General anaesthesia in a patient with motor neuron disease

Abstract

EDITOR: Motor neuron disease is a degenerative disorder of the ganglia in the anterior horn of spinal cord and spinal pyramidal tracts. An example is amyotrophic lateral sclerosis [1]. Motor neurone disease involves initial atrophy of respiratory muscles. In the latter parts of the disease, respiratory weakness occurs with respiratory insufficiency and failure of breathing leading to death [1,2]. Respiratory complications are common and a cause for concern in the management of patients with motor neurone disease. The perioperative pulmonary complication rate has been found to be significantly higher after upper abdominal surgery in patients with muscular disability and complications should be anticipated [3]. It is well documented that patients with motor neurone disease can have problems when swallowing. The risk of aspiration and airway obstruction with the risk of regurgitation has to be regarded as high [2,4,5]. We report a 56-yr-old man, diagnosed with pancreatic carcinoma and amyotrophic lateral sclerosis scheduled for elective Whipple's surgery. At preoperative evaluation, the patient reported difficulties with breathing while talking, and described swallowing problems for the preceding 5 weeks with weakness of lower and upper extremities. Blood pressure was 130/85 mmHg, and electrocardiogram (ECG) and chest radiograph showed no abnormalities. Spirometry was attempted prior to operation, but because of exhaustion of the patient this test had to be stopped. Anaesthetic management was planned with the aim of minimizing the duration of general anaesthesia and its effects on the respiratory centre, chemoreceptors and respiratory muscles [6]. Thoracic epidural anaesthesia was considered, but after discussion of risks and benefits, the patient refused consent for regional anaesthesia. After a 5-h operation, the patient was transferred intubated to our postanaesthesia care unit. When the patient recovered consciousness 8 h after the end of operation, he was ventilated with continuous positive airway pressure (CPAP) and was extubated under controlled conditions 5 h later with a normal breathing pattern and with no signs of respiratory exhaustion. Unfortunately, he had to undergo a second surgical procedure 3 h after extubation. An uncomplicated surgical revision lasting 3 h was performed. After recovery from muscular relaxation as indicated by a train of four ratio of 0.88, PCO2 of 41 mmHg and SPO2 of 97%, an early extubation with no complications was performed. In the postanaesthesia care unit, respiratory insufficiency developed 3 h later, despite an augmented spontaneous breathing pattern, heralded by hypercapnia (PCO2 of 63.4 mmHg). Two days later, the patient was re-intubated because of respiratory exhaustion with a PaCO2 at about 130 mmHg. Tracheostomy was performed 2 days later under general anaesthesia. Thereafter, the patient was transferred awake and breathing with CPAP to the neurological intensive care unit. Slight breathing improvements were observed during subsequent weaning. However, the patient was able to sustain only very brief periods without respiratory support. One month after surgery, the patient was transferred to a secondary care facility, still requiring respiratory support. After the first surgical procedure, we observed almost full recovery of respiration with no necessity for further respiratory support. After a second general anaesthetic procedure within a short period of time, worsening respiratory distress and exhaustion necessitated tracheostomy and implementation of respiratory support. Weaning from respiratory support was not successful during the month the patient spent at our hospital. We agree with the previous reports stipulating that neuromuscular monitoring is essential in administrating non-depolarizing neuromuscular blocking agents to patients with motor neurone disease for general surgery [5,7]. Depolarizing muscle relaxants, such as succinylcholine, are not recommended because of reported rhabdomyolysis and hyperkalemia from denervated muscles, possibly leading to ventricular arrhythmias or fibrillation [8]. As in our case, recovery of train of four was reported from low-dose cisatracurium, which may be a good choice for muscle relaxation in these patients and good respiratory compliance was perceived after extubation. Based upon the present case, we conclude that anaesthesia for major surgery using low doses of cisatracurium and propofol is possible in patients with motor neurone disease. However, repeated surgery in such patients may lead to a considerable increase in respiratory complications. In concordance with previous reports, we suggest that spirometry should be performed prior to major surgery, whenever possible, and recommend the use of neuromuscular monitoring when planning general anaesthesia in these patients [6]. B. Moser P. Lirk M. Lechner M. Gottardis Department of Anaesthesiology and Critical Care Medicine; University of Innsbruck; Innsbruck, Austria