The effect of isotonic infusion on preventing hypotension that will occur with anesthesia induction in patients whose fluid deficit is predicted by pleth variability index

İntroduction: Various factors such as preoperative fasting, anesthetic agents, and positive pressure ventilation for surgical patients all contribute to the reduction of effective circulating blood volume. Patients who will undergo anesthesia often present with an intravascular volume deficit. Pleth variability index (PVI) is a new method that provides automatic and continuous calculation of respiratory variations in pulse oximetry waveform amplitude. The Pleth variability index has been shown to predict fluid sensitivity as accurately as stroke volume variation. The aim of this study is to observe the effects of 500 ml isotonic %0,9 NaCl infusion in preventing hypotension that will occur with anesthesia induction in patients with predicted intravascular volume deficit with PVI. Method: A prospective, randomized, controlled study was conducted between the ages of 18-80, ASA (American Society of Anesthesiologists) I-II, PVI > 15%; 260 patients requiring general anesthesia, mechanical ventilation and endotracheal intubation were included. Induction was achieved with 2 mg/kg propofol and 0.6 mg/kg rocuronium in both groups. While no additional medical treatment was applied to Group 1 before induction of anesthesia, Group 2 was administered as 500 ml isotonic %0,9 NaCl infusion for 10 minutes. Demographic data of the patients, preoperative PVI, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse and saturation values were recorded at 1, 2 and 3 minutes after induction. Results: In Group 1, MAP <65 mmHg in 38.4% of the patients at the 3rd minute after induction; In Group 2, MAP <65 mmHg was found in 6.9% of the patients. After induction, SBP, DBP and MAP values of Group 2 were higher. The PVI values in Group 1 were found to be higher than Group 2 at the 1st, 2nd, and 3rd minutes after induction. Conclusion: By replacing the fluid deficit predicted with PVI in preoperative patients, the frequency of hypotension that may occur due to propofol in anesthesia induction can be reduced. Key Words: Pleth variability index; induction of anesthesia; hypotension; serum physiological; propofol .