ObjectiveTo investigate the effect of noninvasive ventilation (NIV) in patients with myasthenic crisis after thymectomy. Methods31 myasthenic crisis patients after thymectomy who initially used NIV,admitted in the First Affiliated Hospital of Guangzhou Medical University between January 2011 and June 2013,were analyzed retrospectively.They were assigned to two groups according to the successful application of NIV or not,with 13 patients in the NIV success group and 18 patients in the NIV failure group.The related factors including gender,age,APACHEⅡ score when admitted to ICU,the results of blood gas analysis before NIV,thymoma or not,the history of myasthenic crisis,the history of chronic lung disease,and minute ventilation accounted for the largest percentage of predicted value (MVV%pred)were analyzed. ResultsThere were no significant differences in age,gender,or APACHEⅡ score between two groups (P>0.05).The PaCO2 in the NIV success group was lower than that in the NIV failure group.The preoperative MVV%pred in the NIV success group was higher than that in the NIV failure group.There were no significant differences between two groups in pH,PO2,thymoma or not,the history of myasthenic crisis,or the history of chronic lung disease (P>0.05).If using the 45 mm Hg as the cut-off value of PaCO2 and 60% as the cut-off value of MVV%pred,the incidence of PaCO2<45 mm Hg and the incidence of MVV%pred>60% were higher in the NIV success group than those in the NIV failure group (84.6% vs.33.3%, P<0.05;100% vs. 55.6%,P<0.05).Logistic regression analysis revealed that PaCO2<45 mm Hg was an independent influence factor for successful application of NIV in patients with myasthenic crisis after thymectomy. ConclusionPaCO2<45 mm Hg can be a predictor of successful application of NIV in patients with myasthenic crisis after thymectomy.For the patients underwent NIV whose PaCO2<45 mm Hg or MVV%pred<60%,the clinician should predict the possibility of failure and prepared for intubation.
ObjectiveTo analyze the risk factors for post-thymectomy myasthenic crisis (PTMC) and prolonged mechanical ventilation, in myasthenia gravis patients who underwent extended thymectomy. MethodsWe retrospectively analyzed the clinical data of 79 patients including 38 males and 41 females who experienced PTMC and required mechanical ventilation in Daping Hospital between June 2008 and November 2014. Single factor analysis and multivariate analysis were conducted. ResultsMorbidity of PTMC was 20.6% (79/384). Result of single-factor analysis showed that postoperative pneumonia was one of the main reasons of prolonged mechanical ventilation (P < 0.05). Result of multiple-factor analysis showed that the operation time was positively correlated with mechanical ventilation time (P < 0.05). The risk factor of prolonged mechanical ventilation time in PTMC was not associated with sex, age, disease history, myasthenic crisis history, Osserman classification, dosage of pyridostigmine before and after the operation, surgical approach, bleeding volume, other therapies besides mechanical ventilation (P > 0.05). ConclusionMechanical ventilation is one the main therapy of PTMC, operation time, and postoperative pneumonia are the main factors to prolong mechanical ventilation time. In order to decrease morbidity of PTMC and shorten mechanical ventilation time, the operation time should be controlled and pulmonary infection should be avoided.
ObjectiveTo explore the risk factors of myasthenic crisis after thymectomy (MCAT) for patients with myasthenia gravis (MG). MethodsWe searched PubMed, EMbase, The Cochrane Library (Issue 8, 2015), Web of Knowledge, CBM, CNKI and WanFang Data from inception to August 31, 2015, to collect case-control studies and retrospective cohort studies about the MCAT for patients with MG. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Then meta-analysis was performed using Stata 13.0 software. ResultsA total of 17 studies involving 394 patients with myasthenic crisis and 1642 controls were included. Of the 17 studies, 11 were retrospective cohort studies and 6 were case-control studies. The results of meta-analysis showed that:a) univariate analysis indicated that history of myasthenic crisis (OR=8.05, 95%CI 5.80 to 11.15, P<0.01), bulbar symptoms (OR=5.10, 95%CI 3.01 to 8.67, P<0.01), preoperative severity of gravis (Osserman-stage) (OR=10.55, 95%CI 7.28 to 15.30, P<0.01), postoperative pulmonary infection (OR=10.77, 95%CI 3.88 to 29.95, P<0.01), thymoma (OR=2.37, 95%CI 1.50 to 3.75, P<0.01), dose of pyridostigmine (MD=0.45, 95%CI 0.29 to 0.62, P<0.01), AChRAb level >100 nmol/L (OR=12.14, 95%CI 4.80 to 30.73, P<0.01) and operation time (MD=0.57, 95%CI 0.26 to 0.88, P<0.01) were the risk factors of MCAT; b) multivariate analysis showed that, history of myasthenic crisis (OR=5.06, 95%CI 2.30 to 11.14, P<0.01), bulbar symptoms (OR=5.21, 95%CI 2.62 to 10.35, P<0.01), preoperative severity of gravis (Osserman-stage) (OR=5.82, 95%CI 2.60 to 13.04, P<0.01) and AChRAb level >100 nmol/L (OR=8.38, 95%CI 3.31 to 23.08, P<0.01) were the independent risk factors of MCAT. ConclusionThe independent risk factors of MCAT for patients with MG are history of myasthenic crisis, bulbar symptoms, preoperative severity of gravis (Osserman-stage) and AChRAb level >100 nmol/L.