超声监测下腔静脉对呼吸衰竭患者脱机作用的研究

The predictive value of inferior vena cava ultrasound for mechanical weaning outcome

目的探讨通过超声监测下腔静脉(IVC)判断呼吸衰竭患者脱机前后心脏前负荷变化并据此调整心脏前负荷的方法,是否可以提高呼吸衰竭患者的脱机成功率。方法纳入2017年11月至2018年5月我院重症加强治疗病房收治的呼吸衰竭机械通气患者31例,机械通气时间均超过3 d;男20例,女11例;年龄60~83岁,平均年龄(71.2±3.6)岁。将患者随机分为超声组16例和常规组15例,所有病例均符合脱机指征后进行脱机。常规组经自主呼吸试验(SBT)评估进入脱机程序。超声组通过SBT后无机械通气下测量下腔静脉直径及变异率,下腔静脉直径>2.0 cm且变异率<50%者给予利尿剂静注,复测下腔静脉直径达标且通过SBT后给予脱机拔管。脱机成功标准为拔除人工气道后48 h不需再行有创或无创机械通气。记录脱机开始时的急性生理学与慢性健康状况评分系统Ⅱ(APACHEⅡ)评分、动脉血气分析、血浆白蛋白、血电解质钠和钾,以及2 d、7 d和14 d的脱机成功率。结果脱机开始时两组患者APACHEⅡ评分、血浆白蛋白、动脉血氧分压及二氧化碳分压、pH值、血钠、血钾比较差异均无统计学意义(均P>0.05);超声组2 d脱机成功率明显高于常规组(95%比73%,P=0.039),7 d脱机成功率明显高于常规组(87%比66%,P=0.043),14 d脱机成功率与常规组比较差异无统计学意义(68%比53%,P=0.446)。结论利用超声评估下腔静脉后进行容量调整可以明显提高呼吸衰竭患者脱机成功率。

Objective To investigate whether inferior vena cava(IVC) ultrasound can improve the success rate of weaning in patients with respiratory failure by comparing the difference of success rate between ultrasound-guided weaning mode and spontaneous breathing test(SBT) weaning mode. Methods From November 2017 to May 2018,31 respiratory failure patients underwent mechanical ventilation in intensive care unit were randomly divided into an ultrasonic guidance group(16 cases) and a control group(15 cases). All of them were offline after meeting the offline indications. The routine group was assessed by SBT for offline procedures. The diameter and variation rate of inferior vena cava were measured at SBT. IVC diameter >2.0 cm and variation rate < 50% were given intravenous diuretics. After the IVC diameter reached the standard again, the catheter was taken off the machine after passing SBT. The patients of both groups were considered as successfully weaned when they were able to tolerate at least 48 consecutive hours of spontaneous breathing. The following data were recorded at weaning, ie. Acute Physiological and Chronic Health Evaluation Ⅱ(APACHEⅡ) score, arterial blood gas analysis, plasma albumin, serum electrolyte sodium, potassium,7-day and 14-day weaning success rate. Results There were no significant differences in APACHEⅡ score, plasma albumin level, arterial oxygen partial pressure, carbon dioxide partial pressure, pH, blood sodium level or blood potassium level between the two groups at the beginning of weaning(all P>0.05), and the 2-day weaning success rate was higher in the ultrasound group than that in the control group(95% vs. 73%, P=0.039);the 7-day weaning success rate was higher in the ultrasound group than that in the control group(87% vs. 66%, P=0.043). No significant difference was found in the 14-day weaning success rate(68% in the ultrasound group vs. 53% in the control group, P=0.446). Conclusion Ultrasound can improve the success rate of weaning in patients with respiratory failure.