Background A standardized 4-hour adult-based gastric emptying scintigraphy (GES) protocol is increasingly being used in children to evaluate for gastroparesis. We sought to determine the effect of age, anthropometrics, and study duration on GES results using this protocol in children. Methods Retrospective review of children who underwent a 4-hour solid-meal GES study at a tertiary care center. GES results and anthropometric data (e.g., weight, stature, body surface area) were systematically captured. Key Results Of 216 children, 188 (87%) were able to complete the study meal. Children unable to complete the meal were younger and smaller. In multivariate analysis, only increasing body surface area (BSA) was identified as being positively associated with ability to complete the meal (odds ratio: 19.7; P<0.001). Of those completing the meal, 48 (26%) had delayed emptying (4-hour retention value >10%). These children were significantly younger and smaller than those with normal emptying. In multivariate analysis of those completing the meal, only increasing BSA (odds ratio: 0.26; P=0.006) was identified as being negatively associated with delayed emptying. There was a progressive increase in the positive predictive value for identification of delayed gastric emptying as the duration of the study increased (0.25, 0.60, and 0.71 at 1, 2, and 3 hr, respectively) using the 4-hr value as a comparator. Conclusions and Inferences Young children have more difficulty completing the GES meal. Childhood gastric retention is affected by age and anthropometric factors, primarily BSA. The standardized 4-hr GES protocol may need to take these factors into account in children.

This paper reports a micromachined drug delivery device that is wirelessly operated using radiofrequency magnetic fields for implant applications. The controlled release from the drug reservoir of the device is achieved with the microvalves of poly(N-isopropylacrylamide) thermoresponsive hydrogel that are actuated with a wireless resonant heater, which is activated only when the field frequency is tuned to the resonant frequency of the heater circuit. The device is constructed by bonding a 1-mm-thick polyimide component with the reservoir cavity to the heater circuit that uses a planar coil with the size of 5-10 mm fabricated on polyimide film, making all the outer surfaces to be polyimide. The release holes created in a reservoir wall are opened/closed by the hydrogel microvalves that are formed inside the reservoir by in-situ photolithography that uses the reservoir wall as a photomask, providing the hydrogel structures self-aligned to the release holes. The wireless heaters exhibit fast and strong response to the field frequency, with a temperature increase of up to 20°C for the heater that has the 34-MHz resonant frequency, achieving 38-% shrinkage of swelled hydrogel when the heater is excited at its resonance. An active frequency range of ~2 MHz is observed for the hydrogel actuation. Detailed characteristics in the fabrication and actuation of the hydrogel microvalves as well as experimental demonstrations of frequency-controlled temporal release are reported.

Objectives To determine whether gastrointestinal (GI) symptoms (abdominal pain, non-pain GI symptoms, nausea) and/or psychosocial distress differ between children with/without gastroparesis, and secondarily whether the severity of GI symptoms and/or psychosocial distress are related to the degree of gastroparesis. Study design Children 7 – 18 yr. of age (n=100; 63 female) undergoing a 4-hour gastric emptying scintigraphy (GES) study completed questionnaires evaluating GI symptoms, anxiety, and somatization for this prospective study. Spearman correlation, Mann-Whitney, t-test, and chi-square tests were utilized as appropriate for statistical analysis. Results Children with gastroparesis (n=25) were younger than those with normal emptying (12.6 ± 3.5 yr. vs. 14.3 ± 2.6, P=0.01). Because questionnaire responses from 7–10-year-old children were inconsistent, only patient-reported symptoms from 11–18-year-olds were used. Within this older group (n=83), children with gastroparesis (n=17) did not differ from children with normal emptying in severity of GI symptoms or psychosocial distress. In children with gastroparesis, gastric retention at 4 hr was related inversely to vomiting (r=−0.506, P=0.038), nausea (r=−0.536, P=0.019), difficulty finishing a meal (r=−0.582, P=0.014), and CSI-24 score (r=−0.544, P=0.024) and positively correlated with frequency of waking from sleep with symptoms (r=0.551, P=0.022). Conclusions The severity of GI symptoms and psychosocial distress do not differ between children with/without gastroparesis who are undergoing GES. In those with gastroparesis, gastric retention appears to be inversely related to dyspeptic symptoms and somatization, and positively related to waking from sleep with symptoms.