Retention of Inhaled Formaldehyde, Propionaldehyde, and Acrolein in the Dog

Aldehydes in the vapor phase of cigarette smoke are of considerable interest in terms of tissue irritation, ciliatoxicity, and other effects. This study deals with the handling by the canine respiratory tract of formaldehyde, acrolein, and propionaldehyde, which are present in the gas phase in relatively high concentrations. Specific aims included measurement of retention of each compound by the entire respiratory tract and by upper and lower portions under varying conditions of ventilatory rate, tidal volume, and concentration inhaled. Uptake of formaldehyde was always close to 100% regardless of any other factor. The total-tract retention of propionaldehyde and acrolein was much lower and of similar magnitude. In terms of regional uptake, retention of propionaldehyde was greater than that of acrolein in the lower tract and less than that of acrolein in the upper tract.