Alcalinisation des anesthésiques locaux: théoriquement justifiée mais inutile cliniquement

Chassard, D.; Berrada, Khalid; Boulétreau, P

doi:10.1007/bf03011719

Cited by 22 publications

(5 citation statements)

References 56 publications

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“…These results are in close agreement with earlier studies that demonstrated ropivacaine and bupivacaine precipitation when they are alkalinized to physiologic pH with sodium bicarbonate, and lidocaine does not [ 9 10 11 12 ]. However, this phenomenon has not been emphasized in clinical journals or widely appreciated by physicians.…”

Section: Discussionsupporting

confidence: 92%

Crystallization of Local Anesthetics When Mixed With Corticosteroid Solutions

et al. 2016

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ObjectiveTo evaluate at which pH level various local anesthetics precipitate, and to confirm which combination of corticosteroid and local anesthetic crystallizes.MethodsEach of ropivacaine-HCl, bupivacaine-HCl, and lidocaine-HCl was mixed with 4 different concentrations of NaOH solutions. Also, each of the three local anesthetics was mixed with the same volume of 3 corticosteroid solutions (triamcinolone acetonide, dexamethasone sodium phosphate, and betamethasone sodium phosphate). Precipitation of the local anesthetics (or not) was observed, by the naked eye and by microscope. The pH of each solution and the size of the precipitated crystal were measured.ResultsAlkalinized with NaOH to a certain value of pH, local anesthetics precipitated (ropivacaine pH 6.9, bupivacaine pH 7.7, and lidocaine pH 12.9). Precipitation was observed as a cloudy appearance by the naked eye and as the aggregation of small particles (<10 µm) by microscope. The amount of particles and aggregation increased with increased pH. Mixed with betamethasone sodium phosphate, ropivacaine was precipitated in the form of numerous large crystals (>300 µm, pH 7.5). Ropivacaine with dexamethasone sodium phosphate also precipitated, but it was only observable by microscope (a few crystals of 10–100 µm, pH 7.0). Bupivacaine with betamethasone sodium phosphate formed precipitates of non-aggregated smaller particles (<10 µm, pH 7.7). Lidocaine mixed with corticosteroids did not precipitate.ConclusionRopivacaine and bupivacaine can precipitate by alkalinization at a physiological pH, and therefore also produce crystals at a physiological pH when they are mixed with betamethasone sodium phosphate. Thus, the potential risk should be noted for their use in interventions, such as epidural steroid injections.

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Section: Discussionsupporting

confidence: 92%

Crystallization of Local Anesthetics When Mixed With Corticosteroid Solutions

et al. 2016

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“…The size and number of particulates increased in the 0.2% ropivacaine mixture compared to the 0.1% mixture. These results are supported by the fact that the pKa and changed pH of the LA determine the amount of each agent presented in the basic or protonated form [20], and the concentration of the LA determines the absolute amount of each agent. In addition, this is consistent with a previous study which reported that ropivacaine at higher concentration (0.75% and 1%) forms particulates even at pH 6.0 or higher [21].…”

Section: Discussionmentioning

confidence: 80%

Interaction between Dexamethasone, Ropivacaine, and Contrast Media Used in Interventional Pain Treatment: Considerations in Safety

