Assessment of the Densities of Local Anesthetics and Their Combination with Adjuvants. An Experimental Study

Imbelloni, Luiz Eduardo; Moreira, Adriano Dias; Gaspar, Flávia Cunha; Gouveia, Marildo A.; Cordeiro, José Antônio

doi:10.1590/s0034-70942009000200003

Cited by 26 publications

(24 citation statements)

References 10 publications

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“…They also observed that, except for 2% and 1.5% lidocaine with epinephrine, which were both hyperbaric, all the samples were hypobaric, including opioids alone and combined with LA, as were combinations of opioids diluted with saline at usual clinical doses (morphine 250 μg, fentanyl 2.5 to 25 μg and sufentanil 3.3 to 12.5 μg). Similarly, in a Brazilian study, authors used a latest generation densitometer (DMA 4500), based on harmonic mechanical oscillations with a precision of 0.00001 g/mL, to measure the density of the range of LA and most commonly used coadjuvants in spinal anesthesia. The densities of the LA and their combinations with opioids were measured at 20, 25, and 37°C.…”

Section: Mechanisms Governing Spinal Distribution Of Opioidsmentioning

confidence: 99%

Spinal Opioid Bioavailability in Postoperative Pain

Bujedo

2013

Pain Practice

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Opioids have been used for spinal analgesia for more than a century, and their injection epidurally and intrathecally has a key role in the control of postoperative pain. Since the discovery of the endogenous opioid system, 3 decades ago, their use has become more generalized in obstetric analgesia, the management of chronic pain, and acute postoperative pain. To use opioids effectively for this type of analgesia, it is important to understand the pharmacokinetics and clinical pharmacology of these drugs, specifically those that produce analgesia by an intrinsic spinal mechanism. Evidence from animal and human experiments indicates that hydrophilic opioids (such as hydromorphone and morphine) bind more strongly to specific receptors within the dorsal horn of the spinal cord than lipophilic opioids (such as alfentanil, fentanyl, and sufentanil). This can be understood by considering the spinal cord selectivity and bioavailability of these opioids. This difference is attributable to differences in the pharmacokinetic and pharmacodynamic properties of the 2 groups. It is more difficult for lipophilic opioids to reach and remain at sufficiently high concentrations at the site of action due to their sequestration in epidural fat and rapid plasma clearance from both epidural and intrathecal spaces, resulting in analgesia with a limited spread and duration, as well as the appearance of early supraspinal side effects. In contrast, morphine has very different properties, including greater spinal bioavailability and therefore administered neuraxially, it is suitable choice for the treatment of acute postoperative pain. However, when using morphine, a greater incidence of adverse effects can be expected, and it requires careful patient selection.

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Section: Mechanisms Governing Spinal Distribution Of Opioidsmentioning

confidence: 99%

Spinal Opioid Bioavailability in Postoperative Pain

Bujedo

2013

Pain Practice

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“…[7] Density is known to influence the spread of LA, but the effect of adjuvant solution density on its movement in the CSF has not been studied extensively. [89] Therefore, we hypothesised that if we administer LA and the adjuvants separately, it may minimise the effect of the changes in densities and also hence their actions.…”

Section: Introductionmentioning

confidence: 99%

Intrathecal clonidine with hyperbaric bupivacaine administered as a mixture and sequentially in caesarean section: A randomised controlled study

2014

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Background and Aims:Mixing adjuvants with hyperbaric bupivacaine in a single syringe before injecting the drugs intrathecally is an age old practice. In doing so, the density of the hyperbaric solution and also of the adjuvant drugs may be altered, thus affecting the spread of drugs. Administering local anaesthetic and the adjuvants separately may minimise the effect of the changes in densities. We aimed to compare block characteristics, intraoperative haemodynamics and post-operative pain relief in parturients undergoing caesarean section (CS) after administering hyperbaric bupivacaine and clonidine intrathecally as a mixture and sequentially.Methods:In this single-blind prospective randomised controlled study at a tertiary care centre from 2010 to 12, 60 full-term parturients scheduled for elective CSs were divided into two groups on the basis of technique of intrathecal drug administration. Group M received mixture of clonidine (75 mcg) and hyperbaric bupivacaine 0.5% (10 mg) intrathecally, whereas Group B received clonidine (75 mcg) followed by hyperbaric bupivacaine 0.5% (10 mg) through separate syringes. Observational descriptive statistics, analysis of variance test, Wilcoxon test and Chi-square test were used as applicable.Results:Duration of analgesia was significantly longer in Group B (474.33 ± 20.79 min) in which the drug was given sequentially than in Group M (337 ± 18.22 min). Furthermore, the time to achieve highest sensory block and complete motor block was significantly less in Group B without any major haemodynamic instability and neonatal outcome.Conclusions:When clonidine and hyperbaric bupivacaine were administered in a sequential manner, block characteristics improved significantly compared to the administration of the mixture of the two drugs.

