Central venous pressure in space

1996 ◽  
Vol 81 (1) ◽  
pp. 19-25 ◽  
Author(s):  
J. C. Buckey ◽  
F. A. Gaffney ◽  
L. D. Lane ◽  
B. D. Levine ◽  
D. E. Watenpaugh ◽  
...  
Keyword(s):  
Central Venous Pressure ◽  
Space Shuttle ◽  
Venous Pressure ◽  
Life Sciences ◽  
Left Ventricular ◽  
Filling Pressure ◽  
Fluid Distribution ◽  
Central Venous ◽  
Cardiac Filling Pressure ◽  
Cardiac Filling

Gravity affects cardiac filling pressure and intravascular fluid distribution significantly. A major central fluid shift occurs when all hydrostatic gradients are abolished on entry into microgravity (microG). Understanding the dynamics of this shift requires continuous monitoring of cardiac filling pressure; central venous pressure (CVP) measurement is the only feasible means of accomplishing this. We directly measured CVP in three subjects: one aboard the Spacelab Life Sciences-1 space shuttle flight and two aboard the Spacelab Life Sciences-2 space shuttle flight. Continuous CVP measurements, with a 4-Fr catheter, began 4 h before launch and continued into microG. Mean CVP was 8.4 cmH2O seated before flight, 15.0 cmH2O in the supine legs-elevated posture in the shuttle, and 2.5 cmH2O after 10 min in microG. Although CVP decreased, the left ventricular end-diastolic dimension measured by echocardiography increased from a mean of 4.60 cm supine preflight to 4.97 cm within 48 h in microG. These data are consistent with increased cardiac filling early in microG despite a fall in CVP, suggesting that the relationship between CVP and actual transmural left ventricular filling pressure is altered in microG.

scholarly journals Central venous pressure and cardiac function during spaceflight

1998 ◽  
Vol 85 (2) ◽  
pp. 738-746 ◽  
Author(s):  
Ronald J. White ◽  
C. Gunnar Blomqvist
Keyword(s):  
Cardiac Output ◽  
Stroke Volume ◽  
Central Venous Pressure ◽  
Shape Change ◽  
Venous Pressure ◽  
Left Ventricular ◽  
Filling Pressure ◽  
Central Venous ◽  
End Diastolic Volume ◽  
Reference Measurements

Early in spaceflight, an apparently paradoxical condition occurs in which, despite an externally visible headward fluid shift, measured central venous pressure is lower but stroke volume and cardiac output are higher, and heart rate is unchanged from reference measurements made before flight. This paper presents a set of studies in which a simple three-compartment, steady-state model of cardiovascular function is used, providing insight into the contributions made by the major mechanisms that could be responsible for these events. On the basis of these studies, we conclude that, during weightless spaceflight, the chest relaxes with a concomitant shape change that increases the volume of the closed chest cavity. This leads to a decrease in intrapleural pressure, ultimately causing a shift of blood into the vessels of the chest, increasing the transmural filling pressure of the heart, and decreasing the central venous pressure. The increase in the transmural filling pressure of the heart is responsible, through a Starling-type mechanism, for the observed increases in heart size, left ventricular end-diastolic volume, stroke volume, and cardiac output.

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.

scholarly journals Comparison of left ventricular unloading strategies on venoarterial extracorporeal life support

2020 ◽  
Author(s):  
Ali İhsan Hasde ◽  
Mehmet Cahit Sarıcaoğlu ◽  
Nur Dikmen Yaman ◽  
Çağdaş Baran ◽  
Evren Özçınar ◽  
...  
Keyword(s):  
Cardiogenic Shock ◽  
Central Venous Pressure ◽  
Venous Pressure ◽  
Neurological Complications ◽  
Left Ventricular ◽  
Central Venous ◽  
Refractory Cardiogenic Shock ◽  
Pulmonary Capillary ◽  
Va Ecmo ◽  
Wedge Pressure

