previous studies have attempted to determine the temporal relationship between the muscles to establish the activation sequence pattern, assessing functional muscle coordination with cross-correlation or coherence, which is seriously impaired by volume conduction. In the present work, we used conditional Granger causality from surface electromyography signals to analyse the directed functional coordination between different swallowing muscles in both healthy and dysphagic subjects ingesting saliva, water, and yoghurt boluses. In healthy individuals, both bilateral and ipsilateral muscles showed higher coupling strength than contralateral muscles. We also found a dominant downward direction in ipsilateral supra and infrahyoid muscles. In dysphagic subjects, we found a significantly higher right-to-left infrahyoid, right ipsilateral infra-to-suprahyoid, and left ipsilateral supra-to-infrahyoid interactions, in addition to significant differences in the left ipsilateral muscles between bolus types. Our results suggest that the functional coordination analysis of swallowing muscles contains relevant information on the swallowing process and possible dysfunctions associated with dysphagia, indicating that it could potentially be used to assess the progress of the disease or the effectiveness of rehabilitation therapies.

An Investigation of Pulse Oximetry Levels During Swallowing in Healthy Adults and in Individuals with Severe and Very Severe Chronic Obstructive Pulmonary Disease.

To compare pulse oximetry (PO) levels during swallowing in healthy adults and adults with severe chronic obstructive pulmonary disease (COPD). Participants included two groups of 60 healthy adults, balanced for gender. The young group ranged from 18 to 38 years, and the older group from 60 to 87 years. In addition, there were 11 participants with COPD aged 43 to 82 years. PO levels were collected as each participant swallowed 10 mL of water, 10 mL of applesauce, and a piece of diced pear (three trials each). Analyses for the healthy groups revealed neither statistically significant main effects for bolus type nor interactions between gender and age. For between-subject effects, there was no main effect for gender, but there was a large main effect for age, and a gender and age interaction. In the group with COPD, there were no significant differences across bolus types; however, PO measures were consistently lower than the healthy groups for all bolus types. Healthy adults exhibited stable PO levels across bolus types. Adults with COPD, although exhibiting significantly lower PO levels, also remained stable. For clinicians who monitor PO measures, these results offer a more comprehensive understanding of the nature of these measures during swallowing in these groups.

Evaluation of sustained release mineral boluses as a long-term nutrient delivery method for beef cattle

Two studies were conducted to evaluate the efficacy of sustained release mineral boluses as an alternative nutrient delivery method for beef cattle. For both studies 16 ruminally-cannulated cows were used in a completely randomized design. In study 1, we evaluated degradation rates of two bolus prototypes and cow age (2-yr-old versus 3-yr-old cows) over an 87-d study period. In study 2, we evaluated two bolus types (90-d degradation target versus 180-d degradation target), as well as two diet qualities contrasting a low-quality high-fiber forage (> 600 g/kg neutral detergent fiber and < 80 g/kg crude protein, dry matter basis) and high-quality low-fiber forage (< 500 g/kg neutral detergent fiber and> 150 g/kg crude protein, dry matter basis). For both Study 1 & 2, intake and digestion periods were conducted to evaluate cow age (study 1) or diet quality (study 2) effects on intake and rumen/reticulum function. In study 1, models containing an asymptotic effect of day and an interaction between day and bolus type were the best supported of the candidate models for bolus degradation rate. Cow age did not affect (P= 0.48) bolus degradation rates (β^ = -0.81 ± 1.13) and degradation rates were greater (P < 0.01) for bolus prototype B compared to bolus A (β^prototype B = -20.39 ± 1.13; β^prototype A = -9.64 ± 0.81). Bolus degradation rate displayed an asymptotic relationship (P < 0.01) to bolus surface area for prototype A (β^ = 5.83 ± 0.57) and a linear relationship (P < 0.01) for prototype B (β^ = 0.001 ± 0.0001). In study 2, models containing a linear effect of day and an interaction between day and diet were the best supported of the candidate models for the degradation rate of the 90-d and 180-d prototype. In addition, both bolus protoypes displayed a diet quality × time interaction (P < 0.01) for bolus degradation rate. Cattle treated with the 90-d bolus and fed a high-quality diet had a greater (P < 0.01) degradation rate (β^High-quality = -2.64 ± 0.08; β^Low-quality = -1.97 ± 0.10) than the cows that were fed a low-quality diet. In contrast, cattle treated with the 180-d bolus had an inverse effect (P < 0.01), with bolus degradation rates greater (β^Low-quality = -0.09 ± 0.007; β^High-quality = -0.04 ± 0.005) with cows on the low-quality diet versus the high-quality diet. Across both studies, two of four bolus prototypes met target release rates at 90 days. However, bolus prototype degradation characteristics varied and were influenced by diet quality.

