A comparison between vecuronium and atracurium in myasthenia gravis

Effects of General-epidural Anaesthesia on Haemodynamics in Patients with Myasthenia Gravis

OBJECTIVE

The current study aims to explore the effects of general-epidural anaesthesia (GEA) on the perioperative haemodynamics in patients with myasthenia gravis (MG), as well as their extubation time.

METHODS

A total of 42 MG patients (Ossermann I-II b types) receiving elective total thymectomy were randomized into GEA (n = 20) and general anaesthesia alone (GA; n = 22) groups. Changes in their mean arterial pressure (MAP) and heart rate (HR) were recorded before anesthesia and at the time of intubation, skin incision, sternotomy and extubation. Dosages of general anaesthetics during time unit and the time of extubation and complete recovery from the ending of the operation were also recorded.

RESULTS

After anaesthesia, both groups displayed increased MAPs and HRs, with those in the GA group significantly higher than those in the GEA group (p < 0.05). The total consumption of general anaesthetics in the GA group was markedly higher than that in the GEA group (p < 0.01).

CONCLUSION

The GEA group had shorter postoperative extubation and recovery time than the GA group (p < 0.01). General-epidural anaesthesia stabilizes perioperative haemodynamics, reduces the consumption of general anaesthetics and shortens extubation time. It is a feasible and ideal anaesthetic method at present.

Propofol or sevoflurane anesthesia without muscle relaxants allow the early extubation of myasthenic patients

PURPOSE

To compare two non-muscle relaxant anesthetic techniques in myasthenic patients undergoing trans-sternal thymectomy, evaluating the intra- and postoperative conditions including the early extubation in the operating room.

METHODS

Sixty-eight consecutive myasthenic patients undergoing trans-sternal thymectomy were prospectively randomized in two groups: propofol and sevoflurane. In both groups anesthesia was induced with propofol (1-2 mg x kg(-1)) and intubation performed after topical anesthesia of the airway with lidocaine. Anesthesia was maintained in the propofol group (36 patients) with a continuous propofol infusion (3-6 mg x kg(-1) x hr(-1)) and nitrous oxide and, in the sevoflurane group (32 patients), with sevoflurane (end-tidal 1-1.5%) in O2:N2O. Intubating conditions, hemodynamic changes, neuromuscular transmission, postoperative intensive care unit and hospital length of stay and complications were evaluated. Data were analyzed with repeated measure two-way analysis of variance (ANOVA), Chi square test and Student's t test.

RESULTS

Intubating conditions were good in all patients. There were no hemodynamic changes. All patients were extubated in the operating room and none had to be re-intubated for postoperative respiratory depression. Neuromuscular transmission showed minimal changes, more important in the sevoflurane group, and at the end of the procedure the recovery was complete in all patients. We did not observe any other significant differences between the two groups studied.

CONCLUSION

Our data show that these two anesthetic techniques allow the early extubation of myasthenic patients in the operating room.

Multivariate determinants of the need for postoperative ventilation in myasthenia gravis

PURPOSE

Following transsternal thymectomy, up to 50% of patients may require postoperative ventilation. The aim of this study was to identify the variables most useful in predicting the myasthenic patient who needs postoperative mechanical ventilation.

METHODS

We applied multivariate discriminant analysis to preoperative physical, historical, laboratory and intraoperative data of 51 myasthenic patients who underwent transcervical-transsternal thymectomy to select those variables most useful in predicting the postoperative need for mechanical ventilation. The receiver operating characteristic (ROC) curve was also used to describe the discrimination abilities and to explore the trade-offs between sensitivity and specificity of the model.

RESULTS

Discriminant analysis identified seven risk factors that correlated with the need for postoperative ventilation: FVC, FEF25-75%, MEF50% and their percentages of the predicted values, as well as, sex. The model correctly predicted the actual ventilatory outcome in 88.2% of patients. The area under the ROC curve verified that our model correctly predicted the actual ventilatory outcome with a probability of 88.2%.

CONCLUSIONS

This model can be used for predicting the need for postoperative mechanical ventilation in myasthenia gravis patients.