The use of magnesium to prevent laryngospasm after tonsillectomy and adenoidectomy: a preliminary study

Laryngospasm is the most common cause of upper airway obstruction after tracheal extubation. Magnesium has a central nervous system depressant property, which contributes to the depth of anaesthesia. It also has calcium antagonist properties, which provide muscle relaxation. In this study, we aimed to determine the effect of magnesium on preventing laryngospasm.

After approval of the Ethics Committee and informed parental consent, 40 patients, ASA I-II, aged 3-12 years, who were scheduled for tonsillectomy or/and adenoidectomy, were randomly divided into two groups. Anaesthesia was induced with sevoflurane, lidocaine 1 mg x kg-1, alfentanil 10 micro g x kg-1, vecuronium 0.1 mg x kg-1 and maintained with sevoflurane 2% and 60% nitrous oxide in oxygen. After intubation, patients in group I received 15 mg.kg-1 magnesium in 30 ml 0.9% NaCl over 20 min. Patients in group II received 0.9% NaCl alone in the same volume. After reversal of neuromuscular blockade, all patients were extubated at a very deep plane of anaesthesia. The incidence of laryngospasm was determined until the time of discharge from the postanaesthesia care unit.

Although laryngospasm was not observed in group I, it was observed in five patients in group II (25%). The incidence of laryngospasm in group II was significantly higher than group I. The plasma magnesium concentrations were significantly higher in group I than group II.

We found a significant decrease in the incidence of laryngospasm in paediatric patients receiving magnesium. It is suggested that the use of intravenous magnesium intraoperatively may prevent laryngospasm.