Eutectic mixture of local anaesthetics for pain reduction during extracorporeal shockwave lithotripsy: A systematic review and meta-analysis.

A systematic review and meta-analysis was conducted to explore the effect of a eutectic mixture of local anaesthetics (EMLA) on pain reduction during extracorporeal shockwave lithotripsy (ESWL). PubMed, Web of Science, Embase, EBSCO, and Cochrane library databases (updated March 2020) were searched for randomised controlled trials (RCTs) assessing the effect of EMLA for patients that underwent ESWL. The search strategy and study selection process were managed according to the PRISMA statement. Six RCTs were included in the meta-analysis. Overall, the results indicated that EMLA significantly reduced pain compared to the control group (RR = -2.98, 95% CI = -5.82 to -0.13, P = 0.04) with a heterogeneity of I2 = 57% (P = 0.04). Subgroup analysis showed that EMLA did not significantly reduce pain when the patients took an analgesic premedication (RR = -1.46, 95% CI = -5.89 to 2.98, P = 0.52) with a heterogeneity of I2 = 38% (P = 0.52). Conversely, studies without premedication showed a significant pain relief effect (RR = -4.08, 95% CI = -7.36 to -0.65, P = -0.80) with a heterogeneity of I2 = 48% (P = 0.14). Most studies showed there was no difference in the patient's need for analgesics. EMLA was effective for reducing pain during EWSL. However, this analgesic effect was limited and did not reduce the need for analgesics.

Influence of Topical Anesthesia on Superficial Sensitivity: A Double-Blind, Randomized, Placebo-Controlled Study on 48 Healthy Subjects.

BACKGROUND: Topical anesthetics are used in noninvasive transdermal anesthesia to decrease the superficial pain sensation threshold during dermatologic surgery. Combined pain relief and sensitivity loss can avoid discomfort during the surgery. OBJECTIVE: The aim of this placebo-controlled study was to compare the efficacy of 3 commonly used topical agents by collating loss of sensitivity over time. MATERIALS AND METHODS: Three topical anesthetic creams, a topical anti-inflammatory cream, and a moisturizing cream were applied on the left volar forearm of each of the 48 healthy Caucasian participants. Sensitivity was assessed with the dynamic 2-point discrimination and the Semmes-Weinstein test at 0, 60, 90, 120, 150, and 180 minutes after cream application. RESULTS: After 180 minutes, benzocaine showed a significantly lower 2-point discrimination reduction than lidocaine alone and a lidocaine and prilocaine mixture. Sensory threshold measurements by the Semmes-Weinstein test after 60 minutes revealed a significantly higher effect with lidocaine alone and with the lidocaine and prilocaine mixture than with benzocaine. CONCLUSION: The authors found a stronger skin sensitivity reduction by the eutectic lidocaine and prilocaine mixture and lidocaine alone compared with benzocaine. We suggest increased discomfort reduction in topical anesthetic supported dermatologic surgery by the eutectic mixture and lidocaine alone.

Efficacy of Eutectic Mixture of Local Anesthetics on Pain Control During Extracorporeal Shock Wave Lithotripsy: A Systematic Review and Meta-Analysis.

BACKGROUND The efficacy of a eutectic mixture of local anesthetics (EMLA) for pain control in extracorporeal shock wave lithotripsy is unclear. The aim of this study was to assess the effect of EMLA cream on pain control during extracorporeal shock wave lithotripsy. MATERIAL AND METHODS We searched Medline, EMBASE, and the Cochrane Central Register of Controlled Trials to identify relevant randomized controlled trials that compared the pain control efficacies of EMLA vs. placebo. Study eligibility criteria, participants, and interventions: Randomized controlled trials that compared the effect of EMLA with placebo cream for patients underwent extracorporeal shock wave lithotripsy. Study appraisal and synthesis methods: Two review authors extracted data independently using a designed data extraction form and risk of bias by Cochrane Collaboration's tool. RESULTS Nine studies, including 10 randomized controlled trials with 1167 patients, were eligible. The EMLA group experienced less pain (mean difference, -0.47; 95% confidence interval, -0.78 to -0.16; p=0.003) and shorter duration of lithotripsy (mean difference, -1.70, 95% confidence interval: -2.31 to -1.10, p<0.0001) than the placebo group. There were no significant differences in the number of patients who needed extra intravenous medication (p=0.610), number of patients with insufficient extracorporeal shock wave lithotripsy pain control (p=0.530), and number of patients with opioid adverse effects (p=0.320). Limitations: Long interval between the studies, different kinds of lithotripters. CONCLUSIONS EMLA can reduce pain during the ESWL procedure.