Abstract OBJECTIVES Our goal was to compare the haemodynamic effects of different mechanical left ventricular (LV) unloading strategies and clinical outcomes in patients with refractory cardiogenic shock supported with venoarterial extracorporeal membrane oxygenation (VA-ECMO). METHODS A total of 448 patients supported with VA-ECMO for refractory cardiogenic shock between 1 March 2015 and 31 January 2020 were included and analysed in a single-centre, retrospective case–control study. Fifty-three patients (11.8%) on VA-ECMO required LV unloading. Percutaneous balloon atrial septostomy (PBAS), intra-aortic balloon pump (IABP) and transapical LV vent (TALVV) strategies were compared with regards to the composite rate of death, procedure-related complications and neurological complications. The secondary outcomes were reduced pulmonary capillary wedge pressure, pulmonary artery pressure, central venous pressure, left atrial diameter and resolution of pulmonary oedema on a chest X-ray within 48 h. RESULTS No death related to the LV unloading procedure was detected. Reduction in pulmonary capillary wedge pressure was highest with the TALVV technique (17.2 ± 2.1 mmHg; P < 0.001) and was higher in the PBAS than in the IABP group; the difference was significant (9.6 ± 2.5 and 3.9 ± 1.3, respectively; P = 0.001). Reduction in central venous pressure with TALVV was highest with the other procedures (7.4 ± 1.1 mmHg; P < 0.001). However, procedure-related complications were significantly higher with TALVV compared to the PBAS and IABP groups (50% vs 17.6% and 10%, respectively; P = 0.015). We observed no significant differences in mortality or neurological complications between the groups. CONCLUSIONS Our results suggest that TALVV was the most effective method for LV unloading compared with PBAS and IABP for VA-ECMO support but was associated with complications. Efficient LV unloading may not improve survival.

scholarly journals Finger photoplethysmography during the Valsalva maneuver reflects left ventricular filling pressure

2012 ◽  
Vol 302 (10) ◽  
pp. H2043-H2047 ◽  
Author(s):  
Harry A. Silber ◽  
Jeffrey C. Trost ◽  
Peter V. Johnston ◽  
W. Lowell Maughan ◽  
Nae-Yuh Wang ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Amplitude Ratio ◽  
Valsalva Maneuver ◽  
Pulse Amplitude ◽  
Left Ventricular ◽  
Filling Pressure ◽  
Left Heart ◽  
Cardiac Filling Pressure ◽  
Cardiac Filling ◽  
Waveform Amplitude

It is often challenging to assess cardiac filling pressure clinically. An improved system for detecting or ruling out elevated cardiac filling pressure may help reduce hospitalizations for heart failure. The blood pressure response to the Valsalva maneuver reflects left heart filling pressure, but its underuse clinically may be due in part to lack of continuous blood pressure recording along with lack of standardization of expiratory effort. In this study, we tested whether Valsalva-induced changes in the pulse amplitude of finger photoplethysmography (PPG), a technology already widely available in medical settings, correlate with invasively measured left ventricular end-diastolic pressure (LVEDP). We tested 33 subjects before clinically scheduled cardiac catheterizations. A finger photoplethysmography waveform was recorded during a Valsalva effort of 20 mmHg expiratory pressure sustained for 10 s, an effort most patients can achieve. Pulse amplitude ratio (PAR) was calculated as the PPG waveform amplitude just before release of expiratory effort divided by the waveform amplitude at baseline. PAR was well correlated with LVEDP ( r = 0.68; P < 0.0001). For identifying LVEDP > 15 mmHG, PAR > 0.4 was 85% sensitive [95% confidence interval (95CI): 54–97%] and 80% specific (95CI: 56–93%). In conclusion, finger PPG, a technology already ubiquitous in medical centers, may be useful for assessing clinically meaningful categories of left heart filling pressure, using simple analysis of the waveform after a Valsalva maneuver effort that most patients can achieve.

