scholarly journals Accuracy of Current Non-invasive Methods in Estimating Aortic Coarctation Gradients

2020 ◽  
pp. 47-57
Author(s):  
Wejdan Khaled Ba- Atiyah ◽  
Riad Abou Zahr ◽  
Zaheer Ahmad ◽  
Yahia Mohamed El Mahdi ◽  
Mohammed Omar Galal
Keyword(s):  
Blood Pressure ◽  
Retrospective Study ◽  
Pressure Gradient ◽  
Cardiac Catheterization ◽  
Doppler Echocardiography ◽  
Aortic Coarctation ◽  
Cuff Pressure ◽  
Pressure Gradients ◽  
Significant Difference ◽  
Cardiac Catheterizations

Aims: To understand the accuracy of non-invasively obtained blood pressure gradients (cuff vs Doppler gradient) with an invasively measured pressure gradient. Study Design:  Retrospective study. Place and Duration of Study: Department of Pediatrics, Section of Pediatric Cardiology, King Faisal Specialist Hospital & Research Center, Jeddah, Saudi Arabia, between Jan, 2010 till Jan, 2020. Methodology: A retrospective study of patients with CoA who underwent cardiac catheterization between Jan, 2010 till Jan, 2020 was performed. Cuff BP gradients and Doppler echocardiography were measured prior to cardiac catheterization and afterwards, when an intervention was performed. Student t test and Bland-Altman analysis were performed. Results: 55 patients with aortic coarctation underwent 92 cardiac catheterizations. Among them 75 needed interventions. This resulted in a total of 162 cardiac catheterizations (cath), from them 67 pressure gradients included in the analysis. There was no statistically significant difference between mean Doppler measurements and invasively derived catheter gradients (p=0.12). In contrast peak Doppler measurement (p < 0.00001) and cuff blood pressure gradients (p=0.03) showed significant differences to the cath gradient. We found that cuff blood pressure gradients accurately reflected cath measurement in native COA (p=0.40) and in those who weigh less than 10 kg (p=0.67). Mean Doppler measurements had a small tendency for underestimation. Peak Doppler gradient and cuff pressure gradient usually overestimated cath measurement.  Conclusion: The mean Doppler echocardiography seems to be the most accurate among the other noninvasive methods in use to estimate severity of aortic coarctation. It provided reasonable agreement with the invasively obtained aortic coarctation gradient. 

An Analytical Model of the Instantaneous Transvalvular Pressure Gradient Through an Aortic Stenosis

2010 ◽  
Author(s):  
Zahra Keshavarz-Motamed ◽  
Nima Maftoon ◽  
Lyes Kadem
Keyword(s):  
Experimental Data ◽  
Aortic Stenosis ◽  
Pressure Gradient ◽  
Cardiac Catheterization ◽  
Doppler Echocardiography ◽  
Pressure Difference ◽  
Accurate Determination ◽  
Before And After ◽  
Analytical Result

Diagnosis and treatment of aortic stenosis largely depends on accurate determination of the pressure difference before and after the valve, known as transvalvular pressure gradient (TPG). Clinically, TPG is obtained using Doppler echocardiography though sometimes invasive cardiac catheterization has to be used to confirm Doppler echocardiography findings. By solving analytically coupled fluid and solid domain equations, we suggest a formulation that with a good degree of accuracy can be used to calculate TPG. Analytical result is validated using experimental data from literature. The suggested methodology is an alternative to cardiac catheterization and helps to prevent its risks.

scholarly journals The study of oropharyngeal pack soaked in lignocaine with dexamethasone in patients undergoing nasal surgeries

2020 ◽  
Vol 8 (1) ◽  
pp. 22
Author(s):  
Mahendra Agrawal ◽  
Pushpal Gandhi ◽  
Bhavika Agrawal ◽  
Simarn Behl
Keyword(s):  
Blood Pressure ◽  
Retrospective Study ◽  
Systolic Blood Pressure ◽  
Sore Throat ◽  
Pressure Pulse ◽  
Postoperative Sore Throat ◽  
Significant Difference ◽  
Group A ◽  
American Society ◽  
American Society Of Anesthesiologists

