机械通气患者呼气流速受限危险因素分析及其对患者预后的影响

Risk factors for expiratory flow limitation in patients with mechanical ventilation and prognosis

目的评估重症医学科机械通气患者中呼气流速受限的发病率,并确定与呼气流速受限相关的主要临床特征、危险因素和对患者预后的影响。方法选取需要机械通气的患者202例,通过呼气末正压通气(PEEP)试验分为呼气流速受限组和非呼气流速受限组,在患者行机械通气12小时内测定呼吸力学指标,每日测定呼吸力学指标,连测3日。所有患者均行简化急性生理状态评分系统(SAPS)评分和器官衰竭评分(SOFA);改良的英国医学委员会呼吸困难评分量表(mMRC)评定呼吸困难严重程度。结果22.77%的患者存在为呼气流速受限,其中脓毒性休克39例、ARDS 25例、失血性休克27例、慢性阻塞性肺疾病急性恶化32例、急性呼吸衰竭45例、心力衰竭12例和脑血管病合并肺炎22例。呼气流速受限患者的体重指数(BMI)较高,呼气流速受限与心脏病史、慢性肺病史有关(均P<0.05)。呼吸力学数据方面,呼气流速受限患者呼吸困难评分较差,最大气道阻力高,弹性阻力增加,具有较高的呼气末正压和内源性呼气末正压,峰值压较高,氧合指数较低(均P<0.05)。呼气流速受限组患者SOFA评分、SAPSⅡ评分均较高,机械通气时间更长,具有更高的病死率(均P<0.05)。结论BMI高、肺病或心脏病史是重症医学科机械通气患者呼气流速受限的高危因素。呼气流速受限患者的呼吸力学参数更差。呼气流速受限患者机械通气时间较长,住院时间较长,病死率较高,预后差。

Objective To evaluate the incidence of expiratory flow limitation in patients with mechanical ventilation in Intensive Care Unit,and to identify the main clinical characteristics,risk factors and prognostic implications associated with expiratory flow limitation.Methods A total of 202 patients requiring mechanical ventilation in the department of intensive medicine were selected and divided into two groups by positive end-expiratory pressure(PEEP)test:the expiratory flow limitation group and the non-expiratory flow limitation group.The respiratory mechanics indexes were measured within 12 hours after mechanical ventilation and daily for 3 days.All patients were assessed with SAPS score and Sequential Organ Failure Assessment(SOFA)score.The modified British Medical Council dyspnea score scale(mMRC)was used to assess the severity of dyspnea.Results 22.77%of the patients were found to have expiratory flow limitation,including 39 cases of septic shock,25 cases of ARDS,27 cases of hemorrhagic shock,32 cases of acute exacerbation of chronic obstructive pulmonary disease,45 cases of acute respiratory failure,12 cases of heart failure and 22 cases of cerebrovascular disease with pneumonia.Patients with expiratory flow limitation had a higher body mass index(BMI).Limited expiratory velocity was associated with history of heart disease and history of chronic lung disease(all P<0.05).In terms of respiratory mechanics data,patients with expiratory flow limitation had poor scores of dyspnea,high maximum airway resistance and increased elastic resistance,higher positive end-expiratory resistance pressure and endogenous end-expiratory pressure,higher peak pressure and lower oxygenation index(all P<0.05).The SOFA scores and SAPSⅡwere higher in the expiratory flow limitation group,and the mechanical ventilation was longer,with higher mortality(all P<0.05).Conclusion High BMI and a history of lung disease or heart disease are high risk factors for expiratory flow limitation in patients with mechanical ventilation in Intensive Care Unit.The respiratory parameters of patients with expiratory flow limitation were worse.Patients with expiratory flow limitation have longer mechanical ventilation time,longer hospitalization time,higher mortality and poor prognosis.