scholarly journals Non-Invasive Estimation of Cardiac Index in Healthy Volunteers

2018 ◽  
Vol 46 (3) ◽  
pp. 290-296 ◽  
Author(s):  
C. T. Eyeington ◽  
P. Ancona ◽  
L. Cioccari ◽  
N. Luethi ◽  
N. J. Glassford ◽  
...  

The primary objective was to non-invasively measure the cardiac index (CI) and associated haemodynamic parameters of healthy volunteers and their changes with age. This was a single centre, prospective, observational study of healthy volunteers aged between 20 and 59 years, using the ClearSight™ (Edwards Life Sciences, Irvine, CA, USA) device. We recorded 514 observations in 97 participants. The mean CI was 3.5 l/min/m2 (95% confidence interval [95% CI] 3.4 to 3.7 l/min/m2). The mean stroke volume index (SVI) was 47 ml/m2 (95% CI 45 to 49 ml/m2) and the mean systemic vascular resistance index was 2,242 dyne·s/cm5/m2 (95% CI 2,124 to 2,365 dyne·s/cm5/m2). There was an inverse linear relationship between increasing age and CI (P <0.0001), which decreased by 0.044 l/min/m2 (95% CI −0.032 to −0.056 l/min/m2) per year. This change was mostly due to a decrease in SVI of 0.45 ml/m2 (95% CI 0.32 to 0.57 ml/m2) per year (P <0.0001). The mean CI of young healthy humans is approximately 3.5 l/min/m2 and declines by approximately 40 ml/min/m2 per year, mostly due to a decline in stroke volume (SV). These findings have significant implications regarding the clinical interpretation of haemodynamic parameters and the application of these results to individual patients.

EP Europace ◽  
2019 ◽  
Vol 21 (11) ◽  
pp. 1733-1741 ◽  
Author(s):  
Robert S Sheldon ◽  
Lucy Lei ◽  
Juan C Guzman ◽  
Teresa Kus ◽  
Felix A Ayala-Paredes ◽  
...  

Abstract Aims There are few effective therapies for vasovagal syncope (VVS). Pharmacological norepinephrine transporter (NET) inhibition increases sympathetic tone and decreases tilt-induced syncope in healthy subjects. Atomoxetine is a potent and highly selective NET inhibitor. We tested the hypothesis that atomoxetine prevents tilt-induced syncope. Methods and results Vasovagal syncope patients were given two doses of study drug [randomized to atomoxetine 40 mg (n = 27) or matched placebo (n = 29)] 12 h apart, followed by a 60-min drug-free head-up tilt table test. Beat-to-beat heart rate (HR), blood pressure (BP), and cardiac haemodynamics were recorded using non-invasive techniques and stroke volume modelling. Patients were 35 ± 14 years (73% female) with medians of 12 lifetime and 3 prior year faints. Fewer subjects fainted with atomoxetine than with placebo [10/29 vs. 19/27; P = 0.003; risk ratio 0.49 (confidence interval 0.28–0.86)], but equal numbers of patients developed presyncope or syncope (23/29 vs. 21/27). Of patients who developed only presyncope, 87% (13/15) had received atomoxetine. Patients with syncope had lower nadir mean arterial pressure than subjects with only presyncope (39 ± 18 vs. 69 ± 18 mmHg, P < 0.0001), and this was due to lower trough HRs in subjects with syncope (67 ± 30 vs. 103 ± 32 b.p.m., P = 0.006) and insignificantly lower cardiac index (2.20 ± 1.36 vs. 2.84 ± 1.05 L/min/m2, P = 0.075). There were no significant differences in stroke volume index (32 ± 6 vs. 35 ± 5 mL/m2, P = 0.29) or systemic vascular resistance index (2156 ± 602 vs. 1790 ± 793 dynes*s/cm5*m2, P = 0.72). Conclusion Norepinephrine transporter inhibition significantly decreased the risk of tilt-induced syncope in VVS subjects, mainly by blunting reflex bradycardia, thereby preventing final falls in cardiac index and BP.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Matthias Rau ◽  
Kirsten Thiele ◽  
Niels-Ulrik Korbinian Hartmann ◽  
Alexander Schuh ◽  
Ertunc Altiok ◽  
...  

