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Background and Aims Tourniquet use in orthopedic surgeries aids in creating a bloodless surgical field but can lead to complications, notably pain. This study primarily aimed to assess the effectiveness of subanesthetic ketamine in preventing tourniquet-induced hemodynamic responses during arthroscopic knee surgery of adult patients.

Methods This was a retrospective, analytical, observational, cohort type of an epidemiological study conducted at a tertiary care center from March 2023 to November 2023. Forty five adult patients who had arthroscopic surgery of the knee were evaluated to assess the effectiveness of subanesthetic intravenous ketamine for tourniquet pain relief, 21 had received ketamine and 24 did not. The endpoints of this study were changes in the vital signs (systolic blood pressure and heart rate) and use of intraoperative fentanyl.

Results There was a significant decrease in the heart rate of ketamine group at the 45 and 60-minute intervals. In contrast, systolic and diastolic blood pressure measurements did not show noticeable disparities among the groups at most time points, indicating that ketamine’s impact on blood pressure was minimal. The overall usage of intraoperative fentanyl was low in both groups, with a minor increase observed in the non-ketamine group in the later stages of surgery. However, this observed pattern did not achieve statistical significance.

Conclusions A subanesthetic intravenous ketamine dose contributes to a significant reduction in the heart rate during arthroscopic knee surgery, without substantially impacting blood pressure or the need for additional opioid such as the fentanyl.