Survey of muscle relaxant effects management with a kinemyographic-based data archiving system: a retrospective...

In a retrospective quality control study of muscle relaxant management, we assessed unbiased files provided by an automatic archiving system using quantitative monitoring generated by a kinemyographic transducer and suggest improvements for a possible future design. 200 randomly selected files were double checked to collect the values of twitch height ratio (THr), train of four ratio (TOFr) and TOF count in four periods: references values acquisition (REF), maximal level of paralysis, paralysis maintenance, pre-tracheal extubation residual paralysis assessment (RPA). The parameter values were selected according to period-specific predefined rules. A quantitative quality control was based upon standardized cut-offs values. A contextual quality control was based upon the detection of "difficult-to-interpret" episodes. Results were expressed on a descriptive basis only. For the REF period, THrs and TOFrs were lacking in, respectively, 47 and 18 of the 200 recordings analysed. A starting TOFr above 0.90 existed in 119 files. Concomitant THrs and TOFrs >0.90 were evidenced 93 times. During RPA period, TOFr >0.90 was recorded on 82 occasions. The optimal combination of THr >0.80 and TOFr >0.90 was detected in 30 files only. Presence of "difficult to interpret" episodes started with 18 files for the REF period and increased to 42, 86 and 52 in the subsequent ones most of them probably related to the absence of initial calibration procedure. In the real life conditions, a near to optimal quality control is not always observable with the quantitative neuromuscular monitoring studied. To improve the NMT monitoring, the calibration of the sensor should be performed vigorously by the anaesthesia provider and the quality of this calibration must be displayed on the screen of the monitor.