Single injection peribulbar anesthesia with a short needle combined with digital compression.

BACKGROUND: We compare the efficacy of using a 15 mm to the standard 25 mm needle for performing peribulbar blockade. METHODS: Blocks were performed on 150 patients using 15 or 25 mm needle length. Digital compression was applied by the thumb and index finger around the needle hub during injection with 15 mm needle. Anesthetic was injected until lid fullness was noted. Inadequate block was augmented. RESULTS: No significant differences were noted between groups with respect to local anesthetic volume, supplementation, and akinesia. CONCLUSION: Peribulbar blockade performed with a 15 mm needle with digital pressure is comparable to blockade using a 25 mm needle.

Preferential location of lidocaine and etidocaine in lecithin bilayers as determined by EPR, fluorescence and 2H NMR.

We have examined the effect of the uncharged species of lidocaine (LDC) and etidocaine (EDC) on the acyl chain moiety of egg phosphatidylcholine liposomes. Changes in membrane organization caused by both anesthetics were detected through the use of EPR spin labels (5, 7 and 12 doxyl stearic acid methyl ester) or fluorescence probes (4, 6, 10, 16 pyrene-fatty acids). The disturbance caused by the LA was greater when the probes were inserted in more external positions of the acyl chain and decreased towards the hydrophobic core of the membrane. The results indicate a preferential insertion of LDC at the polar interface of the bilayer and in the first half of the acyl chain, for EDC. Additionally, (2)H NMR spectra of multilamellar liposomes composed by acyl chain-perdeutero DMPC and EPC (1:4 mol%) allowed the determination of the segmental order (S(mol)) and dynamics (T(1)) of the acyl chain region. In accordance to the fluorescence and EPR results, changes in molecular orientation and dynamics are more prominent if the LA preferential location is more superficial, as for LDC while EDC seems to organize the acyl chain region between carbons 2-8, which is indicative of its positioning. We propose that the preferential location of LDC and EDC inside the bilayers creates a "transient site", which is related to the anesthetic potency since it could modulate the access of these molecules to their binding site(s) in the voltage-gated sodium channel.

Liquid chromatography-electrospray mass spectrometry determination of free and total concentrations of ropivacaine in human plasma.

A specific and sensitive liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method was developed for the determination of free and total ropivacaine in human plasma. The work-up procedure involved a simple precipitation of plasma proteins with methanol. Etidocaine served as the internal standard. After microscale equilibrium-dialysis, measurement of free ropivacaine levels was performed after direct injection of the dialysate into the chromatograph. The system used a Zorbax eclipse XD8 C8 analytical column packed with 5 microm diameter particles as the stationary phase. The mobile phase consisted of a 15-min gradient (mobile phase A: 0.05% (v/v) trimethylamine in acetonitrile, mobile phase B: 2mM ammonium formate buffer (pH 3)). Mass spectrometric data were acquired in single ion monitoring mode at m/z 275 for ropivacaine and m/z 277 for etidocaine. The drug/internal standard peak area ratios (plasma) or peak areas (dialysate) were linked via a quadratic relationship to concentrations. Precision ranged from 1 to 7.6% accuracy was between 92.6 and 109%. The lower limits of quantitation were 1 microg/l in plasma and 2 microg/l in the dialysate. This method was found suitable for the analysis of plasma samples collected during a clinical trial performed in 30 infants undergoing epidural anaesthesia or continuous psoas compartment block.

Local anesthesia: advances in agents and techniques.

The improvements in agents and techniques for local anesthesia are possibly the most important advances in dental science to have occurred in the past 100 years. The agents currently available in dentistry have most of the characteristics of an ideal local anesthetic. Today's anesthetics can be administered with minimal irritation and little concern for stimulating allergic reactions. A variety of agents are available that provide rapid onset of surgical anesthesia with adequate duration. This article provides a brief review of the local anesthetic agents, formulations, and techniques used in dentistry with special emphasis on newly introduced agents and procedures.

Peribulbar anesthesia and sub-Tenon injection for vitreoretinal surgery: 300 cases.

