Use of ProSeal(®) LMA and thoracic epidural in myasthenia patients for trans-sternal thymectomy: A case series.

Abstract

Myasthenia gravis is an autoimmune disease, resulting from the production of antibodies against the acetylcholine receptors of the neuromuscular endplate. Muscular weakness and fatigability are the hallmarks of myasthenia gravis. Myasthenic patients are sensitive to non-depolarising relaxants and post-operative ventilatory support may be required in high-risk patients. This can be attributed partly to endotracheal intubation and use of intermediate or long-acting muscle relaxants in such cases. The rate of post-operative ventilation after a trans-sternal thymectomy has been reported to be more than 50% in myasthenia gravis patients.[1] Two techniques have been recommended for general anaesthesia in the myasthenic patient. Due to the unpredictable response to succinylcholine and the marked sensitivity to non-depolarising muscle relaxants, some anaesthesiologists avoid muscle relaxants and depend on deep inhalational anaesthesia for tracheal intubation and maintenance of anaesthesia.[2,3] However, others utilise a balanced technique which includes the use of muscle relaxants, without the need for deep inhalational anaesthesia with its concomitant respiratory and cardiovascular side effects, provided neuromuscular transmission is monitored. In this paper, we would like to describe a new and successful technique of using ProSeal® laryngeal mask airway (LMA) with thoracic epidural for three cases who underwent trans-sternal thymectomy. We avoided muscle relaxant during the entire course of surgery and none of our cases required post-operative ventilation.