Sevoflurane as a sole anaesthetic for thymectomy in myasthenia gravis

Anaesthetic management of myasthenia gravis in coronary artery bypass grafting

Myasthenia gravis (MG) is an autoimmune disease affecting the neuromuscular junction causing weakness and fatigability of muscles. Careful perioperative management is required because of the unpredictable susceptibility to muscle relaxants. In this case report, we describe the successful management of a MG patient for normothermic coronary artery bypass graft (CABG) surgery with titrated doses of rocuronium without prolonged postoperative ventilation. We chose rocuronium because full and rapid recovery of neuromuscular blockade is possible with sugammadex. We conclude that using rocuronium is safe during general anaesthesia in MG patients undergoing on-pump CABG when combined with continuous neuromuscular monitoring and careful perioperative management.

Myasthenia gravis and pregnancy

Myasthenia gravis (MG) is an autoimmune disorder with bimodal age of presentation, occurring in young women of reproductive age and at an older age in men. Occasionally, MG is diagnosed during pregnancy. Management of MG includes symptomatic treatment with cholinesterase inhibitors and immunosuppressive therapy for controlling the disease activity. Treatment of MG in women of reproductive age, who may be contemplating pregnancy, requires discussion regarding the choice of medication as well as the understanding of risks/adverse effects involved with various treatments. During the peripartum period, it is essential to ensure careful monitoring of the disease state along with the well-being of the mother and fetus and to coordinate neonatal monitoring overseen by a multidisciplinary team comprising a high-risk maternal fetal medicine specialist, a neurologist familiar with these complex issues, and a neonatologist.

Laparoscopic Sleeve Gastrectomy in a Morbidly Obese Patient with Myasthenia Gravis: A Review of the Management

Myasthenia gravis, a disorder of neuromuscular transmission, presents a unique challenge to the perioperative anesthetic management of morbidly obese patients. This report describes the case of a 27-year-old morbidly obese woman with a past medical history significant for myasthenia gravis and fatty liver disease undergoing bariatric surgery. Anesthesia was induced with intravenous agents and maintained with an inhalational and balanced intravenous technique. The nondepolarizing neuromuscular blocker Cisatracurium was chosen so that no reversal agents were given. Neostigmine was not used to antagonize the effects of Cisatracurium. The goal of this approach was to reduce the risk of complications such as postoperative mechanical ventilation. The anesthetic and surgical techniques used resulted in an uneventful hospital course. Therefore, we can minimize perioperative risks and complications by adjusting the anesthetic plan based on the patient's physiology and comorbidities as well as the pharmacology of the drugs.

Sevoflurane and thoracic epidural anesthesia for trans-sternal thymectomy in a child with juvenile myasthenia gravis

Literature on anesthetic management of juvenile myasthenia gravis (JMG) for thymectomy is limited. Recently, use of inhalational agents and total intravenous anesthesia with propofol and remifentanyl has been reported. All these techniques individually or in combination have been tried to avoid the use of muscle relaxant. We report successful use of sevoflurane as sole anesthetic agent for intubation and in combination with thoracic epidural anesthesia for intraoperative anesthetic management in a 5-year-old child with JMG.

Thymoma removal in a cat with acquired myasthenia gravis: a case report and literature review of anesthetic techniques

HISTORY AND PRESENTATION: A 12 year old, 4.2 kg, domestic long hair, castrated male cat was presented with regurgitation, inability to retract the claws, general weakness, cervical ventroflexion and weight loss. A thymic mass was evident on radiographs. Acetylcholine receptor antibody titer was positive for acquired myasthenia gravis (MG). Thymectomy via midline sternotomy was scheduled. ANESTHETIC MANAGEMENT:  Oxymorphone and atropine were administered subcutaneously as premedication, and anesthesia was induced with etomidate and diazepam given intravenously to effect. The cat's trachea was intubated and anesthesia was maintained with isoflurane in oxygen, and continuous infusions of remifentanil and ketamine. Epidural analgesia with preservative-free morphine was administered prior to surgery. Postoperative analgesia was provided by oxymorphone subcutaneously, interpleural bupivacaine, and fentanyl infusion. Postoperative complications included airway obstruction, hypoxemia and hypercapnia.

FOLLOW-UP

The cat was discharged 3 days after surgery. Discharge medications included pyridostigmine and prednisone. Nine days after surgery, the cat had a significant increase in its activity level, and medications were discontinued. Histopathologically, the mass was consistent with a thymoma. Approximately 6 weeks later the cat became weak again and pyridostigmine and prednisone administration was resumed.

