A Post-mortem Study of the Visco-elastic Properties of the Lungs in Emphysema

An arbitrary index of the viscous resistance involved in ventilation has been devised from measurements of the difference in distensibility of the lungs at different respiration rates.The index of viscous resistance measured in 20 normal human lungs increased with the age of the patient.Comparison of the index of viscous resistance on air with that on hydrogen shows that the increase in viscous resistance demonstrated in normal lungs is not primarily due to bronchial obstruc- tion.It is suggested that what has in the past been termed " loss of pulmonary elasticity " may repre- sent a relative loss of elasticity due to an increase in the viscous element of the visco-elastic response of the lungs.