The Safety of Adding Bupivacaine to the Subcutaneous Infiltration Solution Used for Donor Site Harvest

Systematic literature review of topical local anaesthesia or analgesia to donor site wounds

BACKGROUND

Topical local analgesic and anaesthetic agents have been used both pre- and immediately post-harvest on split-thickness skin graft (STSG) donor site wounds (DSW). There is no systematic review of their effectiveness in providing post-harvest analgesia, or of the possible toxic effects of systemic absorption. This study is designed to address the question of which agent, if any, is favoured over the others and whether there are any safety data regarding their use.

METHODS

Systematic literature review of randomised controlled trials of topical agents applied to STSG DSWs, with a view to providing analgesia. Studies identified via search of Cochrane and EBSCO databases. No restrictions on language or publication year. Primary outcomes: pain at the time of (awake) STSG, and post-harvest pain (up to first dressing change). Secondary outcome was serum medication levels relative to published data on toxic doses. Cochrane risk of bias assessment tool utilised in assessment of included studies. At least 2 reviewers screened and reviewed included studies. A narrative review is presented.

RESULTS

There were 11 studies meeting inclusion criteria. Overall methodological quality and patient numbers were low. Topical eutectic mixture of lidocaine and prilocaine pre-harvest affords good local anaesthesia in awake STSG harvesting. Topical bupivacaine (5 studies) or lidocaine (1 study) gave significantly better post-harvest anaesthesia/analgesia than placebo. Topical morphine performs no better than placebo. Topical local anaesthetic agents at reported doses were all well below toxic serum levels.

CONCLUSIONS

Topical local anaesthetics (lidocaine or bupivacaine) provide good analgesia, both during and after STSG harvest, at well below toxic serum levels, but there are no good data determining the best local anaesthetic agent to use. There is no evidence morphine performs better than placebo.

In vivo study of the efficacy of bupivacaine-eluting novel soy protein wound dressings in a rat burn model

Dealing with wound related pain is an integral part of treatment. Systemic administration of analgesic and anesthetic agents is a common solution for providing pain relief to patients but comes at a risk of severe side effects as well as addiction. To overcome these issues, research efforts were madeto provide a platform for local controlled release of pain killers. We have developed a bilayer soy protein-based wound dressing for the controlled local release of bupivacaine to the wound site. The combination of a dense and a porous layer provides a platform for cell growth and proliferation as well as physical protection to the wound site. The current study focuses on the in vitro bupivacaine release profile from the dressing and the corresponding in vivo results of pain levels in a second-degree burn model on rats. The Rat Grimace Scale method and the Von Frey filaments method were used to quantify both, spontaneous pain and mechanically induced pain. A high burst release of 61.8 ± 1.9% of the loaded drug was obtained during the initial hour, followed by a slower release rate during the following day. The animal trials show that the RGS scores of the bupivacaine-treated group were significantly lower than these of the untreated group, proving a decrease of 51-68% in pain levels during days 1-3 after burn. Hence, successful pain reduction of spontaneous pain as well as mechanically induced pain, for at least three days after burn was achieved. It is concluded that our novel bupivacaine eluting soy protein wound dressings are a promising new concept in the field of local controlled drug release for pain management.

Bupivacaine-eluting soy protein structures for controlled release and localized pain relief: An in vitro and in vivo study

Burn pain is known to be excruciating, and while burn care has greatly advanced, treatment for burn-related pain is lacking. Current pain relief methods include systemic administration of analgesics, which does not provide high drug concentration at the wound site. In the present study, soy protein was used as the base material for bupivacaine-loaded hybrid wound dressings. The effect of the formulation on the drug release profile was studied using high performance liquid chromatography, and the cytotoxicity was tested on human fibroblasts. A second-degree burn model in rats was used to quantify the efficacy of the wound dressings in vivo, using the Rat Grimace Scale. All tested films exhibited high biocompatibility, and the drug release profiles showed rapid release during the initial 5 hr and a continuous slower release for another 24 hr. Significant pain relief was achieved in the animal trials, proving a decrease of 51-68% in pain levels during days 1-3 post-burn. Hence, the results indicate a safe and controlled bupivacaine release for a period of more than 24 hr, effectively treating pain caused by second-degree burns. The understanding of the formulation-properties effects, together with our in vivo study, enables to advance this field toward tailorable systems with high therapeutic potential.

Does perioperative steroid use improve clinical outcomes in open repair of craniosynostosis?

