Incidence and outcome of weaning from mechanical ventilation in medical wards at Thammasat University Hospital

BackgroundWeaning from mechanical ventilation is classified as simple, difficult, or prolonged according to weaning process. Theoretically, simple weaning group usually has better clinical outcomes than non-simple group; however, the results of previous studies were still inconsistent.ObjectivesThe purpose of the study was to determine the incidence, predictors, and outcomes of ventilator weaning and causes of weaning failure.MethodsA prospective observational study was performed between June and December 2013 in all patients (n = 164) who required mechanical ventilation with endotracheal intubation in medical wards at Thammasat University Hospital, Thailand. Duration of weaning, causes of weaning failure, extubation, reintubation, tracheostomy, number of ventilator-free days within 28 days, length of hospital stay, and hospital mortality were measured.Results103 patients were eligible for final analysis. Mean ± SD age was 65.1±17.5 years and 55.3% were males. The incidences of simple, difficult and prolonged weaning were 46.6%, 36.9% and 16.5%, respectively. The mortality rates for simple, difficult, and prolonged weaning were 0%, 10.5% and 23.5% (p = 0.006), respectively. The 3 causes of weaning failure in non-simple weaning were bronchospasm, pneumonia, and malnutrition.ConclusionsNon-simple weaning increased mortality. Bronchospasm, pneumonia, and malnutrition were key risk factors for weaning failure. Strategies are needed to minimize their effects.背景：根据脱机流程，机械通气脱机（weaning from mechanical ventilation）可被划分为简单脱机、困难脱机与延长脱机三类。理论上，简单脱机组的临床预后通常优于非简单脱机组，但既往相关研究的结果仍存在不一致性。 研究目的：本研究旨在明确机械通气脱机的发生率、预测因子、临床结局，以及脱机失败的具体诱因。 研究方法：本研究为前瞻性观察性研究，于2013年6月至12月在泰国法政大学医院（Thammasat University Hospital）的内科病房开展，纳入所有需经气管插管（endotracheal intubation）行机械通气的患者，共计164例。本研究记录了以下指标：脱机时长、脱机失败诱因、拔管情况、再插管情况、气管切开术（tracheostomy）、28天内无呼吸机天数、住院时长以及住院病死率。 研究结果：最终共有103例患者纳入最终分析。受试者的平均年龄为65.1±17.5岁，男性占比55.3%。简单脱机、困难脱机与延长脱机的发生率分别为46.6%、36.9%与16.5%。简单脱机、困难脱机及延长脱机组的病死率分别为0%、10.5%与23.5%（p = 0.006）。在非简单脱机患者中，脱机失败的三大诱因为支气管痉挛、肺炎与营养不良。 研究结论：非简单脱机会升高患者的住院病死率。支气管痉挛、肺炎与营养不良是脱机失败的关键危险因素，亟需制定相关策略以减轻此类因素带来的不良影响。