Background: The aim of this study determines the efficacy of lignocaine lignocaine with dexamethasone used topically in form of oropharyngeal pack in reducing postoperative sore throat (POST), hoarseness and throat irritation.  Methods: This retrospective study total of 70 adult patients included in the lignocaine and dexamethasone (LD) group. LD group patients received combination of 5 ml lignocaine 2% and 2 ml (8 mg) dexamethasone in oropharyngeal packing.Results: There is no significant difference in age, gender, and American society of anesthesiologists (ASA) grade I and II. There was no significant difference the studied group in term of measured hemodynamic indices Systolic blood pressure, diastolic blood pressure, pulse rate, and respiratory rate. Post extubation incidence of mild sore throat was occurred in patients 11 (31.4%) at 30 min, 13 (37.1%) at 2 hours, 6 (17.1%) at 6 hours, and 5 (14.2%) at 5 (14.2%). Moderate sore throat and severe sore throat was not present. Hoarseness of voice was present only 4 (11.4%) at 30 min. There was significant deference in throat irritation. A decrease in incidence of hoarseness was also seen in group LD.  Conclusions: In LD group a positive benefit is seen in form of reduction of POST, hoarseness and throat irritation helping in better recovery of patients.

First Year Experience Of Subcutaneous Bortezomib Use In a University Teaching Hospital

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 5610-5610
Author(s):  
Jean-Philippe Adam ◽  
Emilie Lemieux-Blanchard ◽  
Bernard Lemieux ◽  
Nathalie Letarte
Keyword(s):  
Blood Pressure ◽  
Retrospective Study ◽  
Complete Blood Count ◽  
University Teaching ◽  
First Year Experience ◽  
Hematologic Toxicity ◽  
Skin Reactions ◽  
Cutaneous Toxicity ◽  
Significant Difference ◽  
Before And After

Abstract Introduction Subcutaneous (SC) injection of bortezomib was reported to be safe and effective in myeloma patients. In September 2012, we standardised all bortezomib containing-protocols at our centre and changed the route of administration form intravenous (IV) to subcutaneous. This way of administration is more convenient for patients and staff and is reported to decrease the rate of peripheral neuropathies. Objectives This retrospective study aimed to describe the safety of this new administration technique, specifically regarding change in blood pressure and hematologic toxicity. Blood pressure (BP) was measured before and after each SC injection to evaluate the risk of hypotension, an adverse reaction frequently reported with IV bortezomib administration. Secondly, we wanted to analyse the rate of neutropenia and thrombocytopenia during the treatment to see if a complete blood count (CBC) is needed before every injection, versus only once weekly. Other adverse events were also collected. Methods This retrospective study included all patients who received bortezomib for multiple myeloma or amyloidosis at the Centre hospitalier de l'Université de Montréal (CHUM) between June 1, 2012 and May 31, 2013. Date was collected through medical and pharmaceutical patient records. Our local ethics board approved this study. Results A total of 45 patients received bortezomib for MM or amyloidosis with a median age of 68 years (SD ± 9.3) and 53.3 % were male. Patients received bortezomib in various protocols including Vel-Dex (42.2%), VMP (44.4%) and CyBorD (13.3%). The median starting dose of bortezomib was 1.3 mg/m2 (SD ± 0.13).  Patients received  SC only bortezomib injections (71.1%) or IV only (15.6%)  or were switched from IV to SC (13.3%) for a total of 157 cycles (786 doses). A total of 444 BP values before and 425 BP values after SC bortezomib were analysed. No significant difference was detected between the average systolic BP (125 vs 125; p=0.76), diastolic BP (70 vs 71; p=0.77) or heart rate (79 vs 78; p=0.89) between the 2 measurements. Hypotension, defined as a drop of 20 mmHg of systolic BP, occurred 18 times (4.2%) but systolic BP was never below 90 mmHg. One patient had a severe dysautomia, possibly related to bortezomib that required the discontinuation of the treatment. At our center, CBC are performed prior to each bortezomib dose. Neutropenia occurred in 10 % of the total doses received. Risk factors influencing neutropenia were the use of oral alkylating agent (melphalan and cyclophosphamide) in the regimen and baseline neutrophil count less than 2.0 x 109. Many patients also received bortezomib for a relapsed / refractory disease and were previously exposed to many lines of therapy. Thrombocytopenia occurred in 7,2% of doses received. Cutaneous toxicity occurred mostly with the first patients treated with the SC technique. With time, nursing changed their technique and further skin reactions were less reported. Neuropathy occurred in 21 patients (13 SC, 4 IV, 4 IV to SC), caused dose reductions in 7 patients (2 SC, 2 IV, 3 IV to SC) and treatment discontinuation in 2 patients (SC). Conclusion Our results demonstrate SC bortezomib was well tolerated. The rates of hypotension was quite low. Also rates and intensity of neutropenia and thrombocytopenia varied among different bortezomib containing regimens. Because of the low rate of profound neutropenia, Vel-Dex and VMP protocols can be modified to decrease the number of CBC to once weekly during the cycle rather than before every injection. More data are needed with CyBorD protocol before drawing any conclusions. Disclosures: Adam: Jansen Ortho: Honoraria. Lemieux-Blanchard:Celgene: Honoraria. Lemieux:Jansen Ortho: Honoraria.

