The effect that a tourniquet has on muscle paralytic, specifically rocuronium, and thus muscle paralysis is unknown. The aim of this study was to examine the effect of tourniquet use on the duration of paralytic effect during fracture fixation of the lower extremity and that tourniquet use would prolong the paralytics effect on the muscle distal to it. Patients undergoing open reduction and internal fixation of ankle, tibial plafond, or calcaneus fractures were prospectively evaluated at a single academic level 1 trauma center. After induction of general anesthesia with a short acting paralytic, two twitch monitors were placed, with leads along the facial nerve and leads along the common peroneal. Surgical and anesthesia team ensured that 4/4 twitches were present on the facial nerve and distal to the tourniquet along the common peroneal nerve. Then, the full dose of rocuronium was administered until 0/4 twitches were present prior to tourniquet inflation. ToF (train of four) twitches were monitored at 15 min intervals. A total of 17 ankle fractures, 1 calcaneus, and 7 pilon fractures were included in the study. Mean age was 38.8 years (22–72) and average BMI was 29.9 (22.5–38.5). Average time to regain twitches in the facial nerve was 34.5 min. 19 patients (76%) recovered 3 + twitches in the facial nerve before any twitches in the operative extremity. 19 patients (76%) had 2 or fewer twitches at the extremity for the duration of tourniquet inflation. Recovery of neuromuscular function in the facial nerve was fully restored prior to the operative extremity in 76% of patients. This confirms the hypothesis that the effect of paralysis in the extremity is extended when dosed prior to tourniquet inflation. This study will help the surgeon and the anesthesia team understand the value of correct paralytic timing. This can prevent unnecessary re-dosing by anesthesia in response to facial twitches, and can aid in ensuring the desired level of paralysis in the operative extremity.
Lyons et al. (Fri,) studied this question.