Kikuchi R, Kikuchi K, Hildebrandt J, Yanai M, Sekizawa K, Sasaki H
Department of Geriatric Medicine, Tohoku University School of Medicine, Sendai, Japan.
Respir Physiol. 1995 Jun;100(3):245-52. doi: 10.1016/0034-5687(94)00137-o.
We examined the hypothesis that collateral channels were identical within small airways and ducts, therefore both should respond similarly to chemical and mechanical stresses. A double lumen catheter was wedged into a segmental bronchus of the dog and humidified air or 10% CO2 in air (Vs) flowed at a segmental bronchial pressure (Pb) of 2 cm H2O. A small circular area about 1 cm diameter was peeled from the wedged segment and covered with a capsule glued to the surrounding pleura for measuring either a small airway flow (Vsaw) or capsule pressure (Pcap). Collateral resistance (Rcoll) and small airway resistance (Rsaw) were calculated as Rcoll = Pb/(Vs-Vsaw), Rsaw = (Pb-Pcap)/Vsaw, respectively. Hypocapnia (air) resulted in increases in Rcoll and Rsaw, while hypercapnia (10% CO2) generally had the opposite effect. Gcoll and Gsaw both increased linearly with lung volume (VL). The pattern of the responses of Rsaw closely paralleled those of Rcoll to local hypercapnia and hypocapnia, and to changing VL, implying that the major sites of resistance along collateral channels and along the airways are functionally and structurally similar.
小气道和细支气管内的侧支通道是相同的，因此二者对化学和机械应力的反应应该相似。将双腔导管楔入犬的节段支气管，在2 cm H₂O的节段支气管压力（Pb）下，使湿化空气或含10% CO₂的空气（Vs）流动。从楔入的节段剥下一个直径约1 cm的小圆形区域，并用粘贴在周围胸膜上的胶囊覆盖，以测量小气道流量（Vsaw）或胶囊压力（Pcap）。侧支阻力（Rcoll）和小气道阻力（Rsaw）分别计算为Rcoll = Pb/(Vs-Vsaw)，Rsaw = (Pb-Pcap)/Vsaw。低碳酸血症（空气）导致Rcoll和Rsaw增加，而高碳酸血症（10% CO₂）通常有相反的作用。Gcoll和Gsaw均随肺容积（VL）呈线性增加。Rsaw对局部高碳酸血症和低碳酸血症以及对VL变化的反应模式与Rcoll的反应模式密切平行，这意味着沿侧支通道和气道的主要阻力部位在功能和结构上相似。
