探讨混合超声造影方法在重症患者鼻肠管定位中的作用和效能。

选取2018年5月1日至2018年7月1日于浙江省人民医院重症监护病房（ICU）住院、符合鼻肠管留置指征的危重症患者32例。所有患者均行鼻肠管置入术，利用常规超声及超声解剖定位法探查食管、胃、十二指肠的大致解剖位置，并明确鼻肠管位于消化道内。将微泡超声造影剂与胃窗声学造影剂混合配制，开启超声造影模式，将混合超声造影剂注入鼻肠管，实时观察并记录鼻肠管走行及头端位置。体外实验明确混合超声造影剂最佳配制，以腹部X线检查作为判断鼻肠管定位的"金标准"，以幽门后置管为置管成功的标准，统计32例患者超声造影定位鼻肠管的成功率，计算混合超声造影法定位鼻肠管幽门后置管的敏感度、特异度、阳性预测值、阴性预测值和准确性。

通过体外实验结果显示微泡超声造影剂与胃窗声学造影剂按1:1000与1:500比例配制成混合造影剂，显影效果最佳且稳定，体质量指数<28的患者按1:1000比例配制，体质量指数≥28的患者按1:500比例配制。32例患者通过混合超声造影方法定位鼻肠管，定位成功率达93.8%（30/32），其中一次性成功定位24例，均为幽门后置管，所需时间为（1.71±0.65）min；6例患者行多次混合超声造影检查后，置管定位成功，所需时间为（4.42±0.93）min，其中5例为鼻肠管幽门后置管，1例为鼻肠管胃内折叠。混合超声造影方法定位鼻肠管幽门后置管的敏感度为93.5%，特异度为100.0%，阳性预测值为100.0%，阴性预测值为33.3%，准确性为93.8%。所有患者检查过程中均未出现明显并发症。

混合超声造影方法兼具微泡超声造影剂及胃窗声学造影剂的优势，对重症患者鼻肠管位置的判断具有较高的效能，可快速、准确定位留置鼻肠管的走行及头端，具有较好的临床应用价值。

To evaluate the role and effectiveness of hybrid contrast-enhanced ultrasound imaging technology in positioning indwelling nasointestinal tube in critically ill patients.

Thirty-two critically ill patients who had a nasointestinal tube indwelled were collected from May 1, 2018 to July 1, 2018 in the Intensive Care Unit of Zhejiang Provincial People's Hospital. In these patients, rough anatomical location of the esophagus, stomach, and duodenum was detected by conventional ultrasound and ultrasonic anatomy locating method to ensure that the nasointestinal tube was in the digestive tract. A microbubble ultrasound contrast agent and an oral ultrasound contrast agent were mixed and injected into the nasointestinal tube, and then the tube direction and end position were observed and recorded in real time. The optimal preparation of hybrid ultrasound contrast agent was determined by an in vitro experiment. Using the abdominal X-ray as the gold standard and the tube placed beyond the pylorus as a success marker, the successful positioning rate and the effectiveness of the hybrid contrast-enhanced ultrasound method for verifying the nasointestinal tube beyond the pylorus were assessed.

The results of the in vitro experiment showed that the hybrid ultrasound contrast agent containing the microbubble ultrasound contrast agent and oral ultrasound contrast agent mixed at a ratio of 1:1000 to 1:500 had optimal and stable ultrasound imaging effects. It was prepared at a ratio of 1:1000 and 1:500 for patients with body mass index (BMI)<28 and BMI≥28, respectively. Nasointestinal tubes were successfully positioned by the hybrid contrast-enhanced ultrasound imaging technology in 93.8% (30/32) of the patients, including success at one attempt in 24 cases [time required: (1.71±0.65) minutes] and success after multiple attempts in 6 [time required: (4.42±0.93) minutes], of whom 5 had the tube placed beyond the pylorus and 1 had the tube bent in the stomach. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the hybrid contrast-enhanced ultrasound imaging technology for nasointestinal tube positioning were 93.5%, 100.0%, 100.0%, 33.3%, and 93.8%, respectively. There were no obvious complications in all patients.

The hybrid contrast-enhanced ultrasound imaging technology has the advantages of both the microbubble ultrasound contrast agent and oral ultrasound contrast agent, and can position the direction and end of nasointestinal tube in critically ill patients quickly and accurately.