Lidocaine-bupivacaine Mixture Research Articles

EFFECTS OF LIDOCAINE AND LIDOCAINE-BUPIVOCAINE MIXTURE IN INFRAORBITAL NERVE BLOCKS IN DOGS DURING OPERATIONS ON MAXILLARY TEETH

The use of local anesthetics reduces the intensity of pain stimuli during invasive procedures, thereby reducing postoperative pain intensity. The aim of the study was to determine the onset, duration and extent of regional blocks of the infraorbital nerve and its branches performed by injecting lidocaine and lidocaine-bupivacaine mixture into the infraorbital canal in dogs. Ten clinically healthy dogs, selected according to the principle of clinical analogues, were selected for the trial. Under general anesthesia, a pain stimulus was initiated by needle injection from the dorsolateral side into the gingiva of the maxillary canines, maxillary fourth premolars, and second molars. Changes in physiological indices were recorded on the patient's monitor.Heart rate and respiratory rate were measured. After baseline physiological indices were measured, 1 ml of 2% lidocaine solution was injected into the infraorbital canal (about two-thirds of the canal length) in one group and a mixture of 2% lidocaine and 0.5% bupivacaine (0.5 ml each) in the other group. Data were recorded for 4 hours.When infraorbital nerve blocks were performed in the first and second experimental groups of animals, anesthesia of the maxillary canine on the anesthetized side was achieved in 5 and 10 minutes, respectively. But nerve blocks of the fourth premolar and second molar were successful only in 2 dogs of the first group and 1 dog of the second group, respectively. The average duration of nerve block for the maxillary canine was 110 and 203 minutes after injection of lidocaine and lidocaine-bupivacaine mixture, respectively.Performing an infraorbital nerve block, as was done in this study, successfully blocks the innervation of the maxillary canine, but the results of nerve analgesia of the fourth premolar and second molar were inconsistent. This specific technique should not be used when extracting teeth caudal to the maxillary canine.

Comparison of the efficacy and duration of desensitization of oral structures following injection of a lidocaine-bupivacaine mixture via lateral percutaneous and modified infraorbital approaches in dogs.

To compare efficacy and duration of desensitization of oral structures with a lidocaine-bupivacaine mixture administered via a lateral percutaneous or modified infraorbital approach. 6 healthy adult hound-type female dogs. In this crossover study, dogs were randomized for side (left or right) and maxillary nerve approach (lateral percutaneous or infraorbital), with a 2-week washout period. Dogs were anesthetized, and a 2-mL mixture of 2% lidocaine and 0.5% bupivacaine (50:50 [vol/vol]) was administered with a 22-gauge, 4.5-cm-long catheter inserted through the infraorbital canal (infraorbital approach) or with a shielded stimulating needle to the maxillary nerve (percutaneous approach). Reflex-evoked motor potentials were measured for the maxillary canine tooth, fourth premolar tooth, second molar tooth, and hard palate mucosa ipsilateral to the injected mixture and for the contralateral maxillary canine tooth (control) at three 10-minute intervals before injection (baseline) and at predetermined times after injection for up to 6.7 hours. For each oral structure, the proportion of dogs with desensitization (efficacy) and time to onset and duration of desensitization were compared between approaches. The proportion of dogs with successful nerve blockade did not significantly differ between infraorbital and percutaneous approaches and among the 4 oral structures. Time to onset of desensitization did not differ between approaches, but duration was significantly longer with the infraorbital approach. A modified infraorbital approach with the lidocaine-bupivacaine mixture had similar effects to a lateral percutaneous approach but provided a longer duration of desensitization. Neither approach was universally successful at desensitizing all oral structures.

Comparison of the efficacy and duration of desensitization of oral structures following injection of various volumes of a lidocaine-bupivacaine mixture via an infraorbital approach in dogs.

