Pilot Validation of a New Wireless Patch System as an Ambulatory, Noninvasive Tool That Measures Gut Myoelectrical Signals: Physiologic and Disease Correlations
Lindsay Axelrod, Steve Axelrod, Anand Navalgund, George Triadafilopoulos
Digestive Diseases and Science, 2020 Oct 15, doi: 10.1007/s10620-020-06663-y.
Background and Aims Limited means exist to assess gastrointestinal activity in a noninvasive, objective way that is highly predictive of underlying motility disorders. The aim of this paper is to demonstrate the feasibility of recording myoelectric gastrointestinal activity by cutaneous patches and to correlate myoelectric signals with gastrointestinal function in various clinical settings. Methods A novel wireless patch system (WPS) (G-Tech Medical) that acquires gastrointestinal myoelectrical signals was placed on the patients’ anterior abdomens. Data were transmitted wirelessly to a mobile device with a user interface and forwarded to a cloud server where processing algorithms identified episodes of motor activity, quantified their parameters, and nominally assigned them to specific gastrointestinal organs based on their frequencies. Results The inherent reproducibility of the WPS measurement technique itself and from the underlying gut activity, coupled with source validation and sensitivity to changes in gut activity in several physiologic and pathologic states, demonstrates its feasibility, safety, and performance in clinical settings. Conclusions The novel WPS technology, measuring myoelectric intestinal activity noninvasively and continuously over multiple days, is feasible in a wide range of clinical settings, highlighting its promise in the diagnosis and management of motility disorders. Further research is required for more extensive validation and to determine how best to employ this information to optimize patient care.
Cutaneous Patches to Monitor Myoelectric Activity of the Gastrointestinal Tract in Postoperative Pediatric Patients
Jordan S. Taylor, Vivian de Ruijter , Ryan Brewster , Anand Navalgund , Lindsay Axelrod , Steve Axelrod , James C.Y. Dunn , and James K. Wall
Pediatr Gastroenterol Hepatol Nutr. 2019 Nov;22(6):518-526. Published online Nov 07, 2019. https://doi.org/10.5223/pghn.2019.22.6.518
Purpose: Limited means exist to assess gastrointestinal activity in pediatric patients postoperatively. Recently, myoelectric gastrointestinal activity recorded by cutaneous patches has been shown in adult patients to be predictive of clinical return of gastrointestinal function postoperatively. The aim of this case series is to demonstrate the feasibility of this system in pediatric patients and to correlate myoelectric signals with return of bowel function clinically. Methods: Pediatric patients undergoing abdominal surgery were recruited to have wireless patches placed on the abdomen within two hours postoperatively. Myoelectric data were transmitted wirelessly to a mobile device with a user-interface and forwarded to a cloud server where processing algorithms identified episodes of motor activity, quantified their parameters and nominally assigned them to specific gastrointestinal organs based on their frequencies. Results: Three patients (ages 5 months, 4 year, 16 year) were recruited for this study. Multiple patches were placed on the older subjects, while the youngest had a single patch due to space limitations. Rhythmic signals of the stomach, small intestine, and colon could be identified in all three subjects. Patients showed gradual increase in myoelectric intestinal and colonic activity leading up to the first recorded bowel movement. Conclusion: Measuring myoelectric intestinal activity continuously using a wireless patch system is feasible in a wide age range of pediatric patients. The increase in activity over time correlated well with the patients’ return of bowel function. More studies are planned to determine if this technology can predict return of bowel function or differentiate between physiologic ileus and pathologic conditions.
Monitoring gastric myoelectric activity after pancreaticoduodenectomy for diet “readiness”.
Monica Dua, Anand Navalgund, Steve Axelrod, Lindsay Axelrod, Patrick J. Worth, Jeffrey A. Norton, George A. Poultsides, George Triadafilopoulos, and Brendan C. Visser.
American Journal of Physiology-Gastrointestinal and Liver Physiology 2018. Nov 1; 315(5):G743-G751
Postoperative delayed gastric emptying (DGE) is a frustrating complication of pancreaticoduodenectomy (PD). We studied whether monitoring of postoperative gastric motor activity using a novel wireless patch system can identify patients at risk for DGE. Patients (n = 81) were prospectively studied since 2016; 75 patients total were analyzed for this study. After PD, battery-operated wireless patches (G-Tech Medical) that acquire gastrointestinal myoelectrical signals are placed on the abdomen and transmit data by Bluetooth. Patients were divided into early and late groups by diet tolerance of 7 days [enhanced recovery after surgery (ERAS) goal]. Subgroup analysis was done of patients included after ERAS initiation. The early and late groups had 50 and 25 patients, respectively, with a length of stay (LOS) of 7 and 11 days (P < 0.05). Nasogastric insertion was required in 44% of the late group. Tolerance of food was noted by 6 versus 9 days in the early versus late group (P < 0.05) with higher cumulative gastric myoelectrical activity. Diminished gastric myoelectrical activity accurately identified delayed tolerance to regular diet in a logistical regression analysis [area under the curve (AUC): 0.81; 95% confidence interval (CI), 0.74–0.92]. The gastric myoelectrical activity also identified a delayed LOS status with an AUC of 0.75 (95% CI, 0.67–0.88). This stomach signal continued to be predictive in 90% of the ERAS cohort, despite earlier oral intake. Measurement of gastric activity after PD can distinguish patients with shorter or longer times to diet. This noninvasive technology provides data to identify patients at risk for DGE and may guide the timing of oral intake by gastric “readiness.”