Evaluating 3D-printed Bolus Compared to Conventional Bolus Types Used in External Beam Radiation Therapy.

When treating superficial tumors with external beam radiation therapy, bolus is often used. Bolus increases surface dose, reduces dose to underlying tissue, and improves dose homogeneity. The conventional bolus types used clinically in practice have some disadvantages. The use of Three-Dimensional (3D) printing has the potential to create more effective boluses. CT data is used for dosimetric calculations for these treatments and often to manufacture the customized 3D-printed bolus. The aim of this review is to evaluate the published studies that have compared 3D-printed bolus against conventional bolus types. A systematic search of several databases and a further appraisal for relevance and eligibility resulted in the 14 articles used in this review. The 14 articles were analyzed based on their comparison of 3D-printed bolus and at least one conventional bolus type. The findings of this review indicated that 3D-printed bolus has a number of advantages. Compared to conventional bolus types, 3D-printed bolus was found to have equivalent or improved dosimetric measures, positional accuracy, fit, and uniformity. 3D-printed bolus was also found to benefit workflow efficiency through both time and cost effectiveness. However, factors such as patient comfort and staff perspectives need to be further explored to support the use of 3Dprinted bolus in routine practice.

Dosimetric assessment of brass mesh bolus and transparent polymer-gel type bolus for commonly used breast treatment delivery techniques

We investigated skin dose enhancements of brass mesh bolus (BMB) and a recently developed transparent polymer-gel bolus (PGB) for clinically relevant breast treatment delivery techniques. The dose enhancement of the breast surface with BMB and PGB were compared to that of tissue-equivalent bolus. Three breast treatment plans were generated on CT scans of an anthropomorphic chest phantom: tangential step-and-shoot 3D conformal (3DCRT) planned using Field-in-Field (FiF), tangential sliding-window 3DCRT using Electronic Compensator (EC), and volumetric modulated arc therapy (VMAT). All plans were created using 6 MV photons and a prescription dose (Rx) of 180 cGy per fraction. Skin doses of all 3 plans were measured with radiochromic films, separately delivered in triplicate. Each plan was delivered to the phantom without bolus, and then with BMB (1 or 2 layers; 3 or 10 mm tissue-equivalent), PGB, and Superflab (3, 5, and 10 mm tissue-equivalent). Doses were determined by reading the radiochromic films with a flatbed scanner, and analyzing the images using a calibration curve for each specific batch. For all bolus types and plans, surface doses averaged over the 3 measurements were between 88.4% and 107.4% of Rx. Without bolus, average measured skin doses were between 51.2% and 64.2% of Rx. Skin doses with BMB and PGB were comparable to that with tissue-equivalent bolus. Over all 3 treatment delivery techniques, using BMB resulted in average skin doses of 92.8% and 102.1% for 1- and 2 layers, respectively, and using PGB results in average skin doses of 94.8%, 98.2%, and 99.7% for 3, 5, and 10-mm tissue-equivalent, respectively. The average measured skin doses with BMB and PGB agreed within ± 3% compared to the tissue-equivalent thickness bolus. We concluded that BMB and PGB are clinically equivalent in skin dose enhancement for breast treatment as the 3, 5, and 10 mm tissue-equivalent bolus.

Detection of Aspiration, Penetration, and Pharyngeal Residue During Flexible Endoscopic Evaluation of Swallowing (FEES): Comparing the Effects of Color, Coating, and Opacity.

