A Height-Based Dosing Algorithm of Bupivacaine in Spinal Anesthesia for Decreasing Maternal Hypotension in Cesarean Section Without Prophylactic Fluid Preloading and Vasopressors: A Randomized-Controlled Non-Inferiority Trial

Abstract

BackgroundThere is a high incidence of maternal hypotension in spinal anesthesia for cesarean section. The aim of the study is to investigate whether there is a height-based dosing algorithm of bupivacaine that provides adequate anesthesia with less maternal hypotension.MethodsThere were 2 groups of 280 parturients who did not receive prophylactic fluid preloading: Test and Conventional group. In Test group, a height based dosing algorithm was used to confirm the dose of bupivacaine in parturients without prophylactic vasopressors. In the Conventional group, a constant dose of bupivacaine was used. The complications and quality of anesthesia were evaluated.ResultsIn the Conventional group, the shorter participants had higher incidence of hypotension, faster sensory block time, and more participants with complete motor block (p = 0.030, 2.957 × 10−14, and 0.012). In the Test group, the incidence of hypotension, sensory block time, and number of participants with complete motor block did not change with height (p = 0.199, 0.617, and 0.209). The height-based dosing algorithm of bupivacaine decreased the incidence of hypotension (p = 0.004), induced lower sensory block level and less degree of motor block (p = 3.513 × 10−7 and 5.711 × 10−11). The quality of analgesia, quality of muscle relaxation, and degree of intraoperative comfort were similar in both groups (p = 0.065, 0.498, and 0.483).ConclusionsThe height influences the dose of bupivacaine in spinal anesthesia; without prophylactic fluid pre-loading and vasopressors, the height-based dosing algorithm of bupivacaine is suitable, and meets the cesarean section' requirement with less maternal hypotension.Clinical Trial Registrationwww.ClinicalTrials.gov, identifier: NCT03497364.

Anesthesia characteristic of an algorithm of bupivacaine dose based on height in caesarean section under spinal anesthesia: a retrospective cohort study

“…However, the height is associated with vertebral column length [ 7 ], which has an influence in the block level [ 8 ]. Thus, the local anesthetic’s dose should have an association with the height, which is confirmed by two studies [ 1 , 9 ]. In our last article, when using a constant bupivacaine dose, the shorter parturients have a higher occurrence rate of hypotension, a faster sensory block time or a higher proportion of complete motor block [ 1 ].…”

“…In previous study, we preliminarily verify that the bupivacaine dose depends on the parturient’s height in caesarean section under spinal anesthesia [ 1 ], but which needs to be further investigated. In addition, we have develop an algorithm of bupivacaine dose based on height in spinal anesthesia, which can provide sufficient anesthesia, but induce a low occurrence rate of hypotension in the parturients without prophylactic vasopressors and fluid preloading [ 1 ]. However, the anesthesia characteristic of this algorithm is not thoroughly clear, and it is unclear whether this algorithm is the optimal algorithm.…”

“…In our last article, when using a constant bupivacaine dose, the shorter parturients have a higher occurrence rate of hypotension, a faster sensory block time or a higher proportion of complete motor block [ 1 ]. When the bupivacaine dose is altered based on height, the occurrence rate of hypotension, sensory block time or proportion of complete motor block is similar in parturients with different heights [ 1 ]. However, the baseline data is not analyzed [ 1 ].…”

Consensus on the Southeast Asian management of hypotension using vasopressors and adjunct modalities during cesarean section under spinal anesthesia

“…Thus, block level should be chosen based on height, as supported by two studies [85,86]. Huang et al showed that the block level was highly dependent on the height of the parturient when using a low dose of bupivacaine [83]. A lower dose of local anesthetic results in less blockade and reduces the incidence of hypotension at SA; however, it may cause incomplete analgesia and muscle relaxation [87].…”

“…Several studies have reported no statistical correlation between block level and height [80][81][82]. Huang et al [83] showed that the dose of local anesthetic was not adjusted according to height in many studies. This is an important point for the population of SEA, where most parturients are small.…”