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Edoardo Savarino - One of the best experts on this subject based on the ideXlab platform.
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Post-reflux swallow-induced Peristaltic Wave (PSPW): physiology, triggering factors and role in reflux clearance in healthy subjects.
Journal of gastroenterology, 2020Co-Authors: Mengyu Zhang, Busra Yaman, Sabine Roman, Edoardo Savarino, C. Prakash Gyawali, Jerry D. Gardner, Daniel SifrimAbstract:The underlying physiology of post-reflux swallow-induced Peristaltic Wave (PSPW) is unclear. We aimed to: 1) calculate the probability of a random association between reflux and PSPW; 2) characterize factors that could underlie triggering of PSPW and 3) assess the chemical clearance effect of PSPW in healthy asymptomatic subjects. A total of 251 impedance–pH tracings from healthy asymptomatic subjects were analysed. Twenty consecutive tracings from this pool with 20–40 reflux episodes/24 h and a PSPW index higher than 50% were separately analyzed to evaluate the probability of a random association between reflux and PSPW. The characteristics of reflux episodes followed by a PSPW were compared with those not associated with PSPW. A mean time interval of 29.3 s between a reflux episode and the first swallow captured 71% of total reflux episodes, and 67% of accompanying swallows were non-random. Compared to reflux without PSPW, reflux episodes with PSPW were more frequently acidic (P = 0.048), mixed with gas (P
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post reflux swallow induced Peristaltic Wave pspw physiology triggering factors and role in reflux clearance in healthy subjects
Journal of Gastroenterology, 2020Co-Authors: Mengyu Zhang, Busra Yaman, Sabine Roman, Edoardo Savarino, Jerry D. Gardner, Prakash C Gyawali, Daniel SifrimAbstract:The underlying physiology of post-reflux swallow-induced Peristaltic Wave (PSPW) is unclear. We aimed to: 1) calculate the probability of a random association between reflux and PSPW; 2) characterize factors that could underlie triggering of PSPW and 3) assess the chemical clearance effect of PSPW in healthy asymptomatic subjects. A total of 251 impedance–pH tracings from healthy asymptomatic subjects were analysed. Twenty consecutive tracings from this pool with 20–40 reflux episodes/24 h and a PSPW index higher than 50% were separately analyzed to evaluate the probability of a random association between reflux and PSPW. The characteristics of reflux episodes followed by a PSPW were compared with those not associated with PSPW. A mean time interval of 29.3 s between a reflux episode and the first swallow captured 71% of total reflux episodes, and 67% of accompanying swallows were non-random. Compared to reflux without PSPW, reflux episodes with PSPW were more frequently acidic (P = 0.048), mixed with gas (P < 0.0001), of high proximal extent (P < 0.0001), while awake (P < 0.0001), and with shorter chemical clearance time (P = 0.040). High proximal extent, gas presence and occurring while awake were independent factors associated with PSPW (P < 0.0001). Using a time window between reflux and PSPW of around 30 s, the probability of a chance association is around 30%. Reflux episodes with high proximal extent, containing gas and occurring while awake are important factors associated with PSPW in healthy subjects. Reflux episodes with PSPW have a shorter chemical clearance time.
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postreflux swallow induced Peristaltic Wave index from ph impedance monitoring associates with esophageal body motility and esophageal acid burden
Neurogastroenterology and Motility, 2020Co-Authors: Benjamin D Rogers, Nicola De Bortoli, Arvind Rengarajan, Mentore Ribolsi, Matteo Ghisa, Farhan Quader, R Penagini, Aurelio Mauro, Michele Cicala, Edoardo SavarinoAbstract:Background Postreflux swallow-induced Peristaltic Wave (PSPW) on pH-impedance monitoring and contraction vigor on high-resolution manometry (HRM) both assess esophageal Peristaltic response. We aimed to evaluate relationships between PSPW and esophageal peristalsis on HRM in the context of reflux disease in this multicenter cohort study. Methods pH-impedance and HRM studies performed on patients with persisting reflux symptoms were reviewed from 6 centers (5 in Europe and 1 in US). Total, upright and supine acid exposure time (AET) were evaluated from pH-impedance studies; PSPW index (PSPWI) and mean nocturnal baseline impedance (MNBI) were calculated using standard methodology. Esophageal body contraction vigor was analyzed using distal contractile integral (DCI), and DCI ratio > 1 between single swallows and multiple rapid swallows (MRS) defined presence of contraction reserve. Student's t test, ANOVA, and linear regression were utilized to investigate relationships between PSPW, contraction vigor, and contraction reserve. Key results Of 296 patients (52.8 ± 0.8 yr, 63% F), median PSPWI was 0.475. Only 24.0% had intact DCI; the remainder had varying degrees of hypomotility. As hypomotility increased, PSPWI and MNBI decreased significantly, while total AET and reflux episodes had an inverse response (P ≤ .002 for each). MRS data were available in 167 (56.4%), 72.5% had contraction reserve. MRS cohorts with normal PSPWI had significantly lower reflux burden compared to low PSPWI, regardless of presence or absence of contraction reserve (P ≤ .001). Conclusions and inferences PSPWI correlates with esophageal hypomotility and reflux burden, and complements clinical reflux evaluation. Intact PSPW is more relevant to esophageal reflux clearance than contraction reserve.
