The role of pulmonary and systemic circulation in the tracheal blood supply in rats

The different roles of bronchial and pulmonary circulation in the tracheal blood supply were investigated in 26 female rats: a control group (CG, n = 7), a group with pulmonary hilar ligation (PL, n = 5), another with trachea l transsection (TL, n = 9) and a group with both these procedures (TL&PL, n = 5). Technetium 99-m was injected into the left ventricle postoperatively , and the radioactivity of tracheal samples was calculated as a percentage of injected activity/g tissue (%ID/g). The tracheal uptake averaged 1.9 in group CG, and 1.7, 1.3 and 1.5%ID/g in groups FL, TL and TL&PL, respectivel y. Tracheal transsection (TL) thus reduced the tracheal blood supply by 29. 7% compared with the control group (p < 0.05), whereas the reduction of tra cheal blood supply following pulmonary hilar ligation (PL) was only 10.9% ( n.s.). Tracheal transsection combined with hilar ligation (TL&PL) effected a reduction of 19.9% (n.s.). We conclude that only 10.9% of the tracheal bl ood supply comes from the pulmonary circulation.