Bolus Volume Research Articles

Noninvasive Evaluation of the Biomechanical Accommodations to Bolus Volume during Human Swallowing.

Bolus volume is very important in the biomechanics of swallowing. By noninvasively characterizing swallow responses to volume challenges, we can gain more knowledge on swallowing and evaluate swallowing behavior easily. This study aimed to evaluate the impact of bolus volume on the biomechanical characteristics of oropharyngeal swallowing events with a noninvasive sensing system. Fifteen healthy male subjects were recruited and instructed to swallow 5, 10, and 15 ml of water. The sensing system consisted of a tongue pressure sensor sheet, bend sensor, surface electrodes, and a microphone. They were used to monitor tongue pressure, hyoid activity, surface EMG of swallowing-related muscles, and swallowing sound, respectively. In addition to the onset, the peak time and offset of the above four structures, certain characteristics, such as the duration, peak value, and interval of the structure motions, were measured during the different drinking tasks. The coordination between the hyoid movement and tongue pressure was also assessed. Although no sequence of the structural events changed with volume, most of the timings of the structural events were significantly delayed, except for certain hyoid activities. The swallowing volume did not affect the active durations of the monitored structures, the peak values, or intervals of tongue pressure and supra- and infrahyoid muscle activity, but certain hyoid kinetic phases were prolonged when a larger volume was swallowed. Additionally, sequential coordination between hyoid movement and tongue pressure was confirmed among the three volumes. These findings suggest that oropharyngeal structural movements change in response to bolus volume to facilitate safe swallowing. The noninvasive and quantitative measurements taken with the sensing system provide essential information for understanding normal oropharyngeal swallowing.

A Comparative Study of the Efficacy of Intravenous Bolus of Mephentermine and Phenylephrine in Maintaining Arterial Blood Pressure During Spinal Anaesthesia in Caesarean Section

BACKGROUND
 Spinal anaesthesia is the most popular and elegant approach for obstetric patients undergoing caesarean section due to its several advantages. Hypotension resulting from sympathectomy due to subarachnoid block can have detrimental effects on the foetus as well as the mother, so needs to be prevented and treated adequately. Vasopressors for the treatment of hypotension have a well-established role as vasodilatation is the primary cause of the reduction in arterial blood pressure. The primary objective of the study was to compare mephentermine and phenylephrine with respect to their clinical efficacy in maintaining arterial blood pressure during spinal anaesthesia in caesarean section and the secondary objective was to determine any untoward effects of the study drugs on the mother and foetus.
 METHODS
 This prospective, randomized, comparative, double-blind study was conducted among 90 pregnant women of ASA-I physical status having singleton pregnancies in the age group of 18-30 years undergoing elective as well as emergency caesarean section and were randomly allocated in to two groups. Group M (n=45), received 6 mg of mephenterine as an intravenous bolus (volume made up to 1 ml) and Group P (n=45), received 100 g of phenylephrine as intravenous bolus (volume made up to 1 ml) whenever hypotension occurred after spinal anaesthesia. A comparison of the mean values among the two groups was done using a student t-test. To compare more than two variables, ANOVA test was used. The p-values of less than 0.05 were considered statistically significant.
 RESULTS
 The systolic blood pressure, diastolic blood pressure and mean arterial pressure remained significantly high (P < 0.05) in the phenylephrine group as compared to the mephentermine group. The phenylephrine group also showed a significant fall (P < 0.05) in heart rate as compared to the mephentermine group.
 CONCLUSIONS
 Both the drugs were effective in treating the hypotension caused by spinal anaesthesia without any adverse effects on the mother as well as on neonatal outcome but phenylephrine had a quicker onset, better maintenance of blood pressure and can be preferred in patients in whom tachycardia is undesirable.

Optimization of programmed intermittent epidural bolus volume for different concentrations of ropivacaine in labor analgesia: a biased coin up-and-down sequential allocation trial

