神经通气耦联指数联合B型钠尿肽对慢性心功能不全患者撤机的预测价值

Predictive value of neuro-ventilatory coupling combined with B-type natriuretic peptide in the weaning outcome in patients with chronic cardiac insufficiency

目的探讨神经通气耦联指数（Nvc）联合B型钠尿肽（BNP）对慢性心功能不全患者撤机的指导价值。方法采用回顾性研究方法，选择2010年12月至2015年12月福建医科大学附属闽东医院重症医学科收治的64例准备撤机的慢性心功能不全患者为研究对象，当患者具备撤机条件后进行自主呼吸试验（SBT）30rain，根据撤机结局分为成功组与失败组。记录SBT0、5、30min时膈肌电活动（EAdi）、NVC、BNP、NVC／BNP、呼吸浅快指数（f／VT）、气道闭合压（PO．1）及f/VT·P0．1，比较两组患者各指标的差异，利用受试者工作特征曲线下面积（AUC）评价各指标对撤机的预测价值。结果64例患者中撤机成功37例，撤机失败27例，撤机失败率为42．2％。两组患者性别、年龄、急性生理学与慢性健康状况评分系统Ⅱ（APACHElI）评分、通气时间及撤机前呼吸力学、肺气体交换、血流动力学、心功能等指标差异均无统计学意义。与撤机成功组比较，撤机失败组SBT30rain心排血指数（cI）明显降低，全心舒张期末容积指数（GEDVI）、血管外肺水指数（EVLWI）明显增高（CI（mL·s-1·m-2）：49．68±9．67比54．51±8．84，GEDVI（mL／m2）：747±47比711±37，EVLwI（mL／kg）：7．07±0．81比5．42±1．26，均P〈0．05]。与撤机成功组比较，撤机失败组SBT30min时EAdi显著升高（μV：22．00±7．81比17．30±8．70，P〈0．05）；SBT5min和30min时NVC显著降低，BNP显著升高[NVC（mL／μV）：19．5±7．3比32．8±20．6，17．8±5．6比34．5±18．8；BNP（mg／L）：271±84比232±65，309±76比249±70；均P〈0．05]；SBT0、5、30min时NVC／BNP均显著降低（mL2·ng·μV-1：133．1±59．6比181．2±52．3，84．7±54．9比157．2±102．8，62．5±33．4比151．2±105．3，均P〈0．05）。EAdi、NVC、BNP、NVC／BNP均以SBT30min时对撤机的预测价值最高，AUC分别为0．701、0．819、0．741、0．872（均P〈0．05）；以EAdi〉16．44“V为临界值时敏度度为82％，特异度为62％，正确率为O．71；以NVC〈22．74mL/μV为临界值时敏度度为70％，特异度为82％，正确率为0．76；以BNP〈284．00ng／L为临界值时敏度度为78％，特异度为63％，正确率为0．70；以NVC／BNP〈84．75mL2·ng-1·μV。为临界值时敏感度为88％，特异度为82％，正确率为0．83。f/VT、PO．1及价f/VT·PO．1均不能预测撤机。结论EAdi、NVC及BNP对慢性心功能不全患者撤机具有良好的预测价值，将NVC与BNP联合后预测价值进一步提高。

Objective To evaluate the predictive value of neuro-ventilatory coupling （NVC） combined with B-type natriuretic peptide （BNP） in the weaning outcome in patients with chronic cardiac insufficiency. Methods A retrospective study was conducted. Sixty-four patients with chronic cardiac insufficiency undergoing mechanical ventilation admitted to Department of Critical Care Medicine of Mindong Hospital Affiliated to Fujian Medical University from December 2010 to December 2015 were enrolled. When the patients satisfied criteria for their first spontaneous breathing trial （SBT）, a 30-minute SBT was attempted. The patients were divided into two groups as successful weaning group and weaning failure group. Electrical activity of the diaphragm （EAdi）, NVC, BNP, NVC/BNP, index of rapid shallow breathing （f/VT）, airway occlusion pressure （P0.1） and f/VT P0.1 were measured at 0, 5 and 30 minutes of the SBT, the differences were compared between the success and failure groups. The area under the receiver operating characteristic curve （AUC） was calculated to evaluate the predictive value of each index. Results There were 37 patients successfully weaned in 64 patients enrolled, and 27 patients wean with failure, with the fail wean rate of 42.2%. There was no statistical difference in gender, age, acute physiology and chronic health evaluation II （APACHE Ⅱ） score, duration of ventilation, and the parameters reflecting breathing mechanics, gas exchange, hemodynamics, and cardiac function before weaning between the two groups. Compared with successful weaning group, cardiac index （CI） at 30 minutes of SBT in failed weaning group was significantly lowered, global end diastolic volume index （GEDVI） and extravascular lung water index （EVLWI） were significantly increased [CI （mL·s-1 · m-2）： 49.68 ± 9.67 vs. 54.51 ± 8.84, GEDVI （mL/m2）： 747±47 vs. 711±37, EVLWI （mL/kg）： 7.07±0.81 vs. 5.42±1.26, all P 〈 0.05]. Compared with successful weaning group, EAdi at 30 minutes of SBT in failed weaning group was significantly increased （p.V： 22.00 ± 7.81 vs. 17.30 ± 8.70, P 〈 0.05）, NVC at 5 minutes and 30 minutes of SBT was significantly lowered, and BNP was significantly increased [NVC （mL/μV）： 19.5 ± 7.3 vs. 32.8 ± 20.6, 17.8 ± 5.6 vs. 34.5 ± 18.8; BNP （ng/L）： 271 ± 84 vs. 232 _ 65, 309 ± 76 vs. 249 ± 70, all P 〈 0.05], NVC/BNP at O, 5, and 30 minutes of SBT was significantly decreased （mL2·ng-1-1·μV-1： 133.1 ±59.6 vs. 181.2±52.3, 84.7±54.9 vs. 157.2-± 102.8, 62.5-±33.4 vs. 151.2± 105.3, all P 〈 0.05）. EAdi, NVC, BNP and NVC/BNP presented the largest AUC at 30 minutes of SBT, and the AUC were 0.701, 0.819, 0.741, 0.872, respectively （all P 〈 0.05）. It had the highest sensitivity （82%） and specificity （62%） when EAdi 〉 16.44 μV with correct rate of 0.71; when NVC 〈 22.74 mL/μV, it had the highest sensitivity （70%） and specificity （82%） with correct rate of 0.76; when BNP 〈 284.00 ng/L, the sensitivity and specificity were 78% and 63% with correct rate of 0.70; and when NVC/BNP 〈 84.75 mL2· ng-1· μV-1, it had the highest sensitivity （88%） and specificity （82%） with correct rate of 0.83. f/VT and f/VT· PO.1 presented poor predictive performance in failed patients. Conclusion EAdi, NVC and BNP had higher accuracy in predicting weaning outcome, and NVC/BNP was the best index of weaning outcome in chronic cardiac insufficiency patients.