BACKGROUND AND OBJECTIVES: We carried out a prospective study in order to evaluate the efficacy and safety of peribulbar anaesthesia supplemented by a sub-Tenon injection in case of inadequate analgesia during vitreoretinal surgery. METHODS: We performed 300 consecutive vitreoretinal procedures. Patients received a mean volume of 17+/-4.5 ml of a mixture of etidocaine 1%, bupivacaine 0.50% and hyaluronidase (25 UI/ml). Supplementation was represented by a sub-Tenon infiltration of lidocaine 2% (2 or 3 ml). This volume was not included in the mean volume. RESULTS: Analgesia was adequate throughout surgery without any supplementation in 85% of cases and with a sub-Tenon infiltration in 99%. Akinesia was complete in 82%, mild in 15% and absent in 3% of cases. The sub-Tenon injection was performed immediately before starting the procedure in 58% of cases and during the surgery with a delay of 80+/-21 min in 42%. Eleven patients (3.66%) were agitated during surgery and two of them needed a general anaesthesia to allow for the procedure. Generalised epilepsy was encountered in two patients (0.66%) immediately after the peribulbar injection in one patient and 15 min later in the other. The systolic blood pressure severely decreased between 60 to 70 mm Hg 40 min after the accomplishment of the peribulbar in 2 patients and at 90 min in 2 others. CONCLUSION: Our results demonstrate that peribulbar anaesthesia alone offers excellent analgesia in 85% of patients and supplemented by a sub-Tenon injection in 99%.

Comparison of etidocaine and bupivacaine + lidocaine in retrobulbar anaesthesia.

Etidocaine (15 mg/ml) was compared with bupivacaine (5 mg/ml) combined with lidocaine (10 mg/ml) in retrobulbar anaesthesia. One hundred and twelve patients were randomised into two groups. Supplemental anaesthesia was needed in 41% of cases of the etidocaine group and 32% of the bupivacaine-lidocaine group. Akinesia was evaluated by the surgeon both pre- and postoperatively and was found to be good or complete in more than 95% of both groups. Recovery from the motor and sensory block was investigated three times during the first 24 postoperative hours. The motor block of the orbicular muscle disappeared earlier than that of the globe. Akinesia lasted significantly longer in the etidocaine group than in the bupivacaine-lidocaine group: after 14 h 69% vs 100%, respectively, of the eyes showed normal movements. Sensation in the cornea was also regained more rapidly in patients treated with the mixture.

Toxic systemic reactions of bupivacaine and etidocaine.

Since the introduction of the long-acting agents, bupivacaine in 1983 and etidocaine in 1985, to the dental local anesthetic armamentarium, their use has increased rapidly. Although an estimated one-half million local anesthetic injections are administered in the United States daily, the actual risks of toxicity from these local anesthetic injections remain unknown. Our review of the literature reveals numerous cases of severe adverse reactions associated with the administration of bupivacaine and etidocaine. This case review includes several fatalities, even after injection of only very small amounts of these long-acting local anesthetics. Results from animal studies have demonstrated increased systemic toxicity associated with bupivacaine and etidocaine as compared with lidocaine, the most extreme of which include severe central nervous system and cardiovascular reactions, eventually leading to hemodynamic instability, cardiovascular collapse, and death. Although many aspects of the side effect profile of bupivacaine and etidocaine are common to all local anesthetics, the physiochemical properties of the long-acting local anesthetics enhance their adverse effects. It is therefore imperative that the dental practitioner who uses these long-acting local anesthetics become familiar with the adverse reactions of these drugs.

[Peribulbar anesthesia versus retrobulbar anesthesia with facial nerve block. Techniques, local anesthetics and additives, akinesia and sensory block, complications]. / Peribulbäranästhesie versus Retrobulbäranästhesie mit Fazialisblock. Techniken, Lokalanästhetika und Zusätze, Akinesie und sensible Blockade, Komplikationen.