BACKGROUND

The benefits of routine perioperative steroid use to decrease facial edema, ecchymosis, pain, and reduced length of hospitalization have been reported for many procedures. The role of perioperative steroids after open craniosynostosis surgery remains understudied. The purpose of our study was to assess the safety and efficacy of perioperative steroid administration in open repair of craniosynostosis based on current published clinical evidence.

METHODS

A systematic review of PubMed, EMBASE, ClinicalTrials.gov, and the Cochrane library databases using inclusion and exclusion criteria was performed for articles that studied the efficacy of perioperative steroid use in craniosynostosis patients receiving open cranial repair surgery.

RESULTS

Our review yielded 149 unique citations. One hundred thirty-nine titles were excluded based on predefined criteria. Ten abstracts and 4 articles (n = 14) qualified for full-text screening. Two additional relevant articles were identified using references. Three observational studies were eligible for data abstraction. A Cohen κ coefficient score of 0.88 demonstrated high interrater agreement throughout the screening process. Clinical benefits in this specific population observed were improved control of postoperative edema, earlier time to eye opening, and reduced length of hospital stay. The timing, method, and technique of steroid administration varied between studies.

CONCLUSIONS

The reviewed literature supports a clinical benefit following administration of perioperative steroids for open repair surgery of craniosynostosis. However, the current level of evidence on safety and efficacy remains limited in rigor and volume. Further randomized trials are necessary prior to recommending routine steroid use in our study population.

CLINICAL QUESTION/LEVEL OF EVIDENCE

therapeutic, level III.

Plasma Levels of Lignocaine during Tumescent Local Anaesthesia in Children with Burns

The aim of the study was to assess the changes in plasma lignocaine concentrations over time when the tumescent solution is injected into subcutaneous tissue of children undergoing surgical treatment of burns. Sixteen consecutive children with burns were studied using a prospective study design. After induction of general anesthesia, tumescent lignocaine solution 0.1% with adrenaline in nine patients (adrenaline group) for the treatment of postburn sequelae, or without adrenaline in seven patients (no-adrenaline group) for the treatment of acute burns, was injected into the subcutaneous tissue of burned and donor areas. The maximum dose of lignocaine was 7 mg/kg. Blood samples were collected before the start of the injection as well as at 5, 10, 20, 30, 45, 60, 90 minutes and 2, 4, 8, 12, 24 hours after the infiltration was completed. The course of lignocaine plasma levels was chaotic in the adrenaline group and biphasic during the first hour in the no-adrenaline group. The maximum plasma concentration of lignocaine was 2.09 μg/ml in the adrenaline group and 1.98 μg/ml in the no-adrenaline group. No adverse reactions were noted. Tumescent injection in burned children resulted in lignocaine plasma concentrations that were always lower than the often quoted value of 5 μg/ml, considered to be the toxic plasma threshold in adults. These data lend support to the use of lignocaine using the tumescent technique in burned paediatric patients.

Burn injury pain: the continuing challenge

The development of more effective methods of relieving pain associated with burn injury is a major unmet medical need. Not only is acute burn injury pain a source of immense suffering, but it has been linked to debilitating chronic pain and stress-related disorders. Although pain management guidelines and protocols have been developed and implemented, unrelieved moderate-to-severe pain continues to be reported after burn injury. One reason for this is that the intensity of pain associated with wound care and rehabilitation therapy, the major source of severe pain in this patient population, varies widely over the 3 phases of burn recovery, making it difficult to estimate analgesic requirements. The effects of opioids, the most commonly administered analgesics for burn injury procedural pain, are difficult to gauge over the course of burn recovery because the need for an opioid may change rapidly, resulting in the overmedication or undermedication of burn-injured patients. Understanding the mechanisms that contribute to the intensity and variability of burn injury pain over time is crucial to its proper management. We provide an overview of the types of pain associated with a burn injury, describe how these different types of pain interfere with the phases of burn recovery, and summarize pharmacologic pain management strategies across the continuum of burn care. We conclude with a discussion and suggestions for improvement. Rational management, based on the underlying mechanisms that contribute to the intensity and variability of burn injury pain, is in its infancy. The paucity of information highlights the need for research that explores and advances the identification of mechanisms of acute and chronic burn injury pain.

PERSPECTIVE

Researchers continue to report that burn pain is undertreated. This review examines burn injury pain management across the phases of burn recovery, emphasizing 3 types of pain that require separate assessment and management. It provides insights and suggestions for future research directions to address this significant clinical problem.