The aim of this study was to assess the effects of color, coating, and opacity on the detection of aspiration, penetration, and residue during flexible endoscopic evaluations of swallowing (FEES). Thirty dysphagic adults underwent FEES while swallowing five 5mL thin liquid boluses (1 × each, randomized): white water, blue water, white milk, blue milk, and barium water. To assess the effects of color, blue milk was compared to white milk. To assess the effects of coating, barium, white water, and white milk were compared to each other. To assess the effects of opacity, blue milk was compared to blue water. Videos were blindly analyzed and judged for the presence of pharyngeal residue, penetration, and aspiration. Repeated measures analyses were used to assess differences in the frequency of detection across bolus types. Pharyngeal residue was detected more frequently for liquids that were blue, had a coating effect, or were opaque (p < 0.05) when compared to liquids that were white, did not have a coating effect, or were translucent, respectively. Penetration and aspiration were detected more frequently for liquids that had a coating effect (p < 0.05), but not for liquids that were colored blue or opaque (p > 0.05). Coating appears to be the most important factor detecting thin liquid residue, penetration, and aspiration during FEES. Given these findings, standardized use of boluses that possess a coating effect (e.g., white-dyed water or barium) is highly recommended to enhance the sensitivity of identifying impairments in swallowing safety and efficiency during FEES.

Predicting Swallowing Outcomes from Objective Videofluoroscopic Timing and Displacement Measures in Head and Neck Cancer Patients.

Radiation therapy with or without chemotherapy compromises swallowing efficiency and safety in patients with head and neck cancer (HNC). The resulting dysphagia leads to overall morbidity, with altered diets, reduced nutritional intake, reduced quality of life, and potential interruption of curative cancer treatment. Despite well-documented radiation-related changes in swallowing physiology, scarce research exists on the potential clinical value for measurements of swallowing timing and displacement in this population. This study investigated the discriminatory value of quantitative timing and displacement parameters for the Functional Oral Intake Scale and Penetration Aspiration Scale scores using pre- and post-radiation videofluoroscopy data. Swallowtail Software Version 1 (Belldev Medical, Arlington Heights, IL) was used to obtain objective timing and displacement measurements from the pre- and post-radiation videofluoroscopy data for 31 patients who underwent radiation therapy, with or without chemotherapy, for head and neck cancer. The total pharyngeal transit time (BP2) (p < 0.000, r = 0.43) in pudding bolus trials and the maximal upper esophageal sphincter opening (PESMax/cm) (p = 0.001, r = 0.31) in thin bolus trials were discriminatory for Functional Oral Intake Scale (FOIS). Findings suggest that measurement of post-radiation changes using objective and quantitative parameters may offer some discriminatory value regarding future dysphagia risk and prognosis based on total pharyngeal transit time and degree of UES opening. In addition, the results suggest that different bolus types may offer different discriminatory values in HNC population, and that some timing and displacement variables may have discriminatory value for patients' diet levels independent from any aspiration risk.

462 A Retrospective Review of Effervescent Granules and Glucagon for the Management of Esophageal Food Impactions in a Community Hospital

INTRODUCTION: Esophageal food impaction is one of the more common GI emergencies. While endoscopy is the definitive therapy, pharmacologic therapy does have a role. Despite minimal success, because of the safety profile glucagon is currently recommended as the initial pharmacologic therapy.1–5 Effervescent agents have been limited due to previous concerns of perforation, but studies have been revisited recently with safety and success.5–7 Our aim is to measure EG and glucagon as a primary pharmacologic agent. METHODS: A retrospective study was performed on all patients over 18 between 6/2015-5/2018, with diagnosis of esophageal obstruction or foreign body. Exclusion was transfer to outside facility. Records were reviewed for administration of glucagon and/or effervescent granules, if relief of obstruction was achieved, patient's ability to tolerate secretions and food responsible. Etiology was determined from history, endoscopy report, imaging, and pathology. T-test was performed for statistical significance. RESULTS: Demographic data, along with food bolus types and diagnoses can be found in Table 1. EG was attempted as an initial modality in 20.2% of cases and glucagon in 16.8%. EG was more successful when compared to glucagon (51.2 % vs 14.7%) (P = 0.0216). EG was successful as secondary modality in 75% of cases after glucagon initially failed, as compared to glucagon in 0% (0/9) of cases when EG initially failed (P = 0.0094). Figure 1 highlights success of EG and Glucagon based on diagnosis. There were no major safety events. CONCLUSION: Overall, EG is safe; and appears to overall be more efficacious than glucagon as initial pharmacologic therapy for EFI. This is a worthwhile therapy for both those who are tolerating secretions and those who are not, while glucagon seems to be more effective for secretion tolerant patients. EG was highly successful in patients tolerating secretions, however with a success rate of over 50% with no complications, we suggest it is worth attempting even in those who are not.