Background and objectivesTo date, programmed intermittent epidural bolus (PIEB) has been widely used in obstetric analgesia, while no optimal PIEB regimen has been proposed. This study aimed to assess effective analgesia in 90% of women (EV90) with different concentrations of ropivacaine (0.075% and 0.1%) combined with 0.5 µg/mL sufentanil, at an interval of 40 min using the biased coin design-up-and-down method (BCD-UDM), and to explore whether there is a difference in EV90 with the increase of ropivacaine concentration.MethodsIn total, 103 primiparous women were assigned to two groups, including group A (n = 52) and group B (n = 51). Parturients in group A were treated with 0.075% ropivacaine and 0.5 µg/mL sufentanil, while those in group B were treated with 0.1% ropivacaine and 0.5 µg/mL sufentanil. Used the biased coin up-and-down sequential allocation method to determine the EV90. The secondary outcomes were sensory block level, motor block, and adverse events (hypotension, urinary retention, and pruritus).ResultsThe results revealed that EV90 was 10 mL (95% confidence interval (CI):8.03–11.54) in group A, and EV90 was 9 mL (95% CI:7.49–10.51) in group B by the isotonic regression method. The highest level of the sensory block was T8, and the lowest was T12. No case of hypotension was recorded,and only 4 parturients complained of motor block.ConclusionWith an interval of 40 min, the optimal PIEB bolus volume of 0.075% ropivacaine and 0.5 µg/mL sufentanil was 10 mL, 0.1% ropivacaine and 0.5 µg/mL sufentanil was 9 mL. Moreover, the PIEB volume decreased along with the higher concentration of ropivacaine.Trial registrationChiCTR registration number: ChiCTR2000040917. Registration date: December 15, 2020.

Dysphagia Presentation, Airway Invasion, and Gender Differences in a Clinically Based Sample of People with Parkinson's Disease.

Dysphagia in People with Parkinson's Disease (PWPD) is expected to occur in most individuals. The manifestation of dysphagia and its salient swallow dysfunction characteristics leading to decreased airway safety are not well understood. The aim of this study was to quantify dysphagia presentation and severity, examine contributors to airway invasion, and explore gender differences in dysphagia manifestation in PWPD. 60 PWPD in clinical, healthcare settings underwent a Videofluoroscopic Swallow Study (VFSS) after referral for complaints of dysphagia. VFSS records and videos were analyzed to obtain dysphagia diagnosis, Videofluoroscopic Dysphagia Scale (VDS) scores, laryngeal vestibule kinematic timings, and Penetration-Aspiration Scale scores. Frequencies of VDS component and PAS scores were examined. MANOVA and logistic regression analyses were used to identify predictors of penetration and aspiration. Pharyngeal stage dysphagia was prevalent throughout PWPD and presented more frequently than oral stage dysphagia. Pharyngeal residue was a significant predictor for aspiration events. Laryngeal vestibule closure reaction time (LVCrt) and duration time (LVCd) were significant predictors of airway invasion, as were bolus consistency and volume. LVCrt, LVCd, and pharyngeal stage VDS scores were significantly altered in men compared to women in PWPD. A broad clinical sample of PWPD displayed atypical frequencies of airway invasion and frequent atypical scores of oral and pharyngeal stage physiologies. Thicker and smaller bolus consistencies significantly reduced the odds of airway invasion. Men and women presented with significantly different swallow physiology including prolonged LVCrt, LVCd, and more frequent atypical scores of pharyngeal residue and laryngeal elevation.Journal instruction requires a country for affiliations; however, these are missing in affiliation [1, 2]. Please verify if the provided country are correct and amend if necessary.Yes, USA is correct as the provided country.

Distension contraction plots of pharyngeal/esophageal peristalsis: next frontier in the assessment of esophageal motor function.

Esophageal peristalsis consists of initial inhibition (relaxation) followed by excitation (contraction), both of which move sequentially in the aboral direction. Initial inhibition results in receptive relaxation and bolus-induced luminal distension, which allows propulsion by the contraction with minimal resistance to flow. Similar to the contraction wave, luminal distension has unique waveform characteristics in normal subjects; both are modulated by bolus volume, bolus viscosity, and posture, suggesting a possible cause-and-effect relationship between the two. Distension contraction plots in patients with dysphagia with normal bolus clearance [high-amplitude esophageal contractions (HAECs), esophagogastric junction outflow obstruction (EGJOO), and functional dysphagia (FD)] reveal two major findings: 1) unlike normal subjects, there is luminal occlusion distal to bolus during peristalsis in certain patients, i.e., with type 3 achalasia and nonobstructive dysphagia; and 2) bolus travels through a narrow lumen esophagus during peristalsis in patients with HAECs, EGJOO, and FD. Aforementioned findings indicate a relative dynamic obstruction to the bolus flow during peristalsis and reduced distensibility of esophageal wall in the bolus segment of the esophagus. We speculate that a normal or supernormal contraction wave pushing bolus against resistance is the mechanism of dysphagia sensation in significant number of patients. Representations of distension and contraction, combined with objective measures of flow timing and distensibility are complementary to the current scheme of classifying esophageal motility disorders based solely on the characteristics of contraction phase of peristalsis. Better understanding of the distensibility of the bolus-containing segment of the esophagus during peristalsis will lead to the development of novel medical and surgical therapies in the treatment of dysphagia in significant number of patients.

