Boykin A B, Anderson D, McNamee G M, McNamee J E
Department of Medicine, University of South Carolina School of Medicine, Columbia 29208.
J Appl Physiol (1985). 1993 Apr;74(4):1862-8. doi: 10.1152/jappl.1993.74.4.1862.
Chronic inhalation of tobacco smoke can produce a nonuniform pattern of lung disease, with apical (nondependent) areas affected more often and more severely than other lung regions. This localized tissue damage might be the result of uneven deposition of inhaled smoke aerosol. There is some evidence to suggest that the way in which an aerosol is inhaled can influence its deposition in the lung. This study sought to determine the effects of entrainment timing on the deposition of tobacco smoke in the lung. Anesthetized mechanically ventilated dogs (n = 14) inhaled 35-ml boluses of 14C-labeled mainstream cigarette smoke once per minute in either a supine or erect posture. Boluses were entrained at the start of inspiration (group 1) or at midinspiration (group 2). Lungs were removed, sectioned, and assayed for 14C. Group 1 lungs experienced deposition in regions distant from the tracheal axis, with peripheral lung units averaging twice the deposition of 14C as central units. Group 2 lungs had a more uniform 14C distribution pattern. Early smoke entrainment favored peripheral deposition. One explanation for this finding is that peripheral lung units may have shorter time constants, thus filling sooner and more completely than those located centrally.
长期吸入烟草烟雾会导致肺部疾病呈现不均匀的模式，肺尖（非低垂部位）比其他肺区域更常受到影响且影响更严重。这种局部组织损伤可能是吸入烟雾气溶胶沉积不均匀所致。有一些证据表明，气溶胶的吸入方式会影响其在肺部的沉积。本研究旨在确定夹带时间对烟草烟雾在肺部沉积的影响。对14只机械通气的麻醉犬，使其以仰卧或直立姿势每分钟吸入一次35毫升含14C标记的主流香烟烟雾团注。烟雾团注在吸气开始时（第1组）或吸气中期（第2组）被夹带。取出肺部，切片，并检测14C。第1组肺部在远离气管轴的区域有沉积，外周肺单位的14C沉积量平均是中央单位的两倍。第2组肺部的14C分布模式更均匀。早期夹带烟雾有利于外周沉积。这一发现的一种解释是，外周肺单位的时间常数可能更短，因此比位于中央的肺单位填充得更快、更完全。
