Reduction in injection pain using buffered lidocaine as a local anesthetic before cardiac catheterization. Neutralizing pH of lidocaine reduces pain during Norplant system insertion procedure. Randomized trial of buffered versus plain lidocaine for local anaesthesia in open carpal tunnel decompression. Efficacy of alkalinized lidocaine for reducing pain on intravenous and epidural catheterization. Comparison of three modified lidocaine solutions for use in eyelid anesthesia. Capacity of the clinical picture to characterize low back pain relieved by facet joint anesthesia. Proposed criteria to identify patients with painful facet joints. Establishing intravenous access: a study of local anesthetic efficacy. Comparison of the efficacy of different local anesthetics and techniques of local anesthesia in therapeutic abortions. Evaluation of lidocaine as an analgesic when added to hypertonic saline for sclerotherapy.
Previous reports have suggested that pain associated with the injection of lidocaine is related to the acidic pH of the solution. To determine if the addition of a buffering solution to adjust the pH of lidocaine into the physiologic range would reduce pain during injection, we performed a blinded randomized study in patients undergoing cardiac catheterization. Twenty patients were asked to quantify the severity of pain after receiving standard lidocaine in one femoral area and buffered lidocaine in the opposite femoral area. The mean pain score for buffered lidocaine was significantly lower than the mean score for standard lidocaine (2.7 +/- 1.9 vs. 3.8 +/- 2.2, P = 0.03). The pH adjustment of standard lidocaine can be accomplished easily in the catheterization laboratory before injection and results in a reduction of the pain occurring during the infiltration of tissues. The acidity of lidocaine used as a local anesthetic during the insertion of Norplant System capsules can cause patient discomfort. Buffering lidocaine with sodium bicarbonate significantly reduced pain scores reported by 46 women who participated in this randomized, double-blind study. Derived from a pain scale of 1 to 10, the mean difference in reported pain scores with and without buffering was 1.17 (P = 0.0098) with women using themselves as controls, for an average reduction in pain of 29%. Because this added step minimized patient discomfort, it might make the Norplant System a more attractive option for women apprehensive about insertion pain. We performed a randomized double-blind case-control study in 64 consecutive patients undergoing open carpal tunnel decompression under local anaesthetic to assess the pain experienced on injection of plain lidocaine (pH 6.4) compared with lidocaine buffered with sodium bicarbonate (pH 7.4). The results showed no statistical difference in the pain scores reported by patients. The mean pain scores for all patients were low, and most patients reported that they were "not at all anxious" about receiving a similar injection in the future. To investigate whether increasing the pH of lidocaine could reduce the pain caused by its skin infiltration as well as that caused by intravenous and epidural needle insertion.
                A randomized, double-blind trial was undertaken in patients who were allocated to receive topical anesthesia with either plain (plain group; n = 25) or alkalinized lidocaine (alkalinized group; n = 25). An alkalinized lidocaine solution was prepared by adding 8.4% sodium bicarbonate to a plain 1% lidocaine solution at a ratio of 1 : 10. Pain was assessed using the verbal analog scale (VAS).
                In the alkalinized group, the VAS scores on skin infiltration in the hand (2.5 +/- 1.4) and the back (2.7 +/- 1.4) were significantly lower than the respective scores in the plain group (3.5 +/- 1.4, and 4.9 +/- 1.9). Although the VAS score on intravenous needle insertion did not differ between the two groups, the VAS score on epidural needle insertion was significantly lower in the alkalinized group (1.3 +/- 1.0) than in the plain group (3.6 +/- 1.3).
                Alkalinization of lidocaine was effective in attenuating pain on skin infiltration and on epidural needle insertion. To compare pain on injection and the efficacy of anesthesia of three modified lidocaine solutions for use in eyelid surgery: 1) 2% lidocaine with 1:100,000 epinephrine, 2) 2% lidocaine with 1:100,000 epinephrine buffered 9:1 with 8.4% sodium bicarbonate, and 3) 2% lidocaine with 1:100,000 epinephrine diluted 1:9 with 0.9% bacteriostatic saline solution (with benzyl alcohol).
                In this prospective, randomized, double-masked, controlled clinical trial, 30 consecutive patients undergoing bilateral identical eyelid surgery were randomized to one of three treatment groups. Group 1 received buffered solution on one side and stock solution on the other, group 2 received bacteriostatic saline diluted solution on one side and stock solution on the other, and group 3 received buffered solution on one side and bacteriostatic saline diluted solution on the other. Patients used a 5-point scale to rate the perceived pain on injection and the pain felt during the operative procedure.
                Comparison of mean injection pain scores showed that buffered solution was significantly less painful than unmodified solution (2.2 versus 3.1, p < 0.05), bacteriostatic saline modified solution was significantly less painful than unmodified solution (0.9 versus 3.3, p < 0.05), bacteriostatic saline modified solution was significantly less painful than buffered solution (1.2 versus 2.3, p < 0.05). Comparison of mean intraoperative pain scores demonstrated no significant difference between the solutions in any of the treatment groups.
                For local anesthesia in eyelid surgery, bacteriostatic saline modified solution provides more comfort on injection than either buffered or unmodified lidocaine-epinephrine solution and provides an adequate level of anesthesia that does not differ significantly from either the buffered or unmodified solutions. Prospective randomized study to compare the efficacy of facet joint injection with lidocaine and facet joint injection with saline in two groups of patients with low back pain, with and without clinical criteria that were determined in a previous study to implicate the facet joint as the primary source of the pain.
