Pupillometry to detect pain response during general anaesthesia following unilateral popliteal sciatic nerve block: A prospective, observational study

Sylvain Isnardon, Marc Vinclair, Celine Genty, Amelie Hebrard, Pierre Albaladejo, Jean Francois Payen

Research output: Contribution to journalArticlepeer-review

Abstract

CONTEXT: Pupillary reflex dilation appears to be a reliable indicator of response to noxious stimulation even under general anaesthesia. The ability of pupillometry to detect the effects of extremity blocks during continuous infusion of opioids remains unknown. OBJECTIVE: To explore the performance of pupillometry to detect differences in pupillary reflex dilation response to a standardised noxious stimulus applied to each leg following unilateral popliteal sciatic nerve block during continuous infusion of remifentanil. DESIGN: Prospective, observational study. SETTING: University hospital anaesthesia department, between June 2010 and December 2010. PATIENTS: Twenty-four adult patients undergoing elective foot or ankle surgery under general anaesthesia who requested a peripheral nerve block. Unilateral popliteal sciatic nerve block with 0.75% ropivacaine and 1% lidocaine was performed awake. General anaesthesia was maintained with steady-state infusions of propofol and remifentanil. MAIN OUTCOME MEASURE: Video-based pupillometer was used to determine pupillary reflex dilation during tetanic stimulation (60 m, 100Hz) applied to the skin area innervated by the sciatic nerve for 5 s after the onset of general anaesthesia. RESULTS: Sensory nerve block led to a blunted maximal pupillary reflex dilation response to noxious stimulation compared with the non-blocked leg: median (interquartile range) change from baseline 2% (1 to 4%) versus 17%(13 to 24%), respectively (P<0.01). The differences in the response persisted throughout the 5-s stimulus and the recovery phase. CONCLUSION: These results are a proof of concept. The effects of peripheral nerve block can be detected via the measurement of pupillary reflex dilation response to noxious stimulation of the skin in patients receiving remifentanil.

Original languageEnglish (US)
Pages (from-to)429-434
Number of pages6
JournalEuropean Journal of Anaesthesiology
Volume30
Issue number7
DOIs
StatePublished - Jul 1 2013

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine

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