Phantom Aortic Valve Pressure Gradient: Discrepancies Between Cardiac Catheterization and Doppler Echocardiography

2005 ◽  
Vol 100 (5) ◽  
pp. 1259-1262 ◽  
Author(s):  
Wanda M. Popescu ◽  
Edward Prokop ◽  
John A. Elefteriades ◽  
Kevin Kett ◽  
Paul G. Barash
Keyword(s):  
Aortic Valve ◽  
Pressure Gradient ◽  
Cardiac Catheterization ◽  
Doppler Echocardiography ◽  
Valve Pressure

scholarly journals Influence of pressure gradients on wall pressure beneath a turbulent boundary layer

2018 ◽  
Vol 838 ◽  
pp. 715-758 ◽  
Author(s):  
Elie Cohen ◽  
Xavier Gloerfelt
Keyword(s):  
Pressure Gradient ◽  
Boundary Layers ◽  
Stokes Equations ◽  
Scaling Law ◽  
Pressure Fluctuations ◽  
Turbulent Boundary Layers ◽  
Wall Pressure ◽  
Pressure Gradients ◽  
Wall Pressure Fluctuations ◽  
Significant Difference

This study investigates the effects of a pressure gradient on the wall pressure beneath equilibrium turbulent boundary layers. Excitation of the walls of a vehicle by turbulent boundary layers indeed constitutes a major source of interior noise and it is necessary to take into account the presence of a pressure gradient to represent the effect of the curvature of the walls. With this aim, large-eddy simulations of turbulent boundary layers in the presence of both mild adverse and mild favourable pressure gradients are carried out by solving the compressible Navier–Stokes equations. This method provides both the aeroacoustic contribution and the hydrodynamic wall-pressure fluctuations. A critical comparison with existing databases, including recent measurements, is conducted to assess the influence of a free stream pressure gradient. The analyses of wall-pressure spectral densities show an increase in the low-frequency content from adverse to favourable conditions, yielding higher integrated levels of pressure fluctuations scaled by the wall shear stress. This is accompanied by a steeper decay rate in the medium-frequency portion for adverse pressure gradients. No significant difference is found for the mean convection velocity. Frequency–wavenumber spectra including the subconvective region are presented for the first time in the presence of a pressure gradient. A scaling law for the convective ridge is proposed, and the acoustic domain is captured by the simulations. Direct acoustic emissions have similar features in all gradient cases, even if slightly higher levels are noted for boundary layers subjected to an adverse gradient.

Evaluation of Peak Pressure Gradients in Patients after Melody Valve Implantation: A Comparison of Cardiac Catheterization and Doppler Echocardiography

2014 ◽  
Vol 32 (7) ◽  
pp. 1073-1079 ◽  
Author(s):  
Brenton S. Bauer ◽  
Sybil Zachariah ◽  
Daniel Levi ◽  
Abraham Rothman ◽  
Alvaro Galindo ◽  
...  
Keyword(s):  
Cardiac Catheterization ◽  
Doppler Echocardiography ◽  
Peak Pressure ◽  
Pressure Gradients ◽  
Melody Valve ◽  
Valve Implantation

Pressure Drop During Condensation in Microchannels

2012 ◽  
Author(s):  
H. S. Wang ◽  
J. W. Rose
Keyword(s):  
Pressure Drop ◽  
Pressure Gradient ◽  
Void Fraction ◽  
Annular Flow ◽  
Pressure Gradients ◽  
Flow Solution ◽  
Approximate Models ◽  
Significant Difference ◽  
Friction Pressure ◽  
Flow Pressure

The paper examines the special case of annular laminar flow pressure drop, or more precisely pressure gradient, during condensation in microchannels. This is the only flow regime permitting wholly theoretical solution without having recourse to experimental data. Solutions are obtained and comparisons made with empirical formulae for void fraction (needed to calculate the momentum pressure gradient) when obtaining the friction pressure gradient from experimentally measured or “total” pressure gradient. To date calculations and comparisons are restricted to one fluid (R134a), one channel section and one flow condition. For the case considered it is found that earlier approximate models for estimating void fraction agree quite well with the theoretical annular flow solutions. There is, however, significant difference between momentum pressure gradients obtained from approximate models used in the earlier investigations and that given by the theoretical annular flow solution which is (numerically) higher than all of them. The annular flow solution indicates that the momentum pressure gradient is not small in comparison with the friction pressure gradient. The friction pressure gradient in the annular flow case is appreciably smaller than given by the earlier correlations.

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