BACKGROUND: Retrobulbar anesthesia (RETRO), combined with a facial block, is the most frequently employed method of anesthesia in cataract surgery. There is, however, an increasing tendency to use peribulbar anesthesia (PERI), which is claimed to provide the same degree of anesthesia and akinesia as RETRO while reducing many of the complications. OBJECTIVES OF THE STUDY: Survey of the principal techniques of RETRO, facial block and PERI as well as of the most important local anesthetics and additives; quantitative investigation of resulting akinesia and sensory blockade; comparison of systemic and local complications (literature review). TECHNIQUES OF LOCAL ANESTHESIA: A) RETRO: 1) Atkinson technique: injection within the orbital muscle cone, superonasal eye position during injection; 2) Unsöld technique: primary eye position during injection (advantage: lower risk of optic nerve lesion). - B) Facial block: 1) O'Brien technique: injection anterior to the tragus of the ear, just above the condyloid process of the mandible (disadvantage: frequently blockade of the upper portion only of the peripheral facial nerve); 2) Nadbath/Rehman technique (modified O'Brien block): injection just inferior to the earlobe (advantage: better orbicularis akinesia due to blockade of upper and lower portions of peripheral facial nerve); 3) van Lint technique: infiltration anesthesia at the temporal orbital margin, aiming at the short zygomatic branches of the facial nerve (disadvantage: bad orbicularis akinesia). - C) PERI: 1) Technique with two injections outside the muscle cone (inferotemporally and superonasally), just past the equator; 2) one-injection technique, mostly inferotemporally (disadvantage: worse akinesia). LOCAL ANESTHETICS: A) Short and weak action: lidocaine and prilocaine; advantages: good tissue penetration, low toxicity. - B) Intermediate duration and potency of action: mepivacaine; advantage: pronounced vasoconstrictor activity, alternative to adrenaline. - C) Long and strong action: 1) etidocaine; advantage: pronounced motor blockade, particularly suitable for facial block; 2) bupivacaine; advantage: pronounced sensory blockade, excellent postoperative analgesia; disadvantage: relatively toxic (cave: cardiac and respiratory arrest). - D) Mixtures of local anesthetics: mostly lidocaine-bupivacaine mixture; combines the advantages short-onset action (lidocaine) and long-duration action (bupivacaine). ADDITIVES TO LOCAL ANESTHETICS: Adrenaline: prolongs the action of local anesthetics with short and intermediate duration of action, reduces the incidence of hemorrhages and of intraoperative vitreous bulging. - Hyaluronidase: highly effective for prevention of vitreous bulging. AKINESIA AND SENSORY BLOCKADE: In randomized order, 160 cataract patients received PERI (technique with 2 injections) with 6, 8 or 10 ml of a bupivacaine-lidocaine-hyaluronidase mixture (without facial block) or RETRO (Unsöld technique) with 5 ml of the above mixture, combined with a Nadbath/Rehman facial nerve block (5 ml etidocaine-lidocaine mixture). Measured 20 min after injection (intervening period of oculopression), the smallest ocular motility (Kestenbaum limbus test) was left after RETRO. After administration of PERI - even with a volume of 10 ml - the range of residual ocular motility was always higher, i.e., there was a less reliable globe akinesia than after RETRO. The lid closure force (Straub technique) averaged zero after all methods of anesthesia; however, the smallest spread (highest reliability) was observed after PERI. Complete corneal anesthesia (Draeger esthesiometer) was found in nearly all cases, i.e., RETRO and PERI are comparably effective concerning sensory blockade...

The effect of two different local anaesthetic solutions on pain experience following apicectomy.

Post-operative pain experience following apicectomy of a single maxillary anterior tooth was compared in two groups of patients having this treatment under local anaesthesia. Twenty patients received 3.6 ml of 2% lignocaine with 1:80,000 adrenaline and 23 patients the same volume of 1.5% etidocaine with 1:200,000 adrenaline, as the local anaesthetic agent. Although soft tissue anaesthesia lasted significantly longer when etidocaine with adrenaline was used, pain experience and analgesic intake did not differ between regimens. Lignocaine with adrenaline produced better operating conditions as haemorrhage control was more effective and the quality of operative anaesthesia was more satisfactory than with etidocaine and adrenaline. The use of etidocaine with adrenaline offered no advantages over lignocaine with adrenaline when administered as infiltration anaesthesia for apical surgery.

Comparison of regional ophthalmic anesthesia produced by pH-adjusted 0.75% and 0.5% bupivacaine and 1% and 1.5% etidocaine, all with hyaluronidase.

Two concentrations of etidocaine (1 and 1.5%) and of pH-adjusted bupivacaine (0.5 and 0.75%, pH 6.8), all fortified with hyaluronidase, were compared as local anesthetics in regional ophthalmic surgery for cataract extraction. The series comprised 160 patients assigned randomly to four groups (n = 40). Each patient received one of the four anesthetics in a double blind manner. The technique used was an inferolateral intraconal injection (3 mL) followed by a medial extraconal injection (3 mL). Supplemental injections were given at 10 and 20 min, if needed. At 10 min, globe akinesia was satisfactory in both etidocaine groups and in the 0.75% bupivacaine group (78-80% of patients), but in only 37% of the 0.5% bupivacaine group. In lid akinesia, the 0.75% bupivacaine group gained the highest scores, but there was no significant difference between the groups. Perioperative analgesia was better in both bupivacaine groups, in which only 3 and 5 patients felt pain compared to 7 and 12 in the etidocaine groups (P < 0.05). Of these local anesthetics, pH-adjusted 0.75% bupivacaine is recommended for regional ophthalmic anesthesia.