CONCLUSION

The perioperative management of patients with MG for transsternal thymectomy is a complex task. The increased potential for respiratory compromise requires the anesthesiologist to be familiar with the underlying disease state, and the interaction of anesthetic and non-anesthetic drugs with MG. Careful monitoring of ventilation and oxygenation is indicated postoperatively.

Childhood-onset myasthenia gravis with thymoma

Juvenile myasthenia gravis is an acquired, autoimmune disease occurring before age 16 years. Thymoma is exceedingly rare in children, especially in association with juvenile myasthenia gravis. We describe a 14-year-old boy with juvenile myasthenia gravis and thymoma. He presented with difficulties chewing and swallowing, nasal speech, and fluctuating weakness of the leg muscles. Neurologic examination revealed masticatory and bulbar muscle weakness with nasal speech, proximal muscle weakness, fatigability of the arms and legs, and distal muscle weakness of the legs. A diagnosis of juvenile myasthenia gravis was confirmed by a positive neostigmine test, a decremental response on repetitive nerve stimulation, and increased titers of serum anti-acetylcholine receptor antibodies. The patient received anticholinesterases, corticosteroids, azathioprine, and thymectomy. A pathohistologic analysis of the thymus gland indicated thymoma, Masaoka grade II. After 2 years of an unstable disease course, remission was achieved. Because only 10 cases of thymoma-associated myasthenia gravis are described in the pediatric population, this report offers an important contribution to a better understanding of this rare association.

Anesthesia and myasthenia gravis

Myasthenia gravis (MG) is a disease affecting the nicotinic acetylcholine receptor of the post-synaptic membrane of the neuromuscular junction, causing muscle fatigue and weakness. The myasthenic patient can be a challenge to anesthesiologists, and the post-surgical risk of respiratory failure has always been a matter of concern. The incidence and prevalence of MG have been increasing for decades and the disease is underdiagnosed. This makes it important for the anesthesiologist to be aware of possible signs of the disease and to be properly updated on the optimal perioperative anesthesiological management of the myasthenic patient. The review is based on electronic searches on PubMed and a review of the references of the articles. The following keywords were used: myasthenia gravis AND neuromuscular blocking agents, myasthenia gravis AND sevoflurane, myasthenia gravis AND epidural, myasthenia gravis AND neuromuscular blockade reversal and myasthenia gravis AND pyridostigmine. The articles included were from reviews and clinical trials written in English. MG patients can easily be anesthetized without need for post-surgery mechanical ventilation whether it is general anesthesia or peripheral nerve block. Volatile anesthesia or the use of an epidural for the patient makes it possible to avoid the use of neuromuscular blocking agents, and when used, it should be in smaller doses and the patient should be carefully monitored. This review shows that with thorough pre-operative evaluation, continuing the daily pyridostigmine and careful monitoring the MG patient can be managed safely.

Anaesthetic considerations in paediatric myasthenia gravis

Myasthenia gravis is of particular interest to anaesthetists because of the muscle groups affected, the pharmacology of the neuromuscular junction, and interaction of both the disease and treatment with many anaesthetic drugs. Anaesthetists may encounter children with myasthenia either to facilitate treatment options or to institute mechanical ventilation in the face of a crisis. This paper reviews the literature pertaining to the pathophysiology and applied pharmacology of the disease and explores the relationship between these and the anaesthetic management. In addition to illustrating the tried-and-tested techniques, some newer management options are explored.

[Endotracheal intubation without the use of muscle relaxants in patients with myasthenia gravis]

INTRODUCTION

Although muscle relaxants have been widely used to facilitate endotracheal intubation, the administration of these drugs in myasthenic patients may be associated with adverse events.

MATERIAL AND METHODS

After obtaining Institutional Reviewing Board approval and informed, patient consent, 30 patients with myasthenia gravis were enrolled in a prospective, double-blind, randomized clinical trial. We compared intubating conditions (ease of laryngoscopy, vocal cords, cough, jaw relaxation, limb movement) following fentanyl 2 mg/kg and propofol 2 mg/kg (group PRO, n = 15) vs fentanyl 2 mg/kg and sevoflurane 5% in a 1:2 mixture of oxygen and nitrous oxide (group SEVO, n = 15). The statistical analysis was performed using Student's t test and Chi-quadrate test, p < 0.05 being regarded as significant.

