Cardiac index and stroke volume variation as parameters to guide fluid therapy and hemodynamic management in renal transplantation in comparison to conventional management
Daniel Gonzaga, Eduardo Muñoz. Anesthesiologists in Mexican Social Security Institute

Background.
Fluid therapy and hemodynamics management are corner stones in the transoperatory. In a high risk surgery, as the renal transplantation, these parameters may represent the successful of the surgery.1 Deficient fluid therapy may cause organic hypoperfusion, but also fluid positive imbalances may produce incremental in morbidity and mortality in the critically ill patients. In the past the fluid therapy was based on mathematical calculations, with reposition of fasting, third space, nonsense looses, etc. But, there is a lot of information about fluid therapy guided by goals. 2
There are parameters used to guide fluid and hemodinamyc therapies, some of them called static and dynamic. The main difference is that dynamic could predict responsiveness to fluid therapy. 3
Renal chronic disease produce many changes, including fluid metabolism alterations, and is quite important make good decisions in fluid therapy. Renal transplant surgery implies a critical circumstance, which most be carefully in management. Make the
correct decision is not easy because common parameters as central venous pressure (CVP) and mean arterial pressure (MAP [static parameters]) do not represent correctly the hydric and hemodynamic patient status.4 Dynamic parameters as stroke volume variation (SVV), helped by cardiac index (CI) and systemic vascular resistance (SVR) could conjunctly predict fluid responsiveness and guide hemodinamyc management. 3
Goal of the study
Main objective was to compare and determine differences between conventional management and fluid and hemodynamic therapy guided with SVV and CI in renal transplant patient.
Material and methods
After approval of local Ethics board, was conducted a controlled clinical study performance at General Hospital in the National Medical Centre “La Raza” in Mexico city between March and December 2014. After simple randomization in two groups, 40 each one. Control Group (CG) received parental fluid, vasopressor and inotropic treatment to maintain CVP (Between 10-15 mmHg) and MAP (>90 mmHg), know as conventional management, mean while study group (VG), therapy was guide using FloTrac/Vigileo system by Edwards Lifesciences; if MAP < 90mmHg and VVS >12% = Fluid bolus, if VVS <12% and SVR < 800 d = Norepinephrine, if SVR normal and CI < 2.5 = Dobutamine. (See management algorithms).
Results
Eighty patients were included (40 per group). The two groups were comparable in demographic parameters. The first four comorbidities in both groups were: Type 2
Diabetes, Systemic Hypertension, Obesity and Pulmonary hypertension, no statistical differences between two groups.
Total amount of intravenous fluids in Control group was 2699 (3500-2300 ml) vs 2123 ml (1500-2250ml) in the Study group (p value: 0.015). Consumption of Dobutamine (287.8 vs 185.3 mcg/kg), was higher in Control group (p=0.023), there was no difference in Norepinephrine use between groups (23.8 vs 23.5, p=0.965), total urinary output was 328 in CG vs 410.5 ml in SG (p=0.680).

Conclusions
Management of liquids and hemodynamic therapies oriented by values of SVV, CI and SVR allows a better administration of liquids, inotropes and vasopressors, avoiding positive imbalances and their deleterious effects on patients receiving
kidney transplantation. Is quite important to use less fluids, but how much is too much or too less. That is why monitoring hemodynamic is crucial. 
We demonstrated that goal directed fluid therapy reduces the amount of fluids, but is not only the reduction but the precise moment (timing) for the fluid administration.

1. Cecconi M, et al. Clinical review: Goal-directed therapy - what is the evidence in surgical patients? The effect on different risk groups. Critical Care 2013, 17:209
2. Doherty M, Buggy D.J. Intraoperative fluids: how much is too much? BJA , Vol 1, No 11, 2012.
3. Sabatier C, et al. Assesment of cardiovascular preload and response to volume expansion. Med Intensiva. 2012;36(1):45-55
4. Yost CS, Niemann CU. Anesthesia for Abdominal Organ Transplantation. En: Miller R, editor. Miller’s Anesthesia. 7th edition. Churchill Livingstone Elsevier; 2010. p. 2161-2166

Copyright © 2014 Daniel Gonzaga, Eduardo Muñoz. General Hospital “La Raza”, Mexican Social Security Institute, Mexico City.

Cardiac index and stroke volume variation as parameters to guide fluid therapy and hemodynamic management in renal transplantation in comparison to conventional management