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Background: Pulsatile versus nonpulsatile cardiopulmonary bypass (CPB) perfusion remains debated. Beneficial effects on tissue perfusion, inflammation, and microvascular fluid exchange have been linked to pulsatile perfusion by some investigators and denied by others. This study evaluated fluid extravasation and tissue perfusion during nonpulsatile or pulsatile roller pump-induced CPB perfusion., Methods: Fourteen pigs underwent roller pump-induced pulsatile (n = 7) or nonpulsatile CPB perfusion (n = 7) for 90 minutes. Fluid input/losses, colloid osmotic pressures (plasma/interstitium), hematocrit, serum electrolytes, serum proteins, tissue perfusion, and total tissue water content were measured, and plasma volume and fluid extravasation were calculated., Results: Fluid additions/losses, plasma volume, and fluid extravasation changed similarly in both groups during CPB with no between-group differences. Neither was between-group differences observed for tissue perfusion and total tissue water content, with one exception. Total tissue water content of the right (3.92 ± 0.26 versus 4.32 ± 0.28 g/g dry weight) and left ventricle (4.02 ± 0.25 versus 4.33 ± 0.24 g/g dry weight) was lowered in the pulsatile group., Conclusions: No important differences were found between pulsatile and nonpulsatile CPB perfusion for microvascular fluid balance and tissue perfusion., (Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Objective: To describe how surface cooling compared with core cooling influences fluid and protein distribution, vascular capacity and hemodynamic variables., Methods: 14 anesthetized piglets were, following 60 min normothermic stabilization, randomly cooled by surface cooling (ice-sludge) (n=7) or core cooling (endovascular cooling) (n=7) to about 28 degrees C. Fluid balance, hemodynamic variables, colloid osmotic pressures (plasma/interstitial fluid), hematocrit, serum-albumin and -protein concentrations, intracranial pressure (ICP) and cerebral metabolic markers of ischemia were measured. Fluid shifts and changes in albumin and protein masses were calculated. At the end total tissue water content was assessed and compared with a normothermic control group., Results: Both cooling modes induced an increase in fluid extravasation rate from 33.9 (31.9) and 27.8 (28.0) to 109.0 (16.5) (P=0.006) and 95.6 (29.1) ml/kg/min x 10(-3) (P=0.024) in the surface-cooled and core-cooled groups, respectively. Albumin extravasation was reflected by a significant drop in the albumin mass from 148.8 (11.7) to 111.4 (10.3) (P=0.000) and from 163.4 (27.8) to 136.8 (19.0) g/kg x 10(-2) (P=0.001) in the surface-cooled and core-cooled animals, respectively. Similar findings were obtained concerning serum-protein masses. The total tissue water content increased in most organs including brain in both study groups compared with a control. ICP and cerebral metabolic markers remained normal in both groups., Conclusion: Rapid lowering of body core temperature results in extravasation of water and proteins. The amount of extravated fluid and proteins is similar either cooling is a result of surface cooling or core cooling. Cold-induced fluid extravasation is associated with edema in most tissues including brain.

Objective: Cardiopulmonary bypass (CPB) is associated with fluid overload. We examined how a continuous infusion of hypertonic saline/dextran (HSD) influenced fluid shifts during CPB., Materials and Methods: Fourteen animals were randomized to a control-group (CT-group) or a hypertonic saline/dextran-group (HSD-group). Ringer's solution was used as CPB-prime and as maintenance fluid at a rate of 5 ml/kg/h. In the HSD group, 1 ml/kg/h of the maintenance fluid was substituted with HSD. After 60 min of normothermic CPB, hypothermic CPB was initiated and continued for 90 min. Fluid was added to the CPB-circuit as needed to maintain a constant level in the venous reservoir. Fluid balance, plasma volume, total tissue water (TTW), intracranial pressure (ICP) and fluid extravasation rates (FER) were measured/calculated., Results: In the HSD-group the fluid need was reduced with 60% during CPB compared with the CT-group. FER was 0.38(0.06) ml/kg/min in the HSD-group and 0.74 (0.16) ml/kg/min in the CT-group. TTW was significantly lower in the heart and some of the visceral organs in the HSD-group. In this group ICP remained stable during CPB, whereas an increase was observed in the CT-group (p<0.01)., Conclusions: A continuous infusion of HSD reduced the fluid extravasation rate and total fluid gain during CPB. TTW was reduced in the heart and some visceral organs. During CPB ICP remained normal in the HSD-group, whereas an increase was present in the CT-group. No adverse effects were observed.