RESULTS

The overall intubating conditions were excellent in 67% of patients in the group PRO vs 80% of patients in the group SEVO (p > 0.05). One patient in each group had clinically unacceptable conditions for intubation. The mean intubation score was 5.7 +/- 1.0 in the group PRO vs 5.9 +/- 0.9 in the group SEVO (p > 0.05). Three patients receiving propofol and one patient receiving sevoflurane had mild hoarseness after the surgery (p > 0.05).

CONCLUSION

Both propofol and sevoflurane, supplemented with fentanyl, provide good intubating conditions without the use of muscle relaxants in patients with myasthenia gravis.

The use of desflurane or propofol in combination with remifentanil in myasthenic patients undergoing a video-assisted thoracoscopic-extended thymectomy

BACKGROUND

Although several studies of the use of desflurane in anesthesia have revealed many desirable qualities, there are no data on the use and effects especially on the neuromuscular function of desflurane on myasthenia gravis (MG) patients. The purpose of this study was to evaluate the use of either desflurane or propofol, both combined with remifentanil, in patients with MG undergoing a video-assisted thoracoscopic-extended thymectomy (VATET).

METHODS

Thirty-six MG patients who underwent VATET were enrolled. Nineteen patients were anesthetized with remifentanil and propofol infused with a target-controlled infusion plasma model, and 17 patients with desflurane and remifentanil. No muscle relaxant was used. The intubating conditions, hemodynamic and respiratory changes, neuromuscular transmission and post-operative complications were evaluated.

RESULTS

Neuromuscular transmission was significantly decreased in the desflurane group (6.7%, from 3% to 9% during anesthesia P=or<0.05). The intubating conditions were good in all 36 patients and 35 patients were successfully extubated in the operating room. The time-to-awakening, post-operatory pH and base excess were significantly different in the two groups, with a decreasing mean arterial pressure in the group administered with desflurane. No patients required reintubation due to myasthenic or cholinergic crisis, or respiratory failure. No other significant differences between the two groups studied were observed.

CONCLUSION

Our experience indicates that anesthesia with desflurane plus remifentanil in patients with MG could determine a reversible muscle relaxation effect, but with no clinical implication, allowing a faster recovery with no difference in extubation time and post-operative complications in the two groups.

Laryngeal Mask Airway insertion with total intravenous anesthesia for transsternal thymectomy in patients with myasthenia gravis: report of 5 cases

Myasthenia gravis is a chronic autoimmune disease characterized by a reduction of postsynaptic nicotinic acetylcholine receptors at the neuromuscular junction. Most myasthenia gravis patients require thymectomy. Intravenous (IV) anesthetics may be superior to inhalation agents in these patients. The Laryngeal Mask Airway (LMA), when compared with the endotracheal tube, causes less airway resistance, which in turn may lead to a decreased bronchoconstrictive reflex, less atelectasis, and fewer pulmonary infections. We report 5 patients with myasthenia gravis, who underwent transsternal thymectomy with total IV anesthesia and LMA.

[Anaesthesia of the myasthenic patients during thymectomy]

Myasthenia is a rare autoimmune disease characterized by fluctuating muscle weakness and fatigability due to a reduction in available acetylcholine receptors at the neuromuscular junction. Data of 186 patients suffering from myasthenia were collected retrospectively. All patients underwent thymectomy over a 23 years period from 1981 to 2006 without surgical mortality. Postoperative ventilation was required for more than 24 hours in seven patients and one patient needed postoperative ventilatory support more than seven days. Thymectomy for myasthenia was performed using promethazine and atropine in general anaesthesia. Introduction could be facilitated with propofol, etomidate or thiopental and sevoflurane, avoiding use of any muscle relaxants. Non-depolarizing muscle relaxants were not used during the procedures. Adequate surgical conditions were provided by short-acting inhaled anaesthetics (sevoflurane) and small doses of opiates. 95% of the narcotized patients were immediately extubated after the procedure in the operating room. Length of stay in intensive care unit could have been reduced without any postoperative ventilatory support. Nonsteroid analgesics and nalbuphine were used for pain relief. Anaesthesia of thymectomy is based on volatile gases. Airway complications can be prevented with use of small amounts of anticholinergic drugs, perhaps steroids.

Neuromuscular junction in health and disease

A number of illnesses and other factors can affect the function of the neuromuscular junction (NMJ). These may have an affect at pre- or post-junctional sites. This review outlines the anatomy and the physiology of the NMJ. It also describes the mechanisms and physiological basis of many of the disorders of the NMJ. Finally, the importance of these disorders in anaesthetic practice is discussed.

