McRobbie Donald W, Pritchard Susan E
Radiological Sciences Unit, The Hammersmith Hospitals NHS Trust and Imperial College, Charing Cross Hospital, London, United Kingdom.
J Aerosol Med. 2005 Fall;18(3):325-36. doi: 10.1089/jam.2005.18.325.
The anatomical geometry of the upper airways of five healthy volunteers were studied using three-dimensional inhalation-gated magnetic resonance imaging (MRI) for two dummy inhalation devices of varying airflow resistances (0.049(0.5) and 0.004(0.5) kPa(0.5)(L/min)(1)) using a forced maneuver (sharp inhalation) and tidal breathing. The range of maximum inspiratory pressures (MIP) was 0.02-6 kPa. Significant airway expansion occurred for the lower resistance device with forced maneuver compared with tidal breathing. The mean upper airway volume for forced maneuver through a low-resistance device was 60 (SD 15) cm(3) compared with 38 (SD 9) cm(3) for tidal breathing through the same device. Regionally, these increases occurred in the oropharynx (factor of three increase) and the laryngo-pharynx (factor of two increase). Significant changes did not occur for the buccal and laryngeal regions. No significant airway volume change occurred between the two breathing modes using the high-resistance device. In contrast to an earlier study using tidal breathing, device-related volume changes occurred with forced maneuvers in the oropharynx and laryngopharynx. For the low resistance device, significant differences for the minimum airway equivalent radius at the epiglottis occurred between forced maneuver (8.0 mm) and tidal breathing (5.2 mm), and for the maximum airway diameter in the laryngo-pharynx (12.4 mm vs 9.1 mm). For forced maneuvers, significant differences in maximum airway diameter in the oropharynx were also apparent between the devices (12.6 mm low vs. 9.1 mm high) and also in the laryngopharynx (12.4 mm low vs. 9.4 mm high). The minimum radius at the epiglottis varied significantly between devices under forced maneuver breathing (8.0 mm low vs. 8.3 mm high). There was no correlation between airway expansion or contraction and MIP. A linear relationship was found between airway volume changes and maximum calculated volumetric airflow. This work has implication for the modeling of inhaled aerosol dynamics and in vitro particle impaction studies.
利用三维吸入门控磁共振成像（MRI），对五名健康志愿者的上呼吸道解剖结构进行了研究，研究对象为两种气流阻力不同的模拟吸入装置（分别为0.049(0.5)和0.004(0.5) kPa(0.5)(L/min)(1)），采用强制动作（快速吸气）和潮式呼吸。最大吸气压力（MIP）范围为0.02 - 6 kPa。与潮式呼吸相比，使用低阻力装置进行强制动作时气道出现了显著扩张。通过低阻力装置进行强制动作时，上呼吸道平均容积为60（标准差15）cm³，而通过同一装置进行潮式呼吸时为38（标准差9）cm³。从区域来看，这些增加发生在口咽（增加了三倍）和喉咽（增加了两倍）。颊部和喉部区域未发生显著变化。使用高阻力装置时，两种呼吸模式之间气道容积未发生显著变化。与早期一项使用潮式呼吸的研究不同，在口咽和喉咽进行强制动作时出现了与装置相关的容积变化。对于低阻力装置，会厌处最小气道等效半径在强制动作（8.0 mm）和潮式呼吸（5.2 mm）之间存在显著差异，喉咽处最大气道直径也有显著差异（12.4 mm对9.1 mm）。对于强制动作，口咽处最大气道直径在两种装置之间也有显著差异（低阻力装置为12.6 mm，高阻力装置为9.1 mm），喉咽处同样如此（低阻力装置为12.4 mm，高阻力装置为9.4 mm）。在强制动作呼吸时，会厌处最小半径在两种装置之间有显著差异（低阻力装置为8.0 mm，高阻力装置为8.3 mm）。气道扩张或收缩与MIP之间无相关性。发现气道容积变化与最大计算体积气流之间存在线性关系。这项工作对吸入气溶胶动力学建模和体外颗粒撞击研究具有启示意义。
