Elastic Properties of Collapsing and Expanding Trachea

The compliance of the canine trachea under positive and negative transmural pressures was measured in an in-vivo preparation. The average compliance values found in eight animals were 11.7×10⁻⁶ (dynes/cm²)⁻¹ at zero transmural pressure and 4.9 and 6.9×10⁻⁶ (dynes/cm²)⁻¹ at −20 and +20×10³ dynes/cm² transmural pressure, respectively. These compliances were significantly lower than those measured by others in excised preparations. Stress relaxation was noted at all pressure levels.