NEW & NOTEWORTHY Limited clinical indicators exist after pancreaticoduodenectomy to allow prediction of delayed gastric emptying (DGE). This study introduces a novel, noninvasive, wireless patch system capable of accurately monitoring gastric myoelectric activity after surgery. This system can differentiate patients with longer or shorter times to a regular diet as well as provide objective data to identify patients at risk for DGE. This technology has the potential to individualize feeding regimens based on gastric activity patterns to improve outcomes.
Colon Myoelectric Activity Measured After Open Abdominal Surgery with a Noninvasive Wireless Patch System Predicts Time to First Flatus.
Anand Navalgund, Steve Axelrod, Lindsay Axelrod, Shyamali Singhal, Khoi Tran, Prithvi Legha, George Triadafilopoulos.
Journal of Gastrointestinal Surgery 2018 Nov 2. doi: 10.1007/s11605-018-4030-4. [Epub ahead of print]
Passage of flatus after abdominal surgery signals resolution of physiological postoperative ileus (POI) and often, particularly after complex open surgeries, serves as the trigger to initiate oral feeding. To date, there is no objective tool that can predict time to flatus allowing for timely feeding and optimizing recovery. In an open, prospective study, we examine the use of a noninvasive wireless patch system that measures electrical activity from gastrointestinal smooth muscles in predicting time to first flatus.Eighteen patients who underwent open abdominal surgery at El Camino Hospital, Mountain View, CA, were consented and studied. Immediately following surgery, wireless patches were placed on the patients’ anterior abdomen. Colonic frequency peaks in the spectra were identified in select time intervals and the area under the curve of each peak times its duration was summed to calculate cumulative myoelectrical activity. Patients with early flatus had stronger early colonic activity than patients with late flatus. At 36 h post-surgery, a linear fit of time to flatus vs cumulative colonic myoelectrical activity predicted first flatus as much as 5 days (± 22 h) before occurrence. In this open, prospective pilot study, noninvasive measurement of colon activity after open abdominal surgery was feasible and predictive of time to first flatus. Interventions such as feeding can potentially be optimized based on this prediction, potentially improving outcomes, decreasing length of stay, and lowering costs.
A New Motility Tool: High Concordance Between Internal Smartpill Pressure Recordings and Myoelectric Events Measured by External Wireless G-Tech Patches. Axelrod S, Navalgund A, Axelrod L and Triadafilopoulos G. Digestive Disease Week 2018, Washington DC
Colonic Myoelectrical Activity Measured Non-Invasively after Open Abdominal Surgery Predicts Time to First Flatus/Resolution of Postoperative Ileus. Navalgund A, Singhal S, Tran K, Legha P, Axelrod S, Axelrod L, and Triadafilopoulos G. Digestive Disease Week 2018, Washington DC
Distinctive Electrical Signal Patterns Recorded at the Abdominal Surface in Subjects With Gastroparesis and Gastroesophageal Reflux Disease. Navalgund A, Kafai N, Axelrod S and Triadafilopoulos G. Digestive Disease Week 2016, San Diego, CA
Spatial Localization of Surface-Measured Rhythmic Myoelectric Signals From Stomach, Small Intestine and Colon. Axelrod L, Navalgund A, Axelrod S and Triadafilopoulos G, Digestive Disease Week 2016, San Diego, CA
Signal Acquisition and Analysis of Surface-Measured Myoelectrical Signals of the Human GI tract. Triadafilopoulos G, Axelrod S, Navalgund A, Shah P, Devanaboyina U. ACG 2014 Annual Scientific Meeting and Postgraduate Course. Philadelphia, Pennsylvania Oct 2014
Signal Processing and Preliminary Clinical Utility of Surface-Measured Myoelectrical Signals of the Human GI tract. Triadafilopoulos G, Axelrod S, Navalgund A, Shah P, Devanaboyina U. ACG 2014 Annual Scientific Meeting and Postgraduate Course. Philadelphia, Pennsylvania Oct 2014
Early Clinical Utility of Surface-Measured Myoelectrical Signals of the Human GI tract. Triadafilopoulos G, Axelrod S, Navalgund A, Shah P, Devanaboyina U. ACG 2014 Annual Scientific Meeting and Postgraduate Course. Philadelphia, Pennsylvania Oct 2014