Comparison of two needle lengths in regional ophthalmic anesthesia with etidocaine and hyaluronidase.

The effect of needle length on the efficacy of regional ophthalmic anesthesia in conjunction with cataract surgery was studied in 97 patients using a two-site injection technique. The local anesthetic used was etidocaine 1.5% with hyaluronidase. In 48 patients, the anesthetic was administered inferolaterally with a 22-millimeter needle, and in the other 49 patients, with a 31-millimeter needle. Every patient had a medial injection with a 12-millimeter needle to achieve lid akinesia and to complete the globe akinesia. At 5 minutes, lid akinesia was considered better in the 22-millimeter needle group (P < .005). After one supplemental dose, when necessary, complete globe akinesia was achieved at 15 minutes significantly more often (94% vs 79%) in the 31-millimeter needle group (P < .05). Lid akinesia in the two groups was identical at that time. Eight patients in the short-needle group and three in the long-needle group experienced some pain during surgery. Throughout the study, the required intraorbital anesthetic volumes were smaller in the 31-millimeter needle group. We recommend the use of a 31-millimeter needle inferolaterally in combination with a 12-millimeter needle medially to achieve satisfactory regional anesthesia for cataract surgery.

Visual evoked potentials after retrobulbar or periocular anaesthesia.

The effect of the local anaesthetic agent, etidocaine, on the optic nerve function was examined at regional ophthalmic anaesthesia. Visual evoked potential (VEP) was recorded before and 15 minutes after injection of the anaesthetic agent in 19 patients scheduled for elective cataract surgery (seven retrobulbar and 12 periocular). Both the anaesthetised--that is, the eye to be operated on--and the fellow eye were examined. In the retrobulbar group, two patients displayed non-recordable VEPs while one had virtually non-detectable waves following the anaesthesia. In two retrobulbarly anaesthetised eyes, later peaks were unidentifiable while two other eyes had decreased amplitudes. In the periocular group, in nine patients, there was no clearcut effect on VEP resulting from the anaesthetic. In three patients of this group mild changes in the anaesthetised eyes were found. The differences in the effect of retrobulbarly or periocularly injected anaesthetics on VEP are probably due to the different concentration of the anaesthetic agent around the optic nerve.

Orbicular muscle akinesia: a comparison, using electromyography, of three techniques.

Ninety patients scheduled for elective cataract extraction under local anesthesia received an inferolateral intraconal injection of 4 mL of etidocaine mixed with hyaluronidase. They were divided into three groups of 30 patients each according to the method used to provide orbicular akinesia. Those in group I had a nasal, intraorbital injection; those in group II underwent electrostimulation to locate branches of the facial nerve in the eyelids; and those in group III had the anesthetic agent injected subcutaneously into the lids. Ten minutes after the regional blockade, orbicular muscle activity of the upper eyelid, as measured by electromyography, was found to be higher in group I than in the other two groups. The muscular activity of the lower lid at 10 minutes, or of either of the lids at 20 minutes, was similar in all three groups. The use of electrostimulation did not yield better orbicular akinesia than the infiltration technique alone. Nasal injection improved globe akinesia.

Local anesthetic-induced toxicity may be modified by low doses of flumazenil.

The purpose of this study was to investigate the influence of flumazenil on local anesthetic-induced acute toxicity. For each of the three tested anesthetics (etidocaine, mepivacaine and lidocaine) 6 groups of mice were treated by a single dose of flumazenil (0.125, 0.25, 0.5, 1 and 2 mg/kg), or an equal volume of saline, 15 minutes before the injection of the anesthetic (etidocaine: 50 mg/kg, mepivacaine: 110 mg/kg and lidocaine: 115 mg/kg). The convulsant activity, the time of latency to convulse and the mortality rate were assessed in each group. The local anesthetic-induced mortality was not significantly modified by flumazenil. The convulsant activity of lidocaine and mepivacaine was significantly increased by flumazenil but not for etidocaine. Also, increasing doses of flumazenil decreased the time of latency to obtain lidocaine-induced convulsions. This effect was not obtained with etidocaine or mepivacaine.

