RESUMO
Masseter muscle rigidity (MMR), known as the ‘jaw of steel’, sometimes makes laryngoscope unusable due to the stiffness of the jaw. MMR during general anesthesia was previously considered as an early episode of malignant hyperthermia (MH). Generally, MMR occurs in the pediatric patients after induction with succinylcholine and volatile agents. However, MMR following the administration of non-depolarizing muscle relaxants is uncommon, although described in some reports. We report a case of 62-year-old male patient which developed MMR following intravenous administration of rocuronium during induction of anesthesia. Our patient was not found to be vulnerable to MH. Although fiberoptic nasotracheal intubation had been successfully performed in our case, an unanticipated difficult airway due to MMR can be experienced at any time. Therefore, we should be aware that, although rare, MMR can occur after using non-depolarizing muscle relaxant. Additionally, in case of any incident of MMR, anesthesiologists need to recognize the management of a difficult airway and to maintain adequate oxygenation in a variety of methods according to a difficult airway algorithm.
RESUMO
Masseter muscle rigidity (MMR), known as the ‘jaw of steel’, sometimes makes laryngoscope unusable due to the stiffness of the jaw. MMR during general anesthesia was previously considered as an early episode of malignant hyperthermia (MH). Generally, MMR occurs in the pediatric patients after induction with succinylcholine and volatile agents. However, MMR following the administration of non-depolarizing muscle relaxants is uncommon, although described in some reports. We report a case of 62-year-old male patient which developed MMR following intravenous administration of rocuronium during induction of anesthesia. Our patient was not found to be vulnerable to MH. Although fiberoptic nasotracheal intubation had been successfully performed in our case, an unanticipated difficult airway due to MMR can be experienced at any time. Therefore, we should be aware that, although rare, MMR can occur after using non-depolarizing muscle relaxant. Additionally, in case of any incident of MMR, anesthesiologists need to recognize the management of a difficult airway and to maintain adequate oxygenation in a variety of methods according to a difficult airway algorithm.
RESUMO
The Selectatec mounting system was devised to provide easy and quick on-site fitting of various vaporizers for the anesthetic machine. However, a quick changing system for the vaporizer can also damage the O-ring due to friction between the vaporizer and the Selectatec back bar. We herein report a case of an unexpected anesthetic gas leakage from a damaged O-ring on the Selectatec back bar, which resulted from exchanging the vaporizers between two operations. In cases using the Datex Ohmeda machine, it is not easy to detect leakages from the vaporizers because of the location of the check valve near to the fresh gas outlet. This complicates the use of the positive pressure leakage test to detect a low pressure system leakage on the Selectatec back bar. We recommend the preanesthetic negative pressure or low-flow leakage test to detect a low pressure leakage when exchanging vaporizers on the Selectatec system.