Introduction: 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)., Conclusion: Net fluid balance and fluid extravasation rate were similar in the animals with elevated and with lowered MAP during CPB.

Background: The aim of this study was to evaluate how a continuous infusion of a hyperosmolar/hyperoncotic solution influences fluid shifts and intracranial pressure during cardiopulmonary bypass in piglets. Methods: Fourteen animals, randomized to the control (CT) group or the hypertonic saline/hydroxyethyl starch (HyperHaes®) (HSH) group, received acetated Ringer’s solution as prime and supplemental fluid. The HSH group received, in addition, HyperHaes® 1 ml/kg/h. After 1 h of normothermic cardiopulmonary bypass, hypothermic cardiopulmonary bypass (28 °C) was initiated and continued for 90 min. Fluid balance, plasma volume, tissue water content, acid–base parameters and intracranial pressure were recorded, and protein masses and fluid extravasation rates were calculated. Results: At the start of normothermic cardiopulmonary bypass, the fluid extravasation rates (ml/kg/min) increased from 0.19 (0.06) to 1.57 (0.71) and 0.19 (0.09) to 0.82 (0.14) in the CT and HSH groups, respectively, with no between-group differences ( P = 0.081) During hypothermic cardiopulmonary bypass, the fluid extravasation rates (ml/kg/min) increased from 0.19 (0.14) to 0.51 (0.10) ( P < 0.01) and 0.15 (0.08) to 0.33 (0.08) ( P < 0.05), respectively, with significantly lower extravasation rates in the HSH group ( P < 0.01). In the HSH group, the total fluid gain during cardiopulmonary bypass decreased by about 50% ( P < 0.05) and the tissue water content was significantly lower in the left and right heart as well as in the lungs. The intracranial pressure remained stable in the HSH group, but increased in the CT group. Conclusions: A continuous infusion of HSH (HyperHaes®) during cardiopulmonary bypass reduced the fluid extravasation rate and the total fluid gain during bypass. No electrolyte or acid–base disturbances were present. The intracranial pressure remained stable in the HSH group. [ABSTRACT FROM AUTHOR]

Crystalloids are commonly used as priming solutions during cardiopulmonary bypass (CPB). Consequently, hemodilution is a regular occurrence at the start of a CPB. This study describes the time-course variations of hemodynamic parameters, plasma volume (PV) and fluid exchange following crystalloid hemodilution at start of normothermic CPB. Forty-five anesthetized piglets were given 60-min normothermic CPB. Ringer's solution was used as priming solution and maintenance fluid. Fluid input/losses, PV, colloid osmotic pressures (plasma/interstitium), hematocrit, and s-proteins were measured, and fluid extravasation rates (FER) and intravascular protein-masses calculated. Start of CPB resulted in a 25–30% hemodilution. To keep the fluid level of the CPB-reservoir constant after start of bypass, fluid addition [2.08 ± 0.36 (mean ± SEM) ml kg−1 min−1] was necessary during the first 5 min. Thereafter the fluid needs to be leveled off [0.17 ± 0.03 ml kg−1 min−1 (10–60 min), P < 0.001]. Fluid extravasation rate increased immediately following hemodilution from a baseline value of 0.08 ± 0.01 to 1.75 ± 0.34 ml kg−1 min−1 with a delayed decrease compared to fluid additions, to reach a ‘steady-state’ level of 0.22 ± 0.03 ml kg−1 min−1 after 30 min ( P < 0.001). Differences in time-course variations between fluid added and fluid extravasated were accompanied by changes in PV and mean arterial pressure. The colloid osmotic gradient decreased about 50% throughout the study and could partly explain the increased FER. Acute crystalloid hemodilution contributes to fluid overload during normothermic CPB. The resulting increase in fluid extravasation is, however, moderate, short-lived and levels off to baseline values within 30 min. [ABSTRACT FROM AUTHOR]