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INTRODUCTION: Ineffective esophageal motility (IEM) is a minor motor disorder with potential reflux implications. Contraction reserve, manifested as augmentation of esophageal body contraction after multiple rapid swallows (MRS), may affect esophageal acid exposure time (AET) in IEM. METHODS: Esophageal high-resolution manometry (HRM) and ambulatory reflux monitoring studies were reviewed over 2 years to identify patients with normal HRM, IEM (≥50% ineffective swallows), and absent contractility (100% failed swallows). Single swallows and MRS were analyzed using HRM software tools (distal contractile integral, DCI) to determine contraction reserve (mean MRS DCI to mean single swallow DCI ratio >1). Univariate analysis and multivariable regression analyses were performed to determine motor predictors of abnormal AET in the context of contraction reserve. RESULTS: Of 191 eligible patients, 57.1% had normal HRM, 37.2% had IEM, and 5.8% had absent contractility. Contraction reserve had no affect on AET in normal HRM. Nonsevere IEM (5–7 ineffective swallows) demonstrated significantly lower proportions with abnormal AET in the presence of contraction reserve (30.4%) compared with severe IEM (8–10 ineffective swallows) (75.0%, P = 0.03). Abnormal AET proportions in nonsevere IEM with contraction reserve (32.7%) resembled normal HRM (33.0%, P = 0.96), whereas that in severe IEM with (46.2%) or without contraction reserve (50.0%) resembled absent contractility (54.5%, P ≥ 0.6). Multivariable analysis demonstrated contraction reserve to be an independent predictor of lower upright AET in nonsevere (odds ratio 0.44, 95% confidence interval 0.23–0.88) but not severe IEM. DISCUSSION: Contraction reserve affects esophageal reflux burden in nonsevere IEM. Segregating IEM into severe and nonsevere cohorts has clinical value.

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INTRODUCTION: With the ongoing focus on value-based care, there has been greater emphasis on efficiency and cost-effectiveness of health services, including gastrointestinal endoscopy. Endoscopy unit optimization requires coordination of many providers, staff, equipment, and resources. We aimed to develop a value-stream map for performance of endoscopic procedures performed at a tertiary academic medical center, identify processes associated with delays, and assess if workflow process improved after recent redesign efforts were initiated. METHODS: Data were extracted from 13,663 endoscopic procedures from January 1st, 2018 to April 1st, 2019, at the Center for Advanced Endoscopy (CAE), a 5-room gastrointestinal and pulmonary endoscopy unit. The endoscopy workflow process was mapped (Figure 1) and potential processes associated with delays (lags) identified. We isolated patient process times through the CAE and compared those before and after clinical redesign initiatives were instituted. We additionally extracted clinical characteristics and performed logistic regression to identify potential predictors of delay ≥30 minutes, defined as delay in processes associated with patient transportation (lag 1 or lag 3). RESULTS: Patient clinical characteristics (Table 1) did not differ after implementation of clinical redesign though the proportion of inpatient procedures increased (33.9% vs 37.1%, P = 0.001). The rate of 30-minute delays was high and unchanged after clinical redesign implementation (25.9% vs. 25.9%, P = 0.99). Delays were noted at all three potential processes: procedure room availability (19 minutes), scheduled versus actual start time (49 minutes), and awaiting transport for inpatients to return to medical ward (34 minutes). Multiple logistic regression (Table 3) revealed male gender (OR 1.09, 95% CI: 1.00-1.19, P = 0.04) and inpatient status (OR 5.03, 95% CI: 4.60-5.51, P < 0.001) as significant predictors of delay in CAE workflow process. CONCLUSION: Patient hospitalization status is a contributing factor to delays in the CAE and. though prolonged monitoring of these patients is a logical practice, establishing benefit is needed to justify this action. Optimization of patient transportation services to procedure room and from post-procedure areas is one potential recommendation based on this analysis. This area for improvement is the center of our next optimization efforts and will be evaluated as part of this ongoing project.

We present a monolithic integrated low-threshold Raman silicon laser based on silicon-on-insulator (SOI) rib waveguide ring cavity with an integrated p-i-n diode. The laser cavity consists of a race-track shaped ring resonator connected to a straight bus waveguide via a directional coupler which couples both pump and signal light into and out of the cavity. Reverse biasing the diode with 25V reduces the free carrier lifetime to below 1 ns, and stable, single-mode, continuous-wave (CW) Raman lasing is achieved with threshold of 20mW, slope efficiency of 28%, and output power of 50mW. With zero bias voltage, a lasing threshold of 26mW and laser output power >10mW can be obtained. The laser emission has high spectral purity with a side-mode suppression of >80dB and laser linewidth of <100 kHz. The laser wavelength can be tuned continuously over 25 GHz. To demonstrate the performance capability of the laser for gas sensing application, we perform absorption spectroscopy on methane at 1687 nm using the CW output of the silicon Raman laser. The measured rotationally-resolved direct absorption IR spectrum agrees well with theoretical prediction. This ring laser architecture allows for on-chip integration with other silicon photonics components to provide an integrated and scaleable monolithic device. By proper design of the ring cavity and the directional coupler, it is possible to achieve higher order cascaded Raman lasing in silicon for extending laser wavelengths from near IR to mid IR regions.