scholarly journals Clinical validation of a computerized algorithm to determine mean systemic filling pressure

2021 ◽  
Author(s):  
Loek P.B. Meijs ◽  
Joris van Houte ◽  
Bente C. M. Conjaerts ◽  
Alexander J. G. H. Bindels ◽  
Arthur Bouwman ◽  
...  
Keyword(s):  
Conversion Coefficient ◽  
Intraclass Correlation ◽  
Filling Pressure ◽  
Right Atrial ◽  
Release Date ◽  
Clinical Trial Registration ◽  
Mean Systemic Filling Pressure ◽  
Link Type ◽  
Systemic Filling ◽  
Systemic Filling Pressure

AbstractMean systemic filling pressure (Pms) is a promising parameter in determining intravascular fluid status. Pms derived from venous return curves during inspiratory holds with incremental airway pressures (Pms-Insp) estimates Pms reliably but is labor-intensive. A computerized algorithm to calculate Pms (Pmsa) at the bedside has been proposed. In previous studies Pmsa and Pms-Insp correlated well but with considerable bias. This observational study was performed to validate Pmsa with Pms-Insp in cardiac surgery patients. Cardiac output, right atrial pressure and mean arterial pressure were prospectively recorded to calculate Pmsa using a bedside monitor. Pms-Insp was calculated offline after performing inspiratory holds. Intraclass-correlation coefficient (ICC) and assessment of agreement were used to compare Pmsa with Pms-Insp. Bias, coefficient of variance (COV), precision and limits of agreement (LOA) were calculated. Proportional bias was assessed with linear regression. A high degree of inter-method reliability was found between Pmsa and Pms-Insp (ICC 0.89; 95%CI 0.72–0.96, p = 0.01) in 18 patients. Pmsa and Pms-Insp differed not significantly (11.9 mmHg, IQR 9.8–13.4 vs. 12.7 mmHg, IQR 10.5–14.4, p = 0.38). Bias was −0.502 ± 1.90 mmHg (p = 0.277). COV was 4% with LOA –4.22 − 3.22 mmHg without proportional bias. Conversion coefficient Pmsa ➔ Pms-Insp was 0.94. This assessment of agreement demonstrates that the measures Pms-Insp and the computerized Pmsa-algorithm are interchangeable (bias −0.502 ± 1.90 mmHg with conversion coefficient 0.94). The choice of Pmsa is straightforward, it is non-interventional and available continuously at the bedside in contrast to Pms-Insp which is interventional and calculated off-line. Further studies should be performed to determine the place of Pmsa in the circulatory management of critically ill patients. (www.clinicaltrials.gov; TRN NCT04202432, release date 16-12-2019; retrospectively registered).Clinical Trial Registrationwww.ClinicalTrials.gov, TRN: NCT04202432, initial release date 16-12-2019 (retrospectively registered).

scholarly journals Right atrial pressure and venous return during cardiopulmonary bypass

2017 ◽  
Vol 313 (2) ◽  
pp. H408-H420 ◽  
Author(s):  
Per W. Moller ◽  
Bernhard Winkler ◽  
Samuel Hurni ◽  
Paul Philipp Heinisch ◽  
Andreas Bloch ◽  
...  
Keyword(s):  
Venous Return ◽  
Filling Pressure ◽  
Atrial Pressure ◽  
Right Atrial ◽  
Right Atrial Pressure ◽  
Pump Speed ◽  
Mean Systemic Filling Pressure ◽  
Upstream Pressure ◽  
Systemic Filling ◽  
Systemic Filling Pressure

The relevance of right atrial pressure (RAP) as the backpressure for venous return (QVR) and mean systemic filling pressure as upstream pressure is controversial during dynamic changes of circulation. To examine the immediate response of QVR (sum of caval vein flows) to changes in RAP and pump function, we used a closed-chest, central cannulation, heart bypass porcine preparation ( n = 10) with venoarterial extracorporeal membrane oxygenation. Mean systemic filling pressure was determined by clamping extracorporeal membrane oxygenation tubing with open or closed arteriovenous shunt at euvolemia, volume expansion (9.75 ml/kg hydroxyethyl starch), and hypovolemia (bleeding 19.5 ml/kg after volume expansion). The responses of RAP and QVR were studied using variable pump speed at constant airway pressure (PAW) and constant pump speed at variable PAW. Within each volume state, the immediate changes in QVR and RAP could be described with a single linear regression, regardless of whether RAP was altered by pump speed or PAW ( r2 = 0.586–0.984). RAP was inversely proportional to pump speed from zero to maximum flow ( r2 = 0.859–0.999). Changing PAW caused immediate, transient, directionally opposite changes in RAP and QVR (RAP: P ≤ 0.002 and QVR: P ≤ 0.001), where the initial response was proportional to the change in QVR driving pressure. Changes in PAW generated volume shifts into and out of the right atrium, but their effect on upstream pressure was negligible. Our findings support the concept that RAP acts as backpressure to QVR and that Guyton’s model of circulatory equilibrium qualitatively predicts the dynamic response from changing RAP. NEW & NOTEWORTHY Venous return responds immediately to changes in right atrial pressure. Concomitant volume shifts within the systemic circulation due to an imbalance between cardiac output and venous return have negligible effects on mean systemic filling pressure. Guyton’s model of circulatory equilibrium can qualitatively predict the resulting changes in dynamic conditions with right atrial pressure as backpressure to venous return.

