title: Systematic review of the systemic concentrations of local anaesthetic after transversus abdominis plane block and rectus sheath block.
abstract: Safe and efficacious modalities of perioperative analgesia are essential for enhanced recovery after surgery. Truncal nerve blocks are one potential adjunct for analgesia of the abdominal wall, and in recent years their popularity has increased. Transversus abdominis plane block (TAPB) and rectus sheath block (RSB) have been shown to reduce morphine consumption and improve pain relief after abdominal surgery. These blocks typically require large volumes of local anaesthetic (LA). We aimed to synthesize studies evaluating systemic concentrations of LA after perioperative TAP and RSB to enhance our understanding of systemic LA absorption and the risk of systemic toxicity.
  An independent literature review was performed in accordance with the methods outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. An electronic search of four databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and PubMed) was conducted. Primary articles measuring systemic concentrations of LA after single-shot bolus TAPB or RSB were included.
  Fifteen studies met the inclusion criteria. Rapid systemic LA absorption was observed in all studies. Of a total of 381 patients, mean peak concentrations of LA exceeded toxic thresholds in 33 patients, of whom three reported mild adverse effects. The addition of epinephrine reduced systemic absorption of LA. No instances of seizure or cardiac instability were observed.
  Local anaesthetic in TAPB and RSB can lead to detectable systemic concentrations that exceed commonly accepted thresholds of LA systemic toxicity. Our study highlights that these techniques are relatively safe with regard to LA systemic toxicity.
authors.affiliation: Department of Surgery, South Auckland Clinical Campus, The University of Auckland, Auckland, Otahuhu, New Zealand.
authors.forename: J
authors.initials: J
authors.lastname: Rahiri
authors.affiliation: Tiakina Te Ora, Auckland, Papakura, New Zealand.
authors.forename: J
authors.initials: J
authors.lastname: Tuhoe
authors.affiliation: School of Pharmacy, The University of Auckland, Auckland, New Zealand.
authors.forename: D
authors.initials: D
authors.lastname: Svirskis
authors.affiliation: Department of Anaesthesiology, University of Amsterdam, Amsterdam 1105AZ, The Netherlands.
authors.forename: N J
authors.initials: NJ
authors.lastname: Lightfoot
authors.affiliation: Department of Anaesthesia and Pain Medicine, Counties Manukau Health, Middlemore Hospital, Auckland, New Zealand.
authors.forename: P B
authors.initials: PB
authors.lastname: Lirk
authors.affiliation: Department of Surgery, South Auckland Clinical Campus, The University of Auckland, Auckland, Otahuhu, New Zealand.
authors.forename: A G
authors.initials: AG
authors.lastname: Hill
mesh_terms: D034861:Abdominal Wall; D000779:Anesthetics, Local / Q000009:adverse effects* / Q000493:pharmacokinetics* / Q000633:toxicity; D006801:Humans; D009407:Nerve Block
chemical_list: D000779:Anesthetics, Local
keywords: anaesthetics; drug toxicity; local; nerve block