Local dermal application of a compound lidocaine cream in pain management of cancer wounds.

The aim of this study was to explore the analgesic effect of local application of compound lidocaine/prilocaine cream on cancer wounds during wound care in order to reduce the amount of morphine intake or completely replace the systemic morphine administration and optimize the protocol for cancer wound pain management. All patients were enrolled with a visual analog scale (VAS) pain score ≥4. Before wound care, 60 patients were randomly divided into 2 groups of 30 each: morphine group (10 mg tablet); topical 5% compound lidocaine cream group (0.2 g/cm2). VAS scores, heart rate, and Kolcaba comfort level were recorded for the two groups 10 min before and 10, 15, 20, and 25 min after wound care and data were analyzed statistically. The means for the pain score and heart rate of the topical lidocaine/prilocaine cream group were lower than those of the morphine group (P<0.01) and the Kolcaba comfort level was higher (P<0.01). Local dermal application of the compound lidocaine cream can be used as an alternative to the systemic morphine administration in cancer wound care for its safety and effectiveness. In addition, it can improve the patients' comfort and quality of life.

Contemporary Approaches to Postoperative Pain Management.

LEARNING OBJECTIVES: After reading this article, the participant should be able to: 1. Describe the fundamental concepts of multimodal analgesia techniques and how they target pain pathophysiology. 2. Effectively educate patients on postoperative pain and safe opioid use. 3. Develop and implement a multimodal postoperative analgesia regimen. SUMMARY: For many years, opioids were the cornerstone of postoperative pain control, contributing to what has become a significant public health concern. This article discusses contemporary approaches to multimodal, opioid-sparing postoperative pain management in the plastic surgical patient.

Stellate ganglion block and cardiac sympathetic denervation in patients with inappropriate sinus tachycardia.

BACKGROUND: Inappropriate sinus tachycardia (IST) remains a clinical challenge because patients often are highly symptomatic and not responsive to medical therapy. OBJECTIVE: To study the safety and efficacy of stellate ganglion (SG) block and cardiac sympathetic denervation (CSD) in patients with IST. METHODS: Twelve consecutive patients who had drug-refractory IST (10 women) were studied. According to a prospectively initiated protocol, five patients underwent an electrophysiologic study before and after SG block (electrophysiology study group). The subsequent seven patients had ambulatory Holter monitoring before and after SG block (ambulatory group). All patients underwent SG block on the right side first, and then on the left side. Selected patients who had heart rate reduction ≥15 beats per minute (bpm) were recommended to consider CSD. RESULTS: The mean (SD) baseline heart rate (HR) was 106 (21) bpm. The HR significantly decreased to 93 (20) bpm (P = .02) at 10 minutes after right SG block and remained significantly slower at 97(19) bpm at 60 minutes. Left SG block reduced HR from 99 (21) to 87(16) bpm (P = .02) at 60 minutes. SG block had no significant effect on blood pressure or HR response to isoproterenol or exercise (all P > .05). Five patients underwent right (n = 4) or bilateral (n = 1) CSD. The clinical outcomes were heterogeneous: one patient had complete and two had partial symptomatic relief, and two did not have improvement. CONCLUSION: SG blockade modestly reduces resting HR but has no significant effect on HR during exercise. Permanent CSD may have a modest role in alleviating symptoms in selected patients with IST.

Does smoking increase the anesthetic requirement?

