Heidecker Jay, Huggins John T, Sahn Steven A, Doelken Peter
Department of Pulmonary and Critical Care, Suite 812 CSB, 96 Jonathan Lucas St, PO Box 250630, Charleston, SC 29425, USA.
Chest. 2006 Oct;130(4):1173-84. doi: 10.1378/chest.130.4.1173.
Pneumothorax following ultrasound-guided thoracentesis is rare. Our goal was to explain the mechanisms of pneumothorax following ultrasound-guided thoracentesis in a setting where pleural manometry is routinely used.
We reviewed the patient records and procedure reports of 401 patients who underwent ultrasound-guided thoracentesis. When manometry was performed, pleural space elastance was determined. A model assuming dependence of the pleural space elastic properties on respiratory system elastic properties was used to isolate cases with presumed normal pleural space elastance. Elastance outside mean +/- SD x 2 of the isolated sample was considered abnormal. Four radiographic criteria of unexpandable lung were used: visceral pleural peel, lobar atelectasis, basilar pneumothorax, and pneumothorax with ipsilateral shift.
There were 102 diagnostic thoracenteses, 192 therapeutic thoracenteses with pleural manometry, and 73 therapeutic thoracenteses without manometry. There was one pneumothorax that occurred from lung puncture and eight unintentional pneumothoraces, all of which showed radiographic evidence of unexpandable lung. Four of eight unintentional pneumothoraces had abnormal elastance; none had excessively negative pleural pressure (< -25 cm H(2)O).
Unintentional pneumothoraces cannot be prevented by monitoring for symptoms or excessively negative pressure. These pneumothoraces were drainage related rather than due to penetrating lung trauma or external air introduction. We speculate that unintentional pneumothoraces are caused by transient, parenchymal-pleural fistulae caused by nonuniform stress distribution over the visceral pleura that develop during large-volume drainage if the lung cannot conform to the shape of the thoracic cavity in some patients with unexpandable lung. These fistulae appear to be pressure dependent, and the resulting pneumothoraces rarely require treatment. Drainage-related pneumothorax is an unavoidable complication of ultrasound-guided thoracentesis and appears to account for the vast majority of pneumothoraces occurring in a procedure service.
超声引导下胸腔穿刺术后发生气胸的情况较为罕见。我们的目标是在常规使用胸膜测压的情况下，解释超声引导下胸腔穿刺术后气胸的发生机制。
我们回顾了401例行超声引导下胸腔穿刺术患者的病历和操作报告。进行测压时，测定胸膜腔弹性。使用一个假设胸膜腔弹性特性依赖于呼吸系统弹性特性的模型来分离假定胸膜腔弹性正常的病例。分离样本均值±标准差×2之外的弹性被认为异常。采用了四种肺不可扩张的影像学标准：脏层胸膜剥离、肺叶肺不张、基底气胸和伴有同侧移位的气胸。
有102例诊断性胸腔穿刺术、192例进行胸膜测压的治疗性胸腔穿刺术和73例未进行测压的治疗性胸腔穿刺术。有1例因肺穿刺发生气胸，8例意外气胸，所有这些均显示有肺不可扩张的影像学证据。8例意外气胸中4例弹性异常；均无胸膜腔内压力过高负值（< -25 cm H₂O）。
通过监测症状或过高负压无法预防意外气胸。这些气胸与引流相关，而非由于穿透性肺损伤或外界空气进入。我们推测，意外气胸是由在一些肺不可扩张的患者进行大量引流时，由于脏层胸膜上应力分布不均匀导致的短暂性实质 - 胸膜瘘引起的，如果肺不能顺应胸腔形状。这些瘘似乎与压力有关，由此导致的气胸很少需要治疗。引流相关气胸是超声引导下胸腔穿刺术不可避免的并发症，似乎占操作过程中发生气胸的绝大多数。