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“…At 5min there was no significant change (p=0.801) as n=6 patients acquired a good sensory blockade in Group A among them n=2 reached at a level of thoracic 6 (T6). In Group B only n=1 patient reached level of thoracic 6 (T6) and n=1 at a level of thoracic 8 (T8) 3 Motor block: The loss of motor functions or motor block was observed in a total of n=4 patients in Group A and in n=6 patients in Group B after 1 min interval. Upon reaching the five minute mark the loss of motor function was seen in n=20 patients in Group A and n=22 patients in Group B.…”

Section: Resultsmentioning

confidence: 97%

Spinal Anesthesia; Lower Segment Cesarean Section Comparison of Atients With Hyperbaric Bupivacaine Versus Isobaric Bupivacaine as Used for Spinal Anesthesia

Raza

Bourazza

Kamlaish

et al. 2016

TPMJ

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ABSTRACT… Objective: The purpose of the study is to compare and assess the sensory and motor block along with the associated hemodynamic changes that occur in the patient population operated for a lower segment cesarean section (LSCS), when they are given 0.5% hyperbaric bupivacaine versus 0.5% isobaric bupivacaine as used for spinal anesthesia. Study Design: Prospective double blind randomized trial. Period: 6 months duration from April 2014 to September 2014. Setting: A tertiary care hospital in the city of Karachi, Pakistan. Method: The study population consisted of 60 patients belonging to the ASA 1 and ASA 2 category, who underwent a lower segment cesarean section, and comparative analysis of the efficacy and associated hemodynamic changes of hyperbaric with isobaric bupivacaine. The patient population was segmented into two groups both groups containing 30 patients, group A receiving hyperbaric bupivacaine 0.5% as 2.5ml ( 12.5mg dose ) and the second group designated as, group B receiving isobaric bupivacaine 0.5% as 2.5ml ( 12.5mg dose) intrathecally. The resultant sensory and motor blockade was determined using pin prick and bromage scale respectively. Results: There was a significant difference found among the two groups under study, when compared at 3min interval regarding the sensory blockade. The level of T6 block was reached in 33.33% (n=10) patients belonging to group A and 56.66% (n= 17) patients in group B. It was observed that there was no significant change among the two groups at 5min interval regarding sensory and motor blockade respectively. The immediate sensory blockade with isobaric bupivacaine in group B produced greater decrease in the systolic and mean arterial blood pressure when contrasted with hyperbaric bupivacaine in group A at 5min interval, but after time interval of 45min there was no statistically significant change observed. Conclusions: According to our study the effects of isobaric bupivacaine were more significantly predictable; hence have a higher efficacy, when contrasted against hyperbaric bupivacaine in lower section cesarean section spinal anesthesia. Quick sensory blockade with isobaric bupivacaine was associated with more decrease in blood pressures when contrasted with the hyperbaric bupivacaine, but this result is not statistically significant. Key words:Lower segment cesarean section, Spinal anesthesia, hyperbaric bupivacaine, isobaric bupivacaine.

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Assessment of the Densities of Local Anesthetics and Their Combination with Adjuvants. An Experimental Study

Abstract: The densities of local anesthetics and adjuvants decrease with the increase in temperature and increase when glucose is added. The knowledge of the relative density helps select the most adequate local anesthetic to be administered in the subarachnoid space.

Cited by 26 publications

References 10 publications

Spinal Opioid Bioavailability in Postoperative Pain

Spinal Opioid Bioavailability in Postoperative Pain

Intrathecal clonidine with hyperbaric bupivacaine administered as a mixture and sequentially in caesarean section: A randomised controlled study

Spinal Anesthesia; Lower Segment Cesarean Section Comparison of Atients With Hyperbaric Bupivacaine Versus Isobaric Bupivacaine as Used for Spinal Anesthesia

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