Background/aim: To examine the effects of active and passive smoking on perioperative anesthetic and analgesic consumption. Materials and methods: Patients were divided into three groups: group S, smokers; group PS, passive smokers; and group NS, individuals who did not have a history of smoking and were not exposed to smoke. All patients underwent the standard total intravenous anesthesia method. The primary endpoint of this study was determination of the total amount of propofol and remifentanil consumed. Results: The amount of propofol used in induction of anesthesia was significantly higher in group S compared to groups PS and NS. Moreover, the total consumption of propofol was significantly higher in group S compared to groups PS and NS. The total propofol consumption of group PS was significantly higher than that of group NS (P = 0.00). Analysis of total remifentanil consumption showed that remifentanil use was significantly higher in group S compared to group NS (P = 0.00). Conclusion: The amount of the anesthetic required to ensure equal anesthetic depth in similar surgeries was higher in active smokers and passive smokers compared to nonsmokers.

Incidence and impact factors of intraoperative loss of light perception under sub-Tenon's anesthesia in patients with macular diseases.

PURPOSE: To investigate the incidence and impact factors of intraoperative loss of light perception (LP) under sub-Tenon's anesthesia in patients with macular diseases. METHODS: Eighty-five consecutive patients received standard phacoemulsification combined pars plana vitrectomy (PPV) under sub-Tenon's anesthesia. At several checkpoints during the surgery (the end of phacoemulsification, the end of vitrectomy, and the end of surgery), participants were interviewed about whether they had LP or not after removing the influence of contralateral eye and the photo-bleaching effect. In patients treated with retinal photocoagulation, visual experience on laser flashes was evaluated. RESULTS: Under routine draping, no patients reported loss of LP at all the checkpoints. When the contralateral eye was tightly covered, the rates of LP loss were 84.7%, 97.6%, and 87.1% at the end of phacoemulsification, the end of vitrectomy, and the end of surgery, respectively. When the photo-bleaching effect was also removed, the rates of LP loss were 61.2%, 82.4%, and 56.5% at each checkpoint, respectively, and there were 87.1% (74/85) of patients reporting visual loss in at least one checkpoint. In addition, 76.9% (50/65) of patients could not feel laser flashes during retinal photocoagulation. CONCLUSION: Intraoperative loss of LP under sub-Tenon's anesthesia was a relatively common and reversible event. The conduction block of optic nerve by anesthetic mainly contributed to the visual loss during surgery. Photo-bleaching effect also has some effect on the LP evaluation. Surgeons need to inform and counsel the patients about the intraoperative loss of LP, to prevent any sudden panic attacks in them.

Investigation of the Effects of Spinal Dexamethasone Injection as a Premedication in Rabbit Anesthesia.

Anesthesia and analgesia are important in human and veterinary medicine, especially in surgical procedures. Rodents, avians, and exotic species are required to be anesthetized using an appropriate anesthetic regimen. This study aimed to suggest a new anesthetic drug and method in order to facilitate anesthesia as well as analgesia among rabbits, laboratory animals, and humans. Spinal injection of dexamethasone combined with intramuscular ketamine among rabbits can play the role of premedication agents. A total of 24 healthy white adult rabbits from New-Zealand were equally assigned into four groups. Groups 1, 2, 3, and 4 were subjected to spinal xylazine (5mg/kg) with ketamine (35mg/kg,IM), spinal dexamethasone (0.37mg/kg-four times diluted) with ketamine (35mg/kg,IM), dexamethasone (4mg/kg,IM) with ketamine (35mg/kg,IM), and spinal dexamethasone (0.37mg/kg-four times diluted), respectively. The results showed that there was a significant difference in terms of clinical reflexes recorded for group 2, compared to groups 1 and 3. A significant difference was also observed regarding clinical reflexes between group 2 and the other groups. Furthermore, no abnormality was observed in terms of histological sections within groups 2 and 4. Spinal dexamethasone can be used as a premedication combined with ketamine in rabbit anesthesia.

Analgesic effect of trigger point injection and EMLA for shoulder pain in patients undergoing total laparoscopic hysterectomy: A randomized controlled study.