                To assess the efficacy of single facet joint anesthesia versus placebo (saline injections) and to determine clinical criteria that are predictive of significant relief of LBP after injection.
                There is no syndrome that discriminates between lower back pain caused by facet joint and that caused by other structures. Single or double facet joint anesthesia, and single photon emission computed tomography are expensive and time-consuming procedures for selecting patients in controlled clinical trials with large populations.
                Results of a previous study showed that seven clinical characteristics were more frequent in patients who responded to facet joint anesthesia than in those who did not. In the current study, a group of 43 patients with lower back pain who met at least five criteria were compared with 37 patients who met fewer criteria. Patients randomly received injection of either lidocaine or saline into the lower facet joints. The result was considered positive if more than 75% pain relief was determined by visual analog scale. The patient, the radiologist, and the investigator were blinded. An analysis of variance was used to seek an interaction between clinical group effect and injection effect, and logistic regression analysis to select the best set of variables that would be predictive of minimum pain relief of 75% after the injection.
                There was a significant interaction between clinical group and injection effect (P = 0.003). In patients with back pain, lidocaine provided greater lower-back pain relief than saline (P = 0.01). Lidocaine also-provided greater pain relief in the back pain group than in the nonpain group (P = 0.02). The presence of five among seven variables (age greater than 65 years and pain that was not exacerbated by coughing, not worsened by hyperextension, not worsened by forward flexion, not worsened when rising from flexion, not worsened by extension-rotation, and well-relieved by recumbency), always including the last item, distinguished 92% of patients responding to lidocaine injection and 80% of those not responding in the lidocaine group.
                A set of five clinical characteristics can be used in randomized studies to select lower back pain that will be well relieved by facet joint anesthesia. These characteristics should not, however, be considered as definite diagnostic criteria of lower back pain originating from facet joints. We performed a double-blind, randomized, prospective study to determine the local anesthetic that provided the best analgesia for insertion of an 18-gauge intravenous (i.v.) catheter and to determine whether alkalinization of lidocaine decreases the pain of intradermal injection. There were 280 healthy adult patients assigned randomly to seven different groups: benzyl alcohol 0.9% in normal saline, 2-chloroprocaine 3%, lidocaine 1%, lidocaine 1% with preservative, alkalinized lidocaine 1% with preservative, normal saline, and a control group that received i.v. catheter placement without previous drug injection. A 10-cm visual analog pain scale (VAPS) was used to obtain pain scores after pre-i.v. drug injection and after iv catheter insertion. Benzyl alcohol in normal saline (0.61 +/- 0.11) and alkalinized lidocaine (0.69 +/- 0.10) had the lowest mean pain scores for drug injection and these were significantly different from other drugs (P < 0.05). Alkalinized lidocaine (0.7 +/- 0.18) had the lowest mean pain score for i.v. catheter insertion with nothing (no previous drug injected) (3.47 +/- 0.38) and normal saline (3.97 +/- 0.18) had the highest mean pain scores (P < 0.05). We conclude that alkalinized lidocaine decreased the pain associated with its injection. Alkalinized lidocaine was the best local anesthetic for i.v. catheter placement. Benzyl alcohol in normal saline was also effective. The objectives of this study were to determine whether carbonated or plain lidocaine provides better pain control during abortions and to determine whether deep injections of lidocaine provide better pain control than regular injections of lidocaine.
                Phase 1 was a prospective, randomized, double-blind trial comparing 10 cm3 of 2% carbonated lidocaine with plain lidocaine. In phase 2 the plain lidocaine group in phase 1 was compared prospectively with the next group of patients, in whom a new technique of deep injection was used. A pain scale was administered by the counselor after dilatation and at the end of the procedure.
                The improvement in pain scores with carbonated lidocaine was 8%. The improvement with the deep injection technique was 25%.
                The improvement in pain scores with deep injection was clinically significant and is recommended. The efficacy of sclerosing agents for the treatment of telangiectasias and reticular veins is well established. The injection of these agents is often associated with pain, and it is not uncommon for sclerotherapists to include lidocaine with the sclerosants in an attempt to reduce the pain associated with treatment. However, there are concerns that this may reduce the overall efficacy of the treatment because of dilution of the sclerosant. Patient comfort and overall outcome associated with treatment using HS with lidocaine (LIDO) versus that using HS alone was compared.
                Forty-two patients were prospectively entered into the study and randomized blindly to sclerotherapy with 23.4% HS or 19% LIDO. Study subjects and treating physicians were blinded to the injection solution used. Injection sites were chosen for veins ranging in size from 0.1 to 3 mm. Photographs of the area to be treated were taken, and the patients rated their pain. They were then observed at regular intervals for four months, and clinical data was collected. Thirty-five subjects completed the full follow-up period, and photographs of the injected area were taken again. Three investigators blinded to the treatment assignment then evaluated the photographs and scored the treatment efficacy according to a standardized system.
                In the HS group, 61.9% (13 of 21) patients rated their pain as none or mild, whereas 90.5% (19 of 21) of patients in the LIDO group had no or mild discomfort. This difference is significant, with a P value of.034. There was no difference in the overall efficacy of treatment between the two groups. The groups had similar rates of vein thrombosis and skin necrosis.
                Although lidocaine is often used with sclerosing agents, there are no previous reports in the literature to evaluate its effectiveness in reducing the pain experienced by the patient. In this study, patients receiving LIDO experienced significantly less discomfort at the time of injection than patients who received HS alone. There were no differences in the effectiveness of treatment or in the incidence of complications between the two groups.
Increasing the pH of lidocaine decreased pain on injection and augmented patient comfort and satisfaction.