The Sensitivity of Motor Responses for Detecting Catheter-Nerve Contact During Ultrasound-Guided Femoral Nerve Blocks with Stimulating Catheters
2011; Lippincott Williams & Wilkins; Volume: 113; Issue: 5 Linguagem: Inglês
10.1213/ane.0b013e31822c9887
ISSN1526-7598
AutoresFernando Altermatt, Marcia A. Corvetto, Camila Venegas, Ghislaine C. Echevarría, P. G. M. Bravo, Juan Carlos de la Cuadra-Fontaine, Luis Irribarra,
Tópico(s)Intraoperative Neuromonitoring and Anesthetic Effects
ResumoWe determined the sensitivity of motor responses evoked by stimulating catheters in determining catheter-nerve contact using ultrasonography as reference.Femoral nerves were contacted using stimulating catheters under ultrasonography scanning in 25 patients. The output current was increased from its minimum until quadriceps muscle contraction occurred. The sensitivity of the motor response in determining catheter-nerve contact was calculated using 0.5 mA as current threshold.The current required for catheter stimulation to evoke a motor response ranged between 0.18 and 2.0 mA. Muscle contraction in response to 0.5 mA occurred in 16 of 25 subjects. The sensitivity of motor response for nerve stimulation was 64% (95% confidence interval: 0.43, 0.82).The absence of muscle responses at a stimulating current≤0.5 mA does not necessarily indicate the absence of catheter-nerve contact.
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