BACKGROUD: The purpose of this study was to evaluate the effects of trigger point injection (TPI) and eutectic mixture local anesthetics (EMLA) cream on the postoperative shoulder pain in patients undergoing total laparoscopic hysterectomy. METHODS: In this randomized, single-blinded, and controlled study, total 75 patients were randomly allocated to TPI group (n = 25), EMLA group (n = 25), and control group (n = 25). TPI group received TPIs with 2 mL of 0.2% ropivacaine, and EMLA group received an occlusive dressing with EMLA cream 2 g on both shoulders. Overall, abdominal, and shoulder pains were evaluated at rest and in motion on postoperative day 3. RESULTS: The incidence of shoulder pain was significantly reduced in EMLA group (56%) compared to control (88%) or TPI (88%) groups (P = .025 in both); the severity of shoulder pain was mitigated in EMLA and TPI groups compared to control group (P < .001, each). Consequently, the overall pain decreased in EMLA group and TPI group (P = .023). The patients with exercise habit (n = 31) showed lower incidence of pain than patients without exercise habit (n = 26) (P = .002, P = .005, and P = .037 in overall, abdominal, and shoulder pain, respectively). TPI or EMLA treatments decreased shoulder pain irrespective of exercise habit (P = .001 and P < .001, respectively), but decreased overall pain only in patients without exercise habit (P = .019). Lastly, EMLA lowered overall pain score at the time of first analgesic request in ward compared to control group (P = .02). CONCLUSIONS: TPI and EMLA with occlusive dressing effectively reduced the shoulder pain after total laparoscopic hysterectomy.

Prospective evaluation of anesthetic protocols during pediatric ophthalmic surgery.

PURPOSE: To date, no protocol of anesthesia for pediatric ophthalmic surgery is unanimously recognized. The primary anesthetic risks are associated with strabismus surgery, including oculocardiac reflex, postoperative nausea and vomiting, and postoperative pain. METHODS: This was a prospective, monocentric, observational study conducted in a tertiary pediatric ophthalmic unit. Our anesthetic protocol for strabismus surgery included postoperative nausea and vomiting prevention using dexamethasone and ondansetron. No drug-based prevention of oculocardiac reflex or local/locoregional anesthesia was employed. RESULTS: A total of 106 pediatric ophthalmic surgeries completed between November 2015 and May 2016 were analyzed. The mean patient age was 4.4 (range: 0.2-7.3, standard deviation: 2.4) years. Ambulatory rate was 90%. Oculocardiac reflex incidence was 65% during strabismus surgery (34/52), 50% during congenital cataract surgery (4/8), 33% during intramuscular injection of botulinum toxin (1/3), and 0% during other procedures. No asystole occurred. Postoperative nausea and vomiting incidence was 9.6% after strabismus surgery (5/52) and 0% following the other procedures. One child was hospitalized for one night because of persistent postoperative nausea and vomiting. Postoperative pain generally occurred early on in the recovery room and was quickly controlled. Its incidence was higher in patients who underwent strabismus surgery (27%) than in those who underwent other procedures (9%). CONCLUSION: Morbidity associated with ophthalmic pediatric surgery is low and predominantly associated with strabismus surgery. The benefit-risk ratio and cost-effectiveness of oculocardiac reflex prevention should be questioned. Our postoperative nausea and vomiting rate is low, thanks to the use of a well-managed multimodal strategy. Early postoperative pain is usually well-treated but could probably be more effectively prevented.

