Assessment of pleth variability index (PVI)'s efficiency on intraoperative fluid management in spinal surgeries

In major surgeries, monitorization of fluid and blood treatment is very important on avoiding related complications. ''Pleth variability index'' (PVI) is a method based on respiratory changes in arterial pulse pressure, and also allows non-invasive measurement of fluid treatment. In our prospective study; we aim to compares two methods of intraoperative fluid management on major surgeries: classical measurement method with CVP chasing and management by PVI changes due to hydration. 100 patients, above 18 ages, ASA Class I or II, who have had elective posterior stabilization surgery in Celal Bayar University Medicine Faculty Hospital, included in this study. In all patients had operated, ECG, noninvasive blood pressure, peripheral O2 saturation, ETCO2, end-tidal sevoflurane concentration (eSevo), inspirational sevoflurane concentration (iSevo), temperature (nasopharyngeal) and bispectral index (BIS, Aspect 1000 TM, Aspect Medical Systems nc., Natick, MA, USA) had monitored. In all patients who had general anesthesia, invasive artery and central venous pressure (CVP) had monitored. Patients had separated two randomized equal (n=50) groups. In Group K (chasing with CVP group) fluid requirement replacement, maintenance and insensible loss (4 mL/kg/h) calculated and replaced with crystalloid fluids. In Group PVI, 250 ml crystalloid has given in 5 minutes to patients with >14 PVI. 4 mL/kg/h fluid infusion started to patients with <14 PVI value. Blood loss during surgery was replaced. To all patients; heart rate, mean arterial pressure, peripheral O2 saturation and CVP measured in minutes of 0, 5, 10, 30, 60, 90, 120, 150, and also arterial blood gases (ABG) sample taken because of chasing levels of lactate, hemoglobin, hematocrit on starting of case, in case, end of the case and all values has recorded. In Group PVI; by adding this records, PVI, PI and SpHb values are measured in every 5 minutes. Acquired values have compared in-group and between-groups. Correlation between PVI and CVP changes associated with fluid treatment during surgery has observed during study, and has reported. In comparison fluid management of groups; intraoperative given fluid measure is 3522±1098.1 in Group K and 1914±542.86 in Group PVI. The significant difference has determined in Group K and Group PVI about total given intraoperative fluid volume (p<0.05). Intraoperative given erythrocyte suspension is 0.42±0.57 in Group K and 0.08±0.27 in Group PVI (p<0.05). There is no significant difference between two groups about postoperative given erythrocyte suspension (p>0.05). Also there is no significant difference between Group K and Group PVI about intraoperative hemoglobin values (p>0.05). In Group PVI, there is significant difference in a positive way on analyzing the correlation of SpHb and ABGHb values at 0. and 90.minutes. All in all; is has thought that PVI method is more valuable method than CVP chasing method, because it is non-invasive, gives a chance on having cardiac stability by giving less fluids, and gives more reliable results on assess patient's intravascular fluid volume.