Minimum local anesthetic dose of ropivacaine in real-time ultrasound-guided intraspinal anesthesia for lower extremity surgery: a randomized controlled trial

Abstract

Background: Despite the many advantages real-time ultrasound-guided lumbar anesthesia has over traditional lumbar anesthesia, it seemingly involves a much higher dose of ropivacaine. This study aimed to determine the minimum local anesthetic dose (MLAD) and the 95% confidence interval of ropivacaine at different concentrations in real-time ultrasound-guided lumbar anesthesia for lower extremity surgery.Methods: A total of 60 patients who were consecutively scheduled for selective lower extremity surgery were enrolled. The patients were randomly divided into two groups, which each received different concentrations of ropivacaine at different initial dosages when Dixon's up-and-down sequential method was applied. The high ropivacaine group and the low ropivacaine group received 0.75% and 0.5% ropivacaine, respectively. The patients' baseline characteristics, the MLAD, and the 95% confidence interval were assessed. The highest level of sensory block, time to reach the T10 sensory block, duration for sensory blocks higher than T10, highest plane for sensory block, and onset time and duration for motor block were recorded. Comparisons were also made between the patients' vital signs and adverse reactions. Results:The minimum local anaesthetic dose (MLAD) and 95% confidence interval in the high ropivacaine group and the low ropivacaine group were 17.176 (16.276 to 18.124) and 20.192 (19.256 to 21.174) mg, respectively. Moreover, motor block maintenance was greatly reduced in the 0.5% ropivacaine compared to the 0.75% ropivacaine group (P=0.0309). Conclusions:In real-time ultrasound-guided intraspinal anesthesia for lower extremity surgery, both 0.75% and 0.5% ropivacaine provide satisfactory anesthesia. Our results suggest that shortened motor block duration can hold benefits for patients including earlier mobilization and a quicker rehabilitation process.

Observation of Anesthetic Effect of Dexmedetomidine Combined With Intraspinal Anesthesia in Hip Arthroplasty and its Effect on Postoperative Delirium and Stress Response

“…In addition, due to slow drug metabolism, patients are prone to delayed awakening or even temporary brain dysfunction after surgery, which increases the risk of complications and affects the patient's rehabilitation (16,17). Previous studies have found that intraspinal anesthesia has the characteristics of good analgesic effect, small drug consumption, and the block range is limited to one side, which can effectively reduce the sympathetic activity and reduce vasodilation, thereby reducing the damage to the circulatory system and the occurrence of adverse events, and effectively meeting the basic needs of hip replacement in the elderly (18,19). Our patient avoided endotracheal intubation and mechanical ventilation with relatively low respiratory complications; The incidence of nausea and vomiting is low; Epidural analgesia can be performed with good postoperative analgesic effect.…”

Spiral Computed Tomography Imaging Analysis of Positioning of Lumbar Spinal Nerve Anesthesia under the Concept of Enhanced Recovery after Surgery

“…Intraspinal anesthesia (lumbar spinal nerve anesthesia) is a kind of local anesthesia, which is currently very common in clinic. According to the different injection positions, it can be divided into epidural anesthesia, combined spinal epidural anesthesia, and subarachnoid anesthesia (also known as spinal anesthesia/lumbar anesthesia) [ 1 – 3 ]. Lumbar spinal nerve anesthesia is widely used in cesarean section, lower limb surgery, hemorrhoidectomy, and the supplementary treatment of cardiovascular diseases [ 4 , 5 ].…”

A study to compare 0.5% hyperbaric bupivacaine with 0.5% isobaric ropivacaine intrathecally for elective lower limb surgery.

“…More patients develop bradycardia and need the sympathomimetic drug 4 . The newly introduced drug, i.e., ropivacaine, has a more specific effect on the motor nerve fibers [5][6][7] . Furthermore, this drug has lesser cardiac toxicity 8 .…”