Comparison and reproducibility of transthoracic bioimpedance and dual beam Doppler ultrasound measurement of cardiac function in healthy volunteers.

Ng, H. W.; Walley, Tom; Tsao, Y; Breckenridge, Alasdair

doi:10.1111/j.1365-2125.1991.tb03899.x

Cited by 27 publications

(19 citation statements)

References 14 publications

(17 reference statements)

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“…There was little improvement of agreement when the data were transformed as difference from baseline. Similar conclusions were drawn for the comparison between transthoracic bioimpedance (an automated ZCG-related method (Sramek, 1981) that is essentially different from the standard method used here (de Mey & Belz, 1989;Silke, 1990) and dual beam Doppler ultrasound in estimating postural and ergometric changes of cardiovascular function (Ng et al, 1991). But, in the present study there was far better agreement between the methods provided the data were transformed as % of baseline.…”

Section: Discussionsupporting

confidence: 81%

Agreement and reproducibility of the estimates of cardiovascular function by impedance cardiography and M‐mode echocardiography in healthy subjects.

Mey¹,

Matthews²,

Butzer³

et al. 1992

Brit J Clinical Pharma

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The reproducibility and agreement of the estimates of stroke volume (SV), cardiac output (CO) and total peripheral resistance (TPR) by transthoracic impedance cardiography (ZCG) and M-mode echocardiography (ECHO) were analyzed before and after the placebo-controlled administration of ascending doses of isosorbide dinitrate and nicorandil in 12 healthy subjects. There was no biostatistical agreement between the two methods in estimating cardiovascular function either before or after dosing (ZCG estimated substantially larger SV, CO and lower TPR). But, ZCG and ECHO estimated about similar overall treatment related changes (across treatments and periods) and reached substantially better agreement when the values were expressed as ratio of the baseline before dosing. Such improvement did not occur when the data were expressed as arithmetic difference from baseline. In spite of the improvement of agreement by expressing the data as ratio of baseline, the coefficients of reproducibility between the two methods (circa 25% of baseline) remained too large to judge the methods interchangeable.

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Section: Discussionsupporting

confidence: 81%

Agreement and reproducibility of the estimates of cardiovascular function by impedance cardiography and M‐mode echocardiography in healthy subjects.

Mey¹,

Matthews²,

Butzer³

et al. 1992

Brit J Clinical Pharma

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“…18 To minimize the intrapatient coefficient of variation over time, we standardized the site of application of the electrodes (4 along the neck and 4 at the basis of the thorax) in relation to fixed body landmarks, such as the mastoid processes, the sternoclavicular joints, the extremity of the xiphoid process, and the mid-axillary line. Using this standardization, impedance cardiography proved to be more reproducible in measuring cardiac output, on a day-by-day comparison, than Doppler echocardiography, 19 and is considered suitable to measure individual changes in cardiac output, 18-20 also having been used to evaluate cirrhotic patients, either before 21 or after OLT. 8,22 TPR ϭ MAP ϫ 80/cardiac output…”

Section: Cardiac and Systemic Measurementsmentioning

confidence: 99%

Systemic and splanchnic hemodynamic changes after liver transplantation for cirrhosis: A long-term prospective study

