Volume Optimisation and Cognitive Function in Major Abdominal Surgery
Condition: Cognitive Decline
MeSH terms: Cognitive Dysfunction
Study type: Interventional

Summary: 
      In the last 25 years, there has been a lot of attention directed on reducing perioperative
      morbidity and mortality by improving intraoperative monitoring and hemodynamic optimisation
      of patients. Advanced monitoring devices and new parameters have shifted the focus of
      anaesthesia management from macro- to micro circulation with the emphasis on the determinants
      of oxygen delivery and tissue oxygenation. There is increasing evidence that long-term
      outcome is improved by goal-directed optimisation of hemodynamic parameters (optimisation of
      stroke volume and cardiac output by fluids and inotropic and vasoactive drugs). Besides, new
      monitoring possibilities (depth of anaesthesia and cerebral and tissue oxygenation monitors)
      and adherence to protocols have proved beneficial in reducing morbidity cognitive
      dysfunction.

      However, questions are raised what the optimal goals (healthy population derived normal
      values, preoperative values, maximal values, restrictive fluid management) should be.
      Secondly, all new methods were used separately and there is a lack of studies to show the
      effect of combined (multimodal) monitoring on occurrence of cognitive dysfunction. All
      gathered data indicate that the combined use of new methods with adherence to an appropriate
      protocol might radically improve the perioperative management and outcome of high-risk
      surgical patients.

      The present study tests the hypothesis that intraoperative multimodal monitoring with
      hemodynamic optimisation, BIS-guided anaesthesia and maintenance of optimal cerebral oxygen
      saturation will reduce cognitive dysfunction.
    

Detailed description: 
      BACKGROUND There is increasing evidence that intraoperative aesthetic management influences
      outcomes. (5). Besides this the occurrence of low MAP, low minimum alveolar concentration
      (MAC) and low bispectral index (BIS) increased hospital stay and mortality.

      Conventional intraoperative monitoring can result in occult low levels of blood flow and
      oxygen delivery that lead to complications that only occur days or weeks following surgery
      and give false re-assurance to the anaesthetist that he or she is doing a "good job".
      Advanced monitoring devices and new parameters have shifted the focus of anaesthesia
      management from macro- to microcirculation with the emphasis on the determinants of oxygen
      delivery and tissue oxygenation. There are more and more trials showing that introduction of
      new monitors and treatment protocols with predefined treatment limits or targets
      (goal-directed optimisation of hemodynamic parameters) improves long-term patient outcome and
      reduces morbidity and mortality by over 50%. Several studies have shown benefit when
      individualised; targeted oxygen delivery algorithms incorporating both fluid resuscitation
      and vasoactive drugs were used with high-risk surgical patients. The measurement of regional
      cerebral oxygen saturation can predict cognitive dysfunction after cardiac surgery. BIS
      monitoring facilitates anaesthetic titration, and reduced anaesthetic exposure and decreased
      the risk of postoperative cognitive dysfunction. There is reduction in strokes, less
      mechanical ventilation and shorter length of stay (LOS) with the use of INVOS.

      However, all new methods have been studied separately and there is a lack of studies to show
      the effect of combined (multimodal) monitoring on mortality and occurrence of complications,
      including cognitive decline. All gathered data indicate that the combined use of new methods
      (assessment of fluid status, depth of anaesthesia and tissue oxygenation) with adherence to
      appropriate protocol might radically improve perioperative management and outcome of
      high-risk surgical patients.

      Besides, questions are raised what the optimal goals (healthy population derived normal
      values, preoperative values, maximal values) should be. Lately, studies have shown that
      optimising cardiac output and oxygen delivery to higher (supra-normal) values intra- and
      postoperatively did not affect post-operative complications rate, intensive care unit stay or
      hospital length of stay. Probably the target should be maintaining patient's blood flow and
      oxygen delivery at preinduction levels. The question was also raised in fluid management.
      Liberal approach can lead to oedema of the intestines and other tissues, which may be
      responsible for poor tissue healing and other complications. In abdominal surgery,
      protocol-based fluid restriction reduced the incidence of perioperative complications such as
      cardiopulmonary events and disturbances of bowel motility while improving wound and
      anastomotic healing and reducing hospital stay in comparison to liberal fluid management. One
      of the trials has shown 52% lower rate of major postoperative complications in restrictive
      group than in the conventional group.

      HYPOTHESIS The present study tests the hypothesis that intraoperative multimodal monitoring
      with hemodynamic optimisation, BIS-guided anaesthesia and maintenance of optimal cerebral
      oxygen saturation will reduce cognitive decline.
    

Intervention name(s): multimodal monitoring; placebo
Intervention type(s): Device; Device
Intervention description(s): LiDCO Rapid, unilateral INVOS and unilateral BIS monitors will be applied. Should there be pre-existing carotid stenosis, INVOS sensor will be applied on the same side. In case of pre-existing cerebral pathology, the INVOS sensor will be applied to the contralateral side. Baseline values of nominal stroke index (SI), cardiac index (CI), BIS, mean arterial pressure (MAP) and regional oxygen saturation (rSO2) will be recorded. Basal rSO2 will be recorded prior to preoxygenation which raises the value. • Before the induction, up to 250ml of balanced crystalloid solution will be administered. These will include antibiotics solvents and other pre-induction i.v. therapy.; Before the induction, up to 250ml of balanced crystalloid solution will be administered. These will include antibiotics solvents and other pre-induction i.v. therapy.
Other intervention name(s): LiDCO Rapid, unilateral INVOS, unilateral BIS
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Prevention
Keywords: cognitive decline; hemodynamic monitoring; LIDCO; INVOS; BIS; brain injury biomarkers