Successful resuscitation following ropivacaine-induced systemic toxicity in a neonate

Complications in paediatric regional anaesthesia: a narrative review

Paediatric anaesthesia and paediatric regional anaesthesia are intertwined. Currently, almost all paediatric patients posted for surgery could and should be given a regional block unless and until contraindicated. This is because the scope, techniques, and their benefits have a wide range and complications are rare. The first report that used regional anaesthesia in children was in 1898, and over the last 120 years it has been developed with many scholars’ wisdom, ideas and publications. Paediatric regional anaesthesia (PRA) has many advantages but requires experience and expertise. For a long-time, exclusively landmark-guided techniques were used and gradually the development of new techniques such as the use of neuro-stimulator and ultrasound-guided (USG) blocks developed into PRA. Especially, the application of ultrasonography (US) has revolutionised the practice of PRA. Few limitations of regional anaesthesia can be tackled by the use of US, leading to shorter time to perform the block, reduced time for block onset and use of a smaller volume of local anaesthetic. Life threatening complications of regional anaesthesia are rare and the riskbenefit ratio is favourable. However, a thorough insight into RA complications, no matter how rare they are, is essential for safe practice. This is because they can be life-threatening, and no matter how small the percentage is, when complications occur, for that individual patient statistics is irrelevant.

Drug-induced cardiac abnormalities in premature infants and neonates

The Cardiac Safety Research Consortium (CSRC) is a transparent, public-private partnership that was established in 2005 as a Critical Path Program and formalized in 2006 under a Memorandum of Understanding between the United States Food and Drug Administration and Duke University. Our continuing goal is to advance paradigms for more efficient regulatory science related to the cardiovascular safety of new therapeutics, both in the United States and globally, particularly where such safety questions add burden to innovative research and development. This White Paper provides a summary of discussions by a cardiovascular committee cosponsored by the CSRC and the US Food and Drug Administration (FDA) that initially met in December 2014, and periodically convened at FDA's White Oak headquarters from March 2015 to September 2016. The committee focused on the lack of information concerning the cardiac effects of medications in the premature infant and neonate population compared with that of the older pediatric and adult populations. Key objectives of this paper are as follows: Provide an overview of human developmental cardiac electrophysiology, as well as the electrophysiology of premature infants and neonates; summarize all published juvenile animal models relevant to drug-induced cardiac toxicity; provide a consolidated source for all reported drug-induced cardiac toxicities by therapeutic area as a resource for neonatologists; present drugs that have a known cardiac effect in an adult population, but no reported toxicity in the premature infant and neonate populations; and summarize what is not currently known about drug-induced cardiac toxicity in premature infants and neonates, and what could be done to address this lack of knowledge. This paper presents the views of the authors and should not be construed to represent the views or policies of the FDA or Health Canada.

Awake caudal anaesthesia in neonates/young infants for improved patient safety

Caudal epidural block in a conscious infant is a recognised technique that allows the avoidance of general anaesthesia and risks associated with it. It is also technically easier to perform reliably compared with an awake subarachnoid block in skilled hands.1 While local anaesthetic systemic toxicity is a rare complication of caudal anaesthesia, this case illustrates the potential for caudal anaesthesia done awake in enhancing patient safety through early recognition of local anaesthetic systemic toxicity.

Pharmacokinetics of levobupivacaine following infant spinal anesthesia

BACKGROUND

Infant spinal anesthesia with levobupivacaine has been promoted as a technique to reduce both the risk of postoperative apnea and exposure to volatile anesthesia. There is, however, no pharmacokinetic data to support the currently recommended doses.

AIMS

Our aim was to determine whether infant levobupivacaine spinal anesthesia is associated with plasma concentrations consistent with a low risk of local anesthetic systemic toxicity.

METHODS

This was an open-label pharmacokinetic safety and tolerability study of levobupivacaine spinal anesthesia in infants <55 weeks Post Menstrual Age undergoing lower abdominal surgery. Infants received a spinal anesthetic with levobupivacaine 1 mg·kg(-1) in the left lateral position.

RESULTS

Spinal anesthesia was successful in 25 (86.2%) of 29 infants (postmenstrual age 36-52 weeks; weight 2.2-4.7 kg). The median (IQR) total venous levobupivacaine plasma concentrations was 0.33 (0.25-0.42) μg·ml(-1) and unbound venous levobupivacaine was 19.5 (14.5-38) ng·ml(-1) . Median protein binding was 93.5 (91.4-96%). Alpha-1 acid glycoprotein concentrations were 0.25 (0.17-0.37) g·l(-1) and albumin concentrations were 29 (24-32) g·l(-1) .

