Effects Of Different Spontaneous Breathing Trials On Respiratory Mechanics Parameters And Predictive Value Of Different Index On COPD Patients In Weaning Process

Objective： To compare respiratory mechanics parameters to threedifferent spontaneous breathing trials and Value the predictive effect ofdifferent index on COPD patients in weaning process.Methods：17patients with COPD after mechanical ventilation for at least48hours who were stable and ready for weaning were enrolled. All patientswere underwent three spontaneous breathing trials with automatic tubecompensation (ATC, compensation level100%), low level pressure supportventilation (PSV,7cmH2O) and T-piece. Each spontaneous breathing trialscontinued for10minutes. Before each autonomous respiration experimentended, the following respiratory mechanics parameters were measured,including high airway pressure (PIP), breathing rate (RR), blood oxygensaturation(SaO2), airway occlusion pressure0.1s(P0.1), maximal inspiratorymouth pressure（Pimax）and rapid shallow breathing index(RSBI). Theirdifferences in three spontaneous breathing trials were compared. All patientaccepted the weaning trial under the T-piece with a2hours spontaneousbreathing trial(SBT). In spontaneous breathing experiment carried out for30minutes, P0.1, Pimax and RSBI were detected. The clinical value of P0.1,Pimax and RSBI index for prognosis of successful weaning from COPDpatients were assessed.Results：12patients successfully completed three different modes ofspontaneous breathing test. Compared with the T-piece, P0.1, Pimax, RSBI and RR in patients with COPD using low level PSV and ATC weresignificantly decreased; and PIP, Vt and SaO2were increased. The differenceof each parameter in low level PSV group and ATC group had the statisticalsignificance Compared to T-piece Group（P<0.05）. Compared with the lowPSV group, P0.1, Pimax, RSBI and RR in ATC group were elevated, PIP, Vtand SaO2were reduced. The differences of P0.1、Pimax、RSBI、PIP and RRbetween the two groups were statistically significant(P<0.05).10patientswere successfully weaned from ventilation，and7patients were difficultyweaned from ventilation. P0.1and RSBI in weaning success group werelower than those in weaning failure group（P<0.05）. Pimax in weaningsuccess group was higher than that in weaning failure group (P<0.05). P0.1was superior to RSBI and Pimax in predicting weaning outcomes from COPDpatients, which sensitivity was89%, the specificity was75%and theaccuracy was82%. They were higher than those of Pimax and RSBI.Conclusion：1. For COPD patients in weaning process, both low levelsof PSV and ATC mode of ventilation are better than T-piece mode ofventilation.2. The COPD patients are more comfortable with ATC100%mode of ventilation in spontaneous breathing trial.3. The RSBI, P0.1andPimax as weaning predictor have the significant differences in threespontaneous breathing trials.4. The RSBI, P0.1and Pimax are valuablepredictor for the patients with COPD to wean from mechanical ventilation,and the predicting value of P0.1is biggest.