医学文章阅读——Methods for A Comparative Efficacy Study of Hyperbaric 5% Lidocaine and 1.5% Lidocaine for Spinal Anesthesia

After approval of the study by our scientific committee, 51consenting adult male patients between the ages of 18 and 61 year who were about to undergo inguinal herniorrhaphy during spinal anesthesia were randomly assigned to two groups based on the local anesthetic solution to be used”: Group I (n=25)received 75 mg of lidocaine 1.5% in dextrose 7.5% (5 ml), and Group I(n= 26) received lidocaine 5% in dextrose 7.5% (1.5ml). Ail patients were prehydrated with 500ml of lactated Ringer's solution while noninvasive blood pressure, electrocardiogram (ECG), and pulse oximeter were monitored. Lumbar puncture was then performed with the patient in the sitting position at the L3-4 intervertebral space using a 25-gauge Quirke spinal needle: when clear cerebrospinal fluid was obtained, the anesthetic solution was injected at a rate of 1 ml/5 s. After in jection of the local anesthetic and return of the patient to the supine position, all subsequent monitoring and measurements were conducted by ananesthesiologist blinded to the spinal drug: the level of the sensory blockade was assessed every minute for the first 10 min.every 2 min for the next 10 min, and then every 10 min until the following end points had been determined:(1) the time to onset of anesthesia in the perineum, (2) the time to the maximal level of anesthesia, (3) the time to regression of two dermatomes, and (4) the time to the return of perineal sensation. The onset, degree, and regression of motor block was aiso monitored using a modified Bromage scale, in which 0= no motor block, l=the inability to flex knees 30°.2=the inabitity to flex the ankle, and 3 =complete motor block. It the surgery extended beyond the duration of the surgical anesthesia, the surgical field was infiltrated with bupivicaine 0.25% to allow completion of the surgery, and the time of the infiltration was recorded.

If the level of anesthesia provided by the spinal anesthetic was inadequate for the surgery to start, the patient was dropped from the study. The results for each group were expressed as the mean sem, and the groups were compared by using the two-tailed unpaired t-test、 with a value of # <0. 05 indicating significance.

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