Intraoperative fluid balance during cardiopulmonary bypass: effects of different mean arterial pressures.
BACKGROUND
This study investigated whether two levels of mean arterial pressure (MAP) during cardiopulmonary bypass did influence per-operative fluid shifts.


METHODS
Sixteen pigs underwent 60 minutes of normothermic cardiopulmonary bypass (CPB) followed by 90 minutes of hypothermic CPB. Eight animals had a MAP of 60-80mmHg by norepinephrine (HP group). Another 8 animals had a MAP of 40-45 mmHg by phentolamine (LP group). Blood chemistry, plasma/interstitial colloid osmotic pressures, plasma volume, fluid balance, fluid extravasation rate and tissue water content were measured or calculated.


RESULTS
The plasma volume was significantly lower in the HP group compared with the LP group after 60 minutes of CPB. Net fluid balance was 0.18 (0.05) ml x kg(-1) x min(-1) in the HP group and 0.21 ml x kg(-1) x min(-1) in the LP group (P > 0.05) while fluid extravasation rate was 1.18 (0.5) and 1.13 (0.4) ml x kg(-1) x min(-1) in the HP group and the LP group during CPB (P > 0.05).


CONCLUSIONS
Net fluid balance and fluid extravasation rate were similar in the animals with elevated and with lowered MAP during CPB.
Haugen
Oddbjørn
O
Department of Anaesthesia and Intensive Care, Haukeland University Hospital, Bergen, Norway.
Farstad
Marit
M
Kvalheim
Venny
V
Hammersborg
Stig
S
Husby
Paul
P
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D001810:Blood Volume; D002315:Cardiopulmonary Bypass; D018495:Fluid Shifts; D006439:Hemodynamics; D023421:Models, Animal; D009638:Norepinephrine / Q000494:pharmacology; D009997:Osmotic Pressure; D010646:Phentolamine / Q000494:pharmacology; D013552:Swine; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D000959:Antihypertensive Agents; D014662:Vasoconstrictor Agents; D009638:Norepinephrine; D010646:Phentolamine