Esmolol response in septic shock patients in relation to vascular waterfall phenomenon measured by critical closure pressure and mean systemic filling pressure: a prospective observational study

Background Bedside measurements of critical closure pressure (Pcc) and mean systemic circulation filling pressure (Pmsf) were utilized to evaluate the response to esmolol in septic shock patients, in relation to the vascular waterfall phenomenon and body oxygen supply and demand. Methods This prospective observational self-controlled study included patients with septic shock, newly admitted to the intensive care unit, between August 2019 and January 2021. Pcc and Pmsf, along with the heart rate and other hemodynamic indicators were observed and compared before and 1 h after esmolol IV infusion. Results After 24 h of initial hemodynamic optimization, 56 patients were finally enrolled. After start of esmolol infusion, patients had a significant decrease in cardiac index (CI) (4.0 vs. 3.3 L/min/m2, P < 0.001), a significant increase in stroke index (SI) (34.1 vs. 36.6 mL/m2, P < 0.01), and a significant decrease in heart rate (HR) (116.8 vs. 90.6 beats/min, P < 0.001). After 1 h of treatment with esmolol, patients had a significant increase in Pcc (31.4 vs. 36.7 mmHg, P < 0.01). The difference between Pcc and Pmsf before and after treatment was statistically different (4.0 vs. 10.0 mmHg, P < 0.01). After heart rate control with esmolol, the patients had a significant increase in the body circulation vascular resistance indices (RIs) (15.14 vs. 18.25 mmHg/min/m2/L, P < 0.001). There was an increase in ScvO2 in patients after treatment with esmolol, but the difference was not statistically significant (68.4% vs. 69.8%, P > 0.05), while Pcv-aCO2 was significantly lower (6.3 vs. 4.9 mmHg, P < 0.001) and patients had a significant decrease in blood lactate levels (4.0 vs. 3.6 mmol/L, P < 0.05). Conclusion Patients with septic shock whose heart rate is greater than 95 beats/min after hemodynamic optimization were treated with esmolol, which could effectively control heart rate and reduce CI, as well as improve Pcc and increase the difference between Pcc and Pmsf (known as “vascular waterfall” phenomenon), without affecting MAP, CVP, Pmsf and arteriovenous vascular resistance, and improve the balance of oxygen supply and demand in the body.

Аrterial stiffness and diastolic function of the left ventricle in patients with arterial hypertension and frailty

Introduction. Increased arterial stiffness is one of the key links in the formation of cardiovascular pathology in older age groups. At the same time, the effect of vascular stiffness on myocardial function in cardiac patients with frailty remains insufficiently studied.Aim of study. Тo analyze the data of arterial stiffness and diastolic function of left ventricle (LV) in patients older than 65 years with arterial hypertension and frailty.Materials and methods. The study included 90 outpatient and inpatient patients older than 65 years with the presence of arterial hypertension. All patients were divided into two groups: with the presence and absence of frailty. To identify frailty, we used the questionnaire “Age is not a hindrance”, a short battery of physical activity tests. Methods of volumetric sphygmometry, echocardiography, including tissue Doppler were used. The obtained data were analyzed using a package of statistical programs.Results. The results of a comparative simultaneous non-randomized descriptive study of two groups of patients are presented. The study found that the systolic function, diastolic dysfunction of the left ventricle by the type of slowing down of LV relaxation in both groups did not significantly differ in their indicators. In the group of patients with frailty, LV diastolic dysfunction was significantly more often detected by the type of pseudonormalization – with an increase in filling pressure. When analyzing data of arterial stiffness, differences were obtained in both groups in the left cardio-ankle vascular index (LCAVI), systolic blood pressure (LB SAD), pulse pressure (LB PD) in the left shoulder area, and the delta of average blood pressure in the left ankle area (LA% IDA), which were significantly higher in patients with frailty.Conclusion. In the group of patients with hypertension older than 65 years with frailty, a violation of the LV diastolic function by the type of pseudonormalization with an increase in filling pressure prevails. An increase in filling pressure in the group of patients older than 65 years with hypertension and the presence of frailty is associated with an increase in the complex of indicators characterizing arterial stiffness – the cardio-ankle vascular index, systolic blood pressure, pulse pressure in the left shoulder area, the delta of average blood pressure in the left ankle area.

