Response to cisatracurium in patient with Charcot-Marie-Tooth disease

Abstract

EDITOR: We report the anaesthetic management of a patient with Charcot-Marie-Tooth disease (CMTD) and the response to cisatracurium. A 34-yr-old female with known CMTD was scheduled for laparoscopic cholecystectomy for gall bladder surgery. She underwent a caesarean section in July 1989, receiving thiopental, succinylcholine, nitrous oxide/oxygen and isoflurane. In May 1997, she underwent a second caesarean section under epidural anaesthesia. No adverse events were noted in the anaesthetic records. The CMTD had been diagnosed since adolescence. There was family history of the disease. The patient was being treated with an angiotensin-converting enzyme inhibitor for systemic arterial hypertension. Neurological examination revealed generalized absence of reflexes, decreased proprioceptive sensation, atrophy and distal wasting of upper and lower limbs and equinovarus deformity of the feet. Electromyography showed a severe motor and sensory demyelinating polyneuropathy. Electrocardiogram (ECG) and chest X-ray showed left ventricular hypertrophy signs. Echocardiography demonstrated hypertensive cardiomyopathy and a mild deficit in compliance. A decrease of 5% in forced vital capacity between erect and lying position was indicative of a right diaphragmatic function. The patient was premedicated with ranitidine and metoclopramide 90 min before surgery. In the operating room, she was continuously monitored using ECG, inspired oxygen concentration, oxygen saturation, expired carbon dioxide and blood pressure. Neuromuscular block was monitored by means of accelerography of the adductor pollicis brevis muscle (Tof-Guard®, Biometer; Organon Teknika, The Netherlands). After preoxygenation, induction of anaesthesia was achieved by using remifentanil (0.5 μg kg−1 min−1) and incremental doses of propofol. Muscle relaxation was facilitated with cisatracurium (0.15 mg kg−1). Anaesthesia was maintained with a target-controlled infusion of propofol set at a target plasma concentration of 2.5 μg mL−1 and remifentanil 0.25-0.4 μg kg−1 min−1. After induction of anaesthesia, but before the administration of cisatracurium, the current supplied by the stimulator was adjusted to produce supramaximal stimulation of the ulnar nerve to deliver a train-of-four (TOF) pattern. The times to first measurable effect (lag time) and maximum neuromuscular block (onset time) were 60 and 195 s, respectively. The maximum block obtained was 100% inhibition of T1 (the first twitch of the TOF). Tracheal intubation was then carried out. The T1 recovered to 10% of control value 42 min after the administration of cisatracurium. A supplementary dose of 0.05 mg kg−1 was required every 20 min to maintain T1 below 10% of control value and a total of two supplementary doses were administered throughout surgery. After the last supplementary dose, spontaneous recovery of T1 from 10% to 25%, 75% and 90% of control took 8.5, 25.2 and 29.4 min, respectively. Administration of a mixture of 2 mg neostigmine and 1 mg atropine at 75% recovery of T1 resulted in recovery to 100% in 10 min. After the patient demonstrated adequate strength and appropriate alertness, the endotracheal tube was removed. The operation lasted approximately 130 min. Postoperatively, she remained haemodynamically stable and there were no signs of respiratory compromise. CMTD is a hereditary disorder consisting of demyelinating peripheral neuropathy with muscle atrophy [1]. Non-depolarizing neuromuscular blocking agents have a varying effect on CMTD. The denervation-like process might lead to resistance [2]. However, the loss of motor units and the resultant muscle weakness in these patients might result in sensitivity to non-depolarizing neuromuscular blocking drugs [3,4]. Our patient with CMTD demonstrated a normal response to cisatracurium. A similar observation was reported with atracurium and mivacurium in patients with CMTD [5]. According to various authors, the normal response, or even the moderate resistance to non-depolarizing neuromuscular blocking agents in patients with generalized polyneuropathy, despite muscle weakness and atrophy, could be attributed to upregulation of the acetylcholine receptors at the neuromuscular junction [2,6]. Despite the denervation that occurs in CMTD, succinylcholine appears safe [1], probably because these denervated muscles are severely atrophied. However, it is prudent to avoid succinylcholine in patients with a recent acute exacerbation, since upregulation of the end-plate cholinergic receptors plays a significant role in the hyperkalaemic response to succinylcholine [6]. It is of clinical importance to have continuous monitoring of neuromuscular blockade and also to use small doses of non-depolarizing neuromuscular blocking drugs in patients with CMTD. J. García-Ferreira J. Hernández-Palazón Department of Anaesthesia, Hospital Universitario ‘Virgen de al Arrixaca’, Murcia, Spain