Abstract Background In the EMPA-REG OUTCOME trial (Empagliflozin Cardiovascular Outcome Event Trial) treatment with the sodium-glucose cotransporter-2 (SGLT2) inhibitor empagliflozin significantly reduced heart failure hospitalization (HHF) in patients with type 2 diabetes mellitus (T2D) and established cardiovascular disease. The early separation of the HHF event curves within the first 3 months of the trial suggest that immediate hemodynamic effects may play a role. However, hitherto no data exist on early effects of SGLT2 inhibitors on hemodynamic parameters and cardiac function. Thus, this study examined early and delayed effects of empagliflozin treatment on hemodynamic parameters including systemic vascular resistance index, cardiac index, and stroke volume index, as well as echocardiographic measures of cardiac function. Methods In this placebo-controlled, randomized, double blind, exploratory study patients with T2D were randomized to empagliflozin 10 mg or placebo for a period of 3 months. Hemodynamic and echocardiographic parameters were assessed after 1 day, 3 days and 3 months of treatment. Results Baseline characteristics were not different in the empagliflozin (n = 22) and placebo (n = 20) group. Empagliflozin led to a significant increase in urinary glucose excretion (baseline: 7.3 ± 22.7 g/24 h; day 1: 48.4 ± 34.7 g/24 h; p < 0.001) as well as urinary volume (1740 ± 601 mL/24 h to 2112 ± 837 mL/24 h; p = 0.011) already after one day compared to placebo. Treatment with empagliflozin had no effect on the primary endpoint of systemic vascular resistance index, nor on cardiac index, stroke volume index or pulse rate at any time point. In addition, echocardiography showed no difference in left ventricular systolic function as assessed by left ventricular ejections fraction and strain analysis. However, empagliflozin significantly improved left ventricular filling pressure as assessed by a reduction of early mitral inflow velocity relative to early diastolic left ventricular relaxation (E/eʹ) which became significant at day 1 of treatment (baseline: 9.2 ± 2.6; day 1: 8.5 ± 2.2; p = 0.005) and remained apparent throughout the study. This was primarily attributable to reduced early mitral inflow velocity E (baseline: 0.8 ± 0.2 m/s; day 1: 0.73 ± 0.2 m/sec; p = 0.003). Conclusions Empagliflozin treatment of patients with T2D has no significant effect on hemodynamic parameters after 1 or 3 days, nor after 3 months, but leads to rapid and sustained significant improvement of diastolic function. Trial registration EudraCT Number: 2016-000172-19; date of registration: 2017-02-20 (clinicaltrialregister.eu)


2020 ◽  
Author(s):  
Matthias Rau ◽  
Kirsten Thiele ◽  
Niels-Ulrik Korbinian Hartmann ◽  
Alexander Schuh ◽  
Ertunc Altiok ◽  
...  

