The cuff method: a pilot study of a new method of monitoring neuromuscular function.
BACKGROUND
A new method of monitoring neuromuscular blockade based on a modified blood pressure cuff that incorporates stimulating electrodes was compared with mechanomyography (MMG) ('gold standard').


METHODS
Forty adults and 20 children (ASA I-II) underwent neuromuscular blockade monitoring on the contralateral arms and on the same arm using the new cuff method and MMG. Only train-of-four (TOF) ratios > 0.1 and T(1) heights > 0 were studied. Supramaximal stimulation was also assessed. A device based on a PC with an analogue-to-digital conversion card was used to control and synchronize MMG and the cuff method. The agreement between both methods was assessed using the statistical method of Bland and Altman.


RESULTS
When TOF ratios were >0.7, the bias between the two methods was -0.04 with the limits of agreement ranging from -0.21 to -0.12 (95% CI -0.06 to -0.02). The T(1) > 0 heights bias was -0.01 with the limits of agreement ranging from -0.26 to 0.24 (95% CI -0.02 to -0.003). The sensitivity of the cuff method was 88%, with a specificity of 85% and an accuracy of 86%.


CONCLUSIONS
This pilot study indicates that the cuff method could be useful to monitor neuromuscular blockade according to the bias and limits of agreement compared with MMG, particularly when the degree of blockade was evaluated by TOF ratios > 0.7. The new cuff method is easy and simple to use. However, further studies in a larger number of patients are necessary to confirm these favourable preliminary results.
Rodiera
J
J
Department of Anesthesia, Centro Médico Teknon, Barcelona, Spain. rodiera@btr.es
Serradell
A
A
Alvarez-Gómez
J A
JA
Aliaga
L
L
D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D016292:Procedural Sedation; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation* / Q000379:methods; D009213:Myography / Q000295:instrumentation* / Q000379:methods; D019148:Neuromuscular Blockade / Q000295:instrumentation* / Q000379:methods; D010865:Pilot Projects; D010991:Plethysmography / Q000295:instrumentation* / Q000379:methods