To compare the efficacy and duration of desensitization of oral structures following injection of various volumes of lidocaine-bupivacaine via an infraorbital approach in dogs. 6 healthy adult hound-type dogs. In a randomized crossover study, each dog received 1, 2, and 3 mL of a 2% lidocaine-0.5% bupivacaine mixture (50:50 vol/vol) injected within and near the caudal aspect of the infraorbital canal with a 14-day washout period between treatments. Dogs were anesthetized, and each treatment was administered through a 22-gauge, 4.5-cm-long catheter, which was fully inserted through and then withdrawn 2 cm to the caudal aspect of the infraorbital canal. The reflex-evoked motor potential was measured for the maxillary canine tooth (MC), fourth premolar tooth (MPM4), second molar tooth (MM2), and hard palate mucosa ipsilateral to the injected treatment and for the contralateral MC (control) at predetermined times before and for 6 hours after treatment administration or until the block was no longer effective. For each oral structure, the proportion of dogs with desensitization (efficacy) and time to onset and duration of desensitization were compared among the 3 treatments (injectate volumes). Treatment was not associated with efficacy, time to onset, or duration of desensitization. Regardless of treatment, MC and MPM4 were more frequently desensitized and mean durations of desensitization for MC and MPM4 were longer, compared with those for MM2 and the hard palate. The volume of local anesthetic used for an infraorbital nerve block had no effect on block efficacy or duration.

The value of adding ketamine to lidocaine and bupivacaine mixture in ultrasonic-guided spermatic cord block in scrotal surgery: a randomized double-blind prospective study

Background Spermatic cord block for scrotal surgery avoids the potential risks of neuraxial and general anesthesia and provides long-lasting postoperative analgesia. Aim The aim of this study is to evaluate the value of adding ketamine to lidocaine-bupivacaine mixture for ultrasonic-guided spermatic cord block for patients undergoing scrotal surgery. Patients and methods This study was carried out in Tanta University Hospitals on 50 patients with ASA physical status I and II, age older than or equal to 18 years, who were scheduled for elective scrotal surgery. Patients were randomly allocated into two equal groups using sealed envelopes: 25 patients received ultrasound-guided spermatic cord block by a mixture of lidocaine 5 ml (2%), plain bupivacaine 5 ml (0.5%), and 1-ml normal saline (group 1), and 25 patients received ultrasound-guided spermatic cord block by a mixture of lidocaine 5 ml (2%), plain bupivacaine 5 ml (0.5%), and ketamine (0.5 mg/kg) (group 2). Results There was no significant difference between the demographic data, patient characteristics, heart rate, mean arterial blood pressure, and oxygen saturation in the studied groups. There was significantly rapid onset and prolonged duration of blockade in group 2 and significant increase in visual analog scale score in group 1 at 6 h postoperatively, whereas a significant increase occurred in group 2 at 12 h, postoperatively. There was significant increase in group 1 regarding the amount of rescue analgesia. Conclusion In ultrasound-guided spermatic cord block in scrotal surgery, addition of (0.5 mg/kg) ketamine to lidocaine–bupivacaine mixture improves onset of the block, prolongs postoperative analgesia, and reduces the consumption of postoperative rescue analgesics.

The Intervertebral Disc Functional Cell Models: a New Revolution for in vitro Toxicology Testing

Introduction For diagnostics of discogenic low back pain, local anaesthetics are often used, which may be cytotoxic to intervertebral disc cells. Studies so far have been mainly performed on animal cells. The study aim was to evaluate the effect of local anaesthetics on human intervertebral disc cells in vitro. Material and Methods Annulus fibrosus and nucleus pulposus cells were isolated from human lumbar intervertebral disc fragments and exposed to various concentrations of lidocaine, bupivacaine and their mixture. Saline solution was used as a control. Three different dilutions (undiluted, 1:2 and 1:4) of anaesthetics were tested. The cells were treated for 6, 24 and 48 hours and examined with for viability. Results Nulceus pulposus cells were more susceptible than annulus fibrosus cells to the toxic effects of both anaesthetics. Lidocaine was more toxic with the final cell survival fraction of 0%, 10% and 20%. Bupivacaine presented less cytotoxicity with the final survival of 10%, 60% and 80%. Lidocaine-bupivacaine mixture showed an intermediate toxicological effect. Conclusion Human intervertebral disc cells in vitro are useful for various toxicology tests. They are a valuable model for testing of anesthetic agents. According to the analysis, lidocaine and its mixtures should be avoided due to its high toxicity to the intervertebral disc cells. Bupivacaine was less toxic, especially in 1:4 dilutions and may be recommended for the intradiscal diagnostics.

