Transbronchial lung cryobiopsy is an emerging technique for diagnosing pulmonary rejection. However, no prospective studies of this procedure for critically ill lung transplant recipients who require mechanical ventilation in the intensive care unit (ICU) have been performed.

From March 2017 to January 2020, we performed a prospective, randomised, comparative study to assess the diagnostic yield, histological quality and safety of transbronchial lung biopsy using biopsy forceps, a 1.9-mm cryoprobe or a 2.4-mm cryoprobe.

89 out of 129 consecutive transbronchial biopsy procedures (forceps group, 28 procedures; 1.9-mm cryoprobe group, 31 procedures; 2.4-mm cryoprobe group, 30 procedures) were randomised. Compared with lung samples from the forceps and 1.9-mm cryoprobe groups, lung samples from the 2.4-mm cryoprobe group allowed the most definitive diagnoses (p<0.01 and p=0.02, respectively), the most diagnoses of acute lung rejection (p<0.01 and p=0.01, respectively) and the most diagnoses of rejection severity (p<0.01 and p<0.01, respectively). These samples were larger (p<0.01 and p=0.04, respectively), had the most adequate alveolar tissue (p<0.01 and p=0.02, respectively), had more vessels per procedure (p<0.01 and p=0.01, respectively) and had no significant crush artefacts. Moderate bleeding was observed in 23% of cases (p=0.01 and p=0.08, respectively). No severe bleeding was observed.

Transbronchial lung biopsy using a 2.4-mm cryoprobe allows the safe collection of lung tissue samples from critically ill lung transplant recipients who require mechanical ventilation in the ICU and has good diagnostic performance.

经支气管肺冷冻活检是一种用于诊断肺排斥反应的新兴技术。然而，对于需要在重症监护病房 (ICU) 进行机械通气的危重肺移植受者，尚未对该手术进行前瞻性研究。

从 2017 年 3 月到 2020 年 1 月，我们进行了一项前瞻性、随机、比较研究，以评估使用活检钳、1.9 毫米冷冻探针或 2.4 毫米冷冻探针进行经支气管肺活检的诊断率、组织学质量和安全性。

129 次连续经支气管活检手术中的 89 次（镊子组，28 次；1.9-mm 冷冻探针组，31 次；2.4-mm 冷冻探针组，30 次）被随机分配。与来自镊子和 1.9 毫米冷冻探针组的肺样本相比，来自 2.4 毫米冷冻探针组的肺样本允许最明确的诊断（分别为 p<0.01 和 p=0.02），最多的急性肺排斥诊断（p< 0.01 和 p=0.01，分别）和大多数排斥严重性诊断（分别为 p<0.01 和 p<0.01）。这些样本较大（分别为 p<0.01 和 p=0.04），具有最充足的肺泡组织（分别为 p<0.01 和 p=0.02），每个手术中的血管更多（分别为 p<0.01 和 p=0.01）并且没有明显的挤压伪影。在 23% 的病例中观察到中度出血（p=0.01 和 p=0.08，分别）。没有观察到严重出血。

使用 2.4 毫米冷冻探针的经支气管肺活检可以安全地采集需要 ICU 机械通气的危重肺移植受者的肺组织样本，具有良好的诊断性能。