Local dermal application of a compound lidocaine cream in pain management of cancer wounds

The aim of this study was to explore the analgesic effect of local application of compound lidocaine/prilocaine cream on cancer wounds during wound care in order to reduce the amount of morphine intake or completely replace the systemic morphine administration and optimize the protocol for cancer wound pain management. All patients were enrolled with a visual analog scale (VAS) pain score ≥4. Before wound care, 60 patients were randomly divided into 2 groups of 30 each: morphine group (10 mg tablet); topical 5% compound lidocaine cream group (0.2 g/cm2). VAS scores, heart rate, and Kolcaba comfort level were recorded for the two groups 10 min before and 10, 15, 20, and 25 min after wound care and data were analyzed statistically. The means for the pain score and heart rate of the topical lidocaine/prilocaine cream group were lower than those of the morphine group (P<0.01) and the Kolcaba comfort level was higher (P<0.01). Local dermal application of the compound lidocaine cream can be used as an alternative to the systemic morphine administration in cancer wound care for its safety and effectiveness. In addition, it can improve the patients' comfort and quality of life.

Prolonged Duration Local Anesthesia Using Liposomal Bupivacaine Combined With Liposomal Dexamethasone and Dexmedetomidine.

BACKGROUND: The relatively short duration of effect of local anesthetics has been addressed by encapsulation in drug delivery systems. Codelivery with a single compound that produces an adjuvant effect on nerve block but without intrinsic local anesthetic properties can further prolong the nerve block effect. Here, we investigated whether codelivery of more than 1 encapsulated adjuvant compound can further enhance nerve blockade. METHODS: Liposomes loaded with bupivacaine (Bup), dexamethasone phosphate (DexP), or dexmedetomidine (DMED) were synthesized and its in vitro drug release profiles were determined. Animals (Sprague-Dawley rats) were injected with liposomal Bup (Lipo-Bup) and adjuvants at the sciatic nerve and underwent a modified hot plate test to assess the degree of nerve block. The duration of block was monitored and the tissue reaction was assessed. RESULTS: Coinjection of Lipo-Bup with liposomal DexP (Lipo-DexP) and liposomal DMED (Lipo-DMED) prolonged the duration of sciatic nerve block 2.9-fold compared to Lipo-Bup alone (95% confidence interval, 1.9- to 3.9-fold). The duration of the block using this combination was significantly increased to 16.2 ± 3.5 hours compared to Lipo-Bup with a single liposomal adjuvant (8.7 ± 2.4 hours with Lipo-DMED, P = .006 and 9.9 ± 5.9 hours with Lipo-DexP, P = .008). The coinjection of Lipo-Bup with liposomal adjuvants decreased tissue inflammation (P = .014) but did not have a significant effect on myotoxicity when compared to Lipo-Bup alone. Coinjection of Lipo-Bup with unencapsulated adjuvants prolonged the duration of nerve block as well (25.0 ± 6.3 hours; P < .001) however was accompanied by systemic side effects. CONCLUSIONS: Codelivery of Lipo-DexP and Lipo-DMED enhanced the efficacy of Lipo-Bup. This benefit was also seen with codelivery of both adjuvant molecules in the unencapsulated state, but with marked systemic toxicity.

Effects of a mixture of medetomidine, midazolam and butorphanol on anesthesia and blood biochemistry and the antagonizing action of atipamezole in hamsters.

Syrian golden hamsters (Mesocricetus auratus) are useful laboratory rodents for studying human infectious diseases, metabolic diseases and cancer. In other rodents, such as mice and rats, a mixture of medetomidine, midazolam and butorphanol functions as a useful anesthetic, although it alters some blood biochemical parameters. In this study, we examined the effects of this mixture on anesthesia and blood biochemical parameters, and the action of atipamezole, a medetomidine antagonist, in hamsters. Intramuscular injection of a mixture of medetomidine, midazolam and butorphanol at doses of 0.15, 2.0 and 2.5 mg/kg, respectively, had a short induction time (within 5 min) and produced an anesthetic duration of approximately 100 min in hamsters. We also demonstrated that 0.15 mg/kg of atipamezole, corresponding to the same dose as medetomidine, made hamsters recover quickly from anesthesia. The anesthetic agent markedly altered metabolic parameters, such as plasma glucose and insulin; however, 0.15 mg/kg of atipamezole returned these levels to normal range within approximately 10 min after the injection. The anesthetic also slightly altered mineral levels, such as plasma inorganic phosphorus, calcium and sodium; the latter two were also improved by atipamezole. Our results indicated that the mixture of medetomidine, midazolam, and butorphanol at doses of 0.15, 2.0 and 2.5 mg/kg, respectively, functioned as an effective anesthetic, and atipamezole was useful for antagonizing both anesthesia and biochemical alteration in hamsters.