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the added diagnostic value of postreflux swallow induced Peristaltic Wave index and nocturnal baseline impedance in refractory reflux disease studied with on therapy impedance ph monitoring
Neurogastroenterology and Motility, 2017Co-Authors: Marzio Frazzoni, Manuele Furnari, Salvatore Tolone, Leonardo Frazzoni, N. De Bortoli, Irene Martinucci, Santino Marchi, Vincenzo Giorgio Mirante, V. Savarino, Edoardo SavarinoAbstract:Background On-therapy impedance-pH monitoring in proton pump inhibitor (PPI)-refractory gastroesophageal reflux disease (GERD) yielded conflicting results. We aimed to assess the diagnostic value of postreflux swallow-induced Peristaltic Wave (PSPW) index and mean nocturnal baseline impedance (MNBI) in PPI-refractory heartburn. Methods On-therapy impedance-pH tracings from 189 consecutive patients with PPI-refractory heartburn were blindly reviewed. Patients were subdivided into refractory reflux esophagitis (RRE), healed reflux esophagitis (HRE), non-erosive reflux disease (NERD), and functional heartburn (FH) according to endoscopic and conventional impedance-pH findings. The diagnostic accuracy of PSPW index and MNBI in separating NERD from FH was assessed with receiver-operating-characteristic (ROC) analysis. Objectively documented persistent reflux remission at 3-year follow-up in 53 patients who underwent laparoscopic fundoplication served to evaluate PSPW index and MNBI as independent predictors of PPI-refractory GERD confirmed by positive surgical outcome. Key Results Median PSPW index and MNBI values were significantly lower in 39 RRE (16%; 1145 Ω) than in 41 HRE (25%; 1741 Ω) and in 68 NERD (29%; 2374 Ω) patients, and in all three GERD subgroups compared to 41 FH cases (67%; 3488 Ω) (P<.008). At ROC analysis, comparing NERD to FH the area under the curve was 0.886 with PSPW index and 0.677 with MNBI (P=.005). PSPW index was an independent predictor of PPI-refractory GERD (odds ratio 0.6983, P=.012). Conclusions & Inferences At on-therapy impedance-pH monitoring, PSPW index and MNBI efficiently distinguish PPI-refractory NERD from FH. The PSPW index represents an independent predictor of PPI-refractory GERD.
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The added diagnostic value of postreflux swallow‐induced Peristaltic Wave index and nocturnal baseline impedance in refractory reflux disease studied with on‐therapy impedance‐pH monitoring
Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society, 2016Co-Authors: Marzio Frazzoni, Manuele Furnari, Salvatore Tolone, Leonardo Frazzoni, N. De Bortoli, Irene Martinucci, Santino Marchi, Vincenzo Giorgio Mirante, V. Savarino, Edoardo SavarinoAbstract:Background On-therapy impedance-pH monitoring in proton pump inhibitor (PPI)-refractory gastroesophageal reflux disease (GERD) yielded conflicting results. We aimed to assess the diagnostic value of postreflux swallow-induced Peristaltic Wave (PSPW) index and mean nocturnal baseline impedance (MNBI) in PPI-refractory heartburn. Methods On-therapy impedance-pH tracings from 189 consecutive patients with PPI-refractory heartburn were blindly reviewed. Patients were subdivided into refractory reflux esophagitis (RRE), healed reflux esophagitis (HRE), non-erosive reflux disease (NERD), and functional heartburn (FH) according to endoscopic and conventional impedance-pH findings. The diagnostic accuracy of PSPW index and MNBI in separating NERD from FH was assessed with receiver-operating-characteristic (ROC) analysis. Objectively documented persistent reflux remission at 3-year follow-up in 53 patients who underwent laparoscopic fundoplication served to evaluate PSPW index and MNBI as independent predictors of PPI-refractory GERD confirmed by positive surgical outcome. Key Results Median PSPW index and MNBI values were significantly lower in 39 RRE (16%; 1145 Ω) than in 41 HRE (25%; 1741 Ω) and in 68 NERD (29%; 2374 Ω) patients, and in all three GERD subgroups compared to 41 FH cases (67%; 3488 Ω) (P
