Preoperative risk factors for prolonged postoperative ventilation following thymectomy in myasthenia gravis

Adequate preoperative evaluation and preparation for surgery are required to prevent prolonged mechanical ventilation after thymectomy, and facilitate the recovery of patients with myasthenia gravis (MG). The objective of this study was to identify the preoperative risk factors for extubation failure after thymectomy in patients with MG.

A retrospective study was conducted on 61 patients with MG who underwent extended thymectomy. Several factors were evaluated including patients' demographic data, preoperative medical therapies, medical history, and comorbidities. Multivariate logistic regression analysis was used to identify the predictors of late extubation after thymectomy for MG.

Fourteen patients (22.95%) required breathing support after anesthesia or endotracheal re-intubation within 48 h. Univariate analysis illustrated that the quantitative MG (QMG) grade (odds ratio [OR] = 1.368, P = 0.000), preoperative muscle strength (OR = 0.279, P = 0.000), use of pyridostigmine (OR = 1.011, P = 0.024) and prednisone (OR = 1.059, P = 0.022), preoperative lung function (OR = 4.875, P = 0.016), low preoperative cholinesterase levels (OR = 0.999, P = 0.014), impaired preoperative swallowing muscle activity (OR = 7.619, P = 0.003), and positivity for acetylcholine receptor antibodies (OR = 14.143, P = 0.001) were significant predictors of prolonged postoperative intubation. Multivariate logistic regression analysis revealed that the QMG score (OR = 3.408, P = 0.000) and Myasthenia Gravis Foundation of America (MGFA) classification (OR = 28.683, P = 0.002) were independent risk factors for prolonged postoperative intubation.

The preoperative MGFA clinical classification and QMG score were independent risk factors for prolonged postoperative intubation in patients with MG.