Comparison Between Hyperoncotic and Isooncotic Albumin to Support Blood Loss Replacement

Overview

Fluid intravascular replacement is usually performed with either balanced crystalloids or iso-oncotic colloids, (synthetic colloids, plasma and 5% albumin). Doubts have been raised about synthetic colloids, and albumin solutions have been used more extensively. Albumin is the main protein responsible for plasma oncotic pressure and its volume expansion effect. The mobilization of extravascular fluid by infusing a hyper-oncotic solution like 20% albumin solution has been shown, causing endogenous fluid recruitment and blood volume expansion. The primary objective of this study is to compare the effect on plasma volume expansion and fluid recruitment of 3 different types of fluids (Albumin 5% and Albumin 20% and Ringer-lactate) during the hemorrhagic phase of the cystectomy procedure. Secondary objectives are the assessment of the hemodynamic parameters during surgery and the follow-up of pro-ANP and pro-BNP peptides. Glycocalyx proteins will be followed to evaluate endothelial wall shedding and microcirculation damages.

Bladder cancer occurs mainly in old comorbid patients. The standard treatment of localized muscle invasive bladder cancer is pelvic lymph node dissection and radical cystectomy with urinary diversion. Optimal perioperative fluid management for this surgery is challenging and still controversial in terms of how much to perfuse, choice of fluids to restore hydrated state and volemia. Fluid treatment is usually performed with either balanced crystalloids fluids or iso-oncotic synthetic colloids, or albumin 5%. Because crystalloids quickly equilibrate between the intravascular and interstitial volumes, they are mainly used to treat dehydration and temporary volume deficits. Doubts have been raised about synthetic colloids and the natural albumin has been used more extensively. Albumin is the main protein responsible for plasma oncotic pressure and its volume expansion effect. Iso-oncotic colloids (Albumine 5%) remain intravascular for a prolonged period, but they play a neutral role in terms of endogenous fluid recruitment, as the oncotic pressure is equilibrated between the intra- and extra- vascular territories. An alternative therapeutic option is the mobilization of tissue fluid by infusing a small amount of hyper-oncotic fluid like the albumin 20% solution, which has showed the advantage in its blood volume expansion capacities over crystalloids (endogenous fluid recruitment). The effects of the Albumin 20% solution have until now never been compared in a same perioperative setting to the Albumin 5% nor to Ringer-lactate solution. The investigators will evaluate the physiological effects and their outcomes between these fluid therapies in the frame of blood loss replacement during the hemorrhagic part of cystectomy procedures. The investigators will as well assess the variation of hemodynamic parameters (pro-ANP, pro-BNP) and the resulting microcirculation damages (endothelial wall shedding).