L. Xiao - One of the best experts on this subject based on the ideXlab platform.
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uterine peristalsis before embryo transfer affects the chance of clinical pregnancy in fresh and frozen thawed embryo transfer cycles
Human Reproduction, 2014Co-Authors: Lin Zhu, H.s. Che, L. XiaoAbstract:STUDY QUESTION Does uterine peristalsis influence the chance of clinical pregnancy in an embryo transfer cycle? SUMMARY ANSWER The uterine Peristaltic Wave frequency before embryo transfer is inversely related to the clinical pregnancy rates in fresh and frozen-thawed embryo transfer cycles. WHAT IS KNOWN ALREADY Uterine peristalsis participates in regulating fluid migration after mock embryo transfer, but whether it could potentially influence pregnancy outcomes had remained unclear. STUDY DESIGN, SIZE, DURATION This prospective cohort study included a total of 292 infertile women and was conducted between March 2013 and August 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS Patients underwent fresh embryo transfer in a fresh stimulation cycle with a long down-regulation protocol, a natural frozen-thawed embryo transfer cycle or an artificial frozen-thawed embryo transfer cycle. Uterine Peristaltic activity was assessed before embryo transfer by transvaginal ultrasonography. MAIN RESULTS AND THE ROLE OF CHANCE The uterine Peristaltic Wave frequencies of most patients were between 1.1 and 3.0 Waves/min before embryo transfer (ET). The clinical pregnancy rate was the highest when 3.0 Waves/min. Uterine Peristaltic Wave frequencies of the non-pregnant patient group were higher than that of the clinically-pregnant patient group in all types of transfer, fresh embryo transfer, natural FET or artificial FET cycle. Binary logistic regression analysis demonstrated that the association between uterine Peristaltic Wave frequency before embryo transfer and clinical pregnancy was independently significant (odds ratio: 0.49; 95% confidence interval: 0.34-0.70, P < 0.001). LIMITATIONS, REASONS FOR CAUTION Uterine peristalsis after embryo transfer was not observed in case any possible negative effect of the observation disturbed embryo implantation or caused psychological stress. Uterine peristalsis after embryo transfer may differ from that before embryo transfer. Another limitation of the present study was the lack of uterine Peristaltic Wave type analysis which is also an important parameter to assess uterine activity. WIDER IMPLICATIONS OF THE FINDINGS Patients with uterine peristalsis of <3.0 Waves/min before embryo transfer had a higher chance of pregnancy compared with those with higher frequencies. This could be a promising quantitative marker of uterine receptivity and pregnancy outcome in an embryo transfer cycle. The predictive validity of the cut-off value needs to be tested in further study. STUDY FUNDING/COMPETING INTEREST(S) The study is supported by Hunan Provincial Innovation Foundation for Postgraduates. The authors declare that they have no competing interests in this study.
