[Nociceptive flexion reflex. Principles and applications of the threshold determination].
The threshold for the pain flexion reflex in the lower limb can be used to determine the potency in man of analgesic drugs acting centrally. A new apparatus is, the "algometre", described. Bipolar electrical stimulation (5 stimuli of 1 ms over a period of 10 ms) is applied to the saphenous nerve just behind the external malleolus. An amplifier detects the muscle response (electromyogramme; EMG) at the muscle-tendon junction in the popliteal space; this occurs about 70-130 ms after the painful stimulus. The whole system is linked to a microcomputer. The EMG and EMG/intensity curves are displayed on a colour screen, and can be copied by a colour tracing table. The whole machine is mobile and can be moved from bed to bed. An increase in the threshold during inhalation of 50% nitrous oxide in oxygen was shown. However, the usefulness of the "algometre" in clinical practice remains to be assessed by further studies.
Département d'Anesthésie-Réanimation Chirurgicale 2, Hôpital Claude-Huriez, Lille.
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Dalmas
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Scherpereel
D004558:Electric Stimulation; D004576:Electromyography / Q000295:instrumentation; D006801:Humans; D010146:Pain / Q000503:physiopathology*; D012018:Reflex / Q000502:physiology*; D012684:Sensory Thresholds
Réflexe nociceptif de flexion. Principes et applications de la mesure du seuil.