Objective: We must strive to minimize the intraoperative and postoperative risks for patients who will undergo surgery. In the treatment of obesity, which is becoming an increasingly pressing issue, bariatric surgery has become a recommended option for suitable patients. This study aimed to minimize potential complications in obese patients by considering the frequency of cardiac problems and using preoperative fluid therapy. Material and Methods: The study included 31 obese patients with a Body Mass Index of 30 or above, aged 18-50, who were in the American Society of Anesthesiologists Physical Status Classifications 1-2 group and were scheduled to undergo laparoscopic sleeve gastrectomy. Patients were randomly divided into two groups. The first group did not receive fluid therapy during the preoperative period. In the second group, intravenous crystalloid fluid was administered at a rate of 10 ml/kg/hour over 3 hours in the preoperative period, based on their ideal weight. Cardiac output, stroke volume variation, and stroke volume index measurements were taken at specific times intraoperatively in patients from both groups. These parameters were compared between the groups. Results: Among the cardiac parameters measured with the FloTrac™ sensor, only the stroke volume variation values measured after extubation showed a difference between the groups. There was no statistically significant difference between the groups for the other values. Conclusion: The cardiac output, stroke volume variation, and stroke volume index values measured at various times during the surgery are similar between patients who received preoperative fluid therapy and those who did not. There is a need for more comprehensive studies that involve different fluid therapy models and more patients in this area.