Clinical Study Of Isovolumetric Low Concentration Ropivacaine Hydrochloride In Subarachnoid Block

Objective To study the relationship between sensory block induced by isovolumic low concentration ropivacaine hydrochloride injected into subarachnoid space and the time and concentration of motor block,and to find the optimal concentration of ropivacaine hydrochloride for subarachnoid block anesthesia in short-term lower extremity surgery.At the same time,according to the experiment,we explored whether the separation of sensory-motor block caused by ropivacaine hydrochloride subarachnoid injection was related to the concentration and dose.We also recorded whether the patients had urinary retention and whether they could carry out lower limb activities in bed early after operation,which provided a reference for clinical application of ropivacaine hydrochloride for subarachnoid block and theoretical data support and direction for further research.Guidance to facilitate daytime surgery and rapid surgical recovery(ERAS).Method Ninety patients of ASA grade I-I I,aged 18-60 years,scheduled for elective small-scale operations in lower abdomen,pelvic cavity,lower limbs,anus and perineum under combined spinal-epidural anesthesia were randomly divided into group A,B and C with 30 cases in each group within 90 minutes.The patient was given 2 ml local anesthetics with specific gravity in the subarachnoid space under conventional combined spinal-epidural anesthesia in the left lateral decubitus position,and the sterile syringe was connected to the indwelling epidural catheter 4 cm in the head.After anesthesia,the patient was given a supine position.If the level of sensory block does not reach T8 in 5 minutes,the patient will be turned to head-down 20 degrees.If the level of sensory block is higher than T8,the patient will be swiftly turned to head-up andfoot-down 20 degrees position,and the level of anesthesia will be controlled from T6 to T8 as far as possible.Group A patients were injected with 0.5% ropivacaine hydrochloride 2ml(1% ropivacaine hydrochloride 1ml + 10% glucose 1ml)into subarachnoid space.Group B patients were injected with 0.45% ropivacaine hydrochloride 2ml(1% ropivacaine hydrochloride 0.9ml + 10% glucose 1.1ml)into subarachnoid space.Group C patients were injected with 0.4% ropivacaine hydrochloride 2ml(1% hydrochloric acid).Ropivacaine 0.8ml + 10% glucose 1.2ml preparation)subarachnoid injection.After anesthesia,three groups of patients were electrocuted with piezoelectric ceramics generator to locate the sensory block plane for5 minutes.The onset time and duration of sensory block were recorded.Modified Bromage score(grade 0-no motor nerve block,grade 1-no leg lifting,grade 2-no knee flexion,grade 3-no ankle flexion)was used to determine the onset time of lower limb motor block.The lower limb motor block scores of 5 minutes,10 minutes and 30 minutes after planar fixation were recorded,and the recovery time of lower limb activity to grade 1 of improved Bromage score was recorded.Bromage score 0 time.At the same time,the patient’s proprioception was recorded.Special conditions during operation and complications related to anesthesia after operation were recorded.Result With the decrease of concentration of ropivacaine hydrochloride,the onset time of sensory block and motor block was prolonged.The duration of sensory block and motor block was shortened.The improved Bromage score was gradually decreased with the decrease of concentration of ropivacaine hydrochloride.The separation time of sensory and motor block of 0.45% ropivacaine hydrochloride was longer than that of 0.5% ropivacaine hydrochloride.The separation time of sensory and motor block of 0.5% ropivacaine hydrochloride was longer than that of 0.4%ropivacaine hydrochloride.Ropivacaine hydrochloride could produce sensory-motor block.There were 4 cases of urinary retention in 0.5% concentration group,1 case in0.45% concentration group,and no urinary retention in 0.4% concentration group.There was no significant difference in urinary retention between 0.45% concentration group and 0.4% concentration group.The shorter the time required for the patients inthe three groups to recover to the improved Bromage score to grade 1 with the decrease of concentration,and the greater the difference between the recovery of motor block and the improved Bromage score in the 0.4% concentration group,the longer the recovery time is unstable.The number of patients moving to the ground within 6 hours decreased with the decrease of concentration,and there was no significant difference between0.45% concentration group and 0.4% concentration group.