The effect of preload on electromyographic train-of-four ratio at the first dorsal interosseous muscle during spontaneous recovery from neuromuscular blockade

This study compared the precision and agreement of electromyography with and without preload during recovery from non-depolarising neuromuscular blockade. After induction of anaesthesia and before neuromuscular blockade, the supramaximal current required at the first dorsal interosseous muscle with and without preload was determined. During recovery, train-of-four ratios were recorded using electromyography every 20 seconds. Alternating pairs of measurements (with and without preload) were obtained until spontaneous recovery was achieved. The preload device applied a resting tension of 75 –150 g to the thumb. Bland–Altman analysis for repeated measurements was used to assess precision and agreement of electromyography responses with and without muscle preload. Two hundred and seventy-five sets of repeated measurements were collected from 35 participants. The repeatability coeffic ient for train-of-four ratios recorded by electromyography with a preload was 0.030 (95% confidence intervals, CI, 0.028 to 0.031) versus 0.068 (95% CI 0.064 to 0.072) without. Train-of-four ratios with preload demonstrated a bias of +0.038 (95% CI 0.037 to 0.042) compared to electromyography withou t, with 95% limits of agreement of 0.035–0.111. Preload significantly improved the precision of electromyographic train-of-four ratios, with 95% of consecutive measurements differing by less than 3%. Furthermore, electromyography with preload demonstrated a positive bias of 0.04 compared with elec t...
Source: Anaesthesia and Intensive Care - Category: Anesthesiology Source Type: research