Experimental assessment of the possibility of removing foreign particles from the respiratory tract using total liquid ventilation

Introduction. In the structure of occupational diseases associated with the effects of chemical factors, the pathology of the respiratory organs due to the action of dust, occupies the first place. Among the recommended methods of treating occupational dust pathology, there are no procedures for removing foreign particles from the respiratory tract aimed at eliminating the cause of the disease. Despite the effectiveness of total bronchoalveolar lavage in the treatment of professional dust bronchitis, the method has a number of disadvantages due to the need to use large volumes of saline solution, which can lead to undesirable side effects associated with water balance disorders in the body caused by the absorption of fluid by the lungs during the procedure. In this regard, attention is drawn to the possibility of using perfluorocarbon compounds with low bioavailability for the elimination of foreign microparticles from the lungs by bronchoalveolar lavage or total liquid ventilation (TLV). The study aims to give an experimental assessment of a possible method for the treatment of occupational lung diseases of dust etiology, based on the removal of dust foreign particles from the respiratory tract using perfluorocarbon compounds. Materials and methods. Scientists performed a study on male rabbits of the Soviet Chinchilla breed aged 3-4 months, weighing 2.8-3.6 kg. They used a device of their own design with an open circuit to carry out the procedure of TLV, in which the liquid "washed" the lungs and drained into a special container. Perfluorodecalin was used as a respiratory fluid. At the first stage, rabbits on TLV inhaled for 3 minutes microparticles of silica gel of the LL-254 brand (5/40 microns) marked with a luminescent indicator. At the second stage, after the end of inhalation, the rabbits of the control group continued to be on artificial ventilation with air, and the rabbits of the experimental group were transferred to the TVL for 5 minutes. At the third stage, artificial ventilation of the lungs with air was performed until the end of the action of the muscle relaxant and the restoration of independent breathing. Estimated indicators: the presence of luminous particles on the surface of the trachea, bronchi, on sections of lung tissue and in perfluorodecalin passed through the rabbit's lungs; histomorphological picture of the lungs; indicators of respiratory gases and acid-base state in arterial blood. Results. Elimination of silica gel from airways by TLV procedure was detected by luminescent visualization and histomorphologically. Complete recovery respiratory gases and acid-base status or arterial blood in one hour after procedure proved safety of TLV procedure. Conclusion. TLV procedure is able to remove foreign particles from the respiratory tract. The researchers proved the effectiveness of the procedure according to three criteria: presence of luminescent labeled particles in waste perfluorodecalin after TLV; decrease of luminescent labeled silica gel macroscopic visualization in trachea and bronchi; decrease of silica gel amount in lung tissue detected by microscopic histomorphological methothods; Perfluorodecalin application for foreign (including radioactive) particles removing from respiratory tract is more preferably than saline, because of saline lungs absorption that potentiate particles incorporation in tissue. Five-minutes TLV procedure does not induce markable disturbances of gas exchange monitored by respiratory gases and acid-base status or arterial blood. Complete recovery of these parameters was detected within one hour after procedure. Ethics. The scientists conducted studies involving laboratory animals in compliance with the necessary regulations (the Helsinki Declaration of 2000 on Humane Treatment of Animals and the "Rules for carrying out work using experimental animals" (Order of the Ministry of Health of the USSR No. 755 of 12.08.1977)). The protocol of the study was approved by the Ethics Committee of the Izmerov Research Institute of Occupational Health.