Periocular anaesthesia: technique, effectiveness and complications with special reference to postoperative ptosis.

The effectiveness of periocular anaesthesia and its complications were examined in 100 successive cataract operations. The patients were divided into 3 groups according to the duration of ocular compression with an Autopressor device after administration of periocular anaesthesia. In the control group, no compression was used (C-O, n = 36 patients). In the other two groups, compression was used for 10 (C-10, n = 32) and for 20 (C-20, n = 32) min. No differences in globe or orbicular akinesia were found between the groups. At 10 min, immobilisation of the globe in different directions was attained in 60.1-84.5% of the patients. Compression for an additional 10 min did not significantly improve the akinesia. In contrast, the hitherto undescribed loss of light perception increased with time: 15 patients at 10 min and 22 at 20 min were unable to see light. Chemosis and haematomas in the upper eyelid occurred more often in C-0 than in the other 2 groups. One day postoperatively the average palpebral aperture was smaller in C-0 than in the other two groups. The frequent postoperative ptosis (74.3% on the 1st day) decreased rapidly, but on postoperative day 7, 9 patients still had ptosis. In only one patient was ptosis still recognizable at 6 weeks postoperatively. No serious complications occurred. This study demonstrates that periocular anaesthesia with ocular compression is a suitable method for cataract surgery.

A clinical trial of long-acting local anesthetics for periodontal surgery.

The efficacy of long-acting local anesthetics for anesthesia during periodontal surgery and for analgesia during the immediate postoperative period was evaluated. The rationale for using long-acting local anesthetics such as etidocaine and bupivacaine is that they can provide surgical anesthesia and, because of their long duration, prevent discomfort that may occur for 4-6 hours postoperatively. Two clinical trials were performed. The first enrolled patients requiring bilateral periodontal surgery. Using a matched pair design and double-blind randomized study conditions, 2% lidocaine 1/100,000 epinephrine was compared with 1.5% etidocaine 1/200,000 epinephrine for periodontal surgery. The time until complete recovery and the time until pain onset were found to be longer for the etidocaine surgeries. Postoperative pain appeared more severe, and the need for oral analgesics was greater for the lidocaine surgeries. Surgeons' rating of surgical bleeding was significantly greater for the etidocaine procedures. When matched bilateral surgeries were not available, a second double-blind randomized parallel trial was performed that compared 1.5% etidocaine 1/200,000 epinephrine to 0.5% bupivacaine 1/200,000 epinephrine. No significant differences were seen in the quality of anesthesia, degree of bleeding, or postoperative pain between these two long-acting anesthetics.

Effect of ocular compression (Autopressor) on intraocular pressure in periocular anaesthesia.

One hundred successive patients were operated on for cataract under periocular anaesthesia. The patients were divided into 3 groups to study the effect of extraocular compression on intraocular pressure. In the control group (C-O), no compression was used. In the other 2 groups, compression was applied immediately after local injection of the anaesthetic for either 10 (C-10) or 20 min (C-20). In the control group, a periocular local anaesthetic increased the IOP in 27 of 36 patients, the average increase being 3.8 mmHg (at 10 min). Postanaesthetic compression of the eye led to a decrease in intraocular pressure, which is beneficial for the operative procedure. During the first 10 min, the mean intraocular pressure decreased by 3.1 and 4.0 mmHg in groups C-10 and C-20, respectively. In the C-20 group, there was a further (1.3 mmHg) reduction in intraocular pressure between 10 and 20 min.

Etidocaine hydrochloride in surgical procedures: effects on postoperative analgesia.

Because early research has established the prolonged duration of the effects of etidocaine, this study was performed to determine whether the long-acting local anesthetic can reduce the need for postoperative analgesics after oral surgery.

Long-acting local anesthetics: a review of clinical efficacy in dentistry.

Two long-acting local anesthetics, bupivacaine and etidocaine, have been added to the dental armamentarium. The efficacies, onset times, durations, and hemostatic characteristics of these agents have been well described for a variety of clinical applications. Assessments of their usefulness in managing postoperative pain following oral surgery, endodontics, and periodontics have also been published. This article reviews the clinical utility of these agents and provides recommendations for their safe use in dentistry.