俯卧位神经外科保护性通气患者的液体反应性评估：动态指标的作用、潮气量挑战和呼气末阻塞试验
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Assessment of Fluid Responsiveness in Prone Neurosurgical Patients Undergoing Protective Ventilation: Role of Dynamic Indices, Tidal Volume Challenge, and End-Expiratory Occlusion Test
背景与目的
目前对于俯卧位的患者，脉压变化和每搏量变化（PPV和SVV）的可靠性以及功能性血流动力学试验预测液体反应性的应用尚未建立。由于液体过多与术中和术后并发症有关，因此在这种情况下的围手术期最佳液体管理会是一个挑战。我们设计这项研究来评估基线时的PPV和SVV，通过潮气量（VT）、潮气量挑战（VTC）和呼气末阻塞试验（EEOT）来预测择期脊柱手术中液体反应性的敏感性和特异性。
方 法
研究方案是在俯卧位后术中血液动力学稳定期和使用任何血管升压药前开始的：（1） 在基线时以6 mL/kg预测体重（PBW）设定控制通气量并记录测量结果（T0）；（2） 患者通过中断机械通气30秒进行第一次呼气末阻塞试验（EEOT6）；（3） 再次以6ml/kg PBW通气1分钟，记录第二组测量结果（T1）；（4）通过将VT增加到8 mL/kg PBW，持续1分钟来实施VTC；（5） 1min后，将通气量保持在8 mL/kg PBW记录第三组测量结果（T2）；（6）按照上述方法， 实施第二次呼气末阻塞试验（EEOT8）；（7） 将VT降至6ml/kg PBW持续1分钟，再次记录（T3）；（8） 在10分钟内注入250毫升Ringer溶液作为液体挑战。每一步后，记录一整套血流动力学测量。
结 果
无论是在T3时记录的PPV和SVV值，还是EEOT6或EEOT8时记录的都不能预测液体反应性。应用VTC后PPV的变化预测了液体反应性，曲线下面积为0.96（95%可信区间，0.87-1.00），显示了95.2%的敏感性和94.7%的特异性，截止值增加了12.2%。VTC应用后SVV的变化预测了液体反应性，曲线下面积为0.96（95%可信区间，0.89–1.00），显示了95.2%的敏感性和94.7%的特异性，截止值增加了8.0%。液体挑战给药后脑卒中体积指数变化与VTC应用后PPV和SV的变化呈线性关系(r=0.71；P<0.0001和r=0.68；P<0.0001)。
结 论
对于择期仰卧位神经外科手术患者，PPV、SVV和EEOT的基线值不能预测液体反应性， 而VTC是一种非常可靠的功能性血流动力学试验，有助于指导术中液体治疗。
原始文献摘要
Antonio Messina,Claudia Montagnini,Gianmaria Cammarota ,et al.Assessment of Fluid Responsiveness in Prone Neurosurgical Patients Undergoing Protective Ventilation: Role of Dynamic Indices, Tidal Volume Challenge, and End-Expiratory Occlusion Test.Anesth Analg 2020;130:752–61.
BACKGROUND: In patients in the prone position, the reliability of pulse pressure variation and stroke volume variation (PPV and SVV) and the use of functional hemodynamic tests to predict fluid responsiveness have not previously been established. Perioperatively, in this setting, optimizing fluid management can be challenging, and fluid overload is associated with both intraoperative and postoperative complications. We designed this study to assess the sensitivity and
specificity of baseline PPV and SVV, the tidal volume (VT) challenge (VTC) and the end-expiratory occlusion test (EEOT) in predicting fluid responsiveness during elective spinal surgery.
METHODS: The study protocol was started during a period of intraoperative hemodynamic stability after prone positioning and before the administration of any vasopressor: (1) at baseline, the controlled ventilation was set at 6 mL/kg of predicted body weight (PBW) (T0); (2) patients underwent the first EEOT (EEOT6) by interrupting the mechanical ventilation for 30 seconds; (3) the ventilation was set again at 6 mL/kg PBW for 1 minute (T1); (4) the VTC was applied by increasing
the VT up to 8 mL/kg PBW for 1 minute; (5) the ventilation was kept at 8 mL/kg PBW for 1 minute (T2); (6) a second EEOT (EEOT8) was performed; (7) the VT was reduced back to 6 mL/kg PBW for 1 minute (T3); (8) a fluid challenge of 250 mL of Ringer’s solution was infused over 10 minutes. After each step, a complete set of hemodynamic measurements was recorded.
RESULTS: Neither PPV and SVV values recorded at T3 nor the EEOT6 or the EEOT8 predicted fluid responsiveness. The change in PPV after VTC application predicted fluid responsiveness with an area under the curve of 0.96 (95% confidence interval, 0.87–1.00), showing a sensitivity of 95.2% and a specificity of 94.7%, using a cutoff increase of 12.2%. The change in SVV after VTC application predicted fluid responsiveness with an area under the curve 0.96 (95% confidence interval, 0.89–1.00) showing a sensitivity of 95.2% and a specificity of 94.7%, using a cutoff increase of 8.0%. A linear correlation between stroke volume index changes after fluid challenge administration and the changes in PPV and SVV after VTC application was observed (r = 0.71; P< .0001 and r = 0.68; P < .0001, respectively).
CONCLUSIONS: In prone elective neurosurgical patients, the baseline values of PPV and SVV and the EEOT fail to predict fluid responsiveness, while the VTC is a very reliable functional hemodynamic test and could be helpful in guiding intraoperative fluid therapy.
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翻译：任文鑫 编辑：冯玉蓉 审校：王贵龙