scholarly journals Effect of volume status on the estimation of mean systemic filling pressure

2019 ◽  
Vol 126 (6) ◽  
pp. 1503-1513 ◽  
Author(s):  
Per Werner-Moller ◽  
Soren Sondergaard ◽  
Stephan M. Jakob ◽  
Jukka Takala ◽  
David Berger
Keyword(s):  
Dynamic Model ◽  
Venous Return ◽  
Filling Pressure ◽  
Right Atrial ◽  
Volume Status ◽  
Mean Systemic Filling Pressure ◽  
Volume State ◽  
Systemic Filling ◽  
The Difference ◽  
Systemic Filling Pressure

Various methods for indirect assessment of mean systemic filling pressure (MSFP) produce controversial results compared with MSFP at zero blood flow. We recently reported that the difference between MSFP at zero flow measured by right atrial balloon occlusion (MSFPRAO) and MSFP estimated using inspiratory holds depends on the volume status. We now compare three indirect estimates of MSFP with MSFPRAO in euvolemia, bleeding, and hypervolemia in a model of anesthetized pigs ( n = 9) with intact circulation. MSFP was estimated using instantaneous beat-to-beat venous return during tidal ventilation (MSFPinst_VR), right atrial pressure-flow data pairs at flow nadir during inspiratory holds (MSFPnadir_hold), and a dynamic model analog adapted to pigs (MSFPa). MSFPRAO was underestimated by MSFPnadir_hold and MSFPa in all volume states. Volume status modified the difference between MSFPRAO and all indirect methods (method × volume state interaction, P ≤ 0.020). All methods tracked changes in MSFPRAO concordantly, with the lowest bias seen for MSFPa [bias (confidence interval): −0.4 (−0.7 to −0.0) mmHg]. We conclude that indirect estimates of MSFP are unreliable in this experimental setup. NEW & NOTEWORTHY For indirect estimations of MSFP using inspiratory hold maneuvers, instantaneous beat-to-beat venous return, or a dynamic model analog, the accuracy was affected by the underlying volume state. All methods investigated tracked changes in MSFPRAO concordantly.

Systemic filling pressure in intact circulation determined on basis of aortic vs. central venous pressure relationships

1994 ◽  
Vol 267 (6) ◽  
pp. H2255-H2258 ◽  
Author(s):  
E. A. Den Hartog ◽  
A. Versprille ◽  
J. R. Jansen
Keyword(s):  
Central Venous Pressure ◽  
Flow Resistance ◽  
Venous Pressure ◽  
Aortic Pressure ◽  
Filling Pressure ◽  
Central Venous ◽  
Mean Systemic Filling Pressure ◽  
Systemic Filling ◽  
The Mean ◽  
Systemic Filling Pressure

In the intact circulation, mean systemic filling pressure (Psf) is determined by applying a series of inspiratory pause procedures (IPPs) and using Guyton's equation of venous return (Qv) and central venous pressure (Pcv): Qv = a - b x Pcv. During an IPP series, different tidal volumes are applied to set Pcv at different values. From the linear regression between Qv and Pcv, Psf can be calculated as Psf = a/b. Guyton's equation can also be written as Qv = (Psf - Pcv)/Rsd, where Rsd is the flow resistance downstream of the places where blood pressure is equal to Psf. During an IPP, a steady state is observed. Therefore, we can also formulate the following equation for flow: Qs = (Pao - Psf)/Rsu, where Qs is systemic flow, Rsu is the systemic flow resistance upstream to Psf, and Pao is aortic pressure. Because both flows (Qs and Qv) are equal, it follows that Pao = Psf(1 + Rsu/Rsd) - Rsu/Rsd x Pcv. This equation implies a method to determine mean systemic filling pressure on the basis of Pao measurements instead of flow determinations. Using 22 IPPs in 10 piglets, we determined the mean systemic filling pressure, and we compared the values obtained from the flow curves with those obtained from the aortic pressure curves. The mean difference between the two methods was 0.03 +/- 1.16 mmHg. With the use of Pao measurements, the Psf can be estimated as accurately as in using flow determinations. The advantage of the new method is that estimation of cardiac output is not required.

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