title: Potentially toxic concentrations in blood of total ropivacaine after bilateral transversus abdominis plane blocks; a pharmacokinetic study.
abstract: BACKGROUND
  Elevated blood levels of lidocaine and ropivacaine have been described after transversus abdominis plane (TAP) block.
  
  
  OBJECTIVE
  To investigate the pharmacokinetic profile of ropivacaine after bilateral TAP blocks.
  
  
  METHODS
  Prospective observational pharmacokinetic study.
  
  
  METHODS
  University teaching hospital in Copenhagen, Denmark.
  
  
  METHODS
  Twenty-one adult patients presenting for abdominopelvic surgery with bilateral TAP blocks were enrolled.
  
  
  METHODS
  Ultrasound-guided TAP blocks with bilateral injections of 20 ml ropivacaine 0.5% w/v (total dose 200 mg). Blood was sampled at 0, 10, 30 and 60 min after TAP blocks.
  
  
  METHODS
  Total and free peak blood concentrations (Cmax) of ropivacaine.
  
  
  RESULTS
  Data were analysed from N = 18 patients. The median dose of ropivacaine was 2.7 mg kg(-1) (range: 1.9-4.2 mg kg(-1)). Median total ropivacaine concentrations were 1.0, 1.6 and 1.7 μg ml(-1) at 10, 30 and 60 min, respectively. Six patients (33%) had Cmax values above 2.2 μg ml(-1) and the highest concentration measured was 5.1 μg ml(-1). One patient had a 33% drop in mean arterial blood pressure.
  
  
  CONCLUSIONS
  TAP blocks with bilateral injections of 20 ml ropivacaine 0.5% w/v gave rise to potentially toxic peak blood concentrations of total ropivacaine in one-third of the patients.
authors.affiliation: Department of Anaesthesiology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark. htorup@gmail.com
authors.forename: Henrik
authors.initials: H
authors.lastname: Torup
authors.forename: Anja U
authors.initials: AU
authors.lastname: Mitchell
authors.forename: Torben
authors.initials: T
authors.lastname: Breindahl
authors.forename: Egon G
authors.initials: EG
authors.lastname: Hansen
authors.forename: Jacob
authors.initials: J
authors.lastname: Rosenberg
authors.forename: Ann M
authors.initials: AM
authors.lastname: Møller
mesh_terms: D000009:Abdominal Muscles / Q000294:innervation*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000577:Amides / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics*; D001794:Blood Pressure / Q000187:drug effects; D003718:Denmark; D016903:Drug Monitoring; D005260:Female; D006784:Hospitals, Teaching; D006801:Humans; D007279:Injections, Subcutaneous; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D011446:Prospective Studies; D000077212:Ropivacaine; D018084:Ultrasonography, Interventional
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine