Effect of reduced bronchial circulation on the lung fluid flux in the case of combined burn and smoke inhalation injury in sheep
© BioMed Central Ltd 2005
Published: 7 March 2005
We reported that the bronchial circulation contributes to pulmonary function after acute lung injury with smoke inhalation. But the observation period was 24 hours. We hypothesize that the bronchial circulation plays a major role in the lung injury seen with the combination of burn and smoke inhalation injury.
Merino ewes (n = 13) were surgically prepared for chronic study. After a recovery (5–7 days) they were randomly divided into three groups: (1) the bronchial artery was ligated (n = 5); (2) sham group (n = 5), the bronchial artery was surgically exposed but left intact without ligation; (3) the bronchial artery was exposed, not ligated and the animals were not injured. One day after these operations, under deep halothane anesthesia, two groups received a tracheotomy and were subjected to a 40% third-degree flame burn and insufflated with 48 breaths of cotton smoke inhalation or were sham injured. All sheep were mechanically ventilated and resuscitated by Ringer's lactate for 48 hours. We confirmed the ligation of the bronchial artery with microspheres. Statistics were performed using repeated-measures analysis of variance for repeated measurements and Scheffe's post hoc comparisons was used and P < 0.05 was considered significant. Data are expressed as mean ± standard error of the mean.
After ligation (24 hours), blood flow of the bronchi decreased to 24.48% of the baseline value. Pulmonary dysfunction after the combined injury in the ligation group was significantly reduced. Lung lymph flow, an index of pulmonary transvascular fluid flux, was markedly increased in in the ligated and intact groups. Ligation reduced this response (24 hours: sham 65 ± 5.0; ligation 15.5 ± 7.51; sham–sham 9.4 ± 5.6; 48 hours: sham 64.5 ± 16.5; ligation 12.58 ± 5.743; sham–sham 7.25 ± 3.95 ml/hour). Ligation also improved the PaO2/FiO2 ratio (24 hours: sham 270 ± 99.347; ligation 390.381 ± 53.781; sham–sham 595 ± 13.856; 48 hours: sham 132.5 ± 33.15; ligation 375 ± 62.253; sham–sham 592.33 ± 8.95). PMN production also decreased (24 hours: sham 32.5 ± 31.8; ligation 6.2 ± 2.2; 48 hours: sham 38.3 ± 46.2; ligation 2.7 ± 2.6 × 106).
Bronchial circulation plays a significant role in the lung inflammation after combined burn and smoke inhalation injury.
Supported by National Institutes of Health GM066312, Shriners of N America 8450 and 8954.