Neuromuscular blockade does not change the incidence or severity of pharyngolaryngeal discomfort after LMA anesthesia.
OBJECTIVE
Positive pressure ventilation using a laryngeal mask airway (LMA) has gained increased popularity. This study examined the influence of neuromuscular blockade on the incidence and severity of pharyngolaryngeal discomfort after positive pressure ventilation using a LMA.


METHODS
130 patients were included in this prospective, double-blind, randomized two-centre study. Anesthesia was induced with remifentanil and propofol and maintained using remifentanil and sevoflurane in 30% oxygen and 70% air. Patients were mechanically ventilated at 15 breaths.min(-1) with tidal volumes to maintain Petco(2) 30-40 mmHg. Patients were randomly assigned to receive no neuromuscular blocking agent (NOBLOCK group) or cisatracurium prior to LMA insertion (BLOCK group). Prior to the end of surgery, morphine 3 to 5 mg iv were injected. The ease of insertion of the LMA, cuff pressure, and inspiratory pressure were recorded. Patients were asked immediately after two hours, and 24 hr after surgery to rate sore throat, dysphonia, or dysphagia as absent, minimal, moderate or severe. Continuous and categorical data were compared using t test and Chi-squared test, respectively.


RESULTS
68 and 62 patients were randomized to the NOBLOCK and BLOCK groups, respectively. Successful insertion on first attempt were 89% and 92% in the NOBLOCK and BLOCK groups, respectively. Mean intracuff and inspiratory pressures were 85 +/- 35 mmHg and 13 +/- 3 mmHg for the NOBLOCK group, and 96 +/- 34 mmHg and 15 +/- 2 mmHg for the BLOCK group. The immediate, two and 24 hr postoperative incidences and severity of sore throat, dysphonia, and dysphagia did not differ significantly between the two groups.


CONCLUSIONS
Neuromuscular blockade does not influence the ease or rate of success of LMA insertion nor the incidence and severity of pharyngolaryngeal discomfort after positive pressure ventilation using a LMA.
Department of Anesthesiology, Université de Montréal, Hôtel-Dieu, 3840 St. Urbain, Montréal, Québec H2W 1T8, Canada. thomashemmerling@hotmail.com
Thomas M
TM
Hemmerling
Pierre
P
Beaulieu
Klaus E
KE
Jacobi
Denis
D
Babin
Joachim
J
Schmidt
D000328:Adult; D000701:Analgesics, Opioid / Q000627:therapeutic use; D000768:Anesthesia, General / Q000379:methods*; D001279:Atracurium / Q000031:analogs & derivatives* / Q000627:therapeutic use; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D015994:Incidence; D017214:Laryngeal Masks / Q000009:adverse effects*; D007830:Larynx / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000627:therapeutic use; D019148:Neuromuscular Blockade / Q000379:methods*; D009466:Neuromuscular Blocking Agents / Q000627:therapeutic use; D010614:Pharynx / Q000187:drug effects* / Q000503:physiopathology; D011175:Positive-Pressure Respiration / Q000379:methods; D011446:Prospective Studies; D012720:Severity of Illness Index; D014827:Vocal Cords / Q000187:drug effects; D014832:Voice Disorders / Q000139:chemically induced / Q000188:drug therapy*
D000701:Analgesics, Opioid; D009466:Neuromuscular Blocking Agents; D001279:Atracurium; D009020:Morphine; C101584:cisatracurium