Abstract Background: In the EMPA-REG OUTCOME trial (Empagliflozin Cardiovascular Outcome Event Trial) treatment with the sodium-glucose cotransporter-2 (SGLT2) inhibitor empagliflozin significantly reduced heart failure hospitalization (HHF) in patients with type 2 diabetes mellitus (T2D) and established cardiovascular disease. The early separation of the HHF event curves within the first 3 months of the trial suggest that immediate hemodynamic effects may play a role. However, hitherto no data exist on early effects of SGLT2 inhibitors on hemodynamic parameters and cardiac function. Thus, this study examined early and delayed effects of empagliflozin treatment on hemodynamic parameters including systemic vascular resistance index, cardiac index, and stroke volume index, as well as echocardiographic measures of cardiac function.Methods: In this placebo-controlled, randomized, double blind, exploratory study patients with T2D were randomized to empagliflozin 10 mg or placebo for a period of 3 months. Hemodynamic and echocardiographic parameters were assessed after 1 day, 3 days and 3 months of treatment. Results: Baseline characteristics were not different in the empagliflozin (n=22) and placebo (n=20) group. Empagliflozin led to a significant increase in urinary glucose excretion (baseline: 7.3 ± 22.7 g/24 hrs; day 1: 48.4 ± 34.7 g/24 hrs; p<0.001) as well as urinary volume (1740 ± 601 mL/24 hrs to 2112 ± 837 mL/24 hrs; p=0.011) already after one day compared to placebo. Treatment with empagliflozin had no effect on the primary endpoint of systemic vascular resistance index, nor on cardiac index, stroke volume index or pulse rate at any time point. In addition, echocardiography showed no difference in left ventricular systolic function as assessed by left ventricular ejections fraction and strain analysis. However, empagliflozin significantly improved left ventricular filling pressure as assessed by a reduction of early mitral inflow velocity relative to early diastolic left ventricular relaxation (E/e’) which became significant at day 1 of treatment (baseline: 9.2 ± 2.6; day 1: 8.5 ± 2.2; p=0.005) and remained apparent throughout the study. This was primarily attributable to reduced early mitral inflow velocity E (baseline: 0.8 ± 0.2 m/sec; day 1: 0.73 ± 0.2 m/sec; p=0.003). Conclusions: Empagliflozin treatment of patients with T2D has no significant effect on hemodynamic parameters after 1 or 3 days, nor after 3 months, but leads to rapid and sustained significant improvement of diastolic function.


1994 ◽  
Vol 77 (3) ◽  
pp. 1500-1506 ◽  
Author(s):  
J. L. Fleg ◽  
S. P. Schulman ◽  
F. C. O'Connor ◽  
G. Gerstenblith ◽  
L. C. Becker ◽  
...  

It is unclear whether the markedly enhanced aerobic exercise capacity of older endurance-trained men relative to their sedentary age peers is mediated primarily by central or peripheral cardiovascular mechanisms. To address this question, we performed radionuclide ventriculography with respiratory gas exchange measurements during exhaustive upright cycle ergometry in 16 endurance-trained men aged 63 +/- 7 yr and in 35 untrained men of similar age. As expected, maximal O2 consumption during treadmill exercise was much higher in athletes than in controls. At rest and during fixed submaximal cycle work rates through 100 W, athletes demonstrated lower heart rates and greater stroke volume indexes than controls while maintaining similar cardiac indexes and O2 uptake (VO2). At exhaustion, athletes achieved 53% higher work rates and peak VO2 per kilogram body weight than the sedentary men. The higher peak VO2 in athletes was achieved by a 22.5% larger cardiac index and a 15.6% greater arteriovenous O2 difference. The larger peak cardiac index in the athletes than in sedentary controls was mediated entirely by a greater stroke volume index; peak heart rates were virtually identical. The athletes' greater stroke volume index was achieved through an 11% larger end-diastolic volume index and a 7% higher ejection fraction, both of borderline significance. At exhaustion, athletes demonstrated a lower systemic vascular resistance than controls, despite a higher value at rest. Athletes also showed greater exercise-induced increments in heart rate, stroke volume index, and cardiac index and a greater reduction in systemic vascular resistance from rest to maximal workload.(ABSTRACT TRUNCATED AT 250 WORDS)


Author(s):  
C. E. King ◽  
A. Kermode ◽  
G. Saxena ◽  
P. Carvelli ◽  
M. Edwards ◽  
...  