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Uterine peristalsis before embryo transfer affects the chance of clinical pregnancy in fresh and frozen-thawed embryo transfer cycles
Human reproduction (Oxford England), 2014Co-Authors: Lin Zhu, H.s. Che, L. XiaoAbstract:STUDY QUESTION Does uterine peristalsis influence the chance of clinical pregnancy in an embryo transfer cycle? SUMMARY ANSWER The uterine Peristaltic Wave frequency before embryo transfer is inversely related to the clinical pregnancy rates in fresh and frozen-thawed embryo transfer cycles. WHAT IS KNOWN ALREADY Uterine peristalsis participates in regulating fluid migration after mock embryo transfer, but whether it could potentially influence pregnancy outcomes had remained unclear. STUDY DESIGN, SIZE, DURATION This prospective cohort study included a total of 292 infertile women and was conducted between March 2013 and August 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS Patients underwent fresh embryo transfer in a fresh stimulation cycle with a long down-regulation protocol, a natural frozen-thawed embryo transfer cycle or an artificial frozen-thawed embryo transfer cycle. Uterine Peristaltic activity was assessed before embryo transfer by transvaginal ultrasonography. MAIN RESULTS AND THE ROLE OF CHANCE The uterine Peristaltic Wave frequencies of most patients were between 1.1 and 3.0 Waves/min before embryo transfer (ET). The clinical pregnancy rate was the highest when 3.0 Waves/min. Uterine Peristaltic Wave frequencies of the non-pregnant patient group were higher than that of the clinically-pregnant patient group in all types of transfer, fresh embryo transfer, natural FET or artificial FET cycle. Binary logistic regression analysis demonstrated that the association between uterine Peristaltic Wave frequency before embryo transfer and clinical pregnancy was independently significant (odds ratio: 0.49; 95% confidence interval: 0.34-0.70, P < 0.001). LIMITATIONS, REASONS FOR CAUTION Uterine peristalsis after embryo transfer was not observed in case any possible negative effect of the observation disturbed embryo implantation or caused psychological stress. Uterine peristalsis after embryo transfer may differ from that before embryo transfer. Another limitation of the present study was the lack of uterine Peristaltic Wave type analysis which is also an important parameter to assess uterine activity. WIDER IMPLICATIONS OF THE FINDINGS Patients with uterine peristalsis of
Marzio Frazzoni - One of the best experts on this subject based on the ideXlab platform.
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Postreflux swallow-induced Peristaltic Wave index and nocturnal baseline impedance can link PPI-responsive heartburn to reflux better than acid exposure time.
Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society, 2017Co-Authors: Leonardo Frazzoni, Salvatore Tolone, Marzio Frazzoni, N. De Bortoli, M. Furnari, Irene Martinucci, Helga Bertani, Santino Marchi, Rita Conigliaro, Lorenzo FuccioAbstract:Background Acid exposure time (AET) is considered the most useful parameter to predict response of reflux-related heartburn to medical or surgical treatment. However, recent studies showed high rates of heartburn response to proton pump inhibitor (PPI) therapy in patients with normal AET. We aimed to compare the efficacy of postreflux swallow-induced Peristaltic Wave (PSPW) index and mean nocturnal baseline impedance (MNBI) with AET in linking PPI-responsive heartburn to reflux. Methods Off-therapy impedance-pH tracings from 425 patients, 317 with PPI-responsive and 108 with PPI-refractory heartburn were blindly re-analyzed. Demographic and endoscopic characteristics, conventional impedance-pH variables, PSPW index, and MNBI were assessed with multivariate logistic regression to identify factors independently associated with PPI responsiveness. Prediction models were developed to assess the strength of reflux linkage with factors independently associated with PPI responsiveness by calculating the area under the curve (AUC) at receiver-operating-characteristic (ROC) analysis. Key Results At multivariate logistic regression analysis, AET, MNBI, and PSPW index were the only factors independently associated with PPI responsiveness, abnormal values found in 60%, 76%, and 92% of PPI-responsive cases (P
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postreflux swallow induced Peristaltic Wave index and nocturnal baseline impedance can link ppi responsive heartburn to reflux better than acid exposure time
Neurogastroenterology and Motility, 2017Co-Authors: Leonardo Frazzoni, Salvatore Tolone, Marzio Frazzoni, N. De Bortoli, M. Furnari, Irene Martinucci, Helga Bertani, Santino Marchi, Rita Conigliaro, Lorenzo FuccioAbstract:Background Acid exposure time (AET) is considered the most useful parameter to predict response of reflux-related heartburn to medical or surgical treatment. However, recent studies showed high rates of heartburn response to proton pump inhibitor (PPI) therapy in patients with normal AET. We aimed to compare the efficacy of postreflux swallow-induced Peristaltic Wave (PSPW) index and mean nocturnal baseline impedance (MNBI) with AET in linking PPI-responsive heartburn to reflux. Methods Off-therapy impedance-pH tracings from 425 patients, 317 with PPI-responsive and 108 with PPI-refractory heartburn were blindly re-analyzed. Demographic and endoscopic characteristics, conventional impedance-pH variables, PSPW index, and MNBI were assessed with multivariate logistic regression to identify factors independently associated with PPI responsiveness. Prediction models were developed to assess the strength of reflux linkage with factors independently associated with PPI responsiveness by calculating the area under the curve (AUC) at receiver-operating-characteristic (ROC) analysis. Key Results At multivariate logistic regression analysis, AET, MNBI, and PSPW index were the only factors independently associated with PPI responsiveness, abnormal values found in 60%, 76%, and 92% of PPI-responsive cases (P<.017). At ROC analysis, PSPW index (AUC:.794, P=.002) and MNBI (AUC: 0.742, P=.003), both separately and combined (AUC: 0.811, P<.001) linked reflux with PPI-responsiveness better than AET (AUC: 0.687). Conclusions & Inferences AET, PSPW index, and MNBI are independently associated with PPI-responsive heartburn. PSPW index and MNBI can link PPI-responsive heartburn to reflux better than AET and should become part of the standard analysis of impedance-pH tracings.