Awake anaesthesia for major thoracic surgical procedures: an observational study

OBJECTIVE

Major thoracic surgical procedures are rarely performed under awake anaesthesia. The purpose of this study is to review the experience of a tertiary center in major thoracic surgical procedures done under awake anaesthesia.

METHODS

This single center, single operator, retrospective review of cases of thoracic surgery were done under awake anaesthesia, which included all patients operated on from September 2002 to September 2006. Patients were pre-medicated with intravenous fentanyl 50 microg and midazolam 3mg. Thoracic epidural anaesthesia was done either between T1-T3 and T4-T6 depending on the type of procedure. The block level was verified using warm-cold discrimination. In addition, stellate ganglion block was performed in some patients to achieve cough control. The following data were documented: patients' demographics, the type and approach of procedure, operative time, intraoperative complications, conversion to general anaesthesia, mortality, the need for intensive care unit (ICU) admission and postoperative hospital length of stay.

RESULTS

A total of 79 cases were performed over the study period. The mean age was 37+/-18 years (59% male). Twenty-five patients (32%) underwent thymectomy, 11 patients (13%) lung resection and 8 patients (11%) sympathectomy. The most common approach was thoracoscopy in 61 patients (77%), followed by thoracotomy in 11 patients (14%) and median sternotomy in 3 patients (4%). The median postoperative hospital stay was 1.5 days, with 33% of cases discharged on the same day of operation (day surgery). Only five patients (6%) required ICU admission; three of these patients in 2002 did not need ICU, but epidural policy at that time mandated ICU admission - only 2/79 (2.5% required ICU). One patient died as a result of his underlying metastatic hepatocellular carcinoma 9 days postoperatively. Another patient was converted early to general anaesthesia prior to pneumonectomy after discovery of left upper lobe involvement and he died 3 months later. There was no anaesthesia related mortality.

CONCLUSIONS

We conclude that major thoracic procedure can be safely performed under awake anaesthesia. The technique avoids general anaesthesia and endotracheal intubation, reduces postoperative hospital stay and minimizes intensive care unit admission. This study strongly suggests awake anaesthesia can improve outcomes and reduce cost. A proper multi-center trial to further evaluate this technique is needed.

A combination of total intravenous anesthesia and thoracic epidural for thymectomy in juvenile myasthenia gravis

Juvenile myasthenia gravis is the acquired form of the disease in children and presents with ocular signs, fatigability, weakness and bulbar problems. The majority of patients demonstrate thymic hyperplasia and have been shown to benefit from thymectomy. The main considerations for the anesthesiologist are the degree of muscle weakness, the muscle groups involved and sensitivity to neuromuscular blocking drugs and volatile agents. Total intravenous anesthesia (TIVA) with epidural analgesia is probably the anesthetic technique of choice, although the latter is often avoided, because of the risk of a very high block. Two cases of thymectomy are presented where anesthesia was provided using a combination of TIVA and thoracic epidural analgesia. Both patients tolerated the technique well and had an uncomplicated perioperative course.

Anesthesia and myopathy

PURPOSE OF REVIEW

This report reviews the derangements of neuromuscular transmission in the different types of myopathy.

RECENT FINDINGS

The article covers recent literature on myopathy, whether prejunctional, junctional or postjunctional, as well as intensive care unit myopathy, and outlines the influence of myopathy on the action of both depolarizing and non-depolarizing muscle relaxants.

SUMMARY

The review classifies myopathy according to its cause, and sheds light on the upregulation and downregulation of endplate acetylcholine receptors. These findings are important for both clinical practice, and for research into neuromuscular transmission.

Sevoflurance: approaching the ideal inhalational anesthetic. a pharmacologic, pharmacoeconomic, and clinical review

Sevoflurane is a safe and versatile inhalational anesthetic compared with currently available agents. Sevoflurane is useful in adults and children for both induction and maintenance of anesthesia in inpatient and outpatient surgery. Of all currently used anesthetics, the physical, pharmacodynamic, and pharmacokinetic properties of sevoflurane come closest to that of the ideal anesthetic (200). These characteristics include inherent stability, low flammability, non-pungent odor, lack of irritation to airway passages, low blood:gas solubility allowing rapid induction of and emergence from anesthesia, minimal cardiovascular and respiratory side effects, minimal end-organ effects, minimal effect on cerebral blood flow, low reactivity with other drugs, and a vapor pressure and boiling point that enables delivery using standard vaporization techniques. As a result, sevoflurane has become one of the most widely used agents in its class.