Analgesic effect of perineural magnesium sulphate for sciatic nerve block for diabetic toe amputation: A randomized trial.

BACKGROUND AND OBJECTIVES: High concentrations of local anesthetics may be neurotoxic for diabetic patients. Additive perineural administration of magnesium was reported to decrease the consumption of local anesthetics for nerve block. It was hypothesized that MgSO4 added to dilute ropivacaine was equianalgesic to more concentrated ropivacaine for toe amputations in diabetic patients. METHODS: Seventy diabetic patients were allocated into 3 groups: 1) perineural 200 mg MgSO4 added to 0.25% ropivacaine, 2) 0.25% ropivacaine alone, and 3) 0.375% ropivacaine alone. All patients underwent popliteal sciatic nerve block that was guided by ultrasonography using the respective regimens. Time of onset, duration of motor and sensory block were recorded. Spontaneous and evoked pain score, worst pain score, additional analgesic consumption, satisfaction score and initial time of analgesic requirement of each patient were documented up to 48 hours postoperatively. RESULTS: In comparison with 0.25% ropivacaine alone, magnesium supplement prolonged the duration of sensory block (p = 0.001), as well as better evoked pain score at 6 hour postoperatively (p = 0.001). In comparison with evoked pain score (1.6/10) in group of 0.375% ropivacaine, magnesium plus 0.25% ropivacaine presented a little higher score (2.5/10) at 6 hour postoperatively (p = 0.001), while lower worst pain score (p = 0.001) and less postoperative total analgesic consumption (p = 0.002). CONCLUSIONS: The regimen of adding 200mg MgSO4 to 0.25% ropivacaine for sciatic nerve block yields equal analgesic effect in comparison with 0.375% ropivacaine. These findings have suggested that supplemental MgSO4 could not improve analgesic quality except reducing the total amount of local anesthetics requirement in diabetic toe amputations with sciatic nerve blocks.

Inhalation Conscious Sedation with Nitrous Oxide and Oxygen as Alternative to General Anesthesia in Precooperative, Fearful, and Disabled Pediatric Dental Patients: A Large Survey on 688 Working Sessions.

Aim. To evaluate the effectiveness and the tolerability of the nitrous oxide sedation for dental treatment on a large pediatric sample constituting precooperative, fearful, and disabled patients. Methods. 472 noncooperating patients (aged 4 to 17) were treated under conscious sedation. The following data were calculated: average age; gender distribution; success/failure; adverse effects; number of treatments; kind of dental procedure undertaken; number of dental procedures for each working session; number of working sessions for each patient; differences between males and females and between healthy and disabled patients in relation to success; success in relation to age; and level of cooperation using Venham score. Results. 688 conscious sedations were carried out. The success was 86.3%. Adverse effects occurred in 2.5%. 1317 dental procedures were performed. In relation to the success, there was a statistically significant difference between healthy and disabled patients. Sex and age were not significant factors for the success. Venham score was higher at the first contact with the dentist than during the treatment. Conclusions. Inhalation conscious sedation represented an effective and safe method to obtain cooperation, even in very young patients, and it could reduce the number of pediatric patients referred to hospitals for general anesthesia.

Transcranial flavoprotein-autofluorescence imaging of sound-evoked responses in the mouse auditory cortex under three types of anesthesia.

