Comparison of goal directed hemodynamic therapy and conventional therapy on hemodynamic stability and perioperative clinical outcomes in patients undergoing sitting position neurosurgeries

Anesthesia for sitting position neurosurgeries is associated with a serious risk of hemodynamic instability due to various reasons. This hypotension can  potentially  compromise the  cerebral perfusion which leads to poor patient outcome. Hence, maintenance of an adequate preload with optimal fluid administration, and  prompt treatment of the hypotension are important goals during sitting position neurosurgeries. Perioperative goal-directed hemodynamic therapy (GDHT)  can help to optimize the cardiovascular dynamics, organ perfusion pressure, and tissue oxygen delivery, based on predefined target values of hemodynamic variables that reflect end-organ blood flow in these patients. In contrast to conventional management which is largely guided by vital signs. Hence in this study we aim to compare the effect of GDHT with  conventional hemodynamic  management during these  neurosurgeries. We hypothesize that GDHT provides superior  hemodynamic stability and better  perioperative patient outcomes than conventional hemodynamic  management  in patients undergoing sitting position neurosurgeries.

In GDFT group patients, A protocolized approach will be followed, based on the following hemodynamic indices (by ICON non invasive cardio meter, Osypka Medical GmbH). 

Patients with an SVV > 13 or FTC< normal for their range [based on patient’s body mass index (BMI)] will be considered as fluid responders, and will be given upto three boluses of Normal saline (0.9%) boluses (5ml/kg over 5 mins), till SVV < 13/ FTC within normal range.  Hypotension (>20 % decrease in MAP from the baseline or a MAP < 65mmHg) will be treated as follows:

Ephedrine (three boluses- 6mg IV each, at 5min intervals):   If SVRI < Normal range (based on patients BMI); and CI and contractility indices within normal limits (based on patient’s  BMI) .

Dobutamine (2-20 mcg/kg/min) if CI and  contractility indices  < Normal range (based on  patient’s  BMI)

Norepinephrine (0.01-0.1μg/kg/min) for refractory hypotension.

Colloid [Hydroxyethyl starches boluses (200 ml)] will be  given if  CI  < normal range and  SVV > 13 / FTC < normal range (based on patients BMI)

In conventional group patients,

Normal saline (0.9%) will be administered as a maintenance fluid, to maintain CVP between 6 and 8 mmHg and a urine output of ≥0.5 ml/kg/h.  In case of hypotension, administration of colloids (6% hydroxyethyl starch 130/0.4), vasoactive agents (ephedrine, norepinephrine) and inotropes (dobutamine) will be as per the  discretion of the attending neuroanesthesiologist.