Fade of pulmonary function during residual neuromuscular blockade.
OBJECTIVE
A decrement in evoked muscle force with repetitive nerve stimulation (fade) suggests impaired neuromuscular transmission. We tested the hypothesis that fade of pulmonary function, ie, a decrease in values of FVC with the second spirometric maneuver compared to the first maneuver, occurs during impaired neuromuscular transmission.


METHODS
Prospective study.


METHODS
Six healthy male volunteers.


METHODS
A series of three consecutive spirometric maneuvers was performed every 5 min in six awake healthy volunteers before, during, and after partial paralysis evoked by rocuronium (0.01 mg/kg IV plus 2 to 8 microg/kg/min).


RESULTS
We measured FVC, FEV(1), forced inspiratory volume in 1 s (FIV(1)), peak expiratory flow (PEF), and peak inspiratory flow (PIF) by spirometry, and force of adductor pollicis muscle by mechanomyography (train-of-four [TOF] stimulation). A statistically significant fade (reduction of the second maneuver from the first maneuver) of FVC, FEV(1), FIV(1), PEF, and PIF was observed during neuromuscular blockade. With peak relaxation (TOF ratio, 0.5) fade amounted to medians of 10% (interquartile range [IQR], 9 to 23%), 7% (IQR, 2 to 16%), 31 (IQR, 19 to 47%), 9% (IQR, 3 to 24%), and 30% (IQR, 5 to 43%), respectively. A fade of >or= 10% was always associated with a clinically relevant (>or= 10%) FVC reduction from baseline (ie, FVC before rocuronium administration). However, FVC reduction from baseline was still present in 23% of measurements without a relevant FVC fade.


CONCLUSIONS
A clinically relevant fall (fade) in FVC from the first to the second value during or after neuromuscular blockade suggests impaired pulmonary function and may be due to muscle paralysis. For this reason, the first (best) FVC value may overestimate pulmonary function and expose the patient to an unidentified risk.
Eikermann
Matthias
M
Klinik für Anästhesiologie und Intensivmedizin, Universitätsklinikum Essen, Hufelandstr. 55, D-45122 Essen, Germany. matthias.eikermann@uni-essen.de
Groeben
Harald
H
Bünten
Barbara
B
Peters
Jürgen
J
D000328:Adult; D000732:Androstanols / Q000494:pharmacology*; D006801:Humans; D008297:Male; D009157:Myasthenia Gravis / Q000503:physiopathology*; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*; D011446:Prospective Studies; D015656:Respiratory Mechanics / Q000187:drug effects*; D000077123:Rocuronium; D013147:Spirometry; D014797:Vital Capacity
D000732:Androstanols; D003473:Neuromuscular Nondepolarizing Agents; D000077123:Rocuronium