[A new instrument for neuromuscular transmission monitoring: the accelerometer Tofguard. Comparative study of isometric force transduction in the assessment of pipecuronium dose-response relationship].
Pipecuronium effective doses 50,90,95 (ED50, ED90, ED95) have been obtained with the cumulative dosage method studying the influences of two different anesthetic techniques (TIVA vs isoflurane), of the patients age, of two different monitoring techniques, force transduction vs accelerometry, both evaluated by T1/TC ratio, ratio between Ist muscular response following the muscle relaxant and the values obtained before its injection, and TOFR, ratio between 4th and Ist response of every train. 33 patients, 55 years average age, 66 kgs average weight, ASA 1&2, scheduled for elective operations were anesthetized with propofol-fentanyl-N2O; tracheas were intubate under topical analgesia; maintenance of anesthesia included propofol and fentanyl or isoflurane 1 MAC. Neuromuscular monitoring included the simultaneous measurement of force of thumb adduction (FT 10 Grass) and its acceleration (Tofguard); neuromuscular blockade was evaluated by T1/TC and TOFR. Pipecuronium was administered in small decreasing boluses until 95% of T1/TC depression. Under force monitoring, ED50, ED90, ED95 values were 19, 28, 33 micrograms/kg respectively with T1/TC, being slightly lower with TOF stimulation (15, 24, 26 micrograms/kg); ED's were not influenced by anesthesia and were inversely related to age. Under accelerometry, EDs were always lower (16,27 e 27 micrograms/kg) under T1/TC, while with tof their values were similar to those derived from force measurements. ED's values obtained with T1/TC, either with force than accelerometry, while accelerometry was more sensitive than force for all ED's. EDs values, both under T1/TC than TOF, either with force transduction than accelerometry, resulted highly correlated each other, indicating a substantial agreement between the two mechanical methods of monitoring. It is concluded that the new instrument Tofguard offers the same reliability than force transduction, with the advantages of being smaller, portable and able to calculate directly the depth of neuromuscular blockade.
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Istituto di Anestesiologia e Rianimazione Università degli Studi - Bologna Ospedale S. Orsola-Malpighi.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009469:Neuromuscular Junction / Q000187:drug effects*; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage*; D017300:Pipecuronium / Q000008:administration & dosage*
D003473:Neuromuscular Nondepolarizing Agents; D017300:Pipecuronium
Un nuovo strumento per il monitoraggio della trasmissione neuromuscolare: l'accelerometro Tofguard. Studio comparativo nei confronti della trasduzione isometrica di forza nella valutazione della relazione dose effetto per il pipecuronium.