Comparison Of Three Protocols Of Gradual Withdrawal From Ventilator Support During Weaning From Mechanical Ventilationin Difficult-to-wean Patient

Background Mechanical ventilation (MV) is the major life-support modality during respiratory failure. Once the illness that precipitated respiratory failure (RF) has resolved, MV can be discontinued after the patient was carefully evaluated. Prompt weaning can reduce the ventilator-associated complications, lessen the patient's suffering, decrease the medical fee and raise the success rate. Weaning can be achieved in 24-48 hours in majority of patients after the weaning indexes meet the requirement. But some patients become the difficult-to-wean patients because of weaning failure or the weaning duration exceeding 48-72 hours. The successful weaning in difficult-to-wean patients mainly relies on weaning protocol apart from the illness improvement. Weaning protocol is the standardized procedure that consisted of illness evaluation, ventilator mode's select, and baseline parameters confirmation. Based on the above, the patient can be successfully weaned from the ventilator gradually according to the patients' endurance. Merits of various weaning methods should be primarily based on efficacy (the fraction of patients successfully weaned) and efficiency (the time it takes to discontinue MV). The most sensitive way to test the differences in weaning time is to use survival analysis. Several studies onweaning methods have been performed in the past, but debate on the outcome continues. Two recent multicenter, randomized trials have demonstrated differences in outcome. Brochard and colleagues found PSV leading to significantly shorter weaning time compared to the combined T-piece and SIMV. Esteban and colleagues performed a similar study and concluded that a once-daily trial of T-picce breathing led to the most quickly weaning and the success of T-piece was significantly greater than SIMV and PSV. In China, weaning research have only been performed on different modes and the standardized protocol has never been developed. Ventilator weaning is the traditional physician-directed weaning and it leads to limitation of the success rate of weaning. To assess the difference on efficacy, efficiency and the compliance about three weaning protocols in difficult-to-wean patient, we carried out a prospective, randomized study.Object To compare the difference of efficacy, efficiency and compliance of different weaning protocols in difficult-to-wean patient. The key target of this study is how to set baseline PS level and how to decrease the baseline PS level gradually.Methods 37 difficult-to-wean patients who were divided into three groups were enrolled in this study after clinical evaluation reaching to the requirements. Group 1 (12 patients) were PSV protocol, group 2 (13 patients) SIMV+PSV and group3 (12 patients) other including T-piece, CPAP, SIMV. Standardized protocols were followed for each group. Results There were no significant difference in the main characteristic at theonset of the weaning procedure (P>0.05). On the comparison of weaning efficiency, the probability of continuing on MV which was calculated by using the Kaplan-Meier estimate was found to be significantly lower with PSV and SIMV+PSV (PO.05). On the comparison of weaning efficacy, the success rate with PSV (75%), SIMV+PSV (76.9), and other (40%) was found to be no significant difference (P>0.05).Conclusions To raise the weaning success, the most important and basic thing is to assess the patient's clinical situation comprehensively and have the well judgement on the appropriate weaning time. Dynamic observation of f/Vt is the important index in protocol-directed-weaning. PSV weaning protocol is superior to other protocol such as SIMV, T-piece, and CPAP protocol. We can wean the patient by setting the baseline PS and gradually decreasing it according to the patient's endurance. PSV weaning is the safe, easy-performed and well patients' compliance protocol.