Does tissue pH measurement quantify circulation in the transplanted bronchus in lung transplantation

Ischemia of the airway is the main cause of severe complications in lung transplantation. Tissue-pH is used as an indicator of ischemia in the myocardium and various other tissues. We developed a pH needle probe which can be applied through a bronchoscope to enable repeated measurements of the pH in the bronchus mucosa. In 8 conditioned mongrel dogs (20-25 kg) an autotransplant of a 4-ring segment of the thoracic trachea was performed and wrapped with an omental pedicle flap in 4 of them (omentum group vs control group). PH-measurements of the mucosa were performed at 3 points of the circumference of the normal trachea as well as the transplant. The measurements were done immediately postoperative and at day 3, 8, 14 and 20 using a modified MI 506 pH-needle electrode with an Ag-AgCl skin reference electrode and a Fisher accumet pH-meter (model 910). After 3 weeks or at occurrence of a severe tracheal stenosis macroscopic and histologic examination of the trachea was done. All animals in the omentum group finished the study. One developed severe stenosis due to tracheal malacia. Three of the four control-dogs had a severe tracheal stenosis at day 12, 13 and 16 which necessitated termination of the experiment. The pH-difference between trachea and transplant immediately postoperative was 0.16 +/- 0.02 in the 4 dogs with healed transplants and 0.15 + 0.03 in the 4 dogs with stenosis due to chondromalacia. Follow-up measurements at day 3 and 8 showed a pH-difference of 0.2 for the group with chondromalacia vs. 0.1 for the healed tracheas (not significant).(ABSTRACT TRUNCATED AT 250 WORDS)