CONCLUSION

Total plasma concentrations and unbound (free) concentration of levobupivacaine were consistently lower than concentrations reported in cases of pediatric local anesthetic toxicity. In a small number of infants requiring a repeat spinal of 1 mg·kg(-1) was also associated with acceptable total and free concentrations. We conclude that levobupivacaine at 1 mg·kg(-1) is associated with no systemic side effects in infants receiving awake spinal anesthesia.

A Comparison of Differences Between the Systemic Pharmacokinetics of Levobupivacaine and Ropivacaine During Continuous Epidural Infusion: A Prospective, Randomized, Multicenter, Double-Blind Controlled Trial

BACKGROUND:

Epidural infusion of levobupivacaine and ropivacaine provides adequate postoperative pain management by minimizing side effects related to IV opioids and improving patient outcome. The safety profile of different drugs can be better estimated by comparing their pharmacokinetic profiles than by considering their objective side effects. Because levobupivacaine and ropivacaine have different pharmacokinetic properties, our aim was to investigate whether there is a difference in the pharmacokinetic variability of the 2 drugs in a homogeneous population undergoing continuous epidural infusion. This double-blind, multicenter, randomized, controlled trial study was designed to compare the pharmacokinetics of continuous thoracic epidural infusion of levobupivacaine 0.125% or ropivacaine 0.2% for postoperative pain management in adult patients who had undergone major abdominal, urological, or gynecological surgery. This study is focused on the evaluation of the coefficient of variation (CV) to assess the equivalence in the systemic exposure and interindividual variability between levobupivacaine and ropivacaine and, therefore, the possible differences in the predictability of the plasmatic concentrations of the 2 drugs during thoracic epidural infusion.

METHODS:

One hundred eighty-one adults undergoing major abdominal surgery were enrolled in the study. Patients were randomized to receive an epidural infusion of levobupivacaine 0.125% + sufentanil 0.75 μg/mL or of ropivacaine 0.2% + sufentanil 0.75 μg/mL at 5 mL/h for 48 hours. The primary end point of this study was to analyze the variability of plasma concentration of levobupivacaine and ropivacaine via an area under the curve within a range of 15% of the CV during 48 hours of continuous epidural infusion. The CV shows how the concentration values of local anesthetics are scattered around the median concentration value, thus indicating the extent to which plasma concentration is predictable during infusion. Secondary end points were to assess the pharmacologic profile of the local anesthetics used in the study, including an analysis of mean peak plasma concentrations, and also to assess plasma clearance, side effects, pain intensity (measured with a verbal numeric ranging score, i.e., static Numeric Rating Scale [NRS] and dynamic NRS]), and the need for rescue doses.

RESULTS:

The comparison between the 2 CVs showed no statistical difference: the difference between area under the curve was within the range of 15%. The CV was 0.54 for levobupivacaine and 0.51 for ropivacaine (P = 0.725). The plasma concentrations of ropivacaine approached the C_max significantly faster than those of levobupivacaine. Clearance of ropivacaine decreases with increasing patient age. There were no significant differences in NRS, dynamic NRS scores, the number of rescue doses, or in side effects between groups.

CONCLUSIONS:

Considering the CV, the interindividual variability of plasma concentration for levobupivacaine and ropivacaine is equivalent after thoracic epidural infusion in adults. We found a reduction in clearance of ropivacaine depending on patient age, but this finding could be the result of some limitations of our study. The steady-state concentration was not reached during the 48-hour infusion and the behavior of plasma concentrations of ropivacaine and levobupivacaine during continuous infusions lasting more than 48 hours remains to be investigated, because they could reach toxic levels. Finally, no differences in the clinical efficacy or in the incidence of adverse effects between groups were found for either local anesthetic.

Published ahead of print May 14, 2015

Hypersensitivity reactions to intravenous lipid emulsion in swine: relevance for lipid resuscitation studies

BACKGROUND

Reports in the recent experimental literature have provided contradicting results in different animal species regarding the efficacy of IV lipid emulsion (ILE) in the reversal of cardiovascular and central nervous system symptoms of local anesthetic and other lipophilic drug overdoses. In particular, ILE seemed to be effective in rats, rabbits, dogs, and humans, but not in swine, for which it not only failed to reverse the adverse effects of anesthetics, but the animals also developed a generalized cutaneous mottling or a dusky appearance immediately after ILE, suggestive of another type of toxicity. The latter symptoms arise in complement (C) activation-related pseudoallergy, a hypersensitivity reaction to particulate drugs and agents.

METHODS

Ten Yorkshire swine (15-20 kg) were sedated with ketamine and anesthetized with isoflurane. ILE 1.5 and 5 mL/kg 20% was administered via the ear vein while pulmonary arterial pressure, systemic arterial blood pressure, electrocardiogram, and end-tidal CO2 were recorded continuously. Thromboxane was measured in blood collected at baseline and 2 and 10 minutes after injections. Complement activation by lipid emulsion was also assessed in vitro with soluble terminal complement complex (SC5b-9) and sheep red blood cell assays.

