Aggressive respiratory treatment in myasthenic crisis

Introduction: Myasthenic patients in need for mechanical ventilation, often develop pneumonia or atelectasis. Although there are differences in the incidence of these complications among various institutions, there is no evidence that aggressive treatment shortens the course of the myasthenic crisis. We tried to quantify the severity of lung injury and aggressiveness of respiratory intervention in myasthenic patients admitted to the Neuro-Critical Care Unit (NCCU). Methods: We retrospectively identified all mechanically ventilated myasthenic patients admitted in our unit between 1990 and 1998. A novel respiratory intervention index (RID, comprising the use of suction, intermittent positive pressure breathing or bronchodilator treatments, sighs and chest physiotherapy represented the aggressiveness of the respiratory treatment. The RII was correlated with the lung injury score (LIS) (1), used as a measure of lung involvement and other respiratory variables. Results: Eighteen patients with 24 episodes of respiratory failure were identified. Our patients had less atelectasis and pneumonia than previously published series (2) (46% vs 91%), leading to shorter mechanical support and NCCU stay. Mean RII inversely correlated with forced vital capacity, but not with negative inspiratory force or LIS, although for the latter a trend was observed (P=0.07). Conclusions: This study defines a bench mark for both severity of pulmonary complications and intensity of respiratory therapy in the severe myasthenic patient with mechanical ventilatory compromise. Our results indicate that aggressive respiratory treatment should be used in myasthenic patients in crisis in order to diminish the risk for respiratory complications. These observations should be validated in a prospective study.