Objective To assess the risk factors associated with extubation failure in patients who had successfully passed a spontaneous breathing trial.Methods Patients receiving invasive mechanical ventilation for over 48 h were enrolled in the study，they were admitted into Emergency ICU of Zhongshan Hospital during May 2006 and Oct.2007.A spontaneous breathing trial was conducted by a pressure support of 7 cm H2O for 30 min.Clinical data were prospectively recorded for the patient receiving full ventilatory support before and after the spontaneous breathing trial.Regarding the extubation outcome，patients were divived into extubation success group and extubation failure group.Results A total of 58 patients with a mean（±SD） age of 69.4±12.7 years passed spontaneous breathing trial and were extubated.Extubation failure occurred in 11 patients（19%）.The univariate analysis indicated the following associations with extubation failure：elderly patients（78.1±7.9 years vs 67.4±15.1years，Plt;0.05），higher rapid shallow breathing index（RSBI） value（83±12 breaths·min-1·L-1 vs 68±19 breaths·min-1·L-1，Plt;0.05）and excessive respiratory tract secretions（54.5％ vs 21.3％，Plt;0.05）.Conclusion Among routinely measured clinical variables，elderly patients，higher RSBI value and amount of respiratory tract secretions were the valuable index for predicting extubation failure despite a successful spontaneous breathing trial.
Objective To determine whether B-type natriuretic peptide （BNP） levels combined with Spontaneous breathing trial (SBT) could improve the weaning outcome. Methods Eighty-three patients who were ready to undergo a 90-minute weaning trial （low-pressure support level） were enrolled .Weaning was considered to be successful if the patient passed the trial and sustained spontaneous breathing for more than 48 h after extubation. Plasma BNP was measured just before and at the end of the trial. All patients were divided into a weaning success group and a weaning failure group according to the outcomes of weaning. Categorical variables，expressed as percentages，were analyzed with a chi-square test or a Fisher’s exact test. Continuous variables were expressed as median （25th-75th percentile） and were compared using the Wilcoxon paired test （for related samples） or the Kolgomorov-Smirnov test （for independent samples）. A two-tailed p value of less than 0.05 was taken to indicate statistical significance. Receiver operating characteristic （ROC） curve analysis was performed to assess plasma BNP’s ability to discriminate the subjects who weaned succesfully or failed. Results Overall，13 patients （16.7%） failed the weaning process （6 patients passed the trial but failed extubation）. At the end of SBT，the BNP levels of the weaning failure group were significantly higher than the weaning success group. The BNP levels of the weaning failure group were significantly higher than the weaning success group （Plt;0.001）. The area under cure （AUC） of the ROC curve of BNP to predict the failure of weaning was 0.94±0.03 （Plt;0.001）.At a cut-off level of 123 pg/mL,BNP had a predictive efficiency in weaning outcome as Yourdon’s index of 0.837，sensitivity of 92.3%，and specificity of 91.4%. Conclusion Monitoring the change of BNP during a SBT may improve weaning outcome.
ObjectiveTo compare the difference of respiratory mechanics parameters between three different spontaneous breathing trials on COPD patients in weaning process. Methods17 patients with COPD underwent mechanical ventilation for at least 48 hours who were stable and ready for weaning were enrolled. All patients underwent three spontaneous breathing trials, ie, automatic tube compensation (ATC,compensation level 100%),low level pressure support ventilation (PSV,7 cm H2O) and T-piece. Each spontaneous breathing trials continued for 10 minutes. Before each autonomous respiration experiment ended,the respiratory mechanics parameters including high airway pressure (PIP),breathing rate (RR),blood oxygen saturation (SaO2),airway occlusion pressure at 0.1 second (P0.1),maximal inspiratory mouth pressure(Pimax) and rapid shallow breathing index (RSBI) were measured. Their differences between three spontaneous breathing trials were compared. Results12 patients successfully completed three different methods of spontaneous breathing test. Compared with the T-piece,P0.1,Pimax,RSBI and RR in the COPD patients using low level PSV and ATC were significantly decreased while VT and SaO2 were increased. The difference of each parameter in the low level PSV group and the ATC group had statistical significance compared with T-piece group (P<0.05). Compared with the low PSV group,P0.1,Pimax,RSBI and RR in ATC group were elevated while PIP,VT and SaO2 were reduced. The differences of P0.1,Pimax,RSBI,PIP and RR between two groups were statistically significant (P<0.05). ConclusionFor COPD patients in weaning process with spontaneous breathing trial,both low levels of PSV and ATC are better than T-piece,and the patients are more comfortable with ATC100% than PSV.
ObjectiveTo investigate whether inferior vena cava (IVC) ultrasound can improve the success rate of weaning in patients with respiratory failure by comparing the difference of success rate between ultrasound-guided weaning mode and spontaneous breathing test (SBT) weaning mode.MethodsFrom November 2017 to May 2018, 31 respiratory failure patients underwent mechanical ventilation in intensive care unit were randomly divided into an ultrasonic guidance group (16 cases) and a control group (15 cases). All of them were offline after meeting the offline indications. The routine group was assessed by SBT for offline procedures. The diameter and variation rate of inferior vena cava were measured at SBT. IVC diameter >2.0 cm and variation rate < 50% were given intravenous diuretics. After the IVC diameter reached the standard again, the catheter was taken off the machine after passing SBT. The patients of both groups were considered as successfully weaned when they were able to tolerate at least 48 consecutive hours of spontaneous breathing. The following data were recorded at weaning, ie. Acute Physiological and Chronic Health Evaluation Ⅱ (APACHEⅡ) score, arterial blood gas analysis, plasma albumin, serum electrolyte sodium, potassium, 7-day and 14-day weaning success rate.ResultsThere were no significant differences in APACHEⅡ score, plasma albumin level, arterial oxygen partial pressure, carbon dioxide partial pressure, pH, blood sodium level or blood potassium level between the two groups at the beginning of weaning (all P>0.05), and the 2-day weaning success rate was higher in the ultrasound group than that in the control group (95% vs. 73%, P=0.039); the 7-day weaning success rate was higher in the ultrasound group than that in the control group (87% vs. 66%, P=0.043). No significant difference was found in the 14-day weaning success rate (68% in the ultrasound group vs. 53% in the control group, P=0.446).ConclusionUltrasound can improve the success rate of weaning in patients with respiratory failure.