Table 5.

Levels of neuromuscular block

Level of block	Depth of block	Objective measurement at APM	Subjective evaluation with PNS at APM
Level 5	Complete	PTC = 0	PTC = 0
Level 4	Deep	PTC ≥ 1, TOFC = 0	PTC ≥ 1, TOFC = 0
Level 3	Moderate	TOFC = 1–3	TOFC = 1–3
Level 2b	Shallow	TOFR < 0.4	TOFC = 4, TOF fade present
Level 2a	Minimal	TOFR = 0.4–0.9	TOFC = 4, TOF fade undetectable
Level 1	Adequate recovery	TOFR ≥ 0.9	Cannot be determined

APM adductor pollicis muscle, NMB neuromuscular blockade, PNS peripheral nerve stimulator, PTC posttetanic count, TOF train of four, TOFC train-of-four count, TOFR train-of-four ratio

^aSubjective evaluation of the depth of neuromuscular block is not recommended, but it is included as an interim transition from current practice to the preferred, objective monitoring-based practice. Reproduced with permission [95]