Effect of addition of magnesium to local anesthetics for peribulbar block: A prospective randomized double-blind study

Background:Magnesium sulphate has been used along with local anesthetics in different regional blocks and found to be effective in decreasing the time of onset of the block and increasing the duration of the block.Objective:To evaluate the effect of addition of magnesium sulfate to standard local anesthetics mixture on the time for onset of the globe and lid akinesia for peribulbar block in ophthalmic surgeries.Materials and Methods:Sixty patients with American Society of Anesthesiologists status I to III undergoing ophthalmic surgery under peribulbar block were included in this study. Patients were randomized into two groups. Both the groups received 4.5 ml of 2% lidocaine, 4.5 ml of 0.5% bupivacaine with150 IU hyaluronidase. Group NS received normal saline 1 ml in the peribulbar block and Group MS, magnesium sulfate 50 mg in 1 ml normal saline. The onset of akinesia, satisfactory block and complications were observed by an independent observer.Results:Demographic data was statistically similar. In the Group NS at 3, 5, 10 and 15 min after the block, complete akinesia was seen in 0, 2, 11 and 28 patients respectively. In the Group MS, at 3, 5, 10 and 15 min after the block, complete akinesia was seen in 13, 23, 27 and 28 patients respectively. Patients received magnesium sulfate showed the statistically significant rapid onset of lid and globe akinesia than the control group till 10 min (P < 0.000). None of the patients needed a supplementary block and had complications during the surgery.Conclusion:Addition of 50 mg of magnesium sulfate to the lidocaine-bupivacaine mixture for peribulbar block decreases the onset of akinesia without any obvious side effect.

Toxicity Effects of Lidocaine and Bupivacaine on Human Intervertebral Disc Cells in Vitro

Introduction The treatment and diagnostics of discogenic low back pain often employs local anesthetic agents. Lidocaine and bupivacaine are most commonly used for controlling and relieving the pain in interventional spine procedures. It is known that these local anaesthetics may be cytotoxic to the intervertebral disc cells following the intradiscal injections and that they may provoke or accelerate the intervertebral disc degeneration. However, the potential deletorious effects of these agents to human cells still remain unclear, as studies so far have been predominantly performed on animal cells. The aim of the study was to evaluate the effect of various local anaesthetics on human intervertebral disc cells in vitro and to compare the cytotoxicity of lidocaine, bupivacaine, and mixture of both anaesthetics to saline solution control. Materials and Methods Annulus fibrosus and nucleus pulposus cells were isolated from human lumbar intervertebral disc fragments following discectomies. They were cultured in the microtiter plates and exposed to various concentrations of lidocaine, bupivacaine, as well as their mixture. The saline solution was used as a control. Three different dilutions (undiluted, 1:2 and 1:4) of anesthetic agents were tested. The cells were treated for 6, 24, and 48 hours. They were then examined with the crystal violet cell staining to determine the fraction of cells surviving the treatment. Results Human intervertebral disc cells demonstrated a time- and dose-dependent toxicity to lidocaine and bupivacaine. Nulceus pulposus cells were more susceptible than AF cells to the toxic effects of both anesthetic agents. Lidocaine was the more toxic in all three tested concentrations with the final cell survival fraction of 0, 10, and 20%, respectively. Bupivacaine presented less cytotoxicity than lidocaine with the final survival of 10, 60, and 80%, respectively. Lidocaine-bupivacaine mixture showed an intermediate toxicological effect. The cell death was mainly caused by necrosis rather than apoptosis. Conclusion When incubating the human intervertebral disc cells in vitro with a combination of anesthetic agents commonly used for discography, the cytotoxic effects were observed in a dose- and time-dependent manner. According to our study, lidocaine and its mixtures should be avoided due to its high toxicity to the intervertebral disc cells. Bupivacaine was less toxic, especially when used in 1:4 dilutions and may be thus recommended for the intradiscal diagnostics. It is assumed that the genesis of disc degeneration might be contributed also by the toxic effects of the anaesthetics used, culminating to progressive tissue damage after the diagnostic measures. Disclosure of Interest None declared References Carragee EJ, Hannibal M. Diagnostic evaluation of low back pain. Orthop Clin North Am 2004;35(1):7–16 Lee H, Sowa G, Vo N, et al. Effect of bupivacaine on intervertebral disc cell viability. Spine J 2010;10(2):159–166 Rahnama R, Wang M, Dang AC, Kim HT, Kuo AC. Cytotoxicity of local anesthetics on human mesenchymal stem cells. J Bone Joint Surg Am 2013;95(2):132–137