Abstract Postoperative hypotension is common (occurring in one third of patients) and is associated with worse clinical outcomes. The LiDCO CNAP (continuous non-invasive arterial pressure) device measures haemodynamics but has not been widely adopted in ward environments. Improved early detection of hypotension by CNAP might guide interventions to improve clinical outcomes. We aimed to find the proportion of patients who tolerated LiDCO CNAP for 12 h postoperatively, to unmask episodes of hypotension detected by continuous monitoring and to characterise the haemodynamic profile at the time of hypotension. In this feasibility study, patients undergoing major elective surgery were continuously postoperatively monitored using CNAP. Haemodynamic data gathered from CNAP, including nSVRI (nominal systemic vascular resistance index), nSVI (nominal stroke volume index), SVV (stroke volume variation) and blood pressure, were analysed using Microsoft Excel and GraphPad Prism 8. 104 patients (age (mean ± sd): 68 ± 14, male (56%)) had CNAP sited postoperatively. 39% tolerated the CNAP device for at least 12 h. Within the 104 patients a mean of 81.2 min of hypotension detected by CNAP was not detected by usual care. The proportion of low/normal/high nSVI was 71%, 27% and 2%, nSVRI was 43%, 17% and 40%, respectively. CNAP monitoring was not tolerated for 12 h in the majority of patients. There were many episodes of hypotension unmasked through continuous monitoring. Based on the advanced haemodynamic data provided it is possible that the underlying cause of a third of postoperative hypotensive episodes is vasodilation rather than hypovolaemia. Trial registry number: NCT04010058 (ClinicalTrials.gov) Date of registration: 08/07/2019.


2021 ◽  
Vol 74 (8) ◽  
pp. 1809-1815
Author(s):  
Ulbolhan A. Fesenko ◽  
Ivan Myhal

The aim of the study was to analyze cardiac function during Nuss procedure under the combination of general anesthesia with different variants of the regional block. Materials and methods: The observative prospective study included 60 adolescents (boys/girls=47/13) undergone Nuss procedure for pectus excavatum correction under the combination of general anaesthesia and regional blocks. The patients were randomized into three groups (n=20 in each) according to the perioperative regional analgesia technique: standart epidural anaesthesia (SEA), high epidural anaesthesia (HEA) and bilateral paravertebral anaesthesia (PVA). The following parameters of cardiac function were analyzed: heart rate, estimated cardiac output (esCCO), cardiac index (esCCI), stroke volume (esSV) and stroke volume index (esSVI) using non-invasive monitoring. Results: Induction of anesthesia and regional blocks led to a significant decrease in esCCO (-9.4%) and esCCI (-9.8%), while esSV and esSVI remained almost unchanged in all groups (H=4.9; p=0.09). At this stage, the decrease in cardiac output was mainly due to decreased heart rate. At the stage of sternal elevation we found an increase in esSV, which was more pronounced in the groups of epidural blocks (+23.1% in HEA and +18.5% in SEA). After awakening from anesthesia and tracheal extubation esSV was by 11% higher than before surgery without ingergroup difference. Conclusions: The Nuss procedure for pectus excavatum correction lead to improved cardiac function. increase in stroke volume and its index were more informative than cardiac output and cardiac index which are dependent on heart rate that is under the influence of anaesthesia technique.


Author(s):  
Bernd Saugel ◽  
Elisa-Johanna Bebert ◽  
Luisa Briesenick ◽  
Phillip Hoppe ◽  
Gillis Greiwe ◽  
...  

AbstractIt remains unclear whether reduced myocardial contractility, venous dilation with decreased venous return, or arterial dilation with reduced systemic vascular resistance contribute most to hypotension after induction of general anesthesia. We sought to assess the relative contribution of various hemodynamic mechanisms to hypotension after induction of general anesthesia with sufentanil, propofol, and rocuronium. In this prospective observational study, we continuously recorded hemodynamic variables during anesthetic induction using a finger-cuff method in 92 non-cardiac surgery patients. After sufentanil administration, there was no clinically important change in arterial pressure, but heart rate increased from baseline by 11 (99.89% confidence interval: 7 to 16) bpm (P < 0.001). After administration of propofol, mean arterial pressure decreased by 23 (17 to 28) mmHg and systemic vascular resistance index decreased by 565 (419 to 712) dyn*s*cm−5*m2 (P values < 0.001). Mean arterial pressure was < 65 mmHg in 27 patients (29%). After propofol administration, heart rate returned to baseline, and stroke volume index and cardiac index remained stable. After tracheal intubation, there were no clinically important differences compared to baseline in heart rate, stroke volume index, and cardiac index, but arterial pressure and systemic vascular resistance index remained markedly decreased. Anesthetic induction with sufentanil, propofol, and rocuronium reduced arterial pressure and systemic vascular resistance index. Heart rate, stroke volume index, and cardiac index remained stable. Post-induction hypotension therefore appears to result from arterial dilation with reduced systemic vascular resistance rather than venous dilation or reduced myocardial contractility.


