During anesthesia, neuromuscular blocking agents (NMBA) are routinely used for relaxation of muscles necessary for the conduction of the surgical procedure. Train-of-four (TOF) test is based on supramaximal stimulation of peripheral nerve resulting in four twitches: T1 to T4. The assessment of the NMBA blockade is performed routinely by measurement of the amplitude of compound muscle action potential (CMAP) and calculation of percentage of CMAP decrement from T1 to T4.