4. Discussion
postoperative pain, hypertensive, hypotension, pain
SECONDARY, HYPOTENSION DURING SURGERY
This study examined the impact of a single 0.2 mg/kg dose of esketamine administered at the beginning of induction on various hemodynamic parameters during bariatric surgery. Our primary outcome measure, blood pressure (SBP, DBP, and MAP) before intubation (T2), showed a statistically significant increase in the esketamine group compared to the control group, consistent with previous research findings.Furthermore, we observed that overall blood pressure levels (SBP, DBP, and MAP) from T2 until 5 minutes after incision (T7) were statistically higher in the esketamine group than in the control group. However, it is important to note that the clinical significance of this increase may be limited, potentially due to the relatively low dose of esketamine used in this trial.Our initial hypothesis was that esketamine administration would lead to a reduction in the incidence of hypotension during the induction of anesthesia. Our findings support this hypothesis, as we observed a significant decrease in the incidence of hypotension at key points, including just before intubation (T2), 5 minutes after intubation (T4), at the time of incision (T5), and 5 minutes after incision (T7). Therefore, we recommend the use of a single dose of 0.2 mg/kg esketamine during the induction phase of bariatric surgery procedures.Additionally, we found that the NRS scores at the 24th hour and the use of rescue analgesics were also significantly lower in the esketamine group compared to the control group. This finding is consistent with previous studies, some of which employed higher doses of esketamine (0.25 mg/kg, 0.4 mg/kg).Although HR differences were statistically significant after the administration of dexmedetomidine 0.5 µg/kg for 10 minutes in the esketamine group, these differences were clinically negligible and occurred before esketamine administration. However, HR remained consistently lower in the esketamine group from T2 to T7, with no significant clinical or statistical implications. Other secondary outcomes did not demonstrate clinical or statistical significance.In summary, our findings suggest that a single dose of 0.2 mg/kg esketamine during the induction phase of anesthesia in bariatric surgery patients can significantly reduce the incidence of hypotension during induction and lead to a slight overall increase in blood pressure. Additionally, it appears to decrease postoperative pain at the 24th hour and reduce the need for rescue analgesics. We recommend routinely administering a single dose of 0.2 mg/kg esketamine during the induction phase of anesthesia in bariatric surgery patients to stabilize blood pressure and prevent the incidence of hypotension during surgery. Future studies may explore the use of higher esketamine doses, considering that this study found that the overall increase in blood pressure was not significant. Importantly, our study implies that administering a low dose of esketamine to hypertensive patients should not pose significant risks to their blood pressure stability, offering potential benefits in terms of pain management and opioid reduction.Limitations of this study include its single-center nature, which may impact the generalizability of the results, and the predominance of sleeve gastrectomy patients due to its popularity compared to Roux-en-Y bypass surgery.