Dosimetric Comparison of Existing Bolus Materials to a 3D Printed Custom Bolus

Current bolus types, including synthetic gel and thermoplastic materials, have been shown to be dosimetrically near-water equivalent and are approved for use in the clinic. However, these materials are difficult to conform to irregular surfaces, resulting in air gaps between the bolus and patient surface, contributing to dose differences during treatment delivery. 3D printed bolus materials can solve the problem of air gaps under the bolus and ensure easier setup reproducibility. A 3D printer was used to print a 5mm thick custom scalp bolus made from a rigid plastic chosen because it meets USP class VI requirements and is suitable for medical devices. The bolus shape was designed in the treatment planning system (TPS) to fit the scalp of an anthropomorphic phantom. Custom boluses were created using 5mm and 4.8mm thick synthetic gel (SG) and thermoplastic (TP) sheets respectively. Each material was designed according to standard clinical practice to fit the area specified by the TPS planned bolus. CT scans of the phantom with the three bolus materials were taken to evaluate the fit of each and used to create a simple en face photon treatment plan. For the dose calculation, the Hounsfield Units (HUs) for each bolus were set to match the known HUs of the material. Doses under the different boluses were measured using Gafchromic film and OSLDs and were compared to the corresponding point doses dose from the TPS. The fit, size and shape of the three boluses were compared to the TPS bolus using Hausdorff distances and Dice similarity coefficients (DSCs) of the 3D rendered volumes. The TPS calculated dose under each of the bolus materials was less than 1% different from the dose measured by the film and less than 5% different from the dose measured by the OSLD (see Table 1). Of the three bolus materials, the 3D printed bolus best matched the shape of the planned bolus with a Hausdorff distance of 0.7cm and the TP bolus fit the worst with a Hausdorff distance of 2.0cm. The SG bolus had a Hausdorff distance of 1.8cm. Further, the DSCs between the physical boluses and the TPS planned bolus were 0.78 for SG, 0.77 for the 3D printed rigid, and 0.63 for the TP bolus. Each of the bolus materials is dosimetrically viable for use as scalp bolus as long as the TPS accurately characterizes the HU of the material. If bolus is added to the plan retrospectively, there can be issues with matching bolus thickness and shape using conventional bolus methods. The 3D printed bolus is the best option to match the TPS designed bolus with its high DSCs and low Hausdorff distance, especially for irregular surfaces.Abstract 3636; Table 1Measured and TPS Expected Doses from under the BolusSynthetic GelThermoplastic3D RigidOSLD Dose (cGy)185.0203.0201.5Film Dose (cGy)181.0201.4199.0TPS Calculated Dose (cGy)179.6200.8198.1Difference From Expected - OSLD3.01%1.08%1.69%Difference From Expected - Film0.74%0.30%0.46% Open table in a new tab

Variations in Healthy Swallowing Mechanics During Various Bolus Conditions Using Computational Analysis of Swallowing Mechanics (CASM)

