Spinal anesthesia provides significant advantages over general anesthesia in knee arthroplasty, including reduced blood loss, faster recovery, and fewer complications. However, predicting its duration is critical for patient safety and effective postoperative management. This study evaluates the usability of machine learning (ML) algorithms to predict the termination time of spinal anesthesia and the patient's readiness for mobilization. Using demographic, surgical, and anesthetic variables, ML models were trained to estimate anesthesia duration. Accurate predictions may improve intraoperative planning, optimize postoperative care, and enhance patient outcomes. Integrating ML-based predictive systems into anesthesia practice can contribute to safer, more efficient, and personalized perioperative management.
Patients scheduled to undergo total knee arthroplasty between November 2025 and March 2026 at the Kocaeli City Hospital Operating Theaters.
Patients who have provided written informed consent to participate in the study.
Patients whose surgery is planned under spinal anesthesia.
Patients for whom complete clinical data can be obtained during the study period.
Patients who were converted to general anesthesia during surgery or initially operated under general anesthesia.
Patients who required postoperative intensive care unit (ICU) admission following anesthesia.
Patients who developed surgical complications and for whom postoperative mobilization could not be planned.
Patients with cognitive impairment preventing them from completing pain assessment scales in the postoperative period.
This study will include adult patients undergoing elective total knee arthroplasty (TKA) under spinal anesthesia at Kocaeli City Hospital Operating Theaters between November 2025 and March 2026. All participants will receive spinal anesthesia using 0.5% hyperbaric bupivacaine, and intraoperative monitoring will be conducted in accordance with institutional anesthesia standards. The study population represents a homogeneous surgical group in which spinal anesthesia is routinely applied, allowing for standardized anesthesia protocols and reliable measurement of anesthesia duration. Eligible patients will be classified as ASA Physical Status I or II and aged 18 years or older.
Cohort
Prospective
Spinal Anesthesia (bupivacaine)
Procedure/SurgeryBefore being placed on the operating table, the patient is positioned comfortably and prepared for the procedure. Standardized monitoring is initiated, including five-lead electrocardiography (ECG), non-invasive blood pressure (NIBP), and pulse oximetry (SpO₂). Baseline measurements of heart rate, systolic and diastolic blood pressure, mean arterial pressure (MAP), and oxygen saturation are recorded. An 18- or 20-gauge intravenous line is inserted, and an appropriate crystalloid preload is administered. After ensuring aseptic conditions, the patient is positioned in the sitting posture, and spinal puncture is performed at the L3-L4 or L4-L5 intervertebral space using a 25 Gauge Whitacre needle. Following free flow of cerebrospinal fluid, 0.5% hyperbaric bupivacaine (10-15 mg) is slowly injected. The completion of the injection is
Predictive performance of machine learning
The primary outcome of this study is the predictive performance of machine learning (ML) algorithms in estimating the duration of spinal anesthesia (in minutes) based on preoperative and intraoperative variables. in: R² (Coefficient of Determination). Dimensionless (no unit)
spinal anesthesia termination time
It is the period of time from the moment of completion of spinal anesthesia until the complete resolution of motor blockade in the patient's lower extremities.
Visual Analogue Scale
A tool used to help a person rate the intensity of certain sensations and feelings, such as pain. The visual analog scale for pain is a straight line with one end meaning no pain and the other end meaning the worst pain imaginable. A patient marks a point on the line that matches the amount of pain he or she feels. It may be used to help choose the right dose of pain medicine.
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