The incidence of breakthrough pain associated with programmed intermittent bolus volumes for labor epidural analgesia: a randomized controlled trial

BackgroundIn this randomized, blinded study, we evaluated the effects of different programmed intermittent epidural bolus (PIEB) volumes for labor analgesia on the incidence of breakthrough pain and other analgesic outcomes. MethodsNulliparous women with term cephalic singleton pregnancies who requested labor analgesia had epidural analgesia initiated with 10 mL 0.1% ropivacaine with sufentanil 0.3 μg/mL. The pump was programmed to deliver a 4, 6 or 8 mL bolus every 45 min (groups 4, 6 or 8, respectively). The primary outcome was the incidence of breakthrough pain, defined as inadequate analgesia after two patient-controlled epidural analgesia administrations in a 20-min period. Secondary outcomes included ropivacaine consumption, time of the first patient-controlled epidural analgesia request, duration of the second stage of labor, and incidence of motor block. ResultsAmong 210 women randomly allocated the incidence of breakthrough pain was 34.9%, 19.7%, and 13.1%, for groups 4, 6 and 8, respectively (P=0.011). The incidence of breakthrough pain in group 8 was lower than in group 4 (P=0.006). The median (interquartile range) hourly ropivacaine consumption was 8.2 mg/h (7.1–11.3), 10.4 mg/h (9.2–13.0), and 12.0 mg/h (11.2–13.8) in groups 4, 6 and 8, respectively (P <0.001). Group 8 had a longer duration of effective analgesia and longer second stage of labor than group 4. There was no significant difference between groups in the incidence of motor block. ConclusionThe larger PIEB volumes were preferred for epidural labor analgesia compared with a smaller volume because of improved analgesia without clinically significant increases in adverse effects.

Fluid bolus administration in children, who responds and how? A systematic review and meta-analysis.

Fluid boluses are frequently utilized in children. Despite their frequency of use, there is little objective data regarding the utility of fluid boluses, who they benefit the most, and what the effects are. This study aimed to conduct pooled analyses to identify those who may be more likely to respond to fluid boluses as well as characterize clinical changes associated with fluid boluses. A systematic review of the literature and meta-analysis was conducted to identify pediatric studies investigating the response to fluid boluses and clinical changes associated with fluid boluses. A total of 15 studies with 637 patients were included in the final analyses with a mean age of 650 days ± 821.01 (95% CI 586 to 714) and a mean weight of 10.5kg ± 7.19 (95% CI 9.94 to 11.1). The mean bolus volume was 12.14 ml/kg ± 4.09 (95% CI 11.8 to 12.5) given over a mean of 19.55 min ± 10.16 (95% CI 18.8 to 20.3). The following baseline characteristics were associated with increased likelihood of response [represented in mean difference (95% CI)]: greater age [207.2 days (140.8 to 273.2)], lower cardiac index [-0.5ml/min/m2 (-0.9 to -0.3)], and lower stroke volume [-5.1ml/m2 (-7.9 to -2.3)]. The following clinical parameters significantly changed after a fluid bolus: decreased HR [-5.6bpm (-9.8 to -1.3)], increased systolic blood pressure [7.7 mmHg (1.0 to 14.4)], increased mean arterial blood pressure [5.5 mmHg (3.1 to 7.8)], increased cardiac index [0.3ml/min/m2 (0.1 to 0.6)], increased stroke volume [4.3ml/m2 (3.5 to 5.2)], increased central venous pressure [2.2 mmHg (1.1 to 3.3)], and increased systemic vascular resistance [2.1 woods units/m2 (0.1 to 4.2)]. Fluid blouses increase arterial blood pressure or cardiac output by 10% in approximately 56% of pediatric patients. Fluid blouses lead to significant decrease in HR and significant increases in cardiac output, stroke volume, and systemic vascular resistance. Limited published data are available on the effects of fluid blouses on systemic oxygen delivery.

Intravenous Fluid Bolus Rates Associated with Outcomes in Pediatric Sepsis: A Multi-Center Analysis.