Caudal epidural anti-nociception using lidocaine, bupivacaine or their combination in cows undergoing reproductive procedures

ObjectiveTo evaluate the anti-nociceptive effects of lidocaine, lidocaine-bupivacaine combination or bupivacaine following caudal epidural administration in cows undergoing reproductive procedures. Study designBlinded, randomized experimental study. AnimalsThirty seven healthy Holstein cows (mean weight ± SD, 633 ± 41 kg). MethodsAnimals were allocated randomly to receive one of four treatments: group LID, 0.2 mg kg−1 lidocaine 2%; group LID-BUP, lidocaine-bupivacaine mixture in a 1:1 volume ratio (0.1 mg kg−1 and 0.025 mg kg−1, respectively); group BUP-LD, 0.05 mg kg−1 bupivacaine 0.5%; and group BUP-HD, 0.06 mg kg−1 bupivacaine 0.5%. The onset and duration of perineal anti-nociception were determined using superficial and deep pin pricks and the number of cows with complete perineal anti-nociception was recorded. Parameters were compared using anova followed by Duncan's test where relevant. ResultsMean ± SD time to onset of anti-nociception following epidural administration of BUP-LD was significantly longer than for LID-BUP (p < 0.05). The duration (in minutes) of perineal anti-nociception was significantly longer following epidural administration of BUP-HD (247 ± 31) versus LID-BUP (181 ± 33) and LID (127 ± 25) minutes respectively. The % of cows with complete anti-nociception was increased in the group treated with BUP-HD compared to BUP-LD. Severe ataxia or recumbency did not occur in any groups. Conclusions and clinical relevanceEpidurally administered bupivacaine, at a dose of 0.06 mg kg−1, may provide satisfactory caudal epidural anti-nociception for longer-duration obstetric and surgical procedures.

Comparing lidocaine, bupivacaine and a lidocaine–bupivacaine mixture as a metacarpal block in sheep

Mechanical sensory blocking effects in the metacarpi of rams were compared following perineural injection of saline, 2% lidocaine (LIDO), 0.5% bupivacaine (BUPI), and a 1:1 (volume/volume) mixture of LIDO–BUPI. Saline was also administered in the contralateral metacarpi. Compared with the saline treatment and contralateral controls, the various treatments induced larger area under the curve (AUC) values 0–60min post-treatment (AUC0–60). Administration of BUPI and LIDO–BUPI also induced larger AUC60–120 values (P<0.01). The AUC0–60 and AUC60–120 values with LIDO were less than those achieved with LIDO–BUPI and BUPI (P<0.001), and AUC60–120 values with LIDO–BUPI were less than those obtained with BUPI (P<0.05). Anaesthesia occurred within 5min following the administration of all local anaesthetics and lasted longer in the case of BUPI (110.0±47.3min) than with LIDO (40.0±13.2min) (P<0.01). The duration of anaesthesia was 86.9±66.0min with the LIDO–BUPI combination. Thus this combination offered no apparent advantages over the use of BUPI alone.

Effects of local low-dose rocuronium on the quality of peribulbar anesthesia for cataract surgery

Objectives:Peribulbar anesthesia is associated with delayed and/or incomplete orbital akinesia compared with retrobulbar anesthesia. This study examined the effects of adding rocuronium 5 mg to two different concentrations of lidocaine-bupivacaine mixture on onset time of orbital and eyelid akinesia in patients undergoing cataract surgery.Methods:In a double-blind study, 90 patients were equally randomized to receive a mixture of 0.5 ml normal saline, 4 ml lidocaine 2%, and 4 ml bupivacaine 0.5% (group I), a mixture of rocuronium 0.5 ml (5 mg), 4 ml lidocaine 2%, and 4 ml bupivacaine 0.5% (group II), or a mixture of rocuronium 0.5 ml (5 mg), 4 ml lidocaine 1%, and 4 ml bupivacaine 0.25% (group III). Orbital akinesia was assessed on a 0-8 score (0 = no movement, 8 = normal) at 2 min intervals for 10 min. Time to adequate anesthesia was also recorded. Results are presented as mean±SD.Results:Ocular movement score decreased during the assessment period in all groups. However, at 2 min after block administration, the score decreased to 4±2 (95% CI 3,5) in groups II and III compared with 5±2 (95% CI 4,6) in group I (P<0.01). Time to adequate condition to begin surgery was 9.8±2.9 vs. 6.9±4.1 vs. 7.9±3.9 min for groups I, II, and III, respectively (P=0.01).Conclusion:The addition of rocuronium 5 mg to a mixture of lidocaine 2% and bupivacaine 0.5% shortened the onset time of peribulbar anesthesia in patients undergoing cataract surgery without causing adverse effects.

