Substantiation of the possibility of using bronchoalveolar lavage with perfluorocarbon fluids for the treatment of the alveolar stage of toxic pulmonary edema

Abstract

Introduction. Toxic pulmonary edema is an acute syndrome characterized by the accumulation of fluid in the extravascular spaces of the lungs, impaired gas exchange, the formation of tissue hypoxia and acidosis, which can occur in acute inhalation poisoning with pulmonary toxicants at work. Existing methods of drug and respiratory therapy are ineffective in the development of alveolar pulmonary edema (end-stage acute respiratory distress syndrome; ARDS). In this regard, the search for new approaches to the treatment of this condition, which is characterized by almost 100 % mortality, is of great practical importance. One of such approaches is the use of perfluorocarbon (PFC) fluids, which, due to their unique physical and chemical properties, are able not only to ensure the evacuation of edematous fluid from the alveoli and respiratory tract, but also to restore gas exchange in the parts of the lungs filled with them. This article will present an experimental evaluation of the use of PFC fluids in a model of the alveolar stage of toxic pulmonary edema.
 The goal of the study is to determine the effect of bronchoalveolar lavage (BAL) using perfluorocarbons on the indicators of acute respiratory failure and the outcome of the alveolar stage of toxic pulmonary edema.
 Materials and methods. The study was carried out on male Wistar rats aged 4 months, weighing 180–230 g. Toxic pulmonary edema was initiated by endotracheal injection of 0.1 M HCl solution. Anesthetized rats were intubated with a cannula, then intratracheally injected with 0.1 M HCl solution at a dose of 2 ml/kg and connected to a ventilator. After that, the animals were randomized by weight into groups of 6 individuals each. Animals of the experimental group with a decrease in saturation below 80%, 2–6 procedures of bronchoalveolar lavage (BAL) with PFC-oxygenated liquid in a single dose of 2.0 ml/kg were performed. Heart rate, oxygen saturation, duration of survival, and overall survival by group were recorded.
 The resalts. In all rats, there was a decrease in oxygen saturation (SpO2) and heart rate (HR) after HCl administration, which was restored to the lower limits of normal within 5 minutes. However, after 25 to 30 minutes, the animals experienced a rapid decrease in SpO2, an increase in heart rate, the appearance of wet wheezing in the lungs, and the discharge of foamy fluid from the catheter. Against this background, there was a rapid death of animals, At the same time, the average duration of survival was 30.6±3.3 min. In turn, in the animals of the experimental group, after each BAL procedure, an increase in saturation was noted, it was possible to evacuate a total of 9.1±0.8 ml/kg of edematous fluid from the lungs. It was also noted that the average duration of survival of rats in the experimental group was 1.69 times and amounted to 51.6±3.8 minutes.
 Conclusions. The use of BAL with PFC fluids in the alveolar stage of toxic pulmonary edema makes it possible to evacuate a significant amount of edematous fluid from the lower parts of the lungs due to its displacement by a perfluorocarbon with a higher density; to short-term reduce the severity of manifestations of acute respiratory failure after instillation of oxygenated PFC liquid; to increase the duration of survival of animals by ensuring gas exchange in previously uninvolved parts of the lungs.
 Ethics. The study was conducted in accordance with the ethical principles of the Declaration of Helsinki. The Clinical Study Protocol was reviewed at a meeting of the local Ethics Committee FSBSI IRIOH. Protocol No. 4 of May 25, 2022.