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.
Objective To investigate the influence of pulmonary infection on noninvasive ventilation ( NIV) therapy in hypercapnic acute respiratory failure ( ARF) due to acute exacerbation of chronic obstructive pulmonary disease ( AECOPD) , and evaluate the predictive value of simplified version of clinical pulmonary infection score ( CPIS) for the efficacy of NIV therapy in ARF patients with AECOPD. Methods Eighty-four patients with ARF due to AECOPD were treated by NIV, and were divided into a successful group and an unsuccessful group by the therapeutic effect of NIV. The CPIS and simplified version of CPIS between two groups was compared. The predictive value of simplified version of CPIS for the efficacy of NIV wasevaluated using ROC curve analysis. Results The CPIS and the simplified version of CPIS of the successful treatment group ( 4. 0 ±2. 8, 3. 2 ±2. 4) were lower than those of the unsuccessful group ( 8. 0 ±2. 1, 7. 2 ±1. 8) significantly ( P =0. 006, 0. 007) . The area under ROC curve ( AUC) of CPIS and simplified version of CPIS were 0. 884 and 0. 914 respectively, the cut oint of CPIS and simplified version of CPIS were 6 ( sensitivity of 78. 0% , specificity of 91. 2% ) and 5 ( sensitivity of 80. 0% , specificity of 91. 2% ) respectively. Conclusions The level of pulmonary infection is an important influencing factor on the therapeutic effect of NIV in patients with ARF due to AECOPD. Simplified version of CPIS is a helpful predictor for the effect of NIV on ARF of AECOPD.
Without artificial airway though oral, nasal or airway incision, the bi-level positive airway pressure (Bi-PAP) has been widely employed for respiratory patients. In an effort to investigate the therapeutic effects and measures for the respiratory patients under the noninvasive Bi-PAP ventilation, a therapy system model was designed for virtual ventilation experiments. In this system model, it includes a sub-model of noninvasive Bi-PAP respirator, a sub-model of respiratory patient, and a sub-model of the breath circuit and mask. And based on the Matlab Simulink, a simulation platform for the noninvasive Bi-PAP therapy system was developed to conduct the virtual experiments in simulated respiratory patient with no spontaneous breathing (NSB), chronic obstructive pulmonary disease (COPD) and acute respiratory distress syndrome (ARDS). The simulated outputs such as the respiratory flows, pressures, volumes, etc, were collected and compared to the outputs which were obtained in the physical experiments with the active servo lung. By statistically analyzed with SPSS, the results demonstrated that there was no significant difference (P > 0.1) and was in high similarity (R > 0.7) between the data collected in simulations and physical experiments. The therapy system model of noninvasive Bi-PAP is probably applied for simulating the practical clinical experiment, and maybe conveniently applied to study the technology of noninvasive Bi-PAP for clinicians.
Objective To investigate the application of sequential noninvasive ventilation (NIV) in weaning patients off mechanical ventilation after coronary artery bypass grafting (CABG). Methods From July 2007 to July 2009, 52 patients who underwent CABG with mechanical ventilation for no less than 24 hours and P/F Ratio lower than 150 mm Hg were divided into two groups with random number table. In the sequential NIV group (SNIV group), there were 19 patients including 16 males and 3 females whose ages were 69.26±8.10 years. In the prolonged mechanical ventilation group (PMV group), there were 33 patients including 28 males and 5 females whose ages were 70.06±7.09 years. Clinical data of these two groups were compared and the influence of NIV on the circulation and respiration of the patients were observed. Results The SNIV group weaned off mechanical ventilation earlier than the PMV group (26.46±3.66 h vs. 38.65±9.12 h, P=0.013). The SNIV group held shorter total ventilation time (29.26±21.56 h vs.54.45±86.57 h,P=0.016), ICU stay time (2.44±2.99 d vs. 4.89±7.42 d, P=0.028) and postoperative hospital time (10.82±4.31 d vs. 14.01±19.30 d, P=0.039) than the PMV group. Furthermore, the SNIV group had lower pneumonia rate (5.26% vs. 30.30%, P=0.033) and total postoperative complication rate (10.53% vs.45.45%, P=0.030) than the PMV group. However, there was no significant difference (Pgt;0.05) between the two groups in the successful weaning rate, repeated tracheal intubation rate, tracheotomy rate and mortality 30 days after operation. After NIV, SNIV group had no significant change in heart rate, central vein 〖CM(1585mm〗pressure, pulmonary arterial pressure and pulmonary arterial wedge pressure than the baseline value, while systolic pressure (129.66±19.11 mm Hg vs. 119.01±20.31 mm Hg, P=0.031), cardiacindex ［3.01±0.30 L/(min.m2) vs. 2.78±0.36 L/(min.m2), P=0.043］ and P/F Ratio (205.95±27.40 mm Hg vs. 141.33±9.98 mm Hg, P=0.001) were obviously elevated. Conclusion Sequential NIV is a effective and safe method to wean CABG patients off mechanical ventilation.