Hemodynamic and cardiac electrophysiologic effects of lidocaine-bupivacaine mixture in anesthetized and ventilated piglets.

The sensory blockade induced by a lidocaine-bupivacaine mixture combines the faster onset of lidocaine and the longer duration of bupivacaine. The current study compared the effects of large doses lidocaine (16 mg/kg), bupivacaine (4 mg/kg), and a mixture of 16 mg/kg lidocaine-4 mg/kg bupivacaine on hemodynamic and cardiac electrophysiologic parameters in anesthetized and ventilated piglets. After carotid artery cannulation, a double micromanometer measured mean aortic pressure, left ventricular end diastolic pressure, and the first derivative of left ventricular pressure. Electrocardiogram recording and a bipolar electrode catheter measured RR, PQ, QRS, QT C, JT C, AH, and HV intervals. Lidocaine, bupivacaine, or the mixture was administered intravenously over 30 s, and studied parameters were measured throughout 30 min. Mean aortic pressure decreased in all groups ( P < 0.05). The first derivative of left ventricular pressure was decreased in all groups ( P < 0.001) but to a greater extent with the mixture compared with lidocaine ( P < 0.04). RR, QT C, and JT C intervals were similarly increased in all groups ( P < 0.05). In all groups, PQ, AH, HV, and QRS intervals were widened ( P < 0.001). The lengthening of PQ was greater with bupivacaine ( P < 0.02). The lengthening of AH was greater and delayed with bupivacaine compared with lidocaine ( P < 0.03). The lengthening of HV and the widening of QRS were greater and delayed with bupivacaine ( P < 0.01). The widening of QRS was greater with the mixture than with lidocaine ( P < 0.01). The alterations of ventricular conduction parameters are greater with 4 mg/kg bupivacaine than with a mixture of 16 mg/kg lidocaine-4 mg/kg bupivacaine, whereas the hemodynamic parameters are similarly altered.

Effects of atracurium added to local anesthetics on akinesia in peribulbar block

Background and Objectives: Peribulbar anesthesia (PBA) is widely used in cataract surgery, but the onset time of akinesia is not as rapid as with retrobulbar block. The aim of this study was to evaluate whether addition of low-dose atracurium to the local anesthetic mixture has any effects on akinesia in PBA. Methods: Sixty adults undergoing cataract surgery were randomly allocated to receive either 8 mL of a lidocaine-bupivacaine mixture, plus 0.5 mL 0.9% NaCl (group I) or 8 mL of the same local anesthetic mixture plus 0.5 mL (5 mg) atracurium (group II). The level of akinesia was graded by a observer unaware of group assignment. The onset time and duration of akinesia were also recorded by an observer, again unaware of group assignment. Results: The onset time of complete akinesia in group II was significantly shorter than that in group I (P < .05). In group I, 86% of patients had an akinesia score of 0 (complete akinesia) in the first 10 minutes. The rate of complete akinesia was 93% in group II in the same period. This difference was not significant. The success rate of complete akinesia was 93% in group I and 100% in group II at the end of the measurement interval. None of the group II patients required supplementary block, while 2 patients in group I received additional injections for inadequate akinesia. Conclusion: Atracurium added at a dose of 5 mg to a lidocaine-bupivacaine mixture for peribulbar block decreases the onset time of akinesia and provides better surgical conditions without obvious side-effects. Reg Anesth Pain Med 2002;27:487-490.

Patterns of Nerve Block by Different Combination of Lidocaine-Bupivacaine Mixture.

