Perioperative Hemodynamic Optimization in High-Risk Patients Using Less-Invasive Monitoring Methods
Perioperative Hemodynamic Optimization in High-Risk Patients Using Less-Invasive Monitoring Methods
The aim of this study is to evaluate different strategies of hemodynamic optimization in high
 risk surgical patients during the first twelve postoperative hours in ICU based on a protocol
 guided by a less invasive monitorig tool (Vigileo®), oriented by a fiberoptic central venous
 catheter that allows continuous monitorig of SvcO2 (PreSep®), and a pressure transducer
 (FloTrac®) that allows cardiac output calculation by the standard deviation of mean arterial
 pressure or a standard resuscitation strategy.
Patients submitted to high risk surgical procedures generally show a hyperdynamic pattern due
 to the metabolic response after the surgical trauma. This response is fundamentally dependent
 on their functional reserve and on the treatment. Data from UK show an aged population with
 15 to 30% of mortality in the first thirty days after surgery, generally having respiratory
 or cardiac co-morbidities1. Identification of these patients besides protocol implementation
 aiming to an appropriate support is the basic strategy to warrant a better outcome in the
 post-operative period.

 Shoemaker has established the definition criteria to high risk patients at the end of the
 80's. Those criteria are accepted until today. He too demonstrated the benefits of
 hemodynamic optimization in order to achieve "supra-normal" oxygen delivery.

 Unfortunately, in the years to come, there was a backlash in this concept due to results of
 several heterogeneous and misleading studies that cast doubts about the efficacy of that
 strategy. Heyland, however, observed benefit when the hemodynamic optimization was instituted
 before the surgery.

 In the 90's, support to high risk surgical patients had a new start, with publication of
 several studies demonstrating reduction on morbidity, mortality, and hospital and ICU lengths
 of stay. In a recent metaanalysis of twenty one studies, Kern and Shoemaker concluded that
 there was mortality reduction when hemodynamic optimization was started early before organ
 dysfunction has ensued. There was greater benefit in those studies where the control group
 had a 20% mortality or more and when the therapy achieved differences on oxygen delivery
 between the control and treatment groups.

 Despite the strong evidence favoring hemodynamic optimization, as long as the high risk
 patients are identified, more studies are necessary to better answer some questions such as:
 what is the importance of volemic replacement, what is the best solution to be used, and what
 is the best method for monitoring for the patient response. Catecholamines must be used
 carefully, despite their theoretic capacity of modulating inflammatory response. It appears
 that optimization has to be done early in the pre-operative period when organ dysfunction has
 not ensued yet. We have to discover for how long the optimization has to be maintained during
 and after the surgery.
Inclusion Criteria:

 -  Age > 18 years

 -  High risk elective surgeries* according to adapted Shoemaker criteria.

 -  Request of post-operative support by the surgeon and anesthetist.

 -  Patients that have need of central venous and arterial catheters according to surgeon,
 critical care physician or anesthetist evaluation.

 -  Informed consent will be obtained from all patients enrolled or their next of kin.

 Exclusion Criteria:

 -  Patients with terminal disease, submitted to palliative surgery;

 -  Cardiac failure class IV of NYHA;

 -  Chronic renal failure without dyalisis and intolerant to fluids;