PurposePediatric sepsis guidelines recommend rapid intravenous fluid (IVF) bolus administration rates (BAR). Recent sepsis studies suggest that rapid BAR may be associated with increased morbidity. We aimed to describe the association between emergency department (ED) IVF BAR and clinical outcomes in pediatric sepsis.Patients and MethodsSecondary post-hoc analysis of retrospective cohort data from 19 hospitals in the Pediatric Septic Shock Collaborative (PSSC) database. Patients with presumed septic shock were defined by severe sepsis/septic shock diagnostic codes, receipt of septic shock therapies, or floor-to-ICU transfers within 12 hours from ED admission for septic shock. Patients (2 months–21 years) with complete data on weight, antibiotic receipt, bolus timing, and bolus volumes were included. The primary outcome was 30-day mortality. Associations between BAR and mortality and secondary (intubation or non-invasive positive pressure ventilation = NIPPV) outcomes were assessed using unadjusted and adjusted logistic regression.ResultsThe PSSC database included 6731 patients; 3969 met inclusion and received a median ED volume of 40.2 mL/kg. Seventy-six (1.9%) patients died, 151 (3.8%) were intubated, and 235 (5.9%) had NIPPV administered. The median BAR was 25.7 mL/kg/hr. For each 20 mL/kg/hr increase in BAR, the adjusted odds ratio (aOR) for 30-day mortality [aOR = 1.11 (95% CI 1.01, 1.23)], intubation [aOR = 1.25 (95% CI 1.09, 1.44)], and NIPPV [aOR = 1.20 (95% CI 1.05, 1.38)] significantly increased.ConclusionFaster ED IVF bolus administration rates in this pediatric sepsis database were associated with higher adjusted odds of death, intubation and NIPPV. Controlled trials are needed to determine if these associations are replicable.

Investigation of Human Intrathecal Solute Transport Dynamics Using a Novel in vitro Cerebrospinal Fluid System Analog.

Understanding the relationship between cerebrospinal fluid (CSF) dynamics and intrathecal drug delivery (ITDD) injection parameters is essential to improve treatment of central nervous system (CNS) disorders. An anatomically detailed in vitro model of the complete CSF system was constructed. Patient-specific cardiac- and respiratory-induced CSF oscillations were input to the model in the subarachnoid space and within the ventricles. CSF production was input at the lateral ventricles and CSF absorption at the superior sagittal sinus. A model small molecule simulated drug product containing fluorescein was imaged within the system over a period of 3-h post-lumbar ITDD injections and used to quantify the impact of (a) bolus injection volume and rate, (b) post-injection flush volume, rate, and timing, (c) injection location, and (d) type of injection device. For each experiment, neuraxial distribution of fluorescein in terms of spatial temporal concentration, area-under-the-curve (AUC), and percent of injected dose (%ID) to the brain was quantified at a time point 3-h post-injection. For all experiments conducted with ITDD administration in the lumbar spine, %ID to the brain did not exceed 11.6% at a time point 3-h post-injection. Addition of a 12 mL flush slightly increased solute transport to the brain up to +3.9%ID compared to without a flush (p < 0.01). Implantation of a lumbar catheter with the tip at an equivalent location to the lumbar placed needle, but with rostral tip orientation, resulted in a small improvement of 1.5%ID to the brain (p < 0.05). An increase of bolus volume from 5 to 20 mL improved solute transport to the brain from 5.0 to 6.3%ID, but this improvement was not statistically significant. Increasing bolus injection rate from 5 to 13.3 mL/min lacked improvement of solute transport to the brain, with a value of 6.3 compared to 5.7%ID. The in vitro modeling approach allowed precisely controlled and repeatable parametric investigation of ITDD injection protocols and devices. In combination, the results predict that parametric changes in lumbar spine ITDD-injection related parameters and devices can alter %ID to the brain and be tuned to optimize therapeutic benefit to CNS targets.

Normative values of intra-bolus pressure and esophageal compliance based on 4D high-resolution impedance manometry.

This study aimed to quantify normative values of phase-specific intra-bolus pressure (IBP) and esophageal distensibility using 4D analysis of high-resolution-impedance manometry (HRIM). HRIM studies of supine swallows from 34 normal controls were analyzed with respect to the four phases of bolus transit: (1) accommodation, (2) compartmentalization, (3) peristalsis/esophageal emptying, and (4) ampullary emptying. Phase-specific IBP, bolus volume, and distensibility index (DI) in the esophageal body and esophagogastric junction (EGJ) during phases 1-3 were extracted. The median (5-95th/IQR) IBP values were as follows: phase 1: 4.0 (-2.0-10.4/1.9-5.8)mmHg, phase 2: 5.7 (0.2-14.1/3.6-8.9)mmHg, and phase 3: 11.2 (2.9-19.4/7.7-15.1)mmHg. The median bolus volume calculated by integrating impedance planimetry cross-sectional areas was 4.1ml during the compartmentalization phase. The EGJ-DI at max EGJ diameter during phase 2 and 3 was 2.8 (1.1-9.5/1.8-3.7)mm2 /mmHg and 6.0 (3.2-20.3/5.1-7.8)mm2 /mmHg, respectively. The phase 3 EGJ-DI values (6.0 (3.2-20.3/5.1-7.8)mm2 /mmHg) were similar to those calculated using functional lumen imaging probe (FLIP) at the 60 ml volume on the same subjects (5.8 [3.5-7.2/5.0-6.4]mm2 /mmHg). 4D-HRIM provides a standardized methodology to track the nadir impedance and provide measurements of IBP during maximal distention across phases 1-3 of bolus transit. Median IBP and delta IBP were different across the phases, supporting the need to define IBP by phase. Additionally, the EGJ-DI calculated during phase 3 was similar to the 60-ml EGJ-DI from FLIP in the same subjects suggesting that 4D-HRIM can quantify EGJ opening during primary peristalsis.

