Effect of lobar acid injury on pulmonary perfusion and gas exchange in dogs

Publisher Website
Google Scholar
Abstract
The effect of lobar acid instillation on pulmonary shunt (.ovrhdot.Qs/.ovrhdot.Qt) and lobar shunt [.ovrhdot.Qs(L)/.ovrhdot.Qt], lobar and sublobar pulmonary perfusion (.ovrhdot.QL/.ovrhdot.Qt) and on pulmonary edema in terms of wet-to-dry (W/D) weight ratios were investigated in 6 anesthetized dogs. Before (C) and 3 h (3) after 0.1 N hydrochloric acid (0.3 ml/kg) was instilled into the left lower lobe bronchus, .ovrhdot.QL/.ovrhdot.Qt was measured using differentially labeled microspheres and .ovrhdot.Qs/.ovrhdot.Qt and .ovrhdot.Qs(L)/.ovrhdot.Qt using blood sampled from catheters in the aorta, pulmonary artery and right (RLL) and left (LLL) lower lobe veins. Mean .ovrhdot.Qs/.ovrhdot.Qt (.+-. SD) increased from 5.8 .+-. 1.6 to 8.6 .+-. 2.4% and LLL .ovrhdot.Qs(L)/.ovrhdot.Qt increased from 5.2 .+-. 2.2 to 14.8 .+-. 8.6% (P < 0.05), .ovrhdot.Qs(L)/.ovrhdot.Qt in the RLL control lobe did not change. Edema following acid injury in these intact animals was much less than in comparable studies of excised lobes. The injury was sharply confined in a visibly injured sublobar portion of the LLL (W/D 7.5 .+-. 0.6) compared to the rest of the same lobe (W/D 5.8 .+-. 0.7) and the other lobes (W/D 5.1 .+-. 0.4). Perfusion to the injured portion of LLL decreased from 19.4 .+-. 2.1 to 14.3 .+-. 3.5 (P < 0.05), but did not change in the noninjured portions of either LLL or RLL. Reduction in perfusion to the edematous area correlated with the amount of excess lung liquid, and this reduction in perfusion reduced total pulmonary shunt.