Central venous pressure in space.
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.
Buckey
J C
JC
Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235-9034, USA.
Gaffney
F A
FA
Lane
L D
LD
Levine
B D
BD
Watenpaugh
D E
DE
Wright
S J
SJ
Yancy
C W
CW
Meyer
D M
DM
Blomqvist
C G
CG
D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D002138:Calibration; D002405:Catheterization, Central Venous; D002496:Central Venous Pressure / Q000502:physiology*; D004562:Electrocardiography; D005260:Female; D018495:Fluid Shifts / Q000502:physiology; D006112:Gravitation; D005676:Gravity Suits; D006321:Heart / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology; D013026:Space Flight; D014893:Weightlessness / Q000009:adverse effects