Measurement of intravascular volume status in infants undergoing cranial vault reconstruction for craniosynostosis

Determining the need, optimal timing, amount, and type of fluid for volume expansion in hypovolemic infants is challenging, due to their small intravascular volumes and robust compensatory reserve. To assess markers of fluid responsiveness in hypovolemic infants, we studied those undergoing cranial vault reconstructive surgery–a procedure associated with significant blood loss. We aimed to determine the ability of the Compensatory Reserve Index (CRI) monitor, which provides a continuous, individual-specific, beat-to-beat estimate of central volume status, to distinguish fluid responders from non-responders. A prospective observational pilot study of infants undergoing cranial vault reconstructive surgery for craniosynostosis was performed from May 2019-January 2020. A CardioQ-Esophageal Doppler Monitor, which measures changes in peak aortic velocity, was utilized to distinguish fluid responders- defined as those who demonstrated an increase in peak aortic velocity > 15% following a crystalloid bolus (10 mL/kg). Several static and dynamic variables were analyzed, including the CRI monitor. Each variable's performance was compared using area under the receiver operator curves (AUC), adjusting for age and bolus volume. Twenty subjects were included and a total of 23 boluses (19 crystalloid and 4 blood) were administered. Of all boluses, 7 (all crystalloid) were provided to fluid responders and 16 to non-responders. There were no statistically significant differences in bolus volumes or bolus durations between responders and non-responders. While adjusting for age and bolus volume, CRI performed similarly to other bedside tools to predict fluid responsiveness with an AUC of 0.7024 (95% CI = 0.459, 0.946). Distinguishing infants who are fluid responders from those who are not can be challenging. CRI is a continuous, non-invasive measure that was developed using adult waveform data, yet even in very young patients is able to identify those who may benefit from additional volume expansion. Therapeutic/Care management. Level II.

Real-Time Analysis of Dry-Side Nebulization With Heated Wire Humidification During Mechanical Ventilation.

Recent observational studies of nebulizers placed on the wet side of the humidifier suggest that, after some time, considerable condensation can form, which triggers an occlusion alarm. In the current study, an inline breath-enhanced jet nebulizer was tested and compared in vitro with a vibrating mesh nebulizer on the humidifier dry-inlet side of the ventilator circuit. Two duty cycle breathing patterns were tested during continuous infusion (5 or 10 mL/h) with and without dynamic changes in infusion flow and duty cycle, or bolus delivery (3 or 6 mL) of radiolabeled saline solution. Inhaled mass (IM) was measured by a real-time ratemeter (µCi/min) and analyzed by multiple linear regression. During simple continuous infusion, IM increased linearly for both nebulizer types. IM variability was attributable to the duty cycle (P < .001) (34%) and infusion flow (P < .001) (32%) but independent of nebulizer technology (P = .38) (7%). Dynamic continuous infusion studies that simulate clinical scenarios with ventilator and pump flow changes demonstrated a linear increase in the rate of aerosol that was dependent on pump flow (P < .001) (63%) and minimally dependent on the duty cycle (P = .003) (8%). During bolus treatments, IM increased linearly to plateau. IM variability was attributable to the duty cycle (P < .001) (40%) and residual radioactivity in the nebulizer (P < .001) (20%). Separate analysis revealed that the vibrating mesh nebulizer residual volume contributed 16% of the variability and inline breath-enhanced jet nebulizer contributed 5%. IM variability was independent of bolus volume (P = .82) (1%). System losses were similar (the inline breath-enhanced jet nebulizer: 32% residual in nebulizer; the vibrating mesh nebulizer: 34% in circuitry). Aerosol delivery during continuous infusion and bolus delivery was comparable between the inline breath-enhanced jet nebulizer and the vibrating mesh nebulizer, and was determined by pump flow and initial ventilator settings. Further adjustments in ventilator settings did not significantly affect drug delivery. Expiratory losses predicted by the duty cycle were reduced with placement of the nebulizer near the ventilator outlet.

