每日一题_2022.05.31

A 60-year-old woman is admitted to the hospital with chronic obstructive pulmonary disease exacerbation. She is intubated in the emergency department, and a subclavian triple-lumen catheter is placed for increased IV access due to hypotension. Vasopressors and IV fluids are initiated, but her hypotension persists. A resident uses an ultrasound to examine her lungs for a pneumothorax.

Which of the following ultrasound principles is most applicable to the diagnosis of pneumothorax

A. The absence of lung sliding is more specific than sensitive for pneumothorax.

B. The absence of lung sliding confirms the presence of pneumothorax.

C. In a supine patient, lung sliding is less sensitive than portable chest radiography in detecting pneumothoraces in trauma patients.

D. The presence of A line artifacts rules out a pneumothorax.

E. The presence of B line artifacts rules out a pneumothorax.

答案解析：

气胸常见于ICU患者，估计发生频率为6%。肺滑动是检测它们的有用工具。无肺滑动在检测气胸方面具有高度灵敏度(95.3%)，但特异性较低(91.1%)。在急性呼吸窘迫综合征、肺气肿滤过泡、胸膜固定术和许多其他疾病患者中可以不存在。钝性外伤后仰卧患者肺部超声较正位片对发现气胸更敏感，但x线片特异性更高。线伪影不排除气胸，但B线伪影排除气胸。一条线是胸膜界面的多次反射。B线是由于较高浓度液体导致肺实质内超声波重复反射而从脏壁层胸膜界面突出的垂直线。

正确答案：E

补充内容：

• 1）排除气胸，需要找到一个或多个以下超声征象：肺滑动征、肺搏动征、和或B线。【强推荐】
• 2）肺点可以确认气胸。【强推荐】
• 3）应当综合肺部超声检查和临床情况，决定是否引流。【强推荐】
• 4）应当综合肺部超声情况和临床情况，决定引流位置。【强推荐】
• 5）推荐使用肺点的体表投影来半定量评估气胸的范围。【弱推荐】