The effects of anesthesia on the functional auditory characteristics of cortical neurons, such as spatial and temporal response properties, vary between an anesthetized and an awake subject. However, studies have shown that an appropriate anesthetic method that approaches the awake condition is still useful because of its greater stability and controllability. The present study compared neural response properties from two core fields of the mouse auditory cortex under three anesthetic conditions: urethane; ketamine and xylazine hydrochloride (KX) mixture; and a combination of medetomidine, midazolam, and butorphanol (MMB). To measure sound stimulation in vivo, we recorded flavoprotein-autofluorescent images of endogenous green fluorescence. Under all conditions, fluorescence changes in auditory core subfields in response to tones were observed, and response properties, such as peak intensity, latency, duration, and activated areas were analyzed. Results showed larger response peak intensity, latency, and duration in the core subfields under urethane compared with KX and MMB, with no significant differences between KX and MMB. Conversely, under KX anesthesia the activated areas showed characteristic response properties in a subfield-dependent manner. These results demonstrated the varied effects of anesthesia on response properties in the core subfields of the auditory cortex.

Effect of Sodium Bicarbonate Buccal Infiltration on the Success of Inferior Alveolar Nerve Block in Mandibular First Molars with Symptomatic Irreversible Pulpitis: A Prospective, Randomized Double-blind Study.

INTRODUCTION: The purpose of this prospective, randomized, double-blind study was to evaluate the effect of a buccal infiltration of sodium bicarbonate on the anesthetic success of the inferior alveolar nerve block (IANB) for mandibular first molars in patients with symptomatic irreversible pulpitis. METHODS: One hundred patients diagnosed with symptomatic irreversible pulpitis of a mandibular first molar were selected. The patients randomly received a buccal infiltration injection of either 0.7 mL 8.4% sodium bicarbonate with 0.3 mL 2% lidocaine containing 1:80,000 epinephrine or 0.7 mL sterile distilled water with 0.3 mL 2% lidocaine containing 1:80,000 epinephrine in a double-blind manner. After 15 minutes, all the patients received conventional IANB injection using 3.6 mL 2% lidocaine with 1:80,000 epinephrine. Access cavity preparation was initiated 15 minutes after the IANB injection. Lip numbness was a requisite for all the patients. Success was determined as no or mild pain on the basis of Heft-Parker visual analog scale recordings upon access cavity preparation or initial instrumentation. Data were analyzed using the t, chi-square and Mann-Whitney U tests. RESULTS: The success rate after the buccal infiltration of sodium bicarbonate was 78%, whereas without the buccal infiltration of sodium bicarbonate it was 44% (P < .001). CONCLUSIONS: A buccal infiltration of 0.7 mL 8.4% sodium bicarbonate increased the success rate of IANBs in mandibular first molars with symptomatic irreversible pulpitis.

The effects of lidocaine or a lidocaine-bupivacaine mixture administered into the infraorbital canal in dogs.

OBJECTIVE To determine the onset, duration, and extent of regional nerve blocks performed by administration of lidocaine or lidocaine-bupivacaine into the infraorbital canal in dogs. ANIMALS 6 healthy hound-type dogs. PROCEDURES Under general anesthesia, stimulating needles were inserted into the gingiva dorsolateral to both maxillary canine (MC) teeth and the maxillary fourth premolar (MPM4) and second molar (MM2) teeth on the treatment side. A reflex-evoked muscle potential (REMP) was recorded from the digastricus muscle after noxious electrical stimulation at each site. After baseline measurements, 1 mL of 2% lidocaine solution or a 2% lidocaine-0.5% bupivacaine mixture (0.5 mL each) was injected into the infraorbital canal (at approx two-thirds of the canal length measured rostrocaudally). The REMPs were recorded for up to 7 hours. The REMP data for the contralateral (untreated control) canine tooth were used to normalize results for all stimulation sites. RESULTS With both treatments, nerve block for MC teeth on the treated side was achieved by 5 (n = 5 dogs) or 10 (1) minutes after injection, but nerve block for ipsilateral MPM4 and MM2 teeth was successful for only 3 dogs and 1 dog, respectively. Mean duration of nerve blocks for MC teeth was 120 and 277 minutes following injection of lidocaine and lidocaine-bupivacaine, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Local anesthesia, as performed in this study, successfully blocked innervation of MC teeth, but results for MPM4 and MM2 teeth were inconsistent. This specific technique should not be used during tooth extractions caudal to the MC teeth.