Patterns of Nerve Block by Different Combination of Lidocaine-Bupivacaine Mixture.

Patterns of Nerve Conduction Blockade by Different Combinations of Lidocaine-bupivacaine Mixture

Patterns of Nerve Conduction Blockade by Different Combinations of Lidocaine-bupivacaine Mixture

Block of the brachial plexus branches by the humeral route. A prospective study in 503 ambulatory patients. Proposal of a nerve‐blocking sequence

Brachial plexus is usually approached by the supraclavicular or axillary route. A technique for selective blockade of the branches of the plexus at the humeral canal using electrolocation has recently been proposed. The aim of the present study was to assess the feasibility of this technique in the ambulatory patient and to determine the optimal sequence of nerve-blocking. The nerves originating from the brachial plexus were located in the humeral canal, at the junction of the proximal and the middle third of the arm, with a stimulator and blocked using either lidocaine or a mixture of lidocaine and bupivacaine, depending on the anticipated duration of surgery. The minimal stimulating intensity eliciting an adequate response, type of local anaesthetic and injected volume, and time of onset of surgical anaesthesia were collected. The study included 503 consecutive ambulatory patients due to undergo surgery of the elbow, wrist or hand in one year. Suitable anaesthesia was obtained with the humeral blockade in 82.1% of cases. In the remaining 17.9%, an additional block at the elbow was required, mainly for ulnar and median nerves. The onset times of sensory blocks were the longest for the median nerve, similar for the radial and ulnar nerves, shorter for the musculocutaneous nerve and the shortest for the medial brachial and antebrachial cutaneous nerves. The difference was more significant with the lidocaine-bupivacaine mixture, than with lidocaine alone (P<0.001 vs P<0.05, respectively). The onset times of motor blocks were the longest for the median nerve (P<0.05) and the shortest for the musculocutaneous nerve (P<0.001). Neither nervous nor vascular complications occurred. This study shows that the nerve block at the humeral canal is an efficient and safe technique. Considering the onset times of nerve blocks, the following sequence for blockade can be recommended: median, ulnar, radial, musculocutaneous, medial (brachial and antebrachial) cutaneous nerves. The selective blockade of the main nerves of the upper limb at the humeral canal can be recommended for surgery of the forearm and the hand in the ambulatory patient.

Peribulbäranästhesie versus Retrobulbäranästhesie mit Fazialisblock - Techniken, Lokalanästhetika und Zusätze, Akinesie und sensible Blockade, Komplikationen

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. 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). 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). 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). 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. 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...

Okuläre Kreislaufveränderungen durch Retrobulbäranästhesie mit und ohne Adrenalinzusatz

In 80 patients, retrobulbar anesthesia (RBA; 5 ml of a lidocaine-bupivacaine mixture with hyaluronidase) with or without addition of adrenaline (after-mixing concentration 1:500,000) was performed preoperatively. In 2 examination series, the acute and medium-term effects of RBA on the following ocular circulatory variables were investigated: ocular pulsation volume (PVoc), systolic ciliary and retinal perfusion pressures or blood pressures, respectively (method: oculo-oscillo-dynamography). RBA with adrenaline: Directly after injection, PVoc was reduced by an average of 49%, the ocular perfusion and blood pressures were lowered by averages of 8.0 and 4.3 mmHg, respectively, and the intraocular pressure (Pio; hand-applanation tonometer) was elevated by 3.5 mmHg. 15 min after injection, PVoc and the ocular perfusion and blood pressures were even slightly more reduced, whereas Pio had reassumed its pre-injection level. RBA without adrenaline: During both time periods after injection, the reduction of PVoc averaged 10% less compared to RBA with adrenaline. The changes in ocular perfusion and blood pressures and in Pio, however, were not significantly different from RBA with adrenaline. The lowering of PVoc--which variable is determined mainly by the pulsatile choroidal blood flow--in concert with the lowered ciliary perfusion and blood pressures is indicative of a reduced ciliary blood flow during RBA. Because of the decreased retinal perfusion and blood pressures, there is also a higher risk of reduced blood supply to the retina. Only to some degree, the observed inhibitory RBA effects on ocular circulation can be explained by adrenaline, and to an even smaller degree by the only transient Pio elevation.