Rocuronium 0.3 mg x kg-1 (ED95) induces a normal peak effect but an altered time course of neuromuscular block in patients with Duchenne's muscular dystrophy.
BACKGROUND
In patients with Duchenne's muscular dystrophy (DMD) recovery from neuromuscular block is delayed. It has been assumed that this is because of a higher potency of muscle relaxants in this patient cohort. We determined the peak effect, and the time course of action of rocuronium 0.3 mg x kg(-1) (ED(95)) in DMD patients.


METHODS
Twenty-four patients (12 with DMD and 12 controls; aged 10-18 years) were studied. All patients were anesthetized with propofol and fentanyl/remifentanil. Neuromuscular transmission was monitored by acceleromyography. After induction all patients received a single dose of rocuronium 0.3 mg x kg(-1). The complete time course of action as onset, peak effect and spontaneous recovery was recorded.


RESULTS
The onset time (s) to maximum block was significantly (P < 0.01) prolonged in DMD patients (median: 315; range: 120-465) compared with controls (195, 75-270). The peak effect (% twitch depression relative to baseline) was not different between the groups (DMD: 59-100; controls: 28-100). In the DMD group, recovery was significantly (P < 0.01) delayed compared with controls at all recorded time points. The clinical duration (min) was 40.3 (22-89) in the DMD group vs 9.8 (6-17) in the control group (P < 0.01).


CONCLUSIONS
The similar peak effect in both groups does not confirm the thesis of rocuronium having a higher potency in DMD patients. The documented very long recovery after the ED(95) of rocuronium emphasizes the need for careful assessment of neuromuscular function in DMD patients.
Muenster
Tino
T
Department of Anaesthesiology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.
Schmidt
Joachim
J
Wick
Stefanie
S
Forst
Juergen
J
Schmitt
Hubert J
HJ
D000293:Adolescent; D000732:Androstanols / Q000008:administration & dosage / Q000494:pharmacology*; D000762:Anesthesia Recovery Period; D000771:Anesthesia, Intravenous; D019162:Anesthetics, Combined; D016022:Case-Control Studies; D002648:Child; D004305:Dose-Response Relationship, Drug; D005283:Fentanyl; D006801:Humans; D008297:Male; D020388:Muscular Dystrophy, Duchenne / Q000503:physiopathology*; D009213:Myography; D019148:Neuromuscular Blockade; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000503:physiopathology; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage / Q000494:pharmacology*; D010880:Piperidines; D015742:Propofol; D000077208:Remifentanil; D000077123:Rocuronium; D013997:Time Factors
D000732:Androstanols; D019162:Anesthetics, Combined; D003473:Neuromuscular Nondepolarizing Agents; D010880:Piperidines; D000077208:Remifentanil; D005283:Fentanyl; D000077123:Rocuronium; D015742:Propofol