A Randomised Controlled Study Comparing Pulse Pressure Variation (PPV) and Pleth Variability Index (PVI) for...

Fluid management in the perioperative period is a grey zone in clinical practice of late. Looking back on previous practices, static parameters were the only options. Now, dynamic parameters indicating fluid responsiveness have become a significant part of goal-directed fluid therapy (GDFT). However, the efficacy of this approach has yet to be established in neurosurgery cases where patients are already on lot of diuretics, thus making fluid management more challenging. The present study aims to determine the efficacy of the Pleth Variability Index (PVI) with pulse pressure variation (PPV) in guiding GDFT in patients undergoing neurosurgery for supra-tentorial intracranial space occupying lesions (ICSOLs), in the form of a randomised controlled trial. After randomisation, the patients were categorised into either PVI or PPV groups. Both received a baseline 2 ml/kg/h Lactated Ringer's (RL) infusion. Additional fluid boluses consisted of 250 ml of colloid infused over a 10 min period if PVI was > 15% or PPV was > 13% for at least five minutes. The primary outcome was to determine the serum lactate difference between preoperative and postoperative values, which could fairly predict fluid deficit leading to inadequate perfusion. A total of 74 patients were analysed. Both PVI- and PPV-guided GDFT strategies showed no significant difference in the postoperative lactate values, with a P-value of 0.18. Similarly, the mean total fluid administered, mean blood loss, length of CCU stay, and emetic and hypotension episodes also showed no significant differences among the groups with P-values of 0.41, 0.78, 0.25, 0.30, and 0.67, respectively. For patients undergoing neurosurgery (supratentorial ICSOLs), PVI seems to guide GDFT comparably to PPV regarding tissue perfusion and postoperative complications. However, both the parameters had low sensitivity and specificity, with an area of curve of 0.577 for PPV and 0.423 for PVI, as far as GDFT was concerned.