Operating Modes
TOF mode is the TetraGraph®’s main mode of operation. A sequence of four stimuli, at a frequency of 2 Hz, referred to as Train-of-Four (TOF) is delivered to the peripheral nerve, and the Train-of-Four Ratio (TOFR, or the ratio of the amplitude of the fourth twitch T4, to that of the first twitch, T1) and the TOF Count (TOFC, or the number of discernable twitches) of the evoked EMG responses are calculated and displayed. TOF stimulation is used to assess the depth of neuromuscular blockade and gauge the degree of recovery after reversal. Other operating modes are Post-Tetanic Count (PTC), which is used to determine NMBA management during surgeries that require deep block, and Single Twitch, which is used to deliver a single stimulus and display a single muscle response in the millivolt (mV).