Anesthesia and surgery
normovolemia
DECUBITUS
After patients arrived in the operating room, standard monitoring, including non-invasive blood pressure, electrocardiography, and pulse oximetry was initiated. Non-invasive blood pressure (NIBP) was measured in the contralateral arm to the surgical site with 2.5-min intervals throughout the surgery, while electrocardiography, and pulse oximetry were monitored continuously. To maintain normovolemia, PVi (Radical-7®, Masimo Corp., Irvine, CA, USA), a dynamic index of fluid responsiveness, was also continuously monitored on ipsilateral arm to the surgical site. Oxygen was supplied at 5–6 L/min via a simple facemask.An intravenous peripheral line was accessed at the ipsilateral hand or forearm, and the patients were positioned into their lateral decubitus position. The standard practice was to position patients in a lateral decubitus position with the surgical site downward. However, if the patients expressed discomfort regarding the position, they were placed in a lateral decubitus position with the surgical site upward. SA was performed with hyperbaric bupivacaine 10 mg and fentanyl 15 µg, using 25-gauge needle after skin disinfection. Then, the patients were returned to the supine position, and the insertion of the foley catheter was performed. Intravenous co-hydration with 300 mL of crystalloid was initiated immediately after completion of the intrathecal injection. The success and level of SA was examined on both the left and right sides at 5 min after the intrathecal injection. As all surgeries were conducted in the lateral decubitus position, patients were positioned laterally with the surgical site facing upward. Norepinephrine or normal saline and propofol were connected, and the continuous infusion of norepinephrine or normal saline was initiated through the inserted peripheral line. Propofol was also infused using a target-controlled infusion system (effect-site concentration 1.0–1.5 µg/mL), and was adjusted to maintain a BIS between 60 and 80 and modified observer’s alertness/sedation scale of 3 (responds only after name is called loudly and/or repeatedly). The intraoperative volume status was monitored using PVi values. Considering that the patients were spontaneously breathing and referencing the results of a previous study, fluid was administered to maintain PVi < 19%