Assessment of postoperative nausea and vomiting after bariatric surgery using a validated questionnaire

BACKGROUND: Postoperative nausea and vomiting (PONV) is known to occur after bariatric surgery, with over two thirds of patients affected. However, variability exists in how to objectively measure PONV. OBJECTIVES: The goals of the present study were to use a validated, patient-centered scoring tool, the Rhodes Index of Nausea, Vomiting, and Retching to measure the severity of PONV after bariatric surgery, to directly compare PONV between patients who underwent laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (LRYGB), and to identify risk factors for the development of PONV after bariatric surgery. SETTING: Barnes-Jewish Hospital/Washington University School of Medicine, St. Louis, Missouri, United States of America. METHODS: The Washington University Weight Loss Surgery team prospectively surveyed patients from January 1, 2017 to December 1, 2018 at the following 6 different timepoints: postoperative day (POD) 0, POD 1, POD 2, POD 3 to 4, the first postoperative outpatient visit (POV 1: POD 5-25), and the second postoperative visit (POV 2: POD 25-50). At each timepoint, a cumulative Rhodes score was calculated from the sum of 8 questions. The American Society for Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database was used to collect patient demographic characteristics and perioperative clinical data. RESULTS: A total of 274 patients met study criteria and completed 605 Rhodes questionnaires. Two hundred fifty Rhodes questionnaires were completed by patients after SG and 355 were completed by patients after LRYGB. Total Rhodes scores are statistically higher in LSG patients compared with patients who underwent LRYGB (LSG = 5.45 ± 6.27; LRYGB = 3.08 ± 4.19, P = .0002). Additionally, at the earlier timepoints, scores were higher among patients who underwent LSG than those who had undergone LRYGB as follows: POD 0 (LSG = 6.96 ± 6.50; LRYGB = 2.89 ± 2.90, P = .0115), POD 1 (LSG = 8.20 ± 6.76; LRYGB = 2.88 ± 3.44, P \u3c .0001), and POD 2 (LSG = 4.05 ± 4.88; LRYGB = 2.06 ± 3.43, P = .05). On subset analysis, examining patients who either underwent an LSG or LRYGB, both procedures had a statistically significant PONV peak emerge on POV 2. Last, overall Rhodes scores were statistically higher in female patients compared with male patients (female: 4.43 ± 5.46; male: 2.35 ± 3.90, P = .021). Although the magnitude of the difference varied somewhat across POD time intervals, the difference was most pronounced at POV 2. CONCLUSIONS: This is the largest study using a validated nausea and vomiting questionnaire to objectively measure PONV after bariatric surgery. The factors found to be most associated with increased PONV were LSG and female sex. Ultimately, these data can help bariatric surgery programs, including Washington University Weight Loss Surgery, identify patients who may require more intensive treatment of PONV, particularly POD 0 to 2, and help to identify patients that continue to struggle with PONV in the later surgical recovery phase

Progressive induction of left ventricular pressure overload in a large animal model elicits myocardial remodeling and a unique matrix signature

ObjectivePatients with severe left ventricular pressure overload secondary to aortic stenosis can present with signs and symptoms of heart failure despite normal left ventricular ejection fraction. This process occurs, at least in part, as a result of left ventricular pressure overload–induced extracellular matrix remodeling that promulgates increased left ventricular stiffness and impaired diastolic function. However, the determinants that drive extracellular matrix remodeling in this form of left ventricular pressure overload remain to be fully defined.MethodsLeft ventricular pressure overload was induced in mature pigs (n = 15) by progressive ascending aortic cuff inflation (once per week for 4 weeks), whereby left ventricular mass, left ventricular ejection fraction, and regional myocardial stiffness (rKm) were compared with referent controls (n = 12). Determinants of extracellular matrix remodeling were assessed by measuring levels of mRNA expression for fibrillar collagens, matrix metalloproteinases, and tissue inhibitors of matrix metalloproteinase 1 and 4.ResultsWith left ventricular pressure overload, left ventricular mass and rKm increased by 2- and 3-fold, respectively, compared with control, with no change in left ventricular ejection fraction. Left ventricular myocardial collagen increased approximately 2-fold, which was accompanied by reduced solubility (ie, increased cross-linking) with left ventricular pressure overload, but mRNA expression for fibrillar collagen and matrix metalloproteinases remained relatively unchanged. In contrast, a robust increase in mRNA expression for tissue inhibitors of matrix metalloproteinase-1 and 4 occurred with left ventricular pressure overload.ConclusionsIn a progressive model of left ventricular pressure overload, which recapitulates the phenotype of aortic stenosis, increased extracellular matrix accumulation and subsequently increased myocardial stiffness were not due to increased fibrillar collagen expression but rather to determinants of post-translational control that included increased collagen stability (thereby resistant to matrix metalloproteinase degradation) and increased endogenous matrix metalloproteinase inhibition. Targeting these extracellular matrix post-translational events with left ventricular pressure overload may hold both diagnostic and therapeutic relevance

Integrable microwave filter based on a photonic crystal delay line

The availability of a tunable delay line with a chip-size footprint is a crucial step towards the full implementation of integrated microwave photonic signal processors. Achieving a large and tunable group delay on a millimetre-sized chip is not trivial. Slow light concepts are an appropriate solution, if propagation losses are kept acceptable. Here we use a low-loss 1.5 mm-long photonic crystal waveguide to demonstrate both notch and band-pass microwave filters that can be tuned over the 0 50-GHz spectral band. The waveguide is capable of generating a controllable delay with limited signal attenuation (total insertion loss below 10 dB when the delay is below 70 ps) and degradation. Owing to the very small footprint of the delay line, a fully integrated device is feasible, also featuring more complex and elaborate filter functions.This work was funded by the European Union under the project GOSPEL (grant 219299) and by the Valencian Government (Prometeo GVA 2008-92). We thank S. 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