Effects of Dry Anesthetic Gases on Tracheobronchial Ciliated Epithelium

Abstract

The possibility of damage to the ciliated epithelium of the tracheobronchial tree by dry anesthetic gases was investigated in six patients receiving general anesthesia via endotracheal tube for three hours or more. Controls included 12 patients exposed to 60 per cent relative humidity at room temperature (22–26 C) or saturated humidity at 37 C. Ciliated epithelial cells were obtained by bronchial lavage with 5 ml physiologic saline solution immediately after tracheal intubation and at hourly intervals thereafter. Smears made from the suctioned material were fixed at once, stained by the Papanicolaou method, and examined microscopically. Cellular damage was assessed numerically by a point-scoring system.

Significant changes were found in smears obtained from patients who had breathed dry gases for more than an hour. After three hours of inhalation of dry anesthetic gases, 39 per cent of cells had damage to the cilia and endplate, 39 per cent had developed cytoplasmic changes, and 48 per cent, nuclear changes, in relation to their condition at the onset of anesthesia. No significant changes were found in smears from patients exposed to gases at 60 per cent relative humidity at room temperature or gases saturated with water vapor at body temperature.