The Effect of Swallowing Cues in Healthy Individuals: An Exploratory Study.

The goal of this study was to determine whether providing verbal and visual cues about swallowing changes the timing of swallowing events, and whether this information interacts with bolus volume. 20 healthy adults swallowed 5ml and 15ml liquid barium mixed with orange juice under videofluoroscopy during 2 conditions: one condition absent swallowing-specific cues and one condition with verbal and visual input about the swallowing process. Outcome measures included the timing of 10 swallowing events and the number of swallows per bolus. As expected, volume had a significant effect on all outcome measures (p < 0.05). Three timing events differed by cueing condition: 1. swallowing reaction time was earlier for control (- 9.45ms vs. - 2.01ms, p = 0.033); 2. the time between initial hyoid movement and maximum hyoid elevation was longer for control (152.85ms vs. 143.79ms; p = 0.015); and 3. the onset of upper esophageal sphincter opening occurred later after bolus entry into the pharynx for the swallowing cues condition (111.9ms vs. 103.31ms; p = 0.017); however, effect sizes were small (< 0.2). There was a significant interaction between cue condition and bolus volume on swallowing frequency, such that the mean number of swallows of 15ml boluses was slightly higher during the control condition than during the swallowing cues condition. There were no significant interactions on measures of timing, suggesting distinct mechanisms for the effect of bolus volume and cues on swallowing kinematics. Further research is needed to investigate the effects of different cue modalities and focus (internal vs. external) on swallowing physiology.

Food-Grade Activated Charcoal for Contrast-Enhanced Photoacoustic Imaging of Aspiration: A Phantom Study.

Aspiration pneumonia has the highest attributable mortality of all medical complications post-stroke, or in individuals with progressive neurological diseases. For optimum health outcomes for individuals with dysphagia, a non-invasive and convenient method for objectively detecting aspiration is needed. This study introduces a potential new aspiration screening method based on photoacoustic imaging (PAI), a medical imaging technology that measures the optical contrast of tissue rather than mechanical or elastic properties. In this preliminary study, a tissue-mimicking neck phantom was designed to test the performance of PAI for aspiration screening with a charcoal solution as a contrast agent. A 1064nm wavelength light source was illuminated on the anterior of the neck phantom to induce the photoacoustic effect. The resulting photoacoustic signal of the charcoal contrast in the mock trachea was detected by a linear transducer array with a 2.25MHz central ultrasound frequency. The phantom results showed that charcoal solution at 10mg/ml exhibited strong photoacoustic signals when flowing into the phantom trachea. By overlaying the photoacoustic signals of the charcoal contrast on top of the ultrasound image, we were able to simultaneously visualize the movement of food contrast and a cross-section of tissue structures during mock swallowing. Moreover, we confirmed the ability to detect the flow of charcoal contrast at a small bolus volume of ~ 7 μl through the phantom, suggesting high sensitivity to detect small aspiration events. The study suggests that PAI holds promise to be developed as an aspiration detection tool with charcoal powder as a contrast agent.

Peripheral IV Administration of Hypertonic Saline: Single-Center Retrospective PICU Study.

To determine the frequency and characteristics of complications of peripherally administered hypertonic saline (HTS) through assessment of infiltration and extravasation. Retrospective cross-sectional study. Freestanding tertiary care pediatric hospital. Children who received HTS through a peripheral IV catheter (PIVC). None. We conducted a single-center retrospective review from January 2012 to 2019. A total of 526 patients with 1,020 unique administrations of HTS through a PIVC met inclusion criteria. The primary endpoint was PIVC failure due to infiltration or extravasation. The indication for the administration of HTS infusion was collected. Catheter data was captured, including the setting of catheter placement, anatomical location on the patient, gauge size, length of time from catheter insertion to HTS infusion, in situ duration of catheter lifespan, and removal rationale. The administration data for HTS was reviewed and included volume of administration, bolus versus continuous infusion, infusion rate, infusion duration, and vesicant medications administered through the PIVC. There were 843 bolus infusions of HTS and 172 continuous infusions. Of the bolus administrations, there were eight infiltrations (0.9%). The continuous infusion group had 13 infiltrations (7.6%). There were no extravasations in either group, and no patients required medical therapy or intervention by the wound care or plastic surgery teams. There was no significant morbidity attributed to HTS administration in either group. HTS administered through a PIVC infrequently infiltrates in critically ill pediatric patients. The infiltration rate was low when HTS is administered as a bolus but higher when given as a continuous infusion. However, no patient suffered an extravasation injury or long-term morbidity from any infiltration.

