Determination of the median effective dose (ED50) of bupivacaine and ropivacaine unilateral spinal anesthesia

Abstract

BackgroundUnilateral spinal anesthesia (USpA) has been reported to potentiate spinal anaesthesia and is used in geriatric patients. The purpose of this study was to determine the median effective dose (ED50) of 0.5% hypobaric bupivacaine and 0.5% hypobaric ropivacaine USpA for geriatric patients (age ≥ 70 years) undergoing elective hip replacement surgery.MethodsA total of 60 geriatric patients (age ≥ 70 years) undergoing elective hip replacement surgery were enrolled in this study. The patients were randomized into 2 groups to receive either intrathecal 0.5% hypobaric bupivacaine USpA (group B) or 0.5% hypobaric ropivacaine USpA (group R). Effective anesthesia was defined as a T10 sensory blockade level maintained for more than 60 min, and a Bromage score of 3 on the operation side within 10 min after injection with no additional epidural anesthetic required during surgery. The ED50 of 0.5% hypobaric bupivacaine and 0.5% hypobaric ropivacaine was calculated using the Dixon and Massey formula.ResultsNo significant differences were found between the two groups in terms of demographic data. The ED50 of 0.5% hypobaric bupivacaine USpA was 4.66 mg (95% confidence interval CI 4.69–4.63 mg) mg and that of 0.5% hypobaric ropivacaine USpA was 6.43 mg (95% CI 6.47–6.39 mg) for geriatric patients undergoing hip replacement surgery.Conclusion We find the ED50 were lower, and the ED50 of 0.5% hypobaric bupivacaine and ropivacaine was 4.66 mg (95% CI 4.69–4.63 mg) and 6.43 mg (95% CI 6.47–6.39 mg), respectively, for USpA in geriatric patients (age ≥ 70 years) undergoing elective hip replacement surgery.

The Median Effective Dose of Dexmedetomidine for the Inhibition of Emergence Delirium in Preschool Children Undergoing Tonsillectomy and/or Adenoidectomy: A Retrospective Dose-response Trial

“…The advantage of this method is that a small sample is sufficient, but the disadvantage is that the results are not accurate enough because the sample size at the extreme dose is only 1-3, which leads to serious bias. 24,25 In this study, a large sample of 140 children were included in a wide range of dose groups (7 doses), and thus, the results were less biased and highly reliable.…”

Dose Selection of Ropivacaine for Spinal Anesthesia in Elderly Patients with Hip Fracture: An Up-Down Sequential Allocation Study

“…First, the puncture site for spinal anesthesia was L 2-3 , considering that previous studies have provided some dosage options for L 3-4 . 25 , 29 And due to factors such as hyperosteogenesis and ligament calcification in elderly patients, 30 there are always some cases of failed puncture in the L 3-4 space. At that time, L 2-3 is a safe additional choice.…”

Efficacy of Prophylactic Mg Infusion for Reducing Shivering and Extend the Duration of Analgesia Caesarean Section with Spinal Anesthesia

“…Sensory and motor assessments were performed at 1 min intervals using pinprick testing and the modified Bromage score, respectively. Surgery began when adequate anesthesia to the T6 dermatome was achieved [14]. The duration of surgery (from initial skin incision to the last stitch) were recorded, as were hemodynamic changes and the amount of irrigation fluid used during the procedure.…”

“…Hypotension was treated with intravenous doses of ephedrine. Shivering was graded with a scale similar to that validated by Crossley and Mahajan [14]. Grades were as follows: 0 no shivering; 1 piloerection or peripheral vasoconstriction with no visible shivering; 2 muscular activity in one muscle group; 3 muscular activity in > one muscle group, but not generalized shivering; and 4 shivering involving the whole body.…”