Obesity: Succinylcholine dosing

Succinylcholine dosing for optimal intubating conditions should be based on total body weight. Onset of complete neuromuscular blockade largely remains similar despite variability in dosing. Duration of action of neuromuscular blockade is increased with more liberal dosing.

Optimal succinylcholine dosing for morbidly obese individuals (BMI > 4) was evaluated by randomized controlled trial with outcomes being onset of maximum neuromuscular blockade, intubating conditions, and duration of action of neuromuscular blockade. Groups received 1 mg/kg comparing dosing based on ideal body weight (IBW), lean body weight (LBW), or total body weight (TBW).

Definitions: IBW = 22 x H₂, where H is the height of the patient in meters. LBW = estimated as 130% IBW TBW = patient’s actual weight

Results: Onset of neuromuscular blockade did not differ between groups. Intubating conditions* were significantly better in the group dosed by TBW. Duration of action of neuromuscular blockade differed between groups, TBW > LBW > IBW.

Of note: there were no detected differences in incidence or degree of fasciculation, as well as no differences in non-incisional pain or myalgias in the groups of this study

*Intubating conditions based on relaxation of jaw, ease of maneuvering laryngoscopy blade, vocal cord position and immobility, diaphragmatic movement, and absence of patient reaction to laryngoscopy