Figure 13-27 Hypoxic ventilatory response (HVR) before (control), during steady-state infusion (train-of-four [TOF] ratio = 0.07) of atracurium, pancuronium and vecuronium, and after recovery (TOF > 0.90). Data are presented as means ± SD. *P < .01. (Redrawn from Eriksson LI: Reduced hypoxic chemosensitivity in partially paralysed man. A new property of muscle relaxants? Acta Anaesthesiol Scand 40:520–523, 1996.)