Farghaly Shereen, Galal Mostafa, Hasan Ali A, Nafady Asmaa
Chest Department, Faculty of Medicine, Assiut University Hospital, Egypt.
Anesthesiology Department, South Egypt Cancer Institute, Assiut University Hospital, Egypt.
Aust Crit Care. 2015 Aug;28(3):116-21. doi: 10.1016/j.aucc.2014.12.002. Epub 2015 Jan 6.
Cardiovascular dysfunction has been reported as an important mechanism of weaning failure. Brain natriuretic peptide (BNP) is a sensitive and specific marker for cardiovascular dysfunction.
To determine the value of BNP levels measured at initiation and end of a 2h spontaneous breathing trial (SBT) as a predictor of successful weaning of mechanical ventilation in patients with respiratory illness.
Thirty consecutive patients ready for weaning were prospectively enrolled in this cross-sectional analytic study over a 6-month period. All patients had been on spontaneous mode of weaning for at least 2h. Tidal volume, respiratory rate, rapid shallow breathing index (RSBI), minute ventilation and PaO2/FiO2 were observed at initiation of SBT. BNP was measured at the initiation (BNP1) and at the end of SBT (BNP2). Weaning failure is defined as either the failure of SBT or the need for reintubation within 48 h following extubation.
Out of the 30 included patients, 14 (46.6%) patients had failed weaning. PaCO2 and BNP2 were significantly higher in the patients with failed weaning as compared to those with successful weaning (P = 0.025, P = 0.031 respectively). However, BNP1 levels were not statistically significant between the 2 groups (P = 0.722). On multiple regression analysis, BNP% (percent change in the BNP level during the 2-h SBT) was the only predictor of weaning success. As compared to other weaning parameters, BNP% ≤ 14.9 had the best sensitivity, specificity, positive and negative predictive value.
Measuring the percentage change in the BNP level during a SBT may be a good predictor of weaning success from mechanical ventilation in respiratory patients.
心血管功能障碍被报道为撤机失败的重要机制。脑钠肽（BNP）是心血管功能障碍的敏感且特异的标志物。
确定在2小时自主呼吸试验（SBT）开始和结束时测量的BNP水平作为呼吸系统疾病患者机械通气成功撤机预测指标的价值。
在6个月期间，前瞻性纳入30例准备撤机的连续患者进行这项横断面分析研究。所有患者均处于自主撤机模式至少2小时。在SBT开始时观察潮气量、呼吸频率、快速浅呼吸指数（RSBI）、分钟通气量和动脉血氧分压/吸入氧分数值（PaO2/FiO2）。在SBT开始时（BNP1）和结束时（BNP2）测量BNP。撤机失败定义为SBT失败或拔管后48小时内需要重新插管。
在纳入的30例患者中，14例（46.6%）患者撤机失败。与撤机成功的患者相比，撤机失败的患者PaCO2和BNP2显著更高（分别为P = 0.025，P = 0.031）。然而，两组之间BNP1水平无统计学差异（P = 0.722）。多因素回归分析显示，BNP%（2小时SBT期间BNP水平的变化百分比）是撤机成功的唯一预测指标。与其他撤机参数相比，BNP%≤14.9具有最佳的敏感性、特异性、阳性和阴性预测值。
测量SBT期间BNP水平的变化百分比可能是呼吸系统疾病患者机械通气撤机成功的良好预测指标。
