Train-of-four fade of non depolarizing muscle relaxants: an insight into the mechanism of precurarization

Succinylcholine-associated postoperative myalgia

The subject of postoperative myalgia associated with the use of succinylcholine is reviewed. We discuss the mechanisms of succinylcholine-induced myalgia and the techniques available to prevent and treat the myalgia. In situations where patients are at risk of developing myalgia and succinylcholine is the neuromuscular blocker of choice, the use of a combination of techniques may prove to be a useful strategy.

Comparison of rocuronium and d-tubocurarine for prevention of succinylcholine-induced fasciculations and myalgia

PURPOSE

We compared d-tubocurarine and rocuronium for the prevention of succinylcholine-induced fasciculations and postoperative myalgia (POM) and evaluated the influence of both drugs on the speed of onset and recovery of succinylcholine.

METHODS

Seventy-five women undergoing surgery of short duration were studied. They were randomized to one of three groups: group SAL received normal saline followed three minutes later by 1.0 mg.kg-1 succinylcholine; group ROC received 0.05 mg.kg-1 rocuronium + 1.5 mg.kg-1 succinylcholine; group DTC received 0.05 mg.kg-1 d-tubocurarine + 1.5 mg.kg-1 succinylcholine. Single-twitch stimulation was applied to the ulnar nerve every 10 sec and the EMG response of the adductor pollicis was recorded. Fasciculations were assessed by a blinded observer on a scale of 0-3. Patients were asked 24 and 48 hr later to rate POM using a scale of 0-10.

RESULTS

The interval needed for twitch height to decrease to 10% of initial value after succinylcholine was longer in group ROC (58 +/- 20 sec) (mean +/- SD) compared with group SAL (44 +/- 13 sec) (P < 0.05). Recovery to 20% occurred faster in group ROC (324 +/- 83 sec) than in groups SAL (456 +/- 103 sec) and DTC (450 +/-132 sec) (P < 0.05). Fasciculations were more intense in groups SAL than in groups ROC and DTC (P < 0.001). Patients rated POM as less intense 24hr postoperatively only in group ROC (1.2 +/- 2.4) compared with group SAL (3.3 +/- 3.5) (P < 0.05).

CONCLUSION

Rocuronium prevents succinylcholine-induced fasciculations and POM. Rocuronium also delays the onset of succinylcholine and shortens its duration compared with d-tubocurarine.

Rapid-sequence intubation of head trauma patients: prevention of fasciculations with pancuronium versus minidose succinylcholine

INTRODUCTION

Fasciculations during rapid-sequence intubation may lead to increased intracranial pressure and emesis with aspiration. Standard rapid-sequence intubation requires a nondepolarizing blocking agent before succinylcholine administration.

HYPOTHESIS

Prevention of fasciculations during rapid-sequence intubation of head trauma patients can be accomplished as safely and effectively with minidose succinylcholine as with a defasciculating dose of pancuronium.

DESIGN

A prospective, randomized, double-blind study.

SETTING

An inner-city county trauma center with 70,000 patient visits per year.

PARTICIPANTS

Sequential adult head trauma patients requiring rapid-sequence intubation who had no contraindications to succinylcholine or pancuronium.

INTERVENTIONS

Each head trauma patient requiring rapid-sequence intubation who met the inclusion criteria received standard rapid-sequence intubation maneuvers and lidocaine (1 mg/kg) IV. Patients were randomized to receive either minidose succinylcholine (0.1 mg/kg) or pancuronium (0.03 mg/kg) IV one minute prior to the full paralytic dose of succinylcholine (1.5 mg/kg) IV. Fasciculations were recorded using a graded visual scale.

RESULTS

Of 46 patients, eight of 19 (42%) in the pancuronium group and six of 27 (22%) in the succinylcholine group experienced fasciculations. No statistically significant difference in fasciculations was detected between the two groups using chi 2 analysis. Complete relaxation of the cords was present in all but two patients, one in each group. No patient in either group experienced emesis or significant dysrhythmias.

CONCLUSION

Pretreatment with minidose succinylcholine causes no greater incidence of fasciculations than pancuronium in rapid-sequence intubation of head trauma patients in an ED setting. Thus succinylcholine may be used as the sole paralytic agent in rapid-sequence intubation of head trauma patients.

Effects of precurarisation on suxamethonium-induced postoperative myalgia during the first trimester of pregnancy

Two hundred and fifty women undergoing termination of pregnancy during the first trimester under general anaesthesia were studied to determine the effects of precurarisation on suxamethonium-induced postoperative myalgia and on the need for postoperative analgesics after suxamethonium. Either alcuronium (0.03 mg/kg), atracurium (0.04 mg/kg), tubocurarine (0.05 mg/kg), vecuronium (0.01 mg/kg) or saline was administered in a double-blind manner 4 min before giving suxamethonium. An additional 50 patients were studied who received isoflurane rather than precurarisation and suxamethonium. Every pretreatment prevented fasciculations better than did saline (P less than 0.001). In the saline group, 92% of patients had fasciculations and in the other groups this ranged from 8 to 32%, respectively. On the first postoperative day, 76% of the patients in the saline group had myalgia while myalgia was manifested in 28, 54 and 34% of patients given alcuronium, tubocurarine or vecuronium, respectively (P less than 0.05). Atracurium failed in this effect with 62% having myalgia. In the isoflurane group, none of the patients complained of myalgia on the first postoperative morning. The need for analgesics was less (P less than 0.005) in the isoflurane group (8%) and in the pretreatment groups (18-27%) than in the saline group (42%). It is concluded that precurarisation with tubocurarine, vecuronium or, most effectively, with alcuronium but not with atracurium decreases suxamethonium-induced postoperative myalgia and seems to be necessary also during the first trimester of pregnancy.