title: Thermal quantitative sensory testing to assess the sensory effects of three local anesthetic solutions in a randomized trial of interscalene blockade for shoulder surgery.
abstract: OBJECTIVE
  This study investigated whether quantitative sensory testing (QST) with thermal stimulations can quantitatively measure the characteristics of an ultrasound-guided interscalene brachial plexus block (US-ISB).
  
  
  METHODS
  This was a prospective randomized trial in patients scheduled for arthroscopic shoulder surgery under general anesthesia and US-ISB. Participants and observers were blinded for the study. We assigned the study participants to one of three groups: 0.5% levobupivacaine 15 mL, 0.5% levobupivacaine 15 mL with 1:200,000 epinephrine, and 0.75% ropivacaine 15 mL. We performed thermal QST within dermatomes C4, C5, C6, and C7 before infiltration and 30 min, six hours, ten hours, and 24 hr after performing the US-ISB. In addition, we used QST, a semi-objective quantitative testing method, to measure the onset, intensity, duration, extent, and functional recovery of the sensory block. We also measured detection thresholds for cold/warm sensations and cold/heat pain.
  
  
  RESULTS
  Detection thresholds for all thermal sensations within the ipsilateral C4, C5, C6, and C7 dermatomes increased rapidly (indicating the development of a hypoesthetic state) and reached a steady state after 30 min. This lasted for approximately ten hours and returned to normal detection thresholds by 24 hr. There were no differences detected between the three groups at 24 hr when we compared warm sensation thresholds on one dermatome. Visual inspection of the pooled results per dermatome suggests the ability of QST to detect clinically relevant differences in block intensity per dermatome.
  
  
  CONCLUSIONS
  Quantitative sensory testing can be useful as a method for detecting the presence and characteristics of regional anesthesia-induced sensory block and may be used for the evaluation of clinical protocols. The three local anesthetic solutions exhibited a similar anesthetic effect. The results support the use of QST to assess block characteristics quantitatively under clinical research conditions. This trial was registered at Clinicaltrals.gov, NCT02271867.
authors.affiliation: Department of Anesthesiology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium. luc.sermeus@uza.be.|Department of Anesthesiology, Antwerp University Hospital, Wilrijkstraat 10, 2650, Edegem, Belgium. luc.sermeus@uza.be.
authors.forename: Luc A
authors.initials: LA
authors.lastname: Sermeus
authors.affiliation: Department of Algology and Evidence Based Medicine, Multidisciplinary Pain Center, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium.
authors.forename: Guy H
authors.initials: GH
authors.lastname: Hans
authors.affiliation: Department of Anesthesiology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium.
authors.forename: Tom
authors.initials: T
authors.lastname: Schepens
authors.affiliation: Department of Anesthesiology, AZ Klina, Brasschaat, Belgium.
authors.forename: Nathalie M-L
authors.initials: NM
authors.lastname: Bosserez
authors.affiliation: Department of Anesthesiology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium.
authors.forename: Margaretha B
authors.initials: MB
authors.lastname: Breebaart
authors.affiliation: Department of Anesthesiology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium.
authors.forename: Carine J
authors.initials: CJ
authors.lastname: Smitz
authors.affiliation: Department of Anesthesiology, Antwerp University Hospital, University of Antwerp, Antwerp, Belgium.
authors.forename: Marcel P
authors.initials: MP
authors.lastname: Vercauteren
mesh_terms: D000328:Adult; D000368:Aged; D000779:Anesthetics, Local / Q000494:pharmacology*; D001917:Brachial Plexus; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D011446:Prospective Studies; D012677:Sensation / Q000187:drug effects*; D012684:Sensory Thresholds; D012782:Shoulder / Q000601:surgery*; D012996:Solutions
chemical_list: D000779:Anesthetics, Local; D012996:Solutions