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the added diagnostic value of postreflux swallow induced Peristaltic Wave index and nocturnal baseline impedance in refractory reflux disease studied with on therapy impedance ph monitoring
Neurogastroenterology and Motility, 2017Co-Authors: Marzio Frazzoni, Manuele Furnari, Salvatore Tolone, Leonardo Frazzoni, N. De Bortoli, Irene Martinucci, Santino Marchi, Vincenzo Giorgio Mirante, V. Savarino, Edoardo SavarinoAbstract:Background On-therapy impedance-pH monitoring in proton pump inhibitor (PPI)-refractory gastroesophageal reflux disease (GERD) yielded conflicting results. We aimed to assess the diagnostic value of postreflux swallow-induced Peristaltic Wave (PSPW) index and mean nocturnal baseline impedance (MNBI) in PPI-refractory heartburn. Methods On-therapy impedance-pH tracings from 189 consecutive patients with PPI-refractory heartburn were blindly reviewed. Patients were subdivided into refractory reflux esophagitis (RRE), healed reflux esophagitis (HRE), non-erosive reflux disease (NERD), and functional heartburn (FH) according to endoscopic and conventional impedance-pH findings. The diagnostic accuracy of PSPW index and MNBI in separating NERD from FH was assessed with receiver-operating-characteristic (ROC) analysis. Objectively documented persistent reflux remission at 3-year follow-up in 53 patients who underwent laparoscopic fundoplication served to evaluate PSPW index and MNBI as independent predictors of PPI-refractory GERD confirmed by positive surgical outcome. Key Results Median PSPW index and MNBI values were significantly lower in 39 RRE (16%; 1145 Ω) than in 41 HRE (25%; 1741 Ω) and in 68 NERD (29%; 2374 Ω) patients, and in all three GERD subgroups compared to 41 FH cases (67%; 3488 Ω) (P<.008). At ROC analysis, comparing NERD to FH the area under the curve was 0.886 with PSPW index and 0.677 with MNBI (P=.005). PSPW index was an independent predictor of PPI-refractory GERD (odds ratio 0.6983, P=.012). Conclusions & Inferences At on-therapy impedance-pH monitoring, PSPW index and MNBI efficiently distinguish PPI-refractory NERD from FH. The PSPW index represents an independent predictor of PPI-refractory GERD.
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The added diagnostic value of postreflux swallow‐induced Peristaltic Wave index and nocturnal baseline impedance in refractory reflux disease studied with on‐therapy impedance‐pH monitoring
Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society, 2016Co-Authors: Marzio Frazzoni, Manuele Furnari, Salvatore Tolone, Leonardo Frazzoni, N. De Bortoli, Irene Martinucci, Santino Marchi, Vincenzo Giorgio Mirante, V. Savarino, Edoardo SavarinoAbstract:Background On-therapy impedance-pH monitoring in proton pump inhibitor (PPI)-refractory gastroesophageal reflux disease (GERD) yielded conflicting results. We aimed to assess the diagnostic value of postreflux swallow-induced Peristaltic Wave (PSPW) index and mean nocturnal baseline impedance (MNBI) in PPI-refractory heartburn. Methods On-therapy impedance-pH tracings from 189 consecutive patients with PPI-refractory heartburn were blindly reviewed. Patients were subdivided into refractory reflux esophagitis (RRE), healed reflux esophagitis (HRE), non-erosive reflux disease (NERD), and functional heartburn (FH) according to endoscopic and conventional impedance-pH findings. The diagnostic accuracy of PSPW index and MNBI in separating NERD from FH was assessed with receiver-operating-characteristic (ROC) analysis. Objectively documented persistent reflux remission at 3-year follow-up in 53 patients who underwent laparoscopic fundoplication served to evaluate PSPW index and MNBI as independent predictors of PPI-refractory GERD confirmed by positive surgical outcome. Key Results Median PSPW index and MNBI values were significantly lower in 39 RRE (16%; 1145 Ω) than in 41 HRE (25%; 1741 Ω) and in 68 NERD (29%; 2374 Ω) patients, and in all three GERD subgroups compared to 41 FH cases (67%; 3488 Ω) (P
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analyses of the post reflux swallow induced Peristaltic Wave index and nocturnal baseline impedance parameters increase the diagnostic yield of impedance ph monitoring of patients with reflux disease
Clinical Gastroenterology and Hepatology, 2016Co-Authors: Marzio Frazzoni, Manuele Furnari, Nicola De Bortoli, Edoardo Savarino, Leonardo Frazzoni, Irene Martinucci, Helga Bertani, Santino Marchi, Vincenzo Giorgio Mirante, Rita ConigliaroAbstract:Background & Aims Analyses of impedance parameters such as the post-reflux swallow-induced Peristaltic Wave (PSPW) index and the mean nocturnal baseline impedance (MNBI) have been proposed to increase the accuracy of diagnosis of reflux disease. We assessed whether these improve the diagnostic yield of impedance pH monitoring of reflux disease. Methods We performed a prospective study of consecutive patients with proton pump inhibitor–responsive heartburn who underwent 24-hour impedance pH monitoring at hospitals in Italy from January 2011 through December 2013. Reviewers blindly analyzed off-therapy impedance pH tracings from 289 patients with proton pump inhibitor–responsive heartburn, 68 with erosive reflux disease and 221 with non-erosive reflux disease (NERD), along with 50 healthy individuals (controls). The PSPW index, the MNBI, the esophageal acid exposure time, the number of total refluxes, and the bolus exposure were calculated, as well as the symptom association probability (SAP) and the symptom index (SI). Results In receiver operating characteristic analysis, the area under curve of the PSPW index (0.977; 95% confidence interval, 0.961−0.993) was significantly greater than that of the other impedance pH parameters in identifying patients with reflux disease ( P P = .001). Conclusions The PSPW index and the MNBI increase the diagnostic yield of impedance pH monitoring of patients with reflux disease. Analysis of impedance pH data by calculating the PSPW index and the MNBI can increase the accuracy of diagnosis of patients with reflux disease, compared with pH-only data.
S Srinivas - One of the best experts on this subject based on the ideXlab platform.
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effects of chemical reaction and space porosity on mhd mixed convective flow in a vertical asymmetric channel with peristalsis
Mathematical and Computer Modelling, 2011Co-Authors: S Srinivas, R MuthurajAbstract:This work is aimed at describing MHD mixed convective heat and mass transfer Peristaltic flow through a vertical porous space in the presence of a chemical reaction. The flow is examined in a Wave frame of reference moving with the velocity of the Wave. The channel asymmetry is produced by choosing the Peristaltic Wave train on the walls to have different amplitude and phase. The momentum, energy and concentration equation have been linearized under long-Wavelength approximation. Expressions for dimensionless stream function, temperature and concentration field are constructed. The features of the fluid flow, heat and mass transfer characteristics are analyzed by plotting graphs and discussed in detail.
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mixed convective heat and mass transfer in an asymmetric channel with peristalsis
Communications in Nonlinear Science and Numerical Simulation, 2011Co-Authors: S Srinivas, R Gayathri, M KothandapaniAbstract:Abstract This paper describes the fluid mechanics effects of mixed convective heat and mass transfer in an asymmetric channel with peristalsis. The flow is examined in a Wave frame of reference moving with the velocity of the Wave. The channel asymmetry is produced by choosing the Peristaltic Wave train on the walls to have different amplitudes and phase. The momentum, energy and concentration equations have been linearized under long Wavelength approximation. The analytical solutions for temperature, concentration, velocity and stream function are obtained. The effects of various parameters such as local temperature Grashof number, local mass Grashof number and geometrical parameters on flow variables have been discussed numerically and explained graphically.
