Anaesthesiology department, University of Louvain, CHU UcL Namur, Avenue Dr Gaston Thérasse 1, B-5530, Yvoir, Belgium.
BMC Anesthesiol. 2022 Feb 19;22(1):50. doi: 10.1186/s12871-022-01591-y.
Physiologic narrowing of the central airway occurs during expiration. Conditions in which this narrowing becomes excessive are referred to as expiratory central airway collapse. Expiratory central airway collapse is usually managed by applying positive pressure to the airways, which acts as a pneumatic stent. The particularity of the case reported here included the patient's left main bronchus being permeable during spontaneous breathing but collapsing during general anaesthesia, despite positive pressure ventilation and positive end-expiratory pressure.
We present the case of a 55-year-old man admitted for the placement of a ureteral JJ stent. Rapid desaturation occurred a few minutes after the onset of anaesthesia. After excluding the most common causes of desaturation, fibreoptic bronchoscopy was performed through the tracheal tube and revealed complete collapse of the left main bronchus. The collapse persisted despite the application of positive end-expiratory pressure and several recruitment manoeuvres. After recovery of spontaneous ventilation, the collapse was lifted, and saturation increased back to normal levels. No evidence of extrinsic compression was found on chest X-rays or computed tomography scans.
Cases of unknown expiratory central airway collapse reported in the literature were usually managed with positive pressure ventilation. This approach has been unsuccessful in the case described herein. Our hypothesis is that mechanical bending of the left main bronchus occurred due to loss of the patient's natural position and thoracic muscle tone under general anaesthesia with neuromuscular blockade. When possible, spontaneous ventilation should be maintained in patients with known or suspected ECAC.
中央气道在呼气时会生理性变窄。当这种变窄变得过度时,就会出现呼气性中央气道塌陷。呼气性中央气道塌陷通常通过向气道施加正压来治疗,正压起到气动支架的作用。本报告病例的特殊性在于,尽管给予正压通气和呼气末正压,但患者的左主支气管在自主呼吸时是通畅的,但在全身麻醉时却塌陷了。
我们报告了一例 55 岁男性,因放置输尿管 JJ 支架而入院。麻醉开始后几分钟,患者迅速出现血氧饱和度下降。在排除了最常见的血氧饱和度下降原因后,通过气管导管进行了纤维支气管镜检查,显示左主支气管完全塌陷。尽管给予呼气末正压和多次复张手法,塌陷仍持续存在。恢复自主通气后,塌陷解除,血氧饱和度恢复正常水平。胸部 X 线或计算机断层扫描均未发现明显的外部压迫迹象。
文献中报告的不明原因的呼气性中央气道塌陷病例通常采用正压通气治疗。本病例中,这种方法并不奏效。我们的假设是,由于全身麻醉下神经肌肉阻滞导致患者失去自然体位和胸肌张力,左主支气管发生机械性弯曲。对于已知或疑似 ECAC 的患者,应尽可能保持自主通气。