A Visuoperceptual Measure for Videofluoroscopic Swallow Studies (VMV): A Pilot Study of Validity and Reliability in Adults with Dysphagia

The visuoperceptual measure for videofluoroscopic swallow studies (VMV) is a new measure for analysing the recordings from videofluoroscopic swallow studies (VFSS). This study evaluated the reliability and validity of the pilot version of the VMV using classical test theory (CTT) analysis, informed by the consensus-based standards for the selection of health measurement instruments (COSMIN) guidelines. Forty participants, diagnosed with oropharyngeal dysphagia by fibreoptic endoscopic evaluation of swallowing, were recruited. The VFSS and administration of bolus textures and volumes were conducted according to a standardised protocol. Recordings of the VFSS were rated by three blinded raters: a speech-language pathologist, a radiologist and a phoniatrician. Inter- and intra-rater reliability was assessed with a weighted kappa and resulted in 0.889 and 0.944 overall, respectively. Structural validity was determined using exploratory factor analyses, which found four and five factor solutions. Internal consistency was evaluated with Cronbach’s alpha coefficients, which found all but one factor scoring within an acceptable range (>0.70 and <0.95). Hypothesis testing for construct validity found the expected correlations between the severity of dysphagia and the VMV’s performance, and found no impact of gender on measure performance. These results suggest that the VMV has potential as a reliable and valid measure for VFSS. Further validation with a larger sample is required, and validation using an item response theory paradigm approach is recommended.

Human in silico trials for parametric computational fluid dynamics investigation of cerebrospinal fluid drug delivery: impact of injection location, injection protocol, and physiology

BackgroundIntrathecal drug delivery has a significant role in pain management and central nervous system (CNS) disease therapeutics. A fluid-physics based tool to assist clinicians in choosing specific drug doses to the spine or brain may help improve treatment schedules.MethodsThis study applied computational fluid dynamics (CFD) and in vitro model verification to assess intrathecal drug delivery in an anatomically idealized model of the human CSF system with key anatomic features of the CNS. Key parameters analyzed included the role of (a) injection location including lumbar puncture (LP), cisterna magna (CM) and intracerebroventricular (ICV), (b) LP injection rate, injection volume, and flush volume, (c) physiologic factors including cardiac-induced and deep respiration-induced CSF stroke volume increase. Simulations were conducted for 3-h post-injection and used to quantify spatial–temporal tracer concentration, regional area under the curve (AUC), time to maximum concentration (Tmax), and maximum concentration (Cmax), for each case.ResultsCM and ICV increased AUC to brain regions by ~ 2 logs compared to all other simulations. A 3X increase in bolus volume and addition of a 5 mL flush both increased intracranial AUC to the brain up to 2X compared to a baseline 5 mL LP injection. In contrast, a 5X increase in bolus rate (25 mL/min) did not improve tracer exposure to the brain. An increase in cardiac and respiratory CSF movement improved tracer spread to the brain, basal cistern, and cerebellum up to ~ 2 logs compared to the baseline LP injection.ConclusionThe computational modeling approach provides ability to conduct in silico trials representative of CSF injection protocols. Taken together, the findings indicate a strong potential for delivery protocols to be optimized to reach a target region(s) of the spine and/or brain with a needed therapeutic dose. Parametric modification of bolus rate/volume and flush volume was found to have impact on tracer distribution; albeit to a smaller degree than injection location, with CM and ICV injections resulting in greater therapeutic dose to brain regions compared to LP. CSF stroke volume and frequency both played an important role and may potentially have a greater impact than the modest changes in LP injection protocols analyzed such as bolus rate, volume, and flush.

Thin Liquid Bolus Volume Alters Pharyngeal Swallowing: Kinematic Analysis Using 3D Dynamic CT.

The previous studies reported that different volumes of thick liquid had an impact on spatiotemporal characteristics and pharyngeal response of swallowing. However, the bolus flow and swallowing motion pattern were different between thick and thin liquids. The effects of thin bolus volume on pharyngeal swallowing, especially true vocal cord (TVC) closure is still unclear. This study assessed the temporal characteristics when swallowing different volumes of thin liquid to determine the mechanical adaptation using 320-row area detector computed tomography (320-ADCT) and investigated a change of swallowing physiology including laryngeal closure, particularly TVC closure. Fourteen healthy women (28-45years) underwent 320-ADCT while swallowing of 3, 10, and 20ml of thin liquid barium in 45° semi-reclining position. Kinematic analysis was performed for each swallow including temporal characteristic, structural movements while swallowing, and maximal cross-sectional area of the upper esophageal sphincter (UES) opening. Bolus head reached to pharynx and esophagus earlier in larger volume significantly, indicating faster bolus transport as volume increased. There were significant effects on swallowing mechanism revealing earlier TVC closure and UES opening with increasing volume. Maximum cross-sectional area of the UES opening was increased to accommodate a larger bolus. Differences in mechanical adaptation through bolus transit and motion of swallowing structures were detected across increasing volumes. These volume-dependent adaptations potentially reduce the risk of aspiration. Understanding the swallowing physiological changes as volume increased is helpful for diagnosis and treatment of dysphagia patients as well as outcomes of swallowing rehabilitation in clinical practice.