Bolus properties such as volume, consistency, and density have been shown to influence swallowing through the analysis of kinematics and timing in both normal and disordered swallowing. However, inherent intra- and inter-person variability of swallowing cloud interpretation of group data. Computational analysis of swallow mechanics (CASM) is an established methodology that uses coordinate tracking to map structural movements during swallowing and yields statistically powerful analyses at both the group and individual levels. In this study, the CASM method was used to determine how different bolus properties (volume, consistency, and density) altered swallow mechanics in healthy young adults at the group and individual levels. Videofluoroscopic swallow studies of 10 (4 females) healthy young adults were analyzed using CASM. Five bolus types were administered in each study (3 × 5ml 40% w/v nectar, 3 × 5ml 22% w/v thin, 3 × 5ml 40% w/v thin, 3 × 10ml 22% w/v thin, and 3 × 20ml 22% w/v thin). Canonical variate analyses demonstrated that bolus condition did not affect swallowing mechanics at the group level, but bolus condition did affect pharyngeal swallow mechanics at the individual level. Functional swallow adaptations (e.g., hyoid movement) to bolus conditions were not uniform across participants, consistent with the nonsignificant group finding. These results suggest that individual swallowing systems of healthy young individuals vary in how they respond to bolus different conditions, highlighting the intrinsic variability of the swallow mechanism and the importance of individually tailored evaluation and treatment of swallowing. Findings warrant further investigation with different bolus conditions and aging and disordered populations.

Swallowing Kinematic Differences Across Frozen, Mixed, and Ultrathin Liquid Boluses in Healthy Adults: Age, Sex, and Normal Variability.

The aim of this study was to examine the effects of frozen and mixed-consistency boluses on the swallowing physiology of younger and older adults. We also aimed to quantify factors that lead to increased variability in swallowing outcomes (i.e., age, sex, bolus type). Forty-one healthy adults (18-85 years old) swallowed 5 blocks of 5 different boluses: 10-ml ultrathin liquid, a teaspoon of iced barium, a teaspoon of room-temperature pudding, a teaspoon of frozen pudding, and ultrathin barium with chocolate chips. All data were recorded with videofluoroscopy and underwent detailed timing kinematic measurements. Neither barium ice nor frozen pudding sped up swallow responses. Many healthy adults initiated swallowing with the bolus as deep as the pyriform sinuses. Swallowing temporal kinematics for ultrathin liquid consistencies are most different from all others tested, requiring the best possible physiological swallowing performance in younger and older healthy individuals (i.e., faster reaction times, longer durations) compared with other bolus types tested. In each measure, older adults had significantly longer durations compared with the younger adults. More variability in swallowing kinematics were seen with age and laryngeal vestibule kinematics. This study provides important contributions to the literature by clarifying normal variability within a wide range of swallowing behaviors and by providing normative data from which to compare disordered populations.

Intrapatient study comparing 3D printed bolus versus standard vinyl gel sheet bolus for postmastectomy chest wall radiation therapy

PurposeThis patient study evaluated the use of 3-dimensional (3D) printed bolus for chest wall radiation therapy compared with standard sheet bolus with regard to accuracy of fit, surface dose measured in vivo, and efficiency of patient setup. By alternating bolus type over the course of therapy, each patient served as her own control. Methods and materialsFor 16 patients undergoing chest wall radiation therapy, a custom 5.0 mm thick bolus was designed based on the treatment planning computed tomography scan and 3D printed using polylactic acid. Cone beam computed tomography scanning was used to image and quantify the accuracy of fit of the 2 bolus types with regard to air gaps between the bolus and skin. As a quality assurance measure for the 3D printed bolus, optically stimulated luminescent dosimetry provided in vivo comparison of surface dose at 7 points on the chest wall. Durations of patient setup and image guidance were recorded and compared. ResultsIn 13 of 16 patients, the bolus was printed without user intervention, and the median print time was 12.6 hours. The accuracy of fit of the bolus to the chest wall was improved significantly relative to standard sheet bolus, with the frequency of air gaps 5 mm or greater reduced from 30% to 13% (P < .001) and maximum air gap dimension diminished from 0.5 ± 0.3 to 0.3 ± 0.3 mm on average. Surface dose was within 3% for both standard sheet and 3D printed bolus. On average, the use of 3D printed bolus reduced the setup time from 104 to 76 seconds. ConclusionsThis study demonstrates 3D printed bolus in postmastectomy radiation therapy improves fit of the bolus and reduces patient setup time marginally compared with standard vinyl gel sheet bolus. The time savings on patient setup must be weighed against the considerable time needed for the 3D printing process.

