膈肌超声联合浅快呼吸指数对指导机械通气患者撤机的价值研究

Study on the value of the combination of diaphragmatic ultrasound and RSBI in guiding ventilator weaning of patient with mechanical ventilation

目的:探讨超声指标膈肌厚度变化率(ΔDT)、膈肌移动度(DE)联合浅快呼吸指数(RSBI)对指导机械通气患者成功撤机的价值。方法:前瞻性选取56例接受机械通气时间≥48 h并已进入撤机前自主呼吸试验(SBT)的患者资料,根据撤机结果将患者分为撤机成功组(47例)和撤机失败组(9例)。应用超声技术测定患者的ΔDT和膈肌移动度(DE),计算两组患者浅快呼吸指数(RSBI);应用受试者工作特征(ROC)曲线评估ΔDT、DE及RSBI用于预测呼吸机撤机结果的价值。结果:撤机成功组患者与撤机失败组患者相比,患者的ΔDT明显更高,差异有统计学意义(t=3.721,P<0.05),但DE两组间差异无统计学意义。ΔDT和RSBI用于预测呼吸机成功撤机的ROC曲线下面积(AUC)分别为0.849和0.773,分别以23.04%和52.74次/(L·min)为阈值,其预测患者成功撤机的灵敏度分别为74.5%和93.6%,特异度分别为88.9%和55.6%。结论:膈肌超声指标ΔDT是评价膈肌功能的可靠指标,通过联合RSBI,可更精确地指导呼吸机撤机。

Objective: To explore the value that ultrasound indexes, included change rate of diaphragmatic thickness(ΔDT) and diaphragmatic excursion(DE), combined with rapid shallow breathing index(RSBI) in guiding successful ventilator weaning of patients who received mechanical ventilation. Methods: The data of 56 patients whose mechanical ventilation time were more than or equal to 48 hours and who had entered the spontaneous breathing trial(SBT) before ventilator weaning were selected as perspective method. According to the results of ventilator weaning, the patients were divided into two groups: successful ventilator weaning group(47 cases) and failed ventilator weaning group(9 cases). The ΔDT(ΔDT = inspiratory end diaphragm thickness-expiratory end diaphragm thickness)/inspiratory end diaphragm thickness) and DE(DE=Distance change from the diaphragm to the probe between end of inspiration and expiration) were measured by ultrasonic technique, and then the RSBI(RSBI = respiratory frequency/tidal volume) was calculated. The values of ΔDT, DE and RSBI in predicting the result of ventilator weaning were assessed by using receiver operating characteristics(ROC). Results: The ΔDT of the patients in successful ventilator weaning group was significantly higher than that in failed ventilator weaning group(t=3.721, P<0.05), but there was no significant difference in DE between the two groups. The area under curve(AUC) of Δ DT and RSBI in predicting the successful ventilator weaning of ventilator were 0.849 and 0.773, respectively. The 23.04% and 52.74 times/(L·min) were used as threshold values, respectively. The sensitivities of ΔDT and RSBI were 74.5% and 93.6% respectively, and the specificities of them were 88.9% and 55.6% respectively. Conclusion: The diaphragmatic ultrasonic index ΔDT is a reliable index to evaluate the function of diaphragmatic muscle. By combining RSBI, it can be used to guide ventilator weaning of mechanical ventilator more accurately.