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Peristaltic transport of a newtonian fluid in a vertical asymmetric channel with heat transfer and porous medium
Applied Mathematics and Computation, 2009Co-Authors: S Srinivas, R GayathriAbstract:The problem of Peristaltic flow of a Newtonian fluid with heat transfer in a vertical asymmetric channel through porous medium is studied under long-Wavelength and low-Reynolds number assumptions. The flow is examined in a Wave frame of reference moving with the velocity of the Wave. The channel asymmetry is produced by choosing the Peristaltic Wave train on the walls to have different amplitudes and phase. The analytical solution has been obtained in the form of temperature from which an axial velocity, stream function and pressure gradient have been derived. The effects of permeability parameter, Grashof number, heat source/sink parameter, phase difference, varying channel width and Wave amplitudes on the pressure gradient, velocity, pressure drop, the phenomenon of trapping and shear stress are discussed numerically and explained graphically.
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Peristaltic transport of a jeffrey fluid under the effect of magnetic field in an asymmetric channel
International Journal of Non-linear Mechanics, 2008Co-Authors: M Kothandapani, S SrinivasAbstract:Abstract The Peristaltic flow of a Jeffrey fluid in an asymmetric channel is studied under long Wavelength and low Reynolds number assumptions. The fluid is electrically conducting by a transverse magnetic field. The channel asymmetry is produced by choosing the Peristaltic Wave train on the walls to have different amplitudes and phase. The flow is investigated in a Wave frame of reference moving with the velocity of the Wave. The expressions for stream function, axial velocity and axial pressure gradient have been obtained. The effects of various emerging parameters on the flow characteristics are shown and discussed with the help of graphs. The pumping characteristics, axial pressure gradient and trapping phenomenon have been studied. Comparison of various Wave forms (namely sinusoidal, triangular, square and trapezoidal) on the flow is discussed.
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non linear Peristaltic transport in an inclined asymmetric channel
Communications in Nonlinear Science and Numerical Simulation, 2008Co-Authors: S Srinivas, V PushparajAbstract:Abstract The problem of Peristaltic transport of a hydromagnetic (electrically conducting) viscous incompressible fluid in an inclined planar channel having electrically insulated walls has been investigated under long-Wavelength and low-Reynolds number assumptions. The channel asymmetry is produced by choosing the Peristaltic Wave train on the walls to have different amplitudes and phase. The flow is investigated in a Wave frame of reference moving with the velocity of the Wave. Expressions for velocity field, shear stress and pressure gradient on the wall are obtained. The effects of different parameters entering into the problem are discussed numerically and explained graphically.
Manuele Furnari - One of the best experts on this subject based on the ideXlab platform.
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the added diagnostic value of postreflux swallow induced Peristaltic Wave index and nocturnal baseline impedance in refractory reflux disease studied with on therapy impedance ph monitoring
Neurogastroenterology and Motility, 2017Co-Authors: Marzio Frazzoni, Manuele Furnari, Salvatore Tolone, Leonardo Frazzoni, N. De Bortoli, Irene Martinucci, Santino Marchi, Vincenzo Giorgio Mirante, V. Savarino, Edoardo SavarinoAbstract:Background On-therapy impedance-pH monitoring in proton pump inhibitor (PPI)-refractory gastroesophageal reflux disease (GERD) yielded conflicting results. We aimed to assess the diagnostic value of postreflux swallow-induced Peristaltic Wave (PSPW) index and mean nocturnal baseline impedance (MNBI) in PPI-refractory heartburn. Methods On-therapy impedance-pH tracings from 189 consecutive patients with PPI-refractory heartburn were blindly reviewed. Patients were subdivided into refractory reflux esophagitis (RRE), healed reflux esophagitis (HRE), non-erosive reflux disease (NERD), and functional heartburn (FH) according to endoscopic and conventional impedance-pH findings. The diagnostic accuracy of PSPW index and MNBI in separating NERD from FH was assessed with receiver-operating-characteristic (ROC) analysis. Objectively documented persistent reflux remission at 3-year follow-up in 53 patients who underwent laparoscopic fundoplication served to evaluate PSPW index and MNBI as independent predictors of PPI-refractory GERD confirmed by positive surgical outcome. Key Results Median PSPW index and MNBI values were significantly lower in 39 RRE (16%; 1145 Ω) than in 41 HRE (25%; 1741 Ω) and in 68 NERD (29%; 2374 Ω) patients, and in all three GERD subgroups compared to 41 FH cases (67%; 3488 Ω) (P<.008). At ROC analysis, comparing NERD to FH the area under the curve was 0.886 with PSPW index and 0.677 with MNBI (P=.005). PSPW index was an independent predictor of PPI-refractory GERD (odds ratio 0.6983, P=.012). Conclusions & Inferences At on-therapy impedance-pH monitoring, PSPW index and MNBI efficiently distinguish PPI-refractory NERD from FH. The PSPW index represents an independent predictor of PPI-refractory GERD.
