PERFLUOROCARBON BRONCHOALVEOLAR LAVAGE AND LIQUID VENTILATION VERSUS SALINE BRONCHOALVEOLAR LAVAGE IN ADULT GUINEA-PIG EXPERIMENTAL-MODEL OF MECONIUM INHALATION

Objective:This study compares perfluorocarbon bronchoalveloar lavage ( PFC-BAL) with isotonic saline broncho-alveolar lavage (saline-BAL) in an experimental model of meconium aspiration in adult guinea pigs. Des ign: Prospective controlled experimental study. Patients ann methods: Ten male guinea pigs were given 1 ml of human meconium, diluted to 10% in isotonic saline, via tracheostomy and then artificially ventilated . After stabilization, five animals (control group) underwent BAL with 10 ml/kg isotonic saline solution. After bronchial suctioning, a furt her BAL with 2 ml/kg saline was performed. The other five animals (stu dy group) underwent BAL with 10 ml/kg of PFC (RIMAR 101), Bronchosucti on was effected at 5 min and then a BAL with PFC 2 ml/kg was performed . Both groups received conventional mechanical ventilation during the lavage procedures, Within 20 min all the saline-BAL treated animals di ed, whereas the PFC-BAL treated animals survived and were then treated with total liquid ventilation (TLV) by gravity. Measurements and resu lts: After meconium inhalation in both groups, a large alveolar-arteri al oxygen difference, hypercarbia, severe acidosis and tachycardia wer e noticed. In PFC treated animals, an improvement in blood gases was n oted and acid-base balance remained stable compared to saline-BAL trea ted animals. No haemodynamic change was observed during or after PFC-B AL, while during saline-BAL there was evidence of bradycardia, hypoten sion and respiratory failure, which led to the death of the animals. T he histological lung sections in the PFC-BAL group showed evidence of normal alveolar expansion with a minimal presence of meconium debris i n the small bronchioles. In saline-BAL treated animals, the lung struc ture appeared severely compromised with the presence of meconium in br onchioles and alveoli, intra-alveolar oedema and haemorrhagic areas. C onclusions: This study confirms the detrimental effects of meconium as piration and the impairment of lung function following saline-BAL. By contrast, PFC-BAL and TLV by gravity seemed to prevent absorption of m econium, facilitate its removal, improve gas exchange and reduce lung barotrauma.