Department of Anesthesiology and Critical Care, Medical Center, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany.
Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Sci Rep. 2024 Oct 9;14(1):23585. doi: 10.1038/s41598-024-73844-4.
During use of a laryngeal mask airway, resistance of the device and larynx contribute to the upper airway resistance. Detailed understanding of this combined resistance is crucial to support spontaneously breathing patients appropriately or to take the right measures during respiratory problems. However, their resistive behavior and which of these components determine the upper airway resistance predominantly, has not been characterized systematically. Pressure-flow-relationships of different sizes of a laryngeal mask airway, of a laryngeal model with vocal cord angles between 10° and 60° and of the combination of a laryngeal mask airway size 4 and the laryngeal model were measured. Results were fitted to the expanded Rohrer's equation and resistances were calculated. The laryngeal mask airway and the laryngeal model showed a nonlinear flow-dependent resistive behavior. Decreasing size of the laryngeal mask airway, decreasing vocal cord angles, and increasing flow rates resulted in increased resistances (all p < 0.001). Resistance of the laryngeal mask and the laryngeal model added up to the combined resistance in a summative way, where the vocal cord angle determines 59-98% of the combined resistance in adults. The upper airway resistance during the use of a laryngeal mask airway is a summative resistance with a flow-dependent, nonlinear behavior. Upper airway resistance in adults is primarily determined by the vocal cord angle during use of a laryngeal mask.
在使用喉罩气道时，设备和喉部的阻力会增加上呼吸道阻力。详细了解这种组合阻力对于适当地支持自主呼吸的患者或在出现呼吸问题时采取正确措施至关重要。然而，它们的阻力行为以及这些组件中哪一个主要决定上呼吸道阻力，尚未得到系统地描述。测量了不同尺寸的喉罩气道、声带角度在 10°至 60°之间的喉模型以及喉罩气道尺寸 4 和喉模型的组合的压力-流量关系。结果拟合到扩展的 Rohrer 方程，并计算了阻力。喉罩气道和喉模型显示出非线性的流量依赖性阻力行为。喉罩气道尺寸减小、声带角度减小和流量增加会导致阻力增加（均 p<0.001）。喉罩和喉模型的阻力以累加的方式加起来形成总的阻力，其中声带角度在成人中决定了总阻力的 59-98%。在使用喉罩气道时，上呼吸道阻力是一种具有流量依赖性和非线性行为的总和阻力。在使用喉罩时，成人的上呼吸道阻力主要由声带角度决定。