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The added diagnostic value of postreflux swallow‐induced Peristaltic Wave index and nocturnal baseline impedance in refractory reflux disease studied with on‐therapy impedance‐pH monitoring
Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society, 2016Co-Authors: Marzio Frazzoni, Manuele Furnari, Salvatore Tolone, Leonardo Frazzoni, N. De Bortoli, Irene Martinucci, Santino Marchi, Vincenzo Giorgio Mirante, V. Savarino, Edoardo SavarinoAbstract:Background On-therapy impedance-pH monitoring in proton pump inhibitor (PPI)-refractory gastroesophageal reflux disease (GERD) yielded conflicting results. We aimed to assess the diagnostic value of postreflux swallow-induced Peristaltic Wave (PSPW) index and mean nocturnal baseline impedance (MNBI) in PPI-refractory heartburn. Methods On-therapy impedance-pH tracings from 189 consecutive patients with PPI-refractory heartburn were blindly reviewed. Patients were subdivided into refractory reflux esophagitis (RRE), healed reflux esophagitis (HRE), non-erosive reflux disease (NERD), and functional heartburn (FH) according to endoscopic and conventional impedance-pH findings. The diagnostic accuracy of PSPW index and MNBI in separating NERD from FH was assessed with receiver-operating-characteristic (ROC) analysis. Objectively documented persistent reflux remission at 3-year follow-up in 53 patients who underwent laparoscopic fundoplication served to evaluate PSPW index and MNBI as independent predictors of PPI-refractory GERD confirmed by positive surgical outcome. Key Results Median PSPW index and MNBI values were significantly lower in 39 RRE (16%; 1145 Ω) than in 41 HRE (25%; 1741 Ω) and in 68 NERD (29%; 2374 Ω) patients, and in all three GERD subgroups compared to 41 FH cases (67%; 3488 Ω) (P
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Microscopic Esophagitis, Baseline Impedance and Post-Reflux Swallow-Induced Peristaltic Wave in Functional Heartburn: Useful Diagnostic Tools.
The American journal of gastroenterology, 2016Co-Authors: Manuele Furnari, Salvatore Tolone, Nicola De BortoliAbstract:Microscopic Esophagitis, Baseline Impedance and Post-Reflux Swallow-Induced Peristaltic Wave in Functional Heartburn: Useful Diagnostic Tools
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analyses of the post reflux swallow induced Peristaltic Wave index and nocturnal baseline impedance parameters increase the diagnostic yield of impedance ph monitoring of patients with reflux disease
Clinical Gastroenterology and Hepatology, 2016Co-Authors: Marzio Frazzoni, Manuele Furnari, Nicola De Bortoli, Edoardo Savarino, Leonardo Frazzoni, Irene Martinucci, Helga Bertani, Santino Marchi, Vincenzo Giorgio Mirante, Rita ConigliaroAbstract:Background & Aims Analyses of impedance parameters such as the post-reflux swallow-induced Peristaltic Wave (PSPW) index and the mean nocturnal baseline impedance (MNBI) have been proposed to increase the accuracy of diagnosis of reflux disease. We assessed whether these improve the diagnostic yield of impedance pH monitoring of reflux disease. Methods We performed a prospective study of consecutive patients with proton pump inhibitor–responsive heartburn who underwent 24-hour impedance pH monitoring at hospitals in Italy from January 2011 through December 2013. Reviewers blindly analyzed off-therapy impedance pH tracings from 289 patients with proton pump inhibitor–responsive heartburn, 68 with erosive reflux disease and 221 with non-erosive reflux disease (NERD), along with 50 healthy individuals (controls). The PSPW index, the MNBI, the esophageal acid exposure time, the number of total refluxes, and the bolus exposure were calculated, as well as the symptom association probability (SAP) and the symptom index (SI). Results In receiver operating characteristic analysis, the area under curve of the PSPW index (0.977; 95% confidence interval, 0.961−0.993) was significantly greater than that of the other impedance pH parameters in identifying patients with reflux disease ( P P = .001). Conclusions The PSPW index and the MNBI increase the diagnostic yield of impedance pH monitoring of patients with reflux disease. Analysis of impedance pH data by calculating the PSPW index and the MNBI can increase the accuracy of diagnosis of patients with reflux disease, compared with pH-only data.