Effects of lung lavage on respiratory function of experimental silicosis / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of lung lavage on respiratory function of experimental silicosis.Methods Thirty rats were randomly divided into three group: A, B and C. An intratracheal injection of 50 mg silica in 1 ml of sterile saline was given in group A and B, and in group C the same amount of normal saline was injected into trachea following the anesthesia with ether. Fifteen days later, the animals were anesthetized with an intraperitoneal injection of pentobarbital sodium 30 mg/kg. After endotracheal intubation through a trachotomy, three animals were connected in parallel to a pressure controlled ventilator. The respiratory frequency was set at 28 bpm with a 50% inspiration time, and 100% oxygen was used as the inspiratory gas. Throughout the experiment, the peak inspiratory pressure (PIP) was fixed at 2.45 kPa (25 cm H 2O) and the end expiratory pressure (PEEP) at 0.69 kPa (7.0 cm H 2O). Group A and C was lavaged 10 times respectively and group B was lavaged 20 times. Arterial blood gases, tidal volume, pressure volume and lung lavage fluid constituents were assessed. Results Arterial partial pressure of oxygen (PaO 2 ) in group C was higher than that in group A and B before lavage, increased significantly in group A and decreased significantly in group B and C after lavage, but arterial partial pressure of carbon dioxide (PaCO 2 ) rose gradually in group B and C . The vary amount of PaO 2 and PaCO 2 of group C was more significant than of group B. Tidal volume in group C was higher than that in group A and B before lavage, decreased significantly after lavage in group B and C. There were significant differences among three groups in pressure volume ratio. Protein concentrations in lung lavage fluid of group A and B were much higher than of group C, but phospholipid concentrations in lung lavage fluid had no different.Conclusions Lung lavage can improve respiratory function of early experimental silicosis. Unsuitable lavage may cause respiratory dysfunction.