Observational dose study of intrathecally administered prilocaine in lower extremity surgery

Spinal anesthesia is a commonly preferred anesthetic technique in lower extremity surgeries. The type and dose of local anesthetic used in this method vary depending on the duration of the surgery and patient-specific factors. In our study, we aimed to reduce the routine prilocaine dose used in our clinic to achieve adequate surgical anesthesia while minimizing potential side effects, accelerating patient mobilization, reducing hospital stay and costs, and enhancing patient satisfaction. In this prospective observational dose study included 72 patients aged between 18-65 years, classified as ASA I/II, who underwent lower extremity surgery under spinal anesthesia with an operative duration of less than 60 minutes. Ethical approval was obtained before the study. Demographic data, comorbid conditions, ASA scores, and types of surgery were recorded. Spinal anesthesia techniques, type of needle used, experience of the performing anesthesiologist, and prilocaine dose were documented. Patients were monitored perioperatively, in the postoperative PACU, and in the surgical ward. Perioperative hemodynamic data, block level assessments, mobilization time, first spontaneous voiding time, NRS pain scores, time to first analgesic request, opioid consumption, complications, length of hospital stay, and patient satisfaction were recorded and evaluated. Hemodynamic stability was maintained in all patients across the prilocaine doses used, and an effective surgical process was achieved. Increasing the prilocaine dose resulted in a higher maximum sensory block level and a significantly prolonged block resolution time (p<0.05). Patients receiving lower doses of prilocaine had an earlier time to first spontaneous voiding (p<0.05). Although there was no statistically significant difference between groups regarding mobilization and discharge times, we believe that establishing standardized discharge criteria based on individual patient conditions may lead to earlier mobilization and discharge. This could potentially reduce hospital stay duration and overall costs. Keywords: Lower Extremity, Intrathecal Prilocaine, Prilocaine Dose, Spinal Anesthesia