RESULTS

Significant increases were observed in the pulmonary pressure (median [interquartile range]) within minutes after the administration of ILE, both at doses 1.5 and 5 mL/kg (15 [12-16.5] to 18.5 [16-20] mm Hg, P = 0.0058 and 15.5 [13-17.25] to 39.5 [30.5-48.5], respectively). The systemic arterial blood pressure increased, and the heart rate decreased after both injections. Thromboxane B2 concentration (median [interquartile range]) in the blood plasma increased from a baseline of 617.3 [412.4-920] to 1132 [597.9-1417] pg/mL (P = 0.0055) and from 1276 [1200-2581] to 4046 [2946-8442] pg/mL (P = 0.0017) after the administration of 1.5 and 5 mL/kg ILE, respectively. Intralipid did not cause in vitro complement activation in human serum.

CONCLUSIONS

ILE causes clinically significant hemodynamic changes in pigs, in concert with significant increases in the plasma thromboxane concentration. However, the in vitro tests did not confirm involvement of the complement system in human sera, leaving the underlying mechanism of these findings in doubt. Nonetheless, the observed hemodynamic and biochemical effects of ILE serve as a caveat that the pig is not an ideal model for the study of interventions involving ILE.

Update/Review: changing of use of local anesthesia in the hand

Supplemental Digital Content is available in the text.

Summary:

Among the many advances in local anesthesia of the hand, some of the most significant changes in the last 5 years have been the following: (1) the acceptance of safety of locally infiltrated epinephrine with lidocaine for hemostasis, which has removed the need for sedation, brachial plexus blocks, and general anesthesia for most common hand surgery operations and minor hand trauma. (2) The elimination of the 2 injection finger block technique in favor of the single injection palmar block. (3) Local anesthesia can now be consistently injected in the hand with minimal pain. (4) Liposomal release of local anesthetic after injection into the surgical site can provide pain control up to 3 days. This article reviews the impact and best evidence related to these changes.

[Pediatric caudal anesthesia : importance and aspects of safety concerns]

Caudal block is a safe procedure commonly used for pediatric perioperative analgesia. Complications are extremely rare but nevertheless local and systemic contraindications must be excluded. Optimal safety and quality result when strict attention is paid to technical details. These are discussed in detail in this review. A local anesthetic (LA) containing epinephrine allows early detection of inadvertent intravascular LA administration; therefore an epinephrine/LA mixture is recommended at least for the test dose. In terms of safety the choice of LA itself is probably of secondary importance. Clonidine as an adjuvant has an excellent risk/benefit profile with minimal side effects. Inadvertent systemic LA intoxication is a rare but potentially fatal complication of regional anesthesia and measures for prevention and early detection are essential. Should circulatory arrest occur, immediate resuscitation following standard guidelines is to be initiated including the use of epinephrine as the first line drug. Intravenous administration of lipid solutions may be beneficial as a secondary adjunct to stabilize hemodynamics but is not an alternative to epinephrine.

[Pediatric caudal anesthesia: importance and aspects of safety concerns]

Caudal block is a safe procedure commonly used for pediatric perioperative analgesia. Complications are extremely rare but nevertheless local and systemic contraindications must be excluded. Optimal safety and quality result when strict attention is paid to technical details. A local anesthetic (LA) containing epinephrine allows early detection of inadvertent intravascular LA administration; therefore an epinephrine/LA mixture is recommended at least for the test dose. In terms of safety the choice of LA itself is probably of secondary importance. Clonidine as an adjuvant has an excellent risk/benefit profile with minimal side effects. Inadvertent systemic LA intoxication is a rare but potentially fatal complication of regional anesthesia and measures for prevention and early detection are essential. Should circulatory arrest occur, immediate resuscitation following standard guidelines is to be initiated including the use of epinephrine as the first line drug. Intravenous administration of lipid solutions may be beneficial as a secondary adjunct to stabilize hemodynamics but is not an alternative to epinephrine.

Caudal blocks

Caudal anesthesia is the single most important pediatric regional anesthetic technique. The technique is relatively easy to learn (1), has a remarkable safety record (2), and can be used for a large variety of procedures. The technique has been reviewed in the English (3) and French (4) literature, as well as in German guidelines (5) and in pediatric anesthesia textbooks (6).

Local anesthetics and their adjuncts

Local anesthetics (LA) block propagation of impulses along nerve fibers by inactivation of voltage-gated sodium channels, which initiate action potentials (1). They act on the cytosolic side of phospholipid membranes. Two main chemical compounds are used, amino esters and amino amides. Amino esters are degraded by pseudocholinesterases in plasma. Amino amides are metabolized exclusively by the liver. Only amide LAs will be considered in this article.