2000 ◽  
Vol 92 (2) ◽  
pp. 407-407 ◽  
Author(s):  
Jeremy A. Lieberman ◽  
Richard B. Weiskopf ◽  
Scott D. Kelley ◽  
John Feiner ◽  
Mariam Noorani ◽  
...  

Background The "critical" level of oxygen delivery (DO2) is the value below which DO2 fails to satisfy the metabolic need for oxygen. No prospective data in healthy, conscious humans define this value. The authors reduced DO2 in healthy volunteers in an attempt to determine the critical DO2. Methods With Institutional Review Board approval and informed consent, the authors studied eight healthy, conscious volunteers, aged 19-25 yr. Hemodynamic measurements were obtained at steady state before and after profound acute isovolemic hemodilution with 5% albumin and autologous plasma, and again at the reduced hemoglobin concentration after additional reduction of DO2 by an infusion of a beta-adrenergic antagonist, esmolol. Results Reduction of hemoglobin from 12.5+/-0.8 g/dl to 4.8+/-0.2 g/dl (mean +/- SD) increased heart rate, stroke volume index, and cardiac index, and reduced DO2 (14.0+/-2.9 to 9.9+/-20 ml O2 x kg(-1) x min(-1); all P&lt;0.001). Oxygen consumption (VO2; 3.0+/-0.5 to 3.4+/-0.6 ml O2 x kg(-1) x min(-1); P&lt;0.05) and plasma lactate concentration (0.50+/-0.10 to 0.62+/-0.16 mM; P&lt;0.05; n = 7) increased slightly. Esmolol decreased heart rate, stroke volume index, and cardiac index, and further decreased DO2 (to 7.3+/-1.4 ml O2 x kg(-1) x min(-1); all P&lt;0.01 vs. before esmolol). VO2 (3.2+/-0.6 ml O2 x kg(-1) x min(-1); P&gt;0.05) and plasma lactate (0.66+/-0.14 mM; P&gt;0.05) did not change further. No value of plasma lactate exceeded the normal range. Conclusions A decrease in DO2 to 7.3+/-1.4 ml O2 x kg(-1) min(-1) in resting, healthy, conscious humans does not produce evidence of inadequate systemic oxygenation. The critical DO2 in healthy, resting, conscious humans appears to be less than this value.


1988 ◽  
Vol 16 (3) ◽  
pp. 285-291 ◽  
Author(s):  
J. Tibballs ◽  
S. Malbezin

Cardiac output, blood pressure and heart rate were measured with noninvasive techniques before, during and after induction of anaesthesia with halothane and after intubation in unpremedicated infants and in diazepam-atropine premedicated children presenting for elective surgery. Cardiac output was measured with pulsed doppler echocardiography. Left ventricular shortening fraction was estimated with M-mode echocardiography during induction. Induction with halothane in infants caused significant decrements in blood pressure, cardiac index, stroke volume index and significant depression of left ventricular shortening fraction. Induction with halothane in diazepam-atropine premedicated children caused a significant increase in heart rate but significant decreases in blood pressure, stroke volume index and left ventricular shortening fraction while cardiac index decreased slightly. Intubation in infants caused a mild increase in heart rate compared with pre-induction values but blood pressure, cardiac index and stroke volume index remained below pre-induction values. Intubation in diazepam-atropine premedicated children caused significant increases in heart rate and cardiac index, and a nonsignificant increase in blood pressure but stroke volume index remained significantly below pre-induction values. Healthy infants and children tolerate induction of anaesthesia with halothane to a depth to permit intubation but large reductions in cardiac output and myocardial contractility are expected with subsequent reductions in blood pressure.


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