Performance evaluation study of a commercially available smart patient-controlled analgesia pump with the microbalance method and an infusion analyzer.

BackgroundPatient-controlled analgesia (PCA) has been widely used as an effective medical treatment for pain and for postoperative analgesia. However, improper dose errors in intravenous (IV) administration of narcotic analgesics from a PCA infusion pump can cause patient harm. Furthermore, opioid overdose is considered one of the highest risk factors for patients receiving pain medications. Therefore, accurate delivery of opioid analgesics is a critical function of PCA infusion pumps.MethodsWe designed a microbalance method that consisted of a closed acrylic chamber containing a layer and an oil layer with an electronic balance. A commercially available infusion analyzer (IDA-5, Fluke Co., Everett, WA, USA) was used to measure the accuracy of the infusion flow rate from a commercially available smart PCA infusion pump (PS-1000, UNIMEDICS, Co., Ltd., Seoul, Korea) and compared with the results of the microbalance method. We evaluated the uncertainty of the flow rate measurement using the ISO guide (GUM:1995 part3). The battery life, delay time of the occlusion alarm, and bolus function of the PCA pump were also tested.ResultsThe microbalance method was good in the short-term 2 h measurement, and IDA-5 was good in the long-term 24 h measurement. The two measurement systems can complement each other in the case of the measurement time. Regarding battery performance, PS-1000 lasted approximately 5 days in a 1 ml/hr flow rate condition without recharging the battery. The occlusion pressure alarm delays of PS-1000 satisfied the conventional alarm threshold of occlusion pressure (300-800 mmHg). Average accuracy bolus volume was measured as 63%, 95%, and 98.5% with 0.1 ml, 1 ml, and 2 ml bolus volume presets, respectively. A 1 ml/hr flow rate measurement was evaluated as 2.08% of expanded uncertainty, with a 95% confidence level.ConclusionPS-1000 showed a flow accuracy to be within the infusion pump standard, which is ± 5% of flow accuracy. Occlusion alarm of PS-1000 was quickly transmitted, resulting in better safety for patients receiving IV infusion of opioids. PS-1000 is sufficient for a portable smart PCA infusion pump.

Pharyngo-Esophageal Modulatory Swallow Responses to Bolus Volume and Viscosity Across Time.

Objectives/HypothesisModulation of the pharyngeal swallow to bolus volume and viscosity is important for safe swallowing and is commonly studied using high‐resolution pharyngeal manometry (HRPM). Use of unidirectional pressure sensor technology may, however, introduce variability in swallow measures and a fixed bolus administration protocol may induce time and order effects. We aimed to overcome these limitations and to investigate the effect of time by repeating randomized measurements using circumferential pressure sensor technology.Study DesignSub‐set analysis of data from the placebo arm of a randomized, repeated measures trial.MethodsHRPM with impedance was recorded using a solid‐state catheter with 36 circumferential pressure sensors and 18 impedance segments straddling from hypopharynx to stomach. Testing included triplicates of 5, 10, and 20 ml thin liquid and 10 ml thick liquid boluses, the order of the thin liquid boluses was randomized. The swallow challenges were repeated approximately 10 minutes after finishing the baseline measurement.ResultsWe included 19 healthy adults (10/9 male/female; age 24.5 ± 4.1 year). Intrabolus pressure, all upper esophageal sphincter (UES) opening and relaxation metrics, and flow timing metrics increased with larger volumes. A thicker viscosity decreased UES relaxation time, UES basal pressure, and flow timing metrics, whereas UES opening extent increased. Pre‐swallow UES basal pressure and post‐swallow UES contractile integral decreased over time.ConclusionUsing circumferential pressure sensor technology, the effects of volume and viscosity were largely consistent with previous reports. UES contractile pressures reduced over time. The growing body of literature offers a benchmark for recognizing aberrant pharyngo‐esophageal motor responses.Level of Evidence3 Laryngoscope, 132:1817–1824, 2022