Suppression of spinal cord motoneuron excitability correlates with surgical immobility during isoflurane anesthesia.

摘要: BACKGROUND Recent evidence suggests that the spinal cord is an important site of anesthetic action produces surgical immobility. Inhalation anesthetics depress Hoffmann's reflex (H reflex) and F wave, indicating motoneuron suppression. The aim this study was to assess correlation between isoflurane-induced immobility H- F-wave METHODS baseline H wave were measured before anesthesia in 15 adult patients. After induction, 1% end-tidal isoflurane maintained for 20 min waves reelicited. Using electric stimulus applied forearm grading response as movement or no movement, authors increased decreased concentration 0.1% steps, depending on responses. recorded after each change concentration. suppression analyzed using a paired t test with Bonferroni correction. RESULTS H-reflex amplitude (2.74 +/- 1.63 mV) persistence (70.69 26.19%) at highest allowed are different (P < 0.01) from these (1.97 1.46 mV; 43.16 22.91%) lowest suppressed response. At 0.8% isoflurane, 3.69 1.83 mV 1.01 1.14 without 0.01); 0.29 0.15 0.11 0.06 80 22.36% 34.9 25.75% 0.01). CONCLUSIONS degree correlates response, suggesting isoflurane-suppressive plays significant role producing