Kim

et al. 2022

Medicina

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Background and Objectives: Although epidural steroid injections are used as an effective treatment, this technique is associated with rare but serious ischemic complications, especially when particulate steroids are used. However, recent studies have reported that even if non-particulate steroids are used, particulates are formed by the interaction with some local anesthetics (LA), causing ischemic complications. This observational study evaluated commonly used combinations of non-particulate steroids and LA with contrast media via microscopic analysis and analyzed the chemical properties of each mixture to identify the correlation of particulate formation. Materials and Methods: Commonly used clinical non-particulate and particulate steroids, contrast media, and LA agent combinations were evaluated macroscopically and microscopically. The pH values were also measured at both room temperature (26 °C) and body temperature (36 °C). Where particulates were observed, the particulate size was measured. Results: Macroscopically, the mixture of non-particulate steroid and ropivacaine had a slightly cloudy appearance at all concentrations, but there was no visible particulate. However, when observed under a microscope, the pH-dependent particulate formation was observed at all concentration combinations tested. (0.1% ropivacaine: from 19 μm to 70 μm, and 0.2% ropivacaine: from 37 μm to 108 μm at room temperature (26 °C)). When contrast media was mixed or the temperature was raised to body temperature (36 °C), the number and size of the particulates decreased or dissolved. Conclusions: The combination of ropivacaine and dexamethasone, a non-particulate steroid, mainly used in epidural injections, forms particulates. However, when mixed with contrast media, particulates are dissolved because of changes in pH and factors affecting particulate formation. In fluoroscopy-guided injections, the use of contrast media could resolve particulate formation.

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“…Similarly, in theory, the alkalinization of local anesthetics can also accelerate the onset time of nerve block by increasing the proportion of non-ionized molecules. However, the use of the alkalinization technique is limited in clinical practice for its uncertain efficacy, because the precipitation generated by alkalization of local anesthetic solutions may reduce drug bioavailability [ 4 , 15 ]. The intraneural injection is an another safe and effective approach to influence the characters of the sciatic nerve block [ 16 ].…”

Section: Discussionmentioning

confidence: 99%

The effect of warming ropivacaine on ultrasound-guided subgluteal sciatic nerve block: a randomized controlled trial

He,

Ma,

Zhou

et al. 2023

BMC Anesthesiol

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Background There is a long latent period for the sciatic nerve block before a satisfactory block is attained. Changes in the temperature of local anesthetics may influence the characters of the peripheral nerve block. This study was designed to evaluate the effect of warming ropivacaine on the ultrasound-guided subgluteal sciatic nerve block. Methods Fifty-four patients for distal lower limbs surgery were randomly allocated into warming group (group W, n = 27) or room tempeture group (group R, n = 27) with the ultrasound-guided subgluteal sciatic nerve block. The group W received 30 ml of ropivacaine 0.5% at 30℃ and the group R received 30 ml of ropivacaine 0.5% at 23℃. The sensory and motor blockade were assessed every 2 min for 30 min after injection. The primary outcome was the onset time of limb sensory blockade. Results The onset time of sensory blockade was shorter in group W than in group R (16 (16,18) min vs 22 (20,23) min, p < 0.001), and the onset time of motor blockade was also shorter in group W than in group R (22 (20,24) min vs 26 (24,28) min, p < 0.001). The onset time of sensory blockade for each nerve was shorter in group W than in group R (p < 0.001). No obvious differences for the duration of sensory and motor blockade and the patient satisfaction were discovered between both groups. No complications associated with nerve block were observed 2 days after surgery. Conclusions Warming ropivacaine 0.5% to 30℃ accelerates the onset time of sensory and motor blockade in the ultrasound-guided subgluteal sciatic nerve block and it has no influence on the duration of sensory and motor blockade. Trial registration The trial was registered on October 3, 2022 in the Chinese Clinical Trial Registry (https://www.chictr.org.cn/bin/project/edit?pid=181104), registration number ChiCTR2200064350 (03/10/2022).

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Alcalinisation des anesthésiques locaux: théoriquement justifiée mais inutile cliniquement

Abstract: On the basis of this review, routine alkalinization of local anaesthetics is not recommended.

Cited by 22 publications

References 56 publications

Crystallization of Local Anesthetics When Mixed With Corticosteroid Solutions

Crystallization of Local Anesthetics When Mixed With Corticosteroid Solutions

Interaction between Dexamethasone, Ropivacaine, and Contrast Media Used in Interventional Pain Treatment: Considerations in Safety

The effect of warming ropivacaine on ultrasound-guided subgluteal sciatic nerve block: a randomized controlled trial

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