Central venous pressure and mean circulatory filling pressure in the dogfish Squalus acanthias: adrenergic control and role of the pericardium

2006 ◽  
Vol 291 (5) ◽  
pp. R1465-R1473 ◽  
Author(s):  
Erik Sandblom ◽  
Michael Axelsson ◽  
Anthony P. Farrell
Keyword(s):  
Central Venous Pressure ◽  
Venous Return ◽  
Venous Pressure ◽  
Filling Pressure ◽  
Control Fish ◽  
Central Venous ◽  
Venous Capacitance ◽  
Mean Circulatory Filling Pressure ◽  
Adrenergic Control ◽  
Venous Vasculature

Subambient central venous pressure (Pven) and modulation of venous return through cardiac suction (vis a fronte) characterizes the venous circulation in sharks. Venous capacitance was estimated in the dogfish S qualus acanthias by measuring the mean circulatory filling pressure (MCFP) during transient occlusion of cardiac outflow. We tested the hypothesis that venous return and cardiac preload can be altered additionally through adrenergic changes of venous capacitance. The experiments involved the surgical opening of the pericardium to place a perivascular occluder around the conus arteriosus. Another control group was identically instrumented, but lacked the occluder, and was subjected to the same pharmacological protocol to evaluate how pericardioectomy affected cardiovascular status. Routine Pven was negative (−0.08 ± 0.02 kPa) in control fish but positive (0.09 ± 0.01 kPa) in the pericardioectomized group. Injections of 5 μg/kg body mass ( Mb) of epinephrine and phenylephrine (100 μg/kg Mb) increased Pven and MCFP, whereas isoproterenol (1 μg/kg Mb) decreased both variables. Thus, constriction and relaxation of the venous vasculature were mediated through the respective stimulation of α- and β-adrenergic receptors. α-Adrenergic blockade with prazosin (1 mg/kg Mb) attenuated the responses to phenylephrine and decreased resting Pven in pericardioectomized animals. Our results provide convincing evidence for adrenergic control of the venous vasculature in elasmobranchs, although the pericardium is clearly an important component in the modulation of venous function. Thus active changes in venous capacitance have previously been underestimated as an important means of modulating venous return and cardiac performance in this group.

Central venous pressure in humans during microgravity

1996 ◽  
Vol 81 (1) ◽  
pp. 408-412 ◽  
Author(s):  
N. Foldager ◽  
T. A. Andersen ◽  
F. B. Jessen ◽  
P. Ellegaard ◽  
C. Stadeager ◽  
...  
Keyword(s):  
Central Venous Pressure ◽  
Supine Position ◽  
Pressure Transducer ◽  
Space Shuttle ◽  
Parabolic Flight ◽  
Venous Pressure ◽  
Simulation Studies ◽  
Central Venous ◽  
Healthy Humans ◽  
Intravascular Pressure

Based on the results of head-down simulation studies and the results of parabolic flights, the hypothesis was tested that central venous pressure (CVP) in humans increases during microgravity (weightlessness) compared with during the ground-based supine position. CVP was recorded with an intravascular pressure transducer in seven healthy humans during short (20-s) periods of microgravity created by parabolic-flight maneuvers and in one astronaut before, during, and up to 3 h after launch of the Spacelab D-2 mission (Space Transport System-55). When the subjects were supine during the parabolic maneuver, CVP decreased during microgravity from 6.5 +/- 1.3 to 5.0 +/- 1.4 mmHg (P < 0.05). during the Spacelab D-2 mission, CVP was 6.2 mmHg during the initial minutes of microgravity, which was very similar to the value of 6.5 mmHg in the supine position 3.5 h before launch of the space shuttle. During the subsequent 3 h of weightlessness, CVP during rest varied between 2.0 and 6.2 mmHg. We conclude that CVP during short (20-s) and longer (3-h) periods of microgravity is close to or below that of the supine position on the ground.

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