Comparison between the British and the American/European guidelines for the assessment of left ventricular diastolic function with invasive validation of left ventricular filling pressure

Background Left ventricle diastolic function and filling pressures assessment is still a major challenge to echocardiographer. There are two echo guidelines regarding this issue: the British Society of Echocardiography (BSE 2013) and the American Society of Echocardiography/European Association of Cardiovascular Imaging (ASE/EACVI 2016). The 2016 guidelines, which is an expert consensus and simplified update of 2009 guidelines, needs an invasive validation according to its authors. Recent studies raised questions about the diagnostic accuracy as sensitivity results varied very widely (34% to 87%) and also that of 2009 (43% to 79%). This study validated the diastolic pressure invasively in the cath lab and compared the results with the echo guidline algorithms were done immediately before the catheterization. When possible, it included additional assessment of S/D and Ar-A duration. Purpose Validation of the diagnostic accuracy of the 2009, the updated 2016 ASE/EACVI and 2013 BSE echocardiographic LV filling pressure predicting algorithms, as well as pulmonary veins flow (S/D) and (Ar-A) durations with invasively measured LV-pre-A wave. Methods 124 patients (58.06% males) underwent transthoracic echocardiography immediately before left heart catheterization. A trained echocardiographer obtained E/A mitral flow, E/e', left atrial volume index, TR, EDT, lateral and septal e' to estimate LV filling pressure as normal, elevated or indeterminate using the 2009, 2016 ASE/EACVI algorithms and 2013 BSE algorithm. He also obtained Secondary parameters as (S/D) and (Ar-A) duration. Invasive LV pre-A pressure was the reference of this study, with &gt;12 mm Hg defined as elevated. Results Invasive LV pre-A pressure was elevated in 60 (48.38%) patients. When they could determine LV filling pressure, 2016 sensitivity was 0.36 and specificity 0.94, 2009 had 0.56 sensitivity and 0.90 specificity and 2013 resulted in 0.63 sensitivity and 0.80 specificity. Results of diagnostic accuracy of each algorithm as well as (S/D) and (Ar-A) summarized in tables associated in (picture 1: Tables of results). EDT≥150 msec raised NPV in normal, grade one diastolic dysfunction and indeterminate pressure. Conclusion 2016 was the most specific but the least sensitive with modest NPV and PPV between the 2013 and 2009. 2013 was the most sensitive with the highest indeterminate pressure rate to execlude. Adding S/D or Ar-A duration markedly improved the sensitivity and reduced class indeterminate among all algorithms with more benefit when both combined. EDT had a rule out role in normal, grade one diastolic dysfunction and indeterminate pressure patients. We kindly propose a modification of 2016 algorithm by adding S/D, Ar-A and EDT as optional parameters to increase sensitivity and reduce indeterminate class without affecting simplicity or specificity (picture 2: Proposed algorithms A+B). We recommend future studies to validate the diagnostic accuracy of the proposed algorithms. FUNDunding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Al mouwasat University Hospital and University Heart Surgery Center at Damascus, Syrian Arab Republic. Tables of results Proposed Algorithms A+B

Numerical Study on Flow and Release Characteristics of Gas Extinguishing Agent under Different Filling Pressure and Amount Conditions

The fire-extinguishing system is an indispensable fire-protection facility on the aircraft. In order to guide weight reduction of the aircraft’s fixed gas fire-extinguishing system by improving its release efficiency, so as to improve fuel economy and reduce carbon emissions, the influence of filling pressures and filling amounts on the release efficiency of gas extinguishing agent along pipelines were studied based on numerical simulations. The release process of the fire-extinguishing system was analyzed. The effects of the filling pressure and filling amount of Halon 1301 agent on the release characteristics, such as release time, mass flow rate, and gasification ratio, were studied. Results show that the release process can be divided into three major phases, which are firstly the initial rapid filling of the pipeline, secondly the concentrated release of the liquid extinguishing agent, and thirdly the gas ejection along the pipeline. The second phase can also be subdivided into two stages: the outflow of the liquid extinguishing agent from the bottle, and the release of the residual liquid extinguishing agent along the pipeline. The release characteristics of the fire-extinguishing agent were obviously affected by the filling pressures and filling amounts. When the filling pressure was relatively low (2.832 MPa), increasing the filling pressure can significantly increase the mass flow rate, shorten the release time, and reduce the gasification ratio of the extinguishing agent during the release processes. Under the same filling pressure, with the increase of the filling amount of the extinguishing agent, the release times and the gasification ratio showed a linear increase trend, while the average mass flow rates showed a linear decrease trend.