Evaluation of the ability of perfusion index and pleth variablity index to predict volume changes

OBJECTIVES: The objective of this study is to evaluate the ability of perfusion index and pleth variability index to predict volume changes. METHODS: In our prospective cross-sectional analytical study, the patients were assigned to two groups. Volume replacement group included patients older than 18 years and who received 1000 cc of normal saline as a part of their routine treatment in Department of Emergency Medicine, Ege University. Volume displacement group included blood donors older than 18 years. Adults in both groups gave written consent. In both group, before and after the procedures, vitals, shock indices, cardiac output calculated via ultrasound, inferior vena cava index, perfusion index and pleth variability index were recorded. RESULTS: A total of 101 patients were included in volume replacement group and two patients were excluded because of the instable vitals and drug effect. 104 patients were included in volume displacement group. In volume replacement group, the mean age was 34±15. 61,6% were male and 38,4% were female. Means of pulse rate (81,4±12,9 beat/min and 77,5±11,2 beat/min; p<0,001), shock index (0,680 ± 0,127 and 0,657 ± 0,125; p=0,024), cardiac output (5,3 ± 1,3 L/min and 5,7 ± 1,5 L/min; p = 0,001) and PI (%9,2 ± 6,9 and %6,7 ± 5,2; p = 0,003) were changed statistically significantly before and after procedure, respectively. In volume displacement group, the mean age was 32±8. 95,2% was male and 4,8% was female. Means of means arterial pressure (94,6±8,6 mmHg and 88,6±10,7 mmHg; p<0,001), shock index (0,598 ± 0,092 and 0,629 ± 0,106; p < 0,001), cardiac output (5,1±1,2 L/min and 4,5±1,1 L/min; p<0,001) and PVI (%20,8±8,2 and %26,1±11,7; p <0,001) were changed statistically significantly before and after procedure, respectively. In volume replacement group, change in PI and PVI showed no correlations with the change in other parameters. In volume displacement group, change in PVI was moderately correlated with the change in cardiac output (r=0,370; p<0,01) and change in PVI was moderately correlated with the change in shock index (r=0,306; p<0,01). DISCUSSION: PI decreased statistically significantly during volume replacement, but no correlation was showed between change in PI and PVI and change in other variables. PVI increased statistically significantly during volume displacement. In volume displacement group, change in PI was moderately correlated with change in cardiac output, and PVI was moderately correlated with change in shock index. In both groups, in spontaneously breathing adults, but the direction of the changes were unpredictable. Therefore, PVI may show the volume changes in groups but its use is limited in individuals. Keywords: Perfusion Index, Pleth Variability Index, Fluid Responsiveness, Cardiac Output, IVC Index