et al. 1999

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The effect of orthotopic liver transplantation (OLT) on the systemic and splanchnic hemodynamic alterations of cirrhosis is still largely unknown. The aim of this study was to prospectively investigate the long-term changes induced by OLT on several hemodynamic parameters. In 28 patients undergoing OLT for cirrhosis, the following parameters were measured before surgery and subsequently at 6-month intervals (mean follow-up period, 17 months): cardiac index, mean arterial pressure (MAP), heart rate, total peripheral resistance (TPR), portal vein flow velocity and flow volume, spleen size, and Doppler ultrasound resistance or pulsatility indexes (RI or PI) in the: 1) interlobular renal, 2) superior mesenteric, 3) splenic, and 4) hepatic arteries. The same parameters were measured in 10 healthy controls. After OLT, cardiac index and heart rate significantly decreased (P F .01), while MAP and TPR increased (P F .001), so that any significant difference from controls disappeared. Renal RI progressively decreased, achieving a significant reduction (P F .05) to normal values at the 12th month of follow-up. Portal flow velocity and hepatic and splenic RI returned to values not significantly different from controls. Portal flow volume increased over normal values after OLT (P F .001), and SMA PI, lower than normal before OLT, did not show any statistically significant increase thereafter. Spleen size decreased significantly, but persisted to be larger than in controls. In conclusion, systemic, renal, and most, but interestingly not all, splanchnic circulatory alterations of cirrhosis are restored to normal after OLT. (HEPATOLOGY 1999;30:58-64.)Advanced cirrhosis is accompanied by a peculiar hemodynamic derangement, which has been traditionally included in the hyperkinetic circulatory syndromes. 1,2 This derangement is characterized by high cardiac output, low total peripheral resistance (TPR), mild tachycardia, and low/normal blood pressure, and by various alterations in the peripheral circulation. 2 Among the latter, the most important are those occurring in the renal and splanchnic vascular beds.There is evidence that elevated portal resistance and liver failure are responsible for triggering the circulatory alterations of cirrhosis. 2,3 However, while it is accepted that orthotopic liver transplantation (OLT) restores normal portal resistance and pressure and liver function, 4 conflicting data have been reported about the corresponding modification of the hyperkinetic circulation 5 : some authors found a persistence of elevated cardiac output, 6,7 whereas others found a decrease to normal values. 4,8 No definite explanation accounting for such discrepancy has been proposed until now. Thus, it is still unclear whether or not the cardiac hyperkinetic circulation persists after OLT.The renal circulation of cirrhotic patients is characterized by an arteriolar vasoconstriction, which is especially intense in ascitic patients. 9,10 The two most likely mechanisms inducing renal vasoconstriction in cirrhosis are hypothesized ...

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“…Gisvold & Brubakk [20], with 10 repeated measurements in five subjects, found variability of between 6-11% while Huntsman [18] had a 9.4% coefficient of variability. Ng et al [21] found the coefficient of variation for cardiac output and stroke volume to be 7.9% and 7.4% respectively in six healthy subjects. In 10 volunteers and 25 coronary patients with 8-10 consecutive estimates of flow, the stroke volume reproducibility was 3.8% and 4.4% respectively.…”

Section: Discussionmentioning

confidence: 98%

Haemodynamic comparison of amlodipine and atenolol in essential hypertension using the quantascope

Tham¹,

Herity²,

S³

et al. 1993

Brit J Clinical Pharma

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1 We have utilised a non-imaging echo-Doppler cardiac output device, using the principle of attenuated compensation volume flow (ACVF), to assess the cardiovascular effects of amlodipine and atenolol over 3 months in 24 patients with essential hypertension. 2 Both amlodipine and atenolol, at 4 and 12 weeks, similarly reduced mean arterial pressure (12 weeks amlodipine -12.6 mmHg, atenolol -14.9 mmHg; P < 0.01 for each vs baseline). 3 The heart rate fell on atenolol, both at 4 weeks (amlodipine -3 vs atenolol -12 beats min-'; P < 0.05) and 12 weeks (-1 vs -11 beats min-'; P < 0.05), without change on amlodipine. 4 Stroke volume initially rose on atenolol without change on amlodipine (4 weeks amlodipine -1.3 ml vs atenolol + 10.1 ml; P = 0.05) but between drug effects were not different at 12 weeks. 5 The systemic vascular resistance was reduced on amlodipine (12 weeks: amlodipine -176 dyn s cm-5: P < 0.05) without change on atenolol (atenolol -48 dyn s cm-5: NS). 6 The cardiac stroke work was lowered on amlodipine both at 4 weeks (P < 0.01) and 12 weeks (P < 0.05) and statistically different from the unaltered atenolol values at both time points. 7 Skin nutrient flow or fingertip temperature was not altered by either treatment. 8 These results are consistent with contrasting mechanisms of action -vasodilator for amlodipine and decreased cardiac pumping for atenolol. The greater reduction in cardiac stroke work on amlodipine compared with atenolol warrants further investigation during longer-term studies.

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Comparison and reproducibility of transthoracic bioimpedance and dual beam Doppler ultrasound measurement of cardiac function in healthy volunteers.

Abstract: (Bernstein, 1986a), and the NCCOM3-R7 represents the most recent advances (Bernstein, 1989).The Doppler device depends on the attenuation com-

Cited by 27 publications

References 14 publications

Agreement and reproducibility of the estimates of cardiovascular function by impedance cardiography and M‐mode echocardiography in healthy subjects.

Agreement and reproducibility of the estimates of cardiovascular function by impedance cardiography and M‐mode echocardiography in healthy subjects.

Systemic and splanchnic hemodynamic changes after liver transplantation for cirrhosis: A long-term prospective study

Haemodynamic comparison of amlodipine and atenolol in essential hypertension using the quantascope

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