Chittawattanarat Kaweesak, Kantha Khwannara, Tepsuwan Thitipong
J Med Assoc Thai. 2016 Sep;99 Suppl 6:S145-S152.
Central venous oxygen saturation (ScvO2) is a measure of the balance between oxygen delivery and consumption. The purpose of this study was to evaluate whether ScvO2 predict weaning success and extubation in simple weaning postcardiac surgical patients.
We prospective observed critically ill post-cardiac surgical patients who were intubated and mechanically ventilated between December 2011 and October 2014. All enrolled patients underwent a spontaneous breathing trial (SBT) before extubation. Arterial and venous blood gas analysis, and hemodynamic and ventilator variables were recorded at the beginning of SBT (T1) and before extubation (T2). Weaning success was defined as successful extubation after SBT without re-intubation within 48 hours. The area under the receiver characteristic curve (ROC) demonstrated the ability to discriminate weaning success. Statistical significance was defined as p<0.05.
A total 121 patients were included. Of these, 18 patients (15%) were re-intubation within 48 hours after extubation. There was no statistically significance in age, gender, and type of operations between those who were extubated successfully and those who were re-intubated within 48 hours. Regarding hemodynamic and respiratory parameters, the significant differences were found only in partial arterial oxygen pressure (PaO2; p = 0.048) and PaO2 to oxygen fraction ratio (PF ratio; p=0.048) at T1. There was no difference between the groups in ScvO2 at either T1 or T2. The area under the ROC (95% confidence interval) of ScvO2 was 0.60 (0.47-0.74) and 0.53 (0.39-0.66) at T1 and T2, respectively. Although ScvO2 was combined with rapid shallow breathing index (RSBI), PF ratio and minute volume on the regression model at both T1 and T2, the discrimination ability was not significant increased.
ScvO2 or its combination with RSBI, PF ratio and minute volume does not predict successful weaning from mechanical ventilators and extubation in critically ill post-cardiac surgical patients.
中心静脉血氧饱和度（ScvO2）是衡量氧输送与消耗平衡的指标。本研究旨在评估ScvO2能否预测心脏手术后患者简单撤机过程中的撤机成功率和拔管情况。
我们前瞻性观察了2011年12月至2014年10月期间接受插管和机械通气的心脏手术后重症患者。所有入选患者在拔管前均进行了自主呼吸试验（SBT）。在SBT开始时（T1）和拔管前（T2）记录动脉和静脉血气分析、血流动力学及呼吸机参数。撤机成功定义为SBT后成功拔管且48小时内未再次插管。受试者工作特征曲线（ROC）下面积显示了区分撤机成功的能力。统计学显著性定义为p<0.05。
共纳入121例患者。其中，18例患者（15%）在拔管后48小时内再次插管。成功拔管患者与48小时内再次插管患者在年龄、性别和手术类型方面无统计学显著性差异。关于血流动力学和呼吸参数，仅在T1时的动脉血氧分压（PaO2；p = 0.048）和PaO2与氧分数比值（PF比值；p = 0.048）方面发现显著差异。在T1或T2时，两组间ScvO2无差异。ScvO2在T1和T2时的ROC下面积（95%置信区间）分别为0.60（0.47 - 0.74）和0.53（0.39 - 0.66）。尽管在T1和T2时ScvO2与快速浅呼吸指数（RSBI）、PF比值和分钟通气量联合用于回归模型，但区分能力并未显著提高。
ScvO2或其与RSBI、PF比值和分钟通气量的联合应用不能预测心脏手术后重症患者机械通气撤机和拔管的成功。