Rethinking Residue: Determining the Perceptual Continuum of Residue on FEES to Enable Better Measurement.

The goal of this work was to better understand perceptual judgments of pharyngeal residue on flexible endoscopic evaluation of swallowing (FEES) and the influence of a visual analog scale (VAS) versus an ordinal scale on clinician ratings. The intent was to determine if perceptual judgments of residue were more accurately described by equal or unequal intervals. Thirty-three speech language pathologists rated pharyngeal residue from 75 FEES videos representing a wide range of residue severities for thin liquid, applesauce, and cracker boluses. Clinicians rated their impression of the overall residue amount in each video on a VAS and, in a different session, on a five-point ordinal scale. Residue ratings were made in two separate sessions separated by several weeks. Statistical correlations of the two rating methods were carried out and best-fit models were determined for each bolus type. A total of 2475 VAS ratings and 2473 ordinal ratings were collected. Residue ratings from both methods (VAS and ordinal) were strongly correlated for all bolus types. The best fit for the data was a quadratic model representing unequal intervals, which significantly improved the r 2 values for each bolus type (cracker r 2=0.98, applesauce r 2=0.99, thin liquid r 2=0.98, all p<0.0001). Perceptual ratings of pharyngeal residue demonstrated a statistical relationship consistent with unequal intervals. The present findings support the use of a VAS to rate residue on FEES, allowing for greater precision as compared to traditional ordinal rating scales. Perceptual judgments of pharyngeal residue reflected unequal intervals, an important concept that should be considered in future rating scales.

Respiratory-swallowing coordination in normal subjects: Lung volume at swallowing initiation

This study was designed to investigate the significance of bolus types and volumes, delivery methods and swallowing instructions on lung volume at swallowing initiation in normal subjects in a single experiment using a multifactorial approach. Our broad range goal was to determine optimal lung volume range associated with swallowing initiation to provide training targets for dysphagic patients with disordered respiratory-swallow coordination. Our hypothesis was that swallows would be initiated within a limited range of quiet breathing lung volumes regardless of bolus volume, consistency or task. Results confirmed this hypothesis and revealed that swallows were initiated at mean lung volume=244ml. Cued swallows were initiated at lower quiet breathing volumes than un-cued swallows (cued=201ml; un-cued=367ml). Water boluses were initiated at slightly higher quiet breathing volumes than solids. Data suggest that swallows occur within a restricted range of lung volumes with variation due to instructions, bolus type and other experimental variables.

Pressure topography metrics for high-resolution pharyngeal-esophageal manofluorography-a normative study of younger and older adults.

We aimed to define normative values for novel pressure topography metrics for high-resolution pharyngeal-esophageal manofluorography. The effects of age, gender, and bolus properties were examined. Concurrent high-resolution manometry (HRM) and videofluoroscopy data were collected from 22 younger (aged 21-40) and 22 older (aged 60-80) healthy subjects. Pressure topography was analyzed by correlating pressure domains with videofluoroscopic events. Nine pressure topography metrics of the pharyngeal and proximal esophageal swallow were extracted; four of these were also compared with previously obtained esophageal HRM studies to assess the effects of catheter diameter. Older individuals exhibited more vigorous contractility in the pharynx than did younger subjects with all bolus types, but the greatest values for both groups were with effortful swallow and on that measure the age groups were similar. Upper esophageal sphincter (UES) intrabolus pressure during sphincter opening was also greater in the older subjects. Some gender differences were observed, particularly related to proximal esophageal contractile vigor. Bolus consistency had no consistent effect. Studies using the larger catheter diameter resulted in significantly greater contractile vigor in the UES and proximal esophagus. Older adults exhibited more vigorous pharyngeal contractions than young adults, albeit within a similar range of capacity, perhaps reflecting a compensatory response to other age-related physiological changes. Greater UES intrabolus pressures observed during bolus transit in the older group likely reflect reduced UES